chapter 4 biodiversity - department of the environment · pdf filechapter 4 biodiversity ......

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Prepared by

Denis Saunders (Chair), CSIRO Division of Wildlife and Ecology

Andrew Beattie, Centre for Biodiversity and Bioresources, School ofBiological Sciences, Macquarie University

Susannah Eliott (Research Assistant/Science Writer), Centre for ScienceCommunication, University of Technology, Sydney

Marilyn Fox, School of Geography, University of New South Wales

Burke Hill, CSIRO Division of Fisheries

Bob Pressey, New South Wales National Parks and Wildlife Service

Duncan Veal, Centre for Biodiversity and Bioresources, School of BiologicalSciences, Macquarie University

Jackie Venning, State of Environment Reporting, South AustralianDepartment of Environment and Natural Resources

Mathew Maliel (State of the Environment Reporting Unit member),Department of the Environment, Sport and Territories (Facilitator)

Charlie Zammit (former State of the Environment Reporting Unit member),Department of the Environment, Sport and Territories (formerFacilitator)

Chapter 4

Biodiver s i ty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

‘Still Flying’ from the painting of aWandering Albatross by RichardWeatherly.

A u s t r a l i a : S t a t e o f t h e E n v i r o n m e n t 1 9 9 6

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Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7Human populations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9

Urban development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9Tourism and recreation . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9

Harvesting resources and land use. . . . . . . . . . . . . . . . . . . . . . 4-10Fisheries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10Forestry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11Pastoralism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12Agriculture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12

Introduced species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16Vertebrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16Invertebrates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17Plants. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18Micro-organisms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-20Native species out of place . . . . . . . . . . . . . . . . . . . . . . . 4-20

Pollution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-21Mining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-22Climate change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-22

State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-23The state of ecosystem diversity . . . . . . . . . . . . . . . . . . . . . . . 4-23

Biogeographic regionalisations for Australia . . . . . . . . . . . 4-23Ecosystem diversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-26

The state of species diversity. . . . . . . . . . . . . . . . . . . . . . . . . . 4-30Number and distribution of species . . . . . . . . . . . . . . . . . 4-31Status of species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-32

Genetic diversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-37Habitat loss and degradation . . . . . . . . . . . . . . . . . . . . . . 4-37Habitat fragmentation . . . . . . . . . . . . . . . . . . . . . . . . . . 4-37Introduction of exotic genes . . . . . . . . . . . . . . . . . . . . . . 4-39Changes in gene-flow vectors . . . . . . . . . . . . . . . . . . . . . 4-39

Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-39Types of responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-40

Government responses . . . . . . . . . . . . . . . . . . . . . . . . . . 4-40Community responses. . . . . . . . . . . . . . . . . . . . . . . . . . . 4-43Industry responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-46

Responses to key issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-48Human population patterns . . . . . . . . . . . . . . . . . . . . . . 4-48Land clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-49Harvesting native species. . . . . . . . . . . . . . . . . . . . . . . . . 4-49Introduced species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-50

Content s

Pollution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-50Mining. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-51Climate change. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-51Lack of knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-51Integrated ecosystem-based management of

natural resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-53

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-55

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-56

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-59

BoxesGenetic resources from the wild . . . . . . . . . . . . . . . . . . . . 4-5Soil biodiversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6Changes in urban birds . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9Vegetation clearance and fragmentation . . . . . . . . . . . . . . 4-13Water harvesting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14Pressures on aquatic biodiversity from land use . . . . . . . . 4-15Endangerment categories. . . . . . . . . . . . . . . . . . . . . . . . . 4-16Fire and Australia’s biodiversity . . . . . . . . . . . . . . . . . . . . 4-21Biogeographic regions — a closer look. . . . . . . . . . . . . . . 4-23A snapshot of change to some of Australia’s ecosystems:

1788–1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-26The Wollemi pine — a relic from the age of dinosaurs . . . 4-31The meaning of rarity and threat. . . . . . . . . . . . . . . . . . . 4-34Some patterns of genetic diversity . . . . . . . . . . . . . . . . . . 4-38Ecologically sustainable development and biodiversity:

the need for research. . . . . . . . . . . . . . . . . . . . . . . . . . 4-40International and regional biodiversity agreements

to which Australia is a party . . . . . . . . . . . . . . . . . . . . 4-41Migratory species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-42Conservation of biodiversity: relevant legislation . . . . . . . 4-43Response to species endangerment. . . . . . . . . . . . . . . . . . 4-44Economic mechanisms for conserving biodiversity . . . . . . 4-46Community actions to integrate the landscape . . . . . . . . . 4-47Fraser Island . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-50Location and effectiveness of conservation reserves . . . . . . 4-52

C h a p t e r 4 B i o d i v e r s i t y

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IntroductionAustralia has an immense number of unique andunusual plants, animals and micro-organisms.More than one million species (including micro-organisms) are thought to live in Australia, but lessthan 15 per cent have been formally described. Not only is this living resource part of our culturalidentity, we depend on it for our survival andquality of life. Lack of knowledge about thediversity of life on this continent and the effect ofour activities on this fundamental resource pose themost significant impediment to its conservationand management.

Biodiversity is the variety of all life forms — thedifferent plants, animals and micro-organisms, thegenes they contain and the ecosystems of whichthey form a part. Consequently, biodiversity isconsidered at three levels: ecosystem diversity,species diversity and genetic diversity.

The species in a given area interact with each other,and with their environment, to form complexnetworks known as ecosystems. These differ fromplace to place, thus creating ecosystem diversity.Each ecosystem differs from all others because itcontains a unique combination of species (andtherefore genes) and because these species interactwith each other and with each environment indistinctive ways.

Species diversity is the number of species and theirrelative abundance in a defined area.

Genetic diversity is the variety of genes containedin all the species in a given area. There are so manygenes and different possible combinations of genesthat, for most types of organisms, every individual,population and species is genetically distinct.

As a party to the 1992 international Conventionon Biological Diversity, Australia is committed tothe conservation of biodiversity, to the sustainableuse of ecosystems, species and genetic resourcesand to the equitable sharing of any benefits arisingfrom the utilisation of its genetic resources. TheAustralian Commonwealth, State, and Territorygovernments are responsible for managing humanactivities that threaten biodiversity. It is of realconcern that species, including many that are as yetunrecorded, could become extinct due to humanactivities. For this reason, lack of scientific certaintyregarding the impacts of human activities onbiodiversity cannot be used to justify postponingmeasures to prevent environmental degradation.

Australia has evolved in relative isolation for atleast the past 50 million years. This has resulted ina rich diversity of unique life forms. For example,85 per cent of our flowering plants, 84 per cent ofour mammals, 45 per cent of the birds, 89 per centof the reptiles and 93 per cent of our frogs arefound nowhere else (that is, they are endemic). Of the 600 inshore species of finfish in thesouthern temperate zone, about 85 per cent arefound only in Australian waters.

While most of the large organisms, such asflowering plants and vertebrates, have beendescribed and in some cases studied in detail,relatively little is known about the vast and less-visible world of invertebrates and micro-organisms.Australia has an invertebrate fauna estimated ataround 225000 species, of which only half havebeen described. Where limited data are available,however, some groups are known to be endemic.For example, 90 per cent of Australian springtails(Collembola) and 80 per cent of tiger beetles(Cincindelinae) are found nowhere else. The highlevel of endemism found in our plants and animalsis also likely to be reflected among the micro-organisms. However, even less is known aboutmicro-organisms, their ecology and theirimportance in ecosystems and the vast majority ofthem have yet to be identified.

Areas like the Great Barrier Reef, the species-richrainforests of northern Queensland and theSouthwest Botanical Province of Western Australia(with over one-third of Australia’s plant species, ofwhich 70 per cent are endemic) are internationally


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Ecosystem diversity: Coastal coral reefs,sandy shores, rainforest and grasslandprovide different ecosystems that supportdifferent plants and animals.

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RSpecies diversity: A small area of reef

can contain a wide range of species —fish, corals, feather stars and algae.

Genetic diversity: These starfishbelong to a single species(Patiriella calcar), but variouscolour patterns result fromdifferent genes.

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recognised major centres of biodiversity. Australiais the second-driest continent in the world (afterAntarctica) and its inner arid core accounts formore than 70 per cent of the total land mass.Contrary to popular belief, this arid zonecomprises many different kinds of communitiesand habitats, some with their own unique speciesand many that are highly sensitive to disturbance.

The four main reasons for preserving biodiversityrelate to ecosystem processes, ethics, aesthetics andculture, and economics.

Biodiversity provides the critical processes thatmake life possible and that are often taken forgranted. Healthy, functioning ecosystems arenecessary to maintain the quality of theatmosphere, and to maintain and regulate theclimate, fresh water, soil formation, cycling ofnutrients and disposal of wastes (often referred toas ecosystem services). Biodiversity is essential forcontrolling pest plants, animals and diseases, forpollinating crops and for providing food, clothingand many kinds of raw materials.

Ethical values reflect the view that all species havean inherent right to exist. Biodiversity belongs tothe future as well as the present and no species orgeneration has the right to sequester it for theirexclusive use.

Biodiversity has intrinsic values, such as beauty,tranquility and isolation. Many Australians placehigh values on native plants and animals. Thisregard has contributed to our sense of culturalidentity and is important for spiritual enrichmentand recreation. Retaining biodiversity is also criticalfor maintaining the culture of Aboriginal andTorres Strait Islander peoples.

Some elements of biodiversity have economic valueand can be used to create wealth. Australia’s plantsand animals attract tourists and provide food,medicines and other pharmaceutical products,energy and building materials. The commercialfishing industry, for example, produced catchworth 1.7 billion dollars in 1994–95 (ABARE,1995). Tourists to six protected areas in 1991–92spent more than two billion dollars (Driml, 1994).Ecotourism, which is a growing environmentalbusiness in Australia, has the potential to enhancethe effect of other conservation activities, such aseducation and donations.

Another environmental business attractingattention is biodiversity prospecting. Sponges, forexample, appear to be particularly rich in anti-cancer compounds. Other potentially valuablecompounds include a sunscreen derived from achemical that shallow-water corals use to protectthemselves from ultraviolet rays.


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Micro-organisms in activated sewage sludge. Microbial biodiversity isessential for the many ecosystem services such as the breakdown ofwaste material and cycling of nutrients.

Genetic resources from the wild

Natural compoundsMany chemical compounds produced in nature are used in medicine andtechnology. While an unknown number remain to be discovered, highlevels of investment by the pharmaceutical industry suggest major futurecommercial prospects. Genetic resources are particularly abundant inspecies-rich habitats, such as rainforests and the ocean, but useful genescan be found in any type of environment.

Wild crop relativesCrops usually have less genetic diversity than the wild populations fromwhich they were derived because they have been intensively selected formany generations. Wild relatives often harbour extremely useful genes,like those that protect against disease or drought. Plant breeders can utilisethe genetic diversity of wild crop relatives by hybridising domestic andwild varieties and choosing offspring with improved characteristics.

The soybean (Glycine max), for example, has a very narrow genetic base(Brown et al., 1985). Plants cultivated throughout the world aredescended from a few founders from a single geographic area. However,the genus Glycine contains about 16 species of wild soybeans, many ofwhich are native to tropical northern Australia. These wild species are animportant resource for the improvement of domesticated varieties.Research is underway to transfer the genes for rust and mould resistancefound in native Australian species into agricultural varieties.

Like soybean, cotton has native Australian relatives including Sturt’s desertrose (Gossypium sturtianum), a popular garden plant. Wild Australiancotton species in the genus Gossypium are being studied for their potentialfor crop improvement. Cottonseed is used as a stock food, but must beprocessed to remove the naturally occurring insecticide that the plantmanufactures for its own defence. Australian Gossypium spp. have lowlevels of this compound in their seeds but normal levels in the rest of theplant. Experiments are being conducted to transfer this genetic trait intocultivated cotton varieties.

HThe Pilbara, Western Australia;

Australia’s arid zone containsunique ecosystems, plants and

animals.

Biodiversity provides a vast library of geneticmaterial for use now and in the future, for a varietyof industries including agriculture, medicine andgene technology. A loss in genetic diversity wouldresult in a loss of potential for these industries.Thus, the challenge for Australians is to balancethe exploitation and preservation of biologicalresources to ensure that exploitation does notcompromise the options for the future.

The rate at which development has occurred inAustralia is almost unprecedented. For example, inless than 200 years, land use in the wheat andsheep zones of Australia has changed from one ofpredominantly hunter–gatherer to one of intensiveand extensive harvesting, compared with more than10000 years for the same evolution in the MiddleEast (Hobbs and Hopkins, 1990). Since Europeansettlement, Australia has lost an estimated 75 percent of its rainforests (Winter et al., 1987) andabout 40 per cent of its total forest area (AUSLIG,1990). Nearly 70 per cent of all native vegetationhas been removed or significantly modified byhuman activity since 1788 (see pages 6-8 and 6-9).The rate of land clearance has accelerated overtime, with as much cleared during the last 50 yearsas in the 150 years before 1945.

While primary ecological processes are wellunderstood, we know little about the ecologicalrole of individual species. The maintenance of soilstructure and fertility, for example, depends largelyon the activity of groups of poorly understoodorganisms that constitute soil biodiversity. Loss ofthese organisms results in the disruption ofprocesses essential to agriculture, such as waterintake, nitrogen fixation and other types ofnutrient cycling. Thus, by failing to takeappropriate action to conserve biodiversity,Australia could be losing species vital to thesustainability of its rural industries.

State of the Environment reporting provides aframework to monitor and report on aspects ofbiodiversity essential to Australia’s future, and toreport on responses to changes in its condition.This chapter examines the pressures onbiodiversity, as well as its current condition orstate, and reports on responses to these pressuresand states.


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RElabana Falls,

Lamington National Park;biodiversity values include

beauty, tranquility and also vitalecosystem services:

natural vegetation acts as aneffective filter for sediment in

catchments. When the vegetationis removed, the run-off becomes

discoloured with sediment andcreeks silt up.

Soil biodiversityThe highly diverse biota of the soil performs a wide range ofimportant ecosystem services. They maintain soil health and fertilityby cycling carbon, nitrogen, sulfur and phosphorus and bymaintaining soil structure.

Human activities — such as cultivation, irrigation and the applicationof fertilisers and pesticides — alter both chemical and physicalcharacteristics of the soil. Information on the effects of these impactson soil biodiversity and key ecosystem services is fragmentary.However, it has become apparent that increasing acidification of soilin many parts of Australia is adversely affecting the nitrogen-fixingbacteria so important to the growth of many crop and native plants.Loss of the soil’s biodiversity, as a consequence of cultivation, isassociated with loss of its structure, making it subject to erosion. Thedestruction of its mycorrhizal fungi, which form a symbioticassociation with many plants, can adversely affect the prospects ofrecolonisation of those plants.

While most soil biodiversity is yet to be discovered, it is clear thatspecies of soil biota are tightly linked functionally to above-groundbiota. Thus, preservation of familiar plant and animal biodiversity isdependent on a diverse soil biota.The vast majority of the organisms comprising soil biodiversity are

small and generally unknown

PressureThe ecosystem context The major pressures on biodiversity today resultdirectly and indirectly from the increasing humanpopulation and our lifestyles and expectations: ourneeds and desires for food, water, housing, energy,transportation, recreation and many other aspectsof modern living.

The pressures develop because all human activitiesare carried out within, and thus form part of, somekind of ecosystem. This is most obvious in thecountry, where farms are established in grassland orwoodland ecosystems, remnants of which survivebetween cultivated fields or in the corners ofpaddocks. Fishing is clearly an activity wherespecies are removed from aquatic ecosystems.Towns, suburbs, industrial areas and cities alsoform part of ecosystems that existed long beforedevelopment took place. Fragments of theseoriginal ecosystems persist even when theenvironment appears to be entirely one of humanconstruction; one such remnant, for example, isthe urban wildlife that colonises inner city suburbsor abandoned industrial sites.

Ecosystems are the result of long-term interactionsbetween the physical environment and livingspecies that produce characteristic processes andstructural features. Well-established processesinclude, for example, food chains and soilformation, the development of particular groups ofspecies called communities and, within eachspecies, gene pools distributed among populationsof different sizes. Evolution continuously modifiesecosystems, communities and species, makingchange a natural part of each of these entities. Sotoo is disturbance; many species are unable to gaina foothold in established communities but flourishwhen dominant species are disturbed. The scale ofdisturbance may be as small as soil turnover at awombat burrow or as large as a bushfire, but bothcan cause changes in the species present.

Human activities almost invariably affect the paceand alter the direction of change and the extent ofdisturbance, challenging the ability of ecosystems,communities and species to respond (Saunders etal., 1990). Responses are often far-reaching becauseof the interactions between species and betweendifferent species and their environment, and sohuman pressures cause a cascade of effects.

Cascading effects The best-known examples result from the removalof vegetation for agriculture, forestry or urbandevelopment. Clearing is often so rapid andextensive that natural systems cannot recover. Theremoval of plant species results in the loss of foodfor herbivores and, consequently, carnivores furtherup the food chain. Removal of plant cover leads tothe loss of soils through erosion, or of soil nutrientsthrough leaching. Both processes reduce the vastcomplexes of minute species that comprise soilbiodiversity. Urbanisation and pastoral andagricultural programs that suppress theregeneration of native vegetation make these

changes and losses long-term, perhaps permanent.Loss of vegetation such as mangroves or seagrassesat coastal sites may have far-reaching effectsbecause the juvenile nursery grounds of fish, crabsand prawns are destroyed.

Clearing rarely involves entire landscapes, andmuch effort has been made to understand thebiodiversity of remnant vegetation and othercommunities isolated, like islands, in ‘oceans’ ofrural or urban development. This process, knownas fragmentation, often conceals cascading effectsthat are subtle and hard to detect, but neverthelesshighly threatening. For example, trees in vegetationremnants in city bushland or rural paddocks areoften very long-lived and give the appearance ofhealthy greenery. However, many of these remnantshave no seedlings or saplings. It could be that theinsects that once pollinated the flowers havebecome locally extinct, so the trees do not produceseed, or that ecological conditions have changed sothe species can no longer regenerate.


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HThe ‘living dead’; many long-livedorganisms such as some trees in

agricultural landscapes do notregenerate due to changes

resulting from human activities.

Threat/cause Number of Endangered speciesspecies presumed Past Present and

extinct threat future threat

Agriculture 44 112 50

Grazing 34 51 55

Low numbers - 10 85

Weed competition 4 12 57

Roadworks 1 8 57

Industrial and urban development 3 20 21

Fire frequency - 10 17

Forestry - 10 10

Collecting - 6 17

Mining 1 3 11

Note: Many species are affected by more than one threat. In some cases the past threat may have ceasedand new ones arisen. Other threats include recreation, dieback, clearing, railway maintenance, salinity,insect attack, quarrying, trampling by pigs and buffalo, drainage and flooding.Source: Leigh and Briggs, 1994.

Table 4.1 Pressures on plant biodiversity: major causes of extinction and pastand present threats to endangered plant species

Another reason for the absence of seeds can be lossof genetic diversity. As a population shrinks, sodoes its gene pool. Genes that help species to adaptto changing environments, to win competitiveinteractions with other species or to combatdisease, disappear along with the individuals thatcarry them. These genes are then unavailable to thesurvivors. In small populations, the level ofinbreeding increases, which further decreases theability to adapt to current and future challenges.Many species become highly vulnerable whenpopulations decline because they have strongmechanisms to prevent inbreeding and thusindividuals have few suitable mates.

Biologists believe that many small populationsenter an ‘extinction vortex’, which occurs whensmall numbers of individuals harbour such lowlevels of genetic variation that few offspringsurvive. This further reduces their genetic resourcesand the chances of finding a suitable mate. The process continues until a final generation hasso few individuals and such reduced geneticdiversity that reproduction is no longer possible.This may happen quickly in small, short-livedspecies such as butterflies, but may take a centuryor more for bigger, long-lived species such as largetrees.

Cascading effects commonly follow theintroduction of exotic plants, animals or micro-organisms. Introduced weeds have effects that startat the base of the food chain. They displace nativespecies and even entire communities of nativeplants. The effects flow on to animals, such asinsects and birds, that depend on them for foodand shelter. Higher up the food chain, introducedpredators feed on native animals, both diminishingtheir numbers and competing with nativepredators. Marine animals from other parts of theworld, introduced into coastal waters from ships’ballast, enter and change native food chains and,like weeds, can dominate local communities.Introduced micro-organisms, such as diebackfungus (Phytophthora cinnamomi), invade plantcommunities, killing selected species, anddisrupting ecosystem processes and food webs.

Ecosystem health Assessing the health of ecosystems — that is,determining whether or not their structure andprocesses are intact and they contain the expectedvariety of species — has become an importantresearch objective. In forestry, for example, theremoval of trees for sawlogs and for chippingdisrupts forest structure, function and floristics.Forest-dwelling species rely on the structure orarchitecture provided by trees, shrubs and otherplants for food, nesting places and concealment.The vegetation also plays a major part in regulatingnutrients in the forest. When it is removed,branches and fallen trees that normally rot on theforest floor and recycle nutrients back to the soilcan no longer do so, while rainfall, which isnormally scattered by the tree canopy, falls directlyto earth, flushing soil nutrients and organic matterout of the ecosystem.


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Threatening process Birds Rodents Freshwater Marsupials Reptiles fish

C S C S C S S C S

Habitat clearance and/or fragmentation 32 4 13 3 3 4 35

Altered fire regimes 16 35 1 16 2 10

Grazing and/or trampling 10 35 5 1 6 21

Fishing 3

Disease 3 1

Pollution 7 7

Erosion 1 1

Environmental weeds 2 9 5

Forestry operations 3 14 2 1 1 6

Changed hydrological regimes 1 3 5 4

Climatic variations 2 7 5

Shortage of nest hollows 3 20 1

Predation 8 29 9 13 1 4 14

Competition 3 20 1 11 1

Direct exploitation 10 33 2 3 1

Cropping 21

Urban development 4 3 14

Pasture improvement 12

Soil degradation 9

Visitor disturbance 8

Mining 2 4 6

Rabbit grazing 11 1 2 6

Habitat drainage 4

Rock removal 4

Geomorphic alteration 12 6

Water quality 4 1

Introduced exotic species 9 1 10 5 10

Introduced native species 14 3

Loss of genetic diversity 1 1 2

Road kills 1

Unknown 4 3Note: C — confirmed S — speculativeThe figures in each column are the number of species affected by each process. However, a species maybe affected by more than one process.Source: Garnett, 1992 (a & b); Cogger et al., 1993; Wager and Jackson, 1993; Lee, 1995; and Kennedy,1992.

Table 4.2 Sources of current threats to Australian birds, marsupials, rodents,reptiles and freshwater fish

RMany micro-

organisms arecrucial for the

decomposition oforganic material.Fallen branches

and logs in forestsare broken down

by the action offungi whosereproductive

structures aremushrooms,

toadstools andbracket fungi.

Human populationsOur increasing human population with itsaffluence and technology, has resulted in increasingdemands for natural resources and, in turn,increasing pressures on biodiversity (see Fig. 4.1).

Since 1788 when Europeans colonised Australia,about eight generations have lived on the continentand wrought vast changes to the naturalenvironment. Habitat modification, particularlyremoval of vegetation for agriculture, urbandevelopment and forestry, has been and still is themost significant cause of loss of biodiversity (seeTables 4.1 and 4.2). Tourism, altered fire regimesand the effects of introduced plants and animalsalso adversely affect Australia’s biodiversity.

Urban developmentAustralia has a relatively small, highly urbanisedpopulation, with about 86 per cent of people livingon the coastal fringe (RAC, 1993). About 66 percent live in coastal towns and cities of more than100000 people, located on harbours and estuarieswith considerable biodiversity and habitat richness(NPC, 1992). The concentration of people in theseareas generates a range of pressures on biodiversitythroughout the continent, caused by destruction ofnatural habitat, harvesting of plants and animals,the spread of exotic species and pollution (seepages 4-21 and 8-8).

Huge parts of the continent are used for primaryproduction to feed and clothe Australia’spopulation as well as tens of millions of peopleliving in other countries. The export of goods is amajor factor in maintaining the high standard ofliving that most Australians enjoy. Some of themost intense pressures on biodiversity are thereforein agricultural and pastoral districts that arerelatively sparsely populated.

Tourism and recreationLittle research has been carried out on the effects oftourism on biodiversity. The rapid growth of thetourist industry in Australia is a potential threatthat requires continual monitoring and regulation.Since tourism focuses on areas of particular appealthat often have high biodiversity, the pressures itexerts can be disproportionately high and oftenresult in the destruction of the qualities thatinitially attracted tourists to the area.

Recreational activities frequently affect biodiversityin ways that are not immediately obvious. Forexample, some popular beaches on the New SouthWales coast have been protected from sharks sincethe late 1930s and some in Queensland since theearly 1960s. In Queensland, more than 30000large sharks had been captured in shark nets or onlines by 1988 (Paterson, 1990). Catch rates forlarge sharks declined by 75 per cent over 25 years,suggesting a substantial fall in the sharkpopulation. Similar declines have been reported forwhaler and white pointer sharks off New SouthWales (Reid and Krogh, 1992). Large mesh sharknets also catch other large animals that aregenerally slow-growing with a low replacement

rate. Records from shark nets off Newcastle showmean annual catches of 111 rays, seven dolphins,four turtles, 25 jewfish and four tuna.

Like other types of urban growth, touristdevelopments — such as resort hotels and golfcourses in wetland areas — can have a large impacton biodiversity in the surrounding region. Thedevelopments often take place in sensitiveecosystems, such as at the edge of national parks,on floodplains or close to beaches, accentuating theeffect. An example is the increase in numbers ofsilver gulls (Larus novaehollandiae) and otherscavenging birds, due to the availability of foodfrom urban waste dumps. Populations of silvergulls are increasing at a rate of 10 to 13 per centper year (Blaber et al., in press). Waste dumps attourist resorts on islands encourage gulls, whichalso prey on eggs of other seabirds, increasing


4-9

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. . . . . .

Human population (size, affluence and technology)

Population patterns Harvesting Land use

Introduced species Pollution Mining

Climate change

Ecosystem—Species—Genetic Biodiversity

Figure 4.1 Major pressures on biodiversity

Increasing population size with its attendant demands for naturalresources places increasing pressure on biodiversity

Changes in urban birdsThe County of Cumberland (4273 sq km) surrounds andincludes Sydney. It is the site of the first European settlementin Australia and represents the largest concentration of thehuman population, with 27.5 per cent of Australians livingthere (Cocks, 1992). Development of this area has had amajor impact on the biota, as illustrated by changes to thebird community. At the time of European settlement 283species of birds were believed to have occurred there(excluding seabirds and rare vagrants) (Hoskin et al., 1991).Of these, 11 species (four per cent) are now locally extinct, 76(27 per cent) have decreased in range and/or abundance andonly 39 (14 per cent) have increased in range and/orabundance. As well, five Australian species have invaded thearea because the changes imposed on the landscape suitedthem and 20 exotic species were deliberately released and haveestablished viable populations.

pressure on other species. On Rottnest Island, forexample, predation by silver gulls poses a seriousthreat to fairy terns (Sterna nereis), which breedthere.

Pressures on biodiversity are synergistic, the impactof several activities compounding to produce amuch greater impact than any one alone. Themallee woodland in Western Australia, forexample, has already been severely reduced byclearing for agriculture. Demand in the touristindustry for didgeridoos made from mallee is anadded pressure that on its own would beinsignificant. Other impacts from tourism that cancreate cumulative effects are soil erosion caused byfour-wheel drive vehicles, increases in thefrequency of wildfires and localised nutrient-enrichment of the soil and water from food scrapsand other wastes.

Harvesting resources and land useA number of Australian industries are based on theexploitation of natural resources. They includefisheries, forestry and industries based on the use ofwildlife and wildflowers. While harvesting naturalresources is not necessarily detrimental tobiodiversity, many harvesting practices are notsustainable. These can cause habitat loss,fragmentation and/or modification and reducedpopulations through overexploitation, or acombination of these pressures.

FisheriesAustralia exploits its marine biodiversity — withcommercial harvesting of four species of crabs, fourof lobster, 12 of prawn, three each of abalone andscallops and about 300 species of finfish. Under

good management, the number of fish thatcommercial fishers take can be sustainable,especially if they use species that are present inlarge numbers and that have a high reproductiverate. However, high fishing pressure, especially onlong-lived species, usually leads to over-exploitation. For example, catches of southernbluefin tuna (Thunnus maccoyi), which can live toover 20 years, peaked at 80000 tonnes in 1961 buthave since declined steadily (see Fig. 8.13). Thebreeding stock of this species is now estimated tobe less than 10 per cent of the original (CSIRODivision of Fisheries, unpublished data). While thecommercial catch of many species has beenregulated and quantified, the recreational catch hasbeen largely uncontrolled and for some popularangling species, such as snapper (Pagrus auratus),exceeds the commercial catch.

Heavy fishing pressure can be severe whenpopulations are low due to adverse environmentalfactors. The gemfish (Rexea solandri) was once anabundant species off New South Wales but appearsto have been depleted by a combination of adverseoceanographic conditions and heavy fishing (seeFig. 8.14).

Some forms of harvesting — trawling and dredging — are non-selective and kill largenumbers of non-target species. The unwantedcatch (bycatch) can be very large, as in the case ofthe prawn fishery in northern Australian waters,which catches and discards a total of about 38000tonnes of other species. This is four to six times theweight of prawns caught (Pender et al., 1992).Fisheries research has concentrated on the impactof fishing on commercially valuable species and theeffects of bycatches on other species are poorlyunderstood.

Trawling can cause long-lasting damage to theseabed, resulting in a loss of biodiversity in trawledregions. In some areas, the seabed has a complexcommunity of sponges, soft and hard corals andother bottom-dwelling organisms as well as speciesof large edible fish. In the 1970s, foreign trawlersexploited the fish resource on the north-westerncoast of Australia and, in the process, damaged andremoved some of the seabed structure. Thisresulted in loss of habitat and a dramatic decreasein the numbers of commercially valuable fish.Large areas were subsequently closed to trawlingand alternative methods of fishing encouraged. Thefishery and seabed fauna are now recovering(Sainsbury, 1988).

A minimum size limit — usually set at the size atwhich the animals first mature — protects manycommercially and recreationally important speciesof fish and marine invertebrates. If the stocks aresubjected to heavy fishing pressure, few individualslarger than the minimum legal size survive tospawn and so the successful spawners are thoseindividuals that do so at a smaller size. This processacts as a selection pressure favouring individualswith genes associated with spawning at a smallersize. For example, it appears to be responsible for adownward shift in size at maturity of King Georgewhiting (Sillaginodes punctata) in South Australia


4-10

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. . . . . . . . . .

RSeabed on the north-west

shelf of Australia;. communitiesof sponges and large fish arefound in several areas around

Australia.

HPrawn trawler bycatch:

in addition to prawns, the trawlcollects a variety of animals.

Although these will be dumpedback into the sea, most (except

for hardy species such asbivalves and crabs) will not

survive. Dolphins, seabirds andsharks feed on dead animals at

the surface while fish and crabseat them on the seabed

(Hill and Wassenberg, 1990).They make up an important part

of the diet of these scavengersand appear to have contributed toincreases in populations of some,

such as crested terns (Sternabergii) in the Gulf of Carpentaria

(Blaber et al., in press).

and could cause a reduction in genetic diversitywith the loss from the population of genes formaturity at a larger or older stage (Hill, 1992).

ForestryForests cover a small fraction of the continent (seepages 6-8 and 6-9 and Fig. 4.2). Loggingoperations, including the building of access roads,result in major structural changes in the vegetationand soil from which forests and their fauna maytake a long time to recover. Recovery ofbiodiversity depends upon many factors, includingthe ages and species of the trees remaining, theextent of soil erosion and loss of nutrients and theareas left as sources for recolonisation by the forestflora, fauna and micro-organisms. Researchers havestudied the recovery of biodiversity from previouslogging operations in a range of Australian forestenvironments, but as yet they have identified fewgeneric principles.

The fragmentation of previously continuous areasof forest can have destructive effects on the forestflora and fauna. Some species will become locallyextinct when confined to small ‘islands’ orremnants of habitat that do not support viablepopulations (see page 4-13).

Other uses can compound the pressures associatedwith forestry operations. Grazing, for example,often destroys or alters the composition of theunderstorey and the species that depend upon it,and may result in soil erosion. Tourism andrecreational activities such as hiking, camping, off-road driving, horse-riding, hunting and fishing allhave some impact on biodiversity. Individually theeffects may be localised, but together they can exertmajor pressures on forest biodiversity.


4-11

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. . . . . .

Clearfelling is the localised removal of most or all trees followed by burning of debris.The soil tends to be exposed to erosion, and regrowth is often less diverse, both interms of species and the age of trees.

Modified clearfelling keeps some trees for conservation purposes such as mammalhabitat and to allow further growth of immature trees. The resulting forest retains agreater diversity of species and age classes.

Shelterwood logging in highland forests minimises snow or frost damage toseedlings. Shelter trees are retained and then felled once some regrowth is established.

Selective logging removes individuals or patches of trees at relatively short intervals.There are many variations including focus on a particular species or thinning of smalltrees. The general aim is to retain diversity of species, sizes and ages.

Source: Resource Assessment Commission, 1992.

Figure 4.3 The effects of different logging methods on forest ecosystem structure

Mature stand Immediately after harvesting

Selected groups of treesare harvested

New maturing stand

Trees above a specified girthare harvested

Single scattered treesare harvested

Mature stand Immediately after harvesting New maturing stand

Mature stand Regeneration after harvesting

0

2

4

6

8

10

12 total area

area available for logging

Private forest

Conservation reserve

Other crown land

State forest

Hectares (millions)

Source: Resource Assesment Commission, 1992.

Figure 4.2 Australian forest area by tenure, 1990

Pastoralism The pastoral industry covers an area of 5.4 millionsq km, or about 70 per cent of the continent. Inthe arid zone, despite lower stock densities, theimpact of grazing on biodiversity can be greaterthan it is in high rainfall zones because lowproductivity limits forage and stock compete withnative animals for limited resources. Introducedlivestock trample vegetation and degrade soilstructure, leading to changes in native vegetationcover. In turn, this results in erosion and loss ofspecies associated with native vegetation. Theprovision of water through bore holes, earth tanksand dams, where water was formerly limiting,together with introduced predators, feral herbivoresand altered fire regimes, contribute to changes inarid zone biodiversity.

Overgrazing of native pastures has three maineffects on the diversity of native animals. Firstly, asstock remove long grass, native animals’ sheltersites are depleted and the animals become exposedto predation and weather. Secondly, stock compactthe soil and alter the soil texture, destroyingburrows and making burrowing difficult. Finally,

stock compete with native herbivores for food andwater, a situation which becomes critical in aridregions where such resources are scarce duringdrought. In some cases, the extra watering pointsassociated with pastoralism have resulted inincreases in the abundance of native species able toexploit the situation, like kangaroos (Macropusspp.) and emus (Dromaius novaehollandiae). Thisalso increases grazing pressure on native vegetation. Grazing in arid and semi-arid regions is thought tobe partly responsible for the extinction of 34 plantspecies (41 per cent of the total number of plantspecies lost from Australia since Europeansettlement) and continues to threaten a further 55species in the rangelands or 24 per cent of plantspecies currently listed as endangered (Leigh andBriggs, 1992) (see Table 4.1).

Although the arid zone appears unchanged, aboutone-third of mammal species in the sandy andstony desert ecosystems are known to be regionallyextinct (Burbidge et al., 1988; Burbidge andMcKenzie, 1989). This is the highest regionalextinction rate on the Australian mainland(Kennedy, 1992). Many birds are also in decline.For example, eight per cent of arid zone birds areclassified as rare and threatened nationally and afurther five per cent are uncommon species thathave declined or are at risk in two or more aridregions (Reid and Fleming, 1992).

Research agencies and pastoralists have introduced,and continue to introduce, many exotic grasses inan attempt to make rangelands more profitable.Since 1947, 463 exotic plant species have beenintroduced as pasture. Only five per cent of thesehave proved useful as fodder, yet 13 per cent havebecome problem weeds. These include missiongrass (Pennisetum polystachion), which invadesnative bushland, outcompeting native grasses andchanging fire regimes, and para grass (Brachiariamutica), which has spread into Kakadu NationalPark, reducing habitats for waterbirds. As exoticpasture species are still being introduced,pastoralism poses a continuing threat tobiodiversity in rangeland environments.

AgricultureAgricultural practices adversely affect biodiversityin many ways. Following the initial destruction ofnative vegetation, soil tillage and burning ofstubble lower the microbial biomass in the soil,affecting its structure and ecological processes suchas decomposition rates and nutrient cycling. Soilmicro-organisms help prevent erosion by bindingsoil particles together. Thus tillage can have a long-term impact on soil health, with adverse con-sequences for other soil organisms (see Chapter 6).

The long-term use of pesticides, herbicides andfertilisers has had direct and indirect effects onbiodiversity. Pesticide residues enter the soil andaquatic ecosystems and may be ingested byorganisms, with the harmful effects magnified upthe food chain. Pesticides have been linked withthe death of aquatic organisms in many areas suchas the Namoi Valley in New South Wales andMaroochy River in Queensland. Their use is also


4-12

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. . . . . . . . . .

RIntensive production refers to

sown pastures and all crops forwhich the Australian Bureau of

Statistics collects data. Cropping,the main activity, is dominated by

wheat production, but includesother products as diverse as

sugarcane, cotton, bananas andsoybeans. Much of the easternand south-western parts of the

continent are used to someextent for intensive production,

but not the arid interior or themonsoonal north, which are

widely used for grazing on nativerangelands.

HA fence-line separating grazedfrom ungrazed land illustrateshow soil erosion and loss ofvegetation can result fromovergrazing.

Figure 4.4 Percentage of Statistical Local Areasused for intensive production

30 – 100 20 – 30 10 – 20 1 – 10 0 – 1

area of intense production (%)

Source: compiled by ANCA.


4-13

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. . . . . .

Following European settlement, governments activelyencouraged the clearing of native vegetation to make wayfor pastoralism and agriculture in the higher-rainfall areas.While it is difficult to get accurate estimates of changes invegetation cover over the past 200 years, native vegetation(including regrowth) is still being cleared at a rate of over600000 hectares per year — about half the rate of clearingin the Brazilian Amazon in 1990–91. Most of this is takingplace in Queensland and New South Wales (see page 6-40).Vegetation clearance and fragmentation are the major causesof loss of biodiversity (see Tables 4.1 and 4.2).

The situation in Kellerberrin, a shire in the central wheatbelt of Western Australia about 200 km east of Perth,illustrates the effects on biological diversity of vegetationclearance and fragmentation (Hobbs and Saunders, 1993).

Clearing of native vegetation was not carried out randomly.The heavier soils on valley floors were cleared first and moreextensively, as they were regarded as having most potentialto support agriculture. In the landscape illustrated above,only five per cent of the valley floors (green and blue) arestill covered with native vegetation compared with 63 percent of the highest parts of the landscape (red).

In common with other intensively cleared regions inAustralia, much of the remnant native vegetation is privatelyowned (more than 75 per cent in the diagram below) and isnot regarded as part of the Crown conservation estate.Significant numbers of endangered or restricted species liveon these privately owned remnants and so sympatheticmanagement is required to ensure their survival.

Changes in ecosystem processes Clearing of native vegetation leads to changes in rainfallinterception and evapotranspiration, with more waterflowing across the landscape and infiltrating the water table.In this case, little or no run-off or groundwater rechargeoccurred before clearing. After crops and pasture replacednative vegetation, rainfall run-off measured 25 per cent andrecharge of groundwater was seven per cent. This has causedsaline groundwaters to rise by more than 20metres in someareas since clearing began. Consequently, soil salinity hasincreased, with various effects on remnant vegetation dependingon its position in the landscape. On valley floors, for example,which have an average of 13 500 tonnes of total soluble saltsper hectare stored in the soils, vegetation is highly susceptibleand fresh-water ecosystems are under threat.

Increases in soil erosion cause topsoil and nutrients to movedown slopes and into watercourses. Clearing also results in

changes in the microclimate; radiation at ground levelincreases and higher soil temperatures occur. Cleared areasare subject to a much greater range of extreme temperatures.Wind speed is higher closer to the ground in cleared areas,leading to more rapid loss of soil moisture.

Changes in species distribution and abundance Clearing and fragmentation of native vegetation result inloss of species dependent on it and increases in speciesdependent on the cleared agricultural matrix. For example,of 131 bird species recorded in Kellerberrin, 38 havedeclined or have become locally extinct since it was clearedand 18 have increased. These include 11 species that wereintroduced or invaded the area when suitable habitat wascreated in the agricultural land. Only nine of the 15recorded species of native mammal (excluding bats) are stillfound there.

Isolation of species dependent on remnant vegetation When a remnant is isolated from other native vegetation, itwill be carrying more species than it can carry over time andso some will be lost. This loss will be most rapid for: speciesthat depend entirely on native vegetation, for example, theyellow-plumed honeyeater (Lichenostomus ornatus), which isdependent on eucalypt woodlands, was the most commonhoneyeater in the Kellerberrin area and is now extinct there;those that require large territories, for example, the malleefowl (Leipoa ocellata); and those that exist at low densities,such as the broad-faced potoroo (Potorous platyops). Loss willbe slowest for eucalypts and other species with long genera-tion times, like the salmon gums (Eucalyptus salmonophloia).These still occur along road verges, in agricultural land andin some remnant patches, but few seedlings are growing.

East Yorkrakine Nature Reserve (see left) was isolated fromsurrounding native vegetation in the late 1920s. Since 1974,four species of bird dependent on undisturbed nativevegetation have disappeared from the reserve and others willbe lost in future because the populations are too small andtoo isolated (they will not cross open agricultural land) topersist over time. Remnant vegetation is degrading andspecies are being lost because of: the creation of edges andan increase in edge specialists; the invasion of weeds;nutrient enrichment from agricultural practices (fertilisers orlivestock excrement); grazing by domestic livestock, which iseliminating understorey and litter layers; and changeddisturbance regimes such as fire frequencies.

Vegetation clearance and fragmentation

Distribution of native vegetation in the Kellerberrin area pre-1920 and in 1984.East Yorkrakine Nature Reserve is circled. Source: CSIRO.

Digital elevation model of the Kellerberrin area; remnant vegetation is shown in black.Only five per cent of the valley floors (green and blue) are still covered with nativevegetation compared with 63 per cent of the higher parts of the landscape (red).Source: CSIRO.

associated with eggshell thinning in several speciesof Australian birds, particularly birds of prey andpelicans (Pelecanus conspicillatus) (Olsen et al.,1993). Herbicides used to kill unwanted weedspecies also kill native plants.

Australia has large areas of low-nutrient soils so, togrow crops and improve pasture, farmers havemade widespread and heavy use of fertiliser. Theuse of fertilisers over long periods has disturbedmany soil and aquatic ecosystems by increasingtheir nutrient levels. Native vegetation is adaptedto nutrient-poor soils and is resistant to invasion byexotic species unless soils are disturbed or enrichedby nutrients. As this occurs, so does invasion byintroduced weeds that are better-adapted to highernutrient levels and to exploiting disturbed sites.Increasing nutrient levels in watercourses has led toalgal blooms and an increase in other micro-organisms (see the box on page 4-15 and Fig. 4.6).

Vegetation clearance has caused major changes inthe hydrological balance because native plants usemore water by transpiration than most of theannual species that replaced them, and so morewater flows across the landscape and enters thewater table.


4-14

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. . . . . . . . . .

0

100

200

300

400

500

1975 1978 1981 1984 1987 1990

fungicides

insecticides

herbicides

Sales of agricultural chemicals ($m)

Figure 4.5 Australia’s pesticide profile

Pesticides and herbicides are still widely used in Australia, as shown by the increasing sales trends.These chemicals kill native species as well as pests and so adversely impact on biodiversity. Source: AVCA, cited in Short, 1994.

Water harvesting

Agricultural and urban development in Australia hasdramatically altered the flow of many rivers and streams.These changes have been brought about because of ourdemand for water and a desire to mitigate floods. Manyrivers, particularly in the south-east of the continent, havebeen severely affected by human demand for water. Forexample, 10 megalitres (one ML is a million litres) of anannual volume of 12.2 ML of water entering theCondamine–Ballone–Culgoa–Darling–Murray watercoursefrom the Murray–Darling basin is diverted for human use,thus significantly reducing the actual volume discharged(McComb and Lake, 1990). Many streams in the MountLofty Ranges of South Australia, which were permanent 50years ago, no longer flow in summer. In fact, humans havesignificantly modified the flow of most rivers in south-eastern Australia.

Such changes have significant effects on biodiversity, whichare most obvious when large fish such as Macquarie perch(Macquaria ambigua) or trout cod (Maccullochellamacquariensis) become endangered. However, fish like theseare near the top of complex food chains and it is importantto realise that changes to the vertebrate fauna often reflectless obvious alterations in biodiversity. For example, theRiver Murray crayfish (Euastacus armatus) has declined inrange and abundance and 13 of 14 native snails havedisappeared from the banks of the Murray due to artificialchanges in water level.

The threatening process responsible for loss of biodiversity infresh-water ecosystems is habitat modification, which iscaused by factors such as pollution, salinity, changes in watertemperature or low oxygen. These conditions are oftenexacerbated by reduced flow rates connected with waterharvesting.

Changes in the flow of a river may also affect the terrestrialbiota surrounding a watercourse. For example, changingwater levels in the Murray River due to flood control havebeen associated with the death of large numbers of trees andconsequent loss of habitats. Water impoundments captureand store water that is subsequently redirected to other uses,such as irrigation schemes. These reduce the amount ofchannel submerged in water downstream resulting in a lossof aquatic habitat. Above the impoundment, they will havechanged the environment from flowing water associated withperiodically flooded wetlands to still water associated with apermanently flooded environment. Declines in wetland,riverine habitat and water quality are primary causes for thedecline of several species of frog, aquatic tortoise and lizard.Some 32 species of frog have been recorded as being indecline, and only limited data are available for many otherspecies. Such changes will have a significant impact on boththe aquatic and surrounding terrestrial communities.

Changes in wetland habitats through alteration in waterregimes, water quality and physical disturbance may allfavour the spread of introduced or translocated aquaticplants. Infestations of many aquatic plants indicate thatsignificant degradation has occurred or is occurring ininfested rivers and wetlands.

In uncleared areas of arid and semi-arid regions of Australia,native flora and fauna utilise practically all water fromrainfall or it evaporates and thus only rarely finds its wayinto the groundwater. This balance can easily be disruptedby clearing native vegetation (see the box on page 4-13) orby excessive irrigation. Irrigation involves drenching the soilwith water, some of which will be discharged into thegroundwater. Water deep in underground aquifers is usuallysaline (about 30000 ppm) and thus a rise in water levels canresult in salinisation of the soil and nearby rivers.


4-15

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. . . . . .

Pressures on aquatic biodiversity from land use

Estuaries and the seaOn many parts of the east coast of Australia, estuaries andfloodplains of coastal rivers have been drained for avariety of agricultural and pastoral enterprises or for theestablishment of townships and tourist facilities. Thisoften results in the exposure of sediments containing ironpyrite. Oxidation of this mineral leads to the formation ofhighly acidic soils (acid sulfate soils) with highly acidicrun-off, which can kill fish when flushed into rivers andestuaries (Callinan et al., 1993). The fish may die fromhigh acidity and other chemical properties of the watersuch as high levels of dissolved aluminium. Naturalexposure of the acid-producing sediment also causes fishdeaths.

Flood mitigation structures have exacerbated theseproblems by exposing more sediment in drainage worksand changing drainage patterns. Floodgates prevent thenormal tidal flushes that would neutralise or dilute therun-off water.

In southern Queensland and northern New South Wales,observers have noted seasonal fish kills where fish showsymptoms of a skin disease identified by characteristic redspots that become lethal ulcers. The organism responsible,an exotic fungus (Aphanomyces sp.), cannot invade theintact skin of healthy fish. However, skin damageresulting from exposure to run-off from acid sulfate soilsmay allow the fungus to invade. Scientists haveestablished strong links in the temporal and spatialpatterns of rainfall, drainage from acid sulfate soil areasand outbreaks of ‘red spot’ disease.

Fish deaths are the most obvious symptom of acid run-off, but less mobile organisms such as crabs, worms,molluscs and seagrass beds are also severely affected. All ofthese changes disrupt estuarine food chains and haveeconomic impacts on fisheries.

RiversPeriodic outbreaks of blue-green algal ‘blooms’ in inlandrivers are becoming predictable spring/summer events (seepage 7-48). The timing of the blooms coincides withperiods of low water levels and high temperatures.However, the main causal agents are the enrichment ofriver water with nutrients from farming land and effluentsfrom rural cities and towns. The area sown to cotton hasincreased sharply over the past two decades (see thediagram above and Fig. 7.8). The nutrient load for theDarling Basin for an average year is 440 tonnes ofphosphorus and 1890 tonnes of nitrogen.

A variety of organisms use the nutrients in the water,particularly fresh-water algae that, when they decay, useup the dissolved oxygen and create conditions unsuited toother aquatic organisms. Fish kills are one indication ofdeteriorating water conditions. As blue-green algaecontinue to grow, their toxic by-products increase inconcentration and the water becomes poisonous to landanimals. For example, waterfowl and stock may die fromdrinking the river water and towns can no longer rely onit for domestic purposes.

cotton and sugar cane cotton sugar cane

Statistical Local Areas in which sugarcane (162 500 ha)and cotton (235 200 ha) are grown

This green water taken from the Darling River indicates thepresence of an algal bloom. High nutrient levels can cause algalblooms, sometimes resulting in fish kills.


In many regions, water tables are rising and, insome cases, bringing subsurface salt to the topsoil.In parts of the wheat belt of south-westernAustralia, saline groundwater tables have beenrising by between 0.1 and 1.0 metres per year sinceremoval of native vegetation began. When thesesaline waters reach the root zone of plants theycause widespread death of remnant vegetation (seepage 4-13).

Fragmentation of native vegetation disrupts activitypatterns of mobile species, particularly those thatwill not move over open agricultural land. Somehoneyeaters, for example, may now be restricted topatches of remnant vegetation (Saunders and deRebeira, 1991) and this may prevent them fromcarrying out their role in important plantpollination processes.

Introduced species Many species, for a number of reasons, now occurin areas they formerly did not. Introduced speciescan include exotic organisms, both thoseintroduced for production purposes andintroduced diseases, as well as genetically modifiedorganisms and native species whose range and/or

abundance have changed because of humanactivities. Examples occur in terrestrial and aquaticecosystems.

Introduced species exert a major pressure onbiodiversity. They consume native fauna and floraand compete with native species for habitat, oftento the detriment of those species.

VertebratesAt least 18 exotic mammals have established feralpopulations in Australia, including cats, dogs,foxes, pigs, water buffalo, donkeys, goats andhorses. Many species, such as sparrows (Passerspp.), trout (Trutta spp.) and salmon (Salmotrutta), were introduced by acclimatisation societiesin the 1800s in an attempt to make Australia morelike Europe; others, like the black rat (Rattusrattus), brown rat (R. norvegicus) and house mouse(Mus musculus), were introduced accidentally. Manydomesticated animals were introduced forproduction purposes (Fox and Adamson, 1986).

Cats and foxes prey on a wide range of nativeanimals and have been implicated in the decline, ifnot the extinction, of a number of species. The roleof foxes in the decline of native species is wellestablished. However, much less information existson the role of cats. Studies of the red-tailed blackcockatoo (Calyptohypchus magnificus) in WesternAustralia showed that feral cats climbing into treehollows and preying on nestlings, caused the failureof up to 17 per cent of nests (Saunders, 1991).

Early European settlers introduced rabbits, whichreached plague proportions over much of Australia,affecting native vegetation cover and competingwith native fauna for scarce resources. Rabbits alsotake over burrows from native mammals such asbandicoots and bilbies, seriously reducing thebreeding of these species.

All States and Territories have populations of exoticfish. Most widespread of these are trout, mosquitofish (Gambusia affinis), goldfish (Carassius auratus),European carp (Cyprinus carpio), redfin perch (Perca fluviatilis), and tench (Tenca tenca). All haveexpanded their ranges since first introduction, mostwith human assistance. Tilapia (Oreochromismossambicus), one of the most recent fishintroductions, is now found in many coastal creeksand estuaries in Queensland. Its spread is expectedto continue, since the species can survive in freshand sea water, and is extremely adaptable and aprolific breeder. Trout have been stockedintensively since the late 1800s, although climaticconditions have largely limited their spread sincethe mid 1900s. Goldfish are the most widespreadof the exotic fish species in Australia, being foundin every major drainage system from the FitzroyRiver in Queensland to south-western Australiaand Tasmania.

Exotic fish have been implicated in the decline ofnine endangered, eight vulnerable and five rare orcommon native fish species. Trout alone areassumed wholly or partially responsible for declinesin the abundance and range of nine native fishspecies as well as for changes in speciescomposition and abundance of stream invertebrates.


4-16

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. . . . . . . . . .

1000

800

600

400

200

0

250

200

150

100

50

1978 1979 1980 1981 1982 1983 1984 1985 1986

0

Phosphate phosphorus micrograms per litre

Chlorophyll a micrograms per litre

Phosphate

Nodularia

Figure 4.6 Long-term pattern of cyanobacterial blooms (Nodularia spumigena)in the Peel–Harvey estuary, Western Australia and its relationship tophosphate discharge from agricultural fertilisers in the previous winter period

Source: Hillman et al., 1990.

Endangerment categories

Presumed extinct A species is presumed extinct at a particular time if it has not been locatedin nature during the preceding 50 years, or during the preceding 10 yearsif thorough searching has been undertaken during the period.

Endangered Species in danger of extinction include those whose survival is unlikely ifthe causal factors (threats) continue operating. This also applies to specieswhose numbers have been reduced to such a critical level, or whosehabitats have been so drastically reduced, that they are in immediatedanger of extinction.

VulnerableThese are species believed likely to move into the ‘endangered’ category inthe next 25 years if the threats continue operating.

InvertebratesMany invertebrate species have been introducedfrom overseas, but most have attracted littleattention because they are small and little is knownabout their effects on native species andecosystems. However, some introductions are bothobvious and destructive.

The European wasp (Vespula germanica) appears tohave arrived in timber shipments. The nests werefirst seen in the Sydney area in 1978 and sincethen the wasp has not only spread widely, but itsbiology has changed significantly. In its nativeNorthern Hemisphere, colonies are generallyannual, the onset of winter killing all individuals

except the fertilised queens, which have to startcolonies from scratch the following year. InAustralia, however, the relatively warm winters donot kill colonies, which consequently becomeperennial and grow large with enormous numbersof workers. They prey on native insects, includingcommercially important pollinators, and attack softfruits.

Pacific oysters (Crassostrea gigas) were introducedinto Australia between 1947 and 1970 to establishan oyster industry in the southern States. NativeSydney rock oysters (Saccostrea commercialis) arenot suitable for culture in the cool waters ofTasmania and Victoria. Despite attempts to


4-17

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. . . . . .

Figure 4.7 Occurrence of six species of introduced mammals

The entire continent is occupiedby at least one of these feralspecies. Cats occur virtuallyeverywhere, rabbits and foxesoccur mainly in the south and notin the far north, pigs are found inthe east, north and south-west,goats in the east and west anddonkeys mainly in the north-west.

Grid cells (one degree of latitudeby one degree of longitude).

Source: Compiled by ANCA.

Cats Donkeys

Foxes Goats

Pigs Rabbits

prevent the introducedoysters from invading NewSouth Wales, they graduallyspread up the coast where,because of their longbreeding season, prolificproduction of spat and rapidgrowth, they are replacing theindigenous Sydney rockoysters by settling on andsmothering them along withother rock fauna (Hollidayand Nell, 1987).

The Gouldian finch(Erythura gouldiae), whichnow has a very patchydistribution in tropicalnorthern Australia, hasundergone a seriouspopulation decline over thepast 20–30 years. Such hasbeen the extent of its declinethat large flocks are rarelyencountered and the birdshave disappeared altogetherfrom parts of their former

range. A study of possible causal factors (Tidemannet al., 1992) demonstrated that finches in the wildsuffered high incidences of infestation with an air-sac mite (Sternostoma tracheacolum). Aviarypopulations are susceptible to infection by themite, which interferes with breathing. Affectedbirds may live for many months or die quicklydepending on the severity of the infection. Themite was first described in aviary birds in SouthAfrica and to date has not been widely reported inwild bird populations in the Southern Hemisphere.

Other introduced terrestrial invertebrates that havehit headlines are tiny springtails that displacenative species (important in the decomposition ofleaves), garden snails, the so-called Argentine ants,West Indian termites, a millipede and severalvarieties of cockroaches.

Introduced species also affect marine ecosystems.About 70 species are known to have beenintroduced into Australian waters. Many havecome in as fouling organisms on the hulls of ships.Others have been introduced in ballast-waterdischarge. A total of 121 million tonnes of ballastwater from overseas are released into our watersannually from international shipping and a further34 million tonnes are translocated betweenAustralian ports. This water carries many exoticmarine organisms, including plants, animals andmicro-organisms and at least 20 exotic species arebelieved to have been introduced into Australianwaters this way. Many of these may have littleeffect, but several will impact on marine biodiversity.

Northern Pacific starfish (Asterias amurensis) wereprobably introduced into Tasmanian waters inballast water from Japan. They can live in watertemperatures of up to about 24°C and are thuscapable of spreading to much of southernAustralia. These are large starfish — adults canreach up to 40 cm across — and are prolificbreeders, each individual producing up to 19million eggs at a spawning. They can grow rapidly— reaching a size of 12 cm in less than a year. Tensof thousands have been removed from the Derwentestuary in Hobart, where they have reacheddensities of up to five per sq m. Pacific starfishhave been found to eat many species that occur onthe seabed, and thus the large numbers of starfishmay have a devastating effect on populations ofseabed organisms (see the box on page 8-17).

PlantsIntroduced plants are an acute and insufficientlyappreciated ecological problem. On a nationalscale, populations of the most invasive species areexpanding. Plant species not native to Australianow account for about 15 per cent of our totalflora. About half of them invade native vegetationand about one-quarter are regarded as seriousenvironmental weeds or have the potential to beserious weeds (see Table 4.3). The largestproportion of environmental weeds are horti-cultural species that have escaped from cultivation.Almost all of Australia’s native vegetation has been,or is likely to be, invaded by exotic species thatcould result in changes to the structure, speciescomposition, fire frequency and abundance ofnative communities. Those species of greatestconcern include rubber vine (Cryptostegiagrandiflora), blue thunbergia (Thunbergiagrandiflora), the semi-aquatic grasses hymenachne(Hymenachne amplexicaulis) and aleman grass(Echinochloa polystachia), para grass (Brachiariamutica), giant sensitive plant (Mimosa pigra) andathel pine (Tamarix aphylla).

The rubber vine, which entangles trees and othervegetation and eventually smothers them, isspreading at an alarming rate through the riversystems of southern Cape York and the Queenslandpart of the Gulf of Carpentaria and along the coastas far south as the Burnett River near Bundaberg,destroying the riverside vegetation in these regions.


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. . . . . . . . . .

HThe Gouldian finch (Erythuragouldiae) has been affected by anintroduced mite and hasdisappeared from large parts ofits former range.

Figure 4.8 Number of weed species by area

The numbers refer to thosespecies officially listed as noxiousby the States and Territories andindicate the many problems withintroduced plants considered tohave serious adverse effects onbiodiversity and production. Themap does not necessarily indicatethe extent to which ecosystemsor native species are affected byweeds; some seriousenvironmental weeds occur bothin areas of high and low weeddiversity.

Grid cells (one degree of latitudeby one degree of longitude).

The boundaries indicate InterimBiogeographic Regions forAustralia.

196 – 260 131 – 195 66 – 130 1 – 65

no. of weed species

Source: compiled by ANCA


4-19

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. . . . . .

Species Key community/habitat affected Nature of impact/threat

Prickly acacia Mitchell grasslands Replaces perennial Astrebla spp. with annuals or bare soil and is(Acacia nilotica) a long-term threat to the Mitchell grass biome;small tree/shrub converts grassland to shrubland

Para grass Wetlands and streams in the wet-dry and Planted for ponded pasture but spreading into non-target areas(Brachiaria mutica) wet tropics and sub tropics destroying waterbird breeding habitats and choking tropical semi-aquatic streams; replaces native vegetation

Buffel grass Moist ‘refuges’ and river banks Threatening keystone habitats by displacing native vegetation(Cenchrus ciliaris) in the arid zone and altering the fire regime; likely to reduce fauna resourcesgroundcover

Bitou bush Range of coastal systems: foredune, Displaces native vegetation with unknown effects on fauna(Chrysanthemoides monilifera heath, littoral rainforest; range of rotundata) coastal and sub-coastal systems

Boneseed(C.m. monilifera) shrub

Rubber vine Gallery and other riparian communities Smothers trees and shrubs and shades out the ground layer; (Cryptostegia grandiflora) in the wet-dry tropics; destroys riparian vegetation including gallery forestsshrub/vine dry rainforest (vine thickets) threatening associated fauna; forms impenetrable thickets in

Queensland’s Gulf river systems

Water hyacinth Standing surface waters especially where Aggressively invades open water with potential for very rapid (Eichhornia crassipes) nutrient levels are high; occurs in all growth; still spreading in Australia despite extensive control aquatic mainland States but particularly tropics measures; alters aquatic ecosystems

and sub-tropics

Aleman grass Wetlands in the wet-dry and wet tropics; As for para grass; recent introduction and not yet widespread(Echinochloa polystachia) grows in water up to 2 m but larger than para grass with greater potential for damagesemi-aquatic

Reed sweetgrass Margins of creeks, rivers and ponded areas Used as a pasture or ornamental plant but is spreading(Glyceria maxima) up to 1 m deep; temperate species eastern to non-target areas; chokes the habitatsemi-aquatic States

Hymenachne As for para grass but can grow in water Recently introduced as ponded pasture species, so not yet(Hymenachne amplexicaulis) up to 2 m widespread, but has potential to modify tropical wetlands totally semi-aquatic if not controlled

Giant sensitive plant Disturbed areas especially flood plains Totally displaces native species leaving bare mud if removed;(Mimosa pigra) in the wet-dry tropics spreads by floodssmall tree/shrub, semi-aquatic

Bridal creeper Spreading through wide range of habitats Smothers ground and shrub layers(Myrsiphyllum asparagoides) in southern Australiacreeper

Parkinsonia Ephemeral wetlands and riparian Invades mesic habitats and seasonal wetlands(Parkinsonia aculeata) communities in the wet-dry tropics threatening waterbird habitats of continental significancesmall tree/shrub

Mission grass Dry forests and woodlands of the Displaces native sorghum changing the fire regime,(Pennisetum polystachion) wet-dry tropics which potentially reduces recruitment potential ofgroundcover woodland species of high conservation significance

Mesquite Semi-arid and arid riparian and other Similar to prickly acacia but has a wider range of soil(Prosopis spp.) communities; Mitchell grasslands tolerancessmall tree/shrub

Salvinia Stationary and slow-moving water bodies, Aggressively invades open water with potential for(Salvinia molesta) especially where nutrient levels are very rapid growth; still spreading in Australia despiteaquatic high; all mainland States and Territories extensive control measures; alters aquatic ecosystems

Athel pine Dryland river systems; currently small Displaces native trees; salinises soil; changes(Tamarix aphylla) infestations hydrology and geomorphology; reduces fauna resourcessmall tree

Blue thunbergia Tropical lowland rainforest in far Vigorous vine rapidly spreading and smothering native(Thunbergia grandiflora) north Queensland, especially along vegetation to the canopy; infestation in early stagesvine watercourses

Japanese kelp Near-shore habitats along east Spreading at rate of 10 km per year with(Undaria pinnatifida) coast of Tasmania potential to spread along southern coastlinemarine kelp

Source: Humphries et al., 1991

Table 4.3 Australia’s worst environmental weeds

Another species spreading alongthe river systems is the athel pine,which displaces native vegetation— usually river red gum(Eucalyptus camaldulensis) — andcan change river flow andsedimentation regimes. It isconsidered a threat to all thewatercourses of arid Australia. So far ithas become established along severalhundred kilometres of the FinkeRiver, the largest river system inthe arid zone.

Some 65 species of aquatic plantshave become weeds in Australianinland waters. About 15 of these

are significant pests and 13 have the potential tobecome so. These species have been introducedeither intentionally, for economic, aesthetic ormanagement reasons, or accidentally through theaquarium and agricultural industries. One exampleof an introduced aquatic plant is the giant sensitiveplant, which infests wetlands of the NorthernTerritory. It rapidly reduces the number of speciesof native plants and animals, and alters seasonalwetlands from predominantly native grassland toshrubland dominated by a single species.

Japanese kelp (Undaria pinnatifida) was probablyintroduced via ballast water discharge and isspreading widely in southern waters. This species isknown to displace native seaweeds, changingseabed habitats and altering species composition.

Micro-organisms Introduced species sometimes carry diseases thatcan infect native species. The introduced fungusPhytophthora cinnamomi, causes a disease, known asdieback, that is devastating many nativecommunities in southern Australia and is now themost important threat to the biodiversity ofStirling Range National Park in Western Australia.By killing key species in those systems, thepathogen is threatening entire communities andecosystems. In highly susceptible genera (such asBanksia, Grevillea and Dryandra), 80 to 100 percent of infected individuals may die, exposingground that is then invaded by weeds. Thenumbers of birds in affected areas in Two PeoplesBay Nature Reserve in Western Australia have beenreduced significantly because of the effects ofPhytophthora infection on the vegetation (Hart, inpress).

The impact of other introduced micro-organismson native animals is largely unknown, although anintroduced fish virus (epizootic haematopoieticnecrosis or EHN virus) may have been responsiblefor the decline of the Macquarie perch in Lake Eildon.

Native species out of placeOutside their natural range, native species may beas serious a threat to biodiversity as exotic ones.Many are spreading beyond their usual habitat orincreasing in abundance due to human activitiessuch as clearing, cropping, pastoralism, tree-planting on farms and in gardens and landscapingof roads and railways.

Much of the pastoral land in the central-westernareas of New South Wales and Queensland hasbecome densely infested with shrubs. These so-called woody weeds (including Eremophiliamitchellii, E. sturtii and Cassia nemophila) occurnaturally in the pastoral regions but have spread atthe expense of other native species due toovergrazing and changed fire regimes. BeforeEuropean settlement, regular fires checked theirspread. However, overgrazing, which removes theperennial grass cover, reduces the capacity of theland to carry fire. Longer periods between fireshave allowed young plants to develop beyond theirvulnerable stage, and once established they are ableto survive fire. Dense thickets of these shrubsprevent pasture growth and impede mustering ofstock.

The galah (Cacatua roseicapilla) was formerlyassociated with the river systems of the arid zone.However, development has created vast areas ofsuitable habitat (grasses, cereal crops and abundantwater), encouraging the bird to colonise much ofAustralia. This expansion has brought the galahinto contact with other species formerly outside itsrange. One of these is Carnaby’s cockatoo(Calyptorhynchus latirostris), a black cockatoo ofsouth-western Australia, which has disappearedfrom more than one-third of its range in the last25 years due to loss of food and habitat. Thiscockatoo also suffers from competition with galahsover nest sites. In addition, galahs remove barkfrom the trunks of some of their nest trees, whichin severe cases leads to the death of the trees andhas become a significant cause of mortality inextensively cleared semi-arid woodlands with poorrecruitment of trees.

Not only can introduced species reduce thenumbers of indigenous organisms, they mayhybridise with closely related endemic species,changing the genetic composition of thepopulation. In some cases, hybrids resulting frominterbreeding between endemic and closely relatednon-endemic species are more vigorous than theoriginal stock. This can lead to reduction oreventual elimination of the indigenous species. Theescape of rosemary grevillea (Grevillearosmarinifolia) from gardens, for example, hasresulted in hybridisation with a rarer endemicspecies, G. glabella. The resulting hybrids are morevigorous and may replace the parental G. glabella.


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. . . . . . . . . .

Two Peoples Bay, WesternAustralia; red, purple, orange andlight red represent diebacklocations. The other coloursrepresent dieback-free areas. Source: Behn and Campbell,1992.

P

HThis kelp (Undaria) was probablyintroduced from Japan in ballastwater and is a conspicuousunderwater plant on theTasmanian coast.

Pollution The release of pollutants into the environment isan actual and potential threat to biodiversity,particularly in regions close to industrial sites andhighly urbanised areas. Urban stormwater maycontain high levels of contaminants such as faecalbacteria, nutrients, chromium, cadmium, lead,nickel, hydrocarbons and chlorinatedhydrocarbons. In rural areas, irrigation run-offoften contains insecticides, fertilisers and herbicidesthat have been applied to crops and may affectfresh-water and marine ecosystems. Nutrients fromurban effluent and agricultural chemicals, forexample, are polluting inshore reefs of the GreatBarrier Reef, killing coral and encouraging thegrowth of sessile algae.

Pollutants can act in a synergistic way to causeuncertain long-term impacts. These impacts arecompounded by the cyclic nature of ecosystemprocesses, which disperse pollutants widely fromtheir sources and may affect biodiversity atconsiderable distances from the original source.

Potential effects of pollutants on ecosystemsinclude changes in the abundance of species,interruption of energy and nutrient flows,modification of habitats, reductions in soil, waterand air quality, and changes to the stability andresilience of ecosystems. As an example, industrialdischarges into Cockburn Sound in WesternAustralia have been associated with massive loss ofseagrasses and substantial levels of contaminationof sediments and fish (see page 8-25).

Natural enrichment in the sea occurs mainly inupwelling areas where water rich in nutrients risesto the surface and is used by algae, chiefly diatoms.A variety of small animals, which form part of theextremely diverse marine plankton and whichinclude larval stages of many fish and crustaceans,feed on these diatoms. More than 5000 species ofdiatoms are found in Australian waters. Effluentsfrom sewage and from agricultural run-off are highin nitrogen and phosphorus, but are lacking insilica. Thus diatoms — which require silica —cannot make use of these nutrients and they areused by other species of algae — especiallydinoflagellates — that do not require silica. Thisresults in a major shift in species composition,


4-21

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. . . . . .

RGalahs remove

bark from some of their

nest trees. In extreme

cases this maylead to the death

of the tree.

Fire and Australia’s biodiversityThe January 1994 wildfires in eastern New South Wales provided a vividreminder of how destructive some of the natural forces affecting ourlandscape can be. Fire is a natural disturbance and the Australian biota hasevolved under its influence. However, its contemporary pattern differsfrom the one that occurred before the arrival of Europeans.

The pattern comprises the frequency (expected return-time) of fire. Thisin turn affects its intensity, since litter accumulates between outbreaks, andthe longer the interval the greater the amount of litter or fuel that canaccumulate. The third important part of the pattern is the season in whichfire usually occurs. In much of Australia, some or all of these componentsof the fire regime have changed. This in turn affects the way thatcommunities of plants, animals and micro-organisms respond to fire.

Most often, people, by their actions, bring about the changes in firefrequency (and intensity) or seasonality. Some areas are protected. Thus,fires may be suppressed in urban bushland close to houses, schools andcommercial buildings to prevent destruction of property. Such practiceswill cause biological changes. More commonly, bushland areas are burntmore frequently than they were prior to European settlement. For somespecies of plants and animals, the time between fires may be insufficient toallow their natural reproduction. For example, in shrubland aroundSydney the heath banksia (Banksia ericifolia) first flowers in the seventhyear after a fire, and the fruit are not mature until at least the eighth year.This means that if bushland such as Royal National Park is burnt morefrequently than every eight years, that species of banksia will becomelocally extinct.

Species Time since fire (years)

2 3 4 5 6 7 8

Mitre weed (Mitrasacme polymorpha)

Flannel flower (Actinotus helianthi)

Woollsia (Woollsia pungens)

Sydney boronia (Boronia ledifolia)

Pink wax-flower (Eriostemon australasius)

Guinea flower (Hibbertia monogyna)

Sweet-scented wattle (Acacia suaveolens)

Wedge-pea (Gompholobium grandiflorum)

Heath banksia (Banksia ericifolia)

Dagger hakea (Hakea teretifolia)

Source: Benson, 1985.

Flowering times for selected plants from sandstone shrublands near Sydney

from a plankton community dominated bydiatoms to one dominated by dinoflagellate algae.Dinoflagellate blooms cause a range of seriousproblems from massive fish kills associated with redtides to paralytic shellfish poisoning in humans (seeChapter 8).

MiningMining affects the environment and associatedbiota through the removal of vegetation andtopsoil, the displacement of fauna, the release ofpollutants into the air and water and theproduction of mine overburden. When pyrite (irondisulfide) is brought to the surface during themining of coal and metal ores it is oxidised tosulfuric acid, which in turn mobilises heavy metals.This acid mine waste can severely pollute rivers,causing loss of biodiversity. The Rum Jungle Minein the Northern Territory, for example, released130 tonnes of copper, 100 tonnes of manganese,40 tonnes of zinc and 13 000 tonnes of sulfate intothe Finnis River in one year. In submarine miningoperations, equivalent disruptions occur in theimmediate environs of the mine or drilling site.Whether terrestrial or marine, mining sites arenumerous but generally of relatively small totalarea (see Fig. 6.3). Extensive mining operations,such as open-cut extraction of coal, bauxite andmanganese, as well as sand mining in coastalheathlands, have caused long-term changes tobiodiversity despite recent attempts atrehabilitation (Fox, 1990).

Climate changeThe impact of climate change on biodiversity isdifficult to assess since it depends largely on therate of change and the compounding effects ofother pressures such as habitat loss andfragmentation. While most scientists agree that theclimate is changing, it is not yet possible todistinguish human-induced change from naturalclimatic variations.

As the global climate warms, the preferred climaticconditions for a species will shift to higher altitudesand latitudes. Survival will depend on its ability torelocate quickly enough and the availability ofalternative habitats. Species most at risk are thosewith small population sizes that have slow growthrates with poor dispersal abilities and recruitment.The disruption of migration paths by humanactivities will also influence the ability of organismsto adjust geographically to climate change. Regionsof urban development, agriculture and pastoralismwill act as barriers, preventing the movement ofmany species from one remnant habitat to another.

A recent study into the impact of global warmingon the distribution of vertebrates (Dexter et al.,1995) found that the habitats of many ofAustralia’s endangered vertebrates are likely tocontract significantly in the advent of climatechange (see Table 4.4). Under one scenario, 46 outof 57 endangered species examined would contractin range.


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. . . . . . . . . .

Species Vertebrate Loss of core climateorder area (%)

Kowari (Dasyuroides byrnei) Mammal 99.6–100

Red-tailed phascogale (Phascogale calura) Mammal 99.4–100

Central rock-rat (Zyzomys pedunculatus) Mammal 94.0–100

Forty-spotted pardalote (Pardalotus quadragintus) Bird 86.0–100

Swan galaxias (Galaxias fontanus) Fish 81.8–100

Dusky hopping-mouse (Notomys fuscus) Mammal 78.9–100

Heath rat (Pseudomys shortridgei) Mammal 71.7–100

Broad-headed snake (Hoplocephalus bungaroides) Reptile 65.1–98.9

Northern hairy-nosed wombat (Lasiorhinus krefftii) Mammal 59.4–100

Carpentaria grass wren (Amytornis dorotheae) Bird 51.6– 100

Climate change due to increasing greenhouse gases is a potential threatening process to Australia’sbiodiversity. Some vertebrate species may be driven to extinction due to loss of core habitat.Source: Dexter et al., 1995

Table 4.4 Ten vertebrate species most threatened by climate change

Mine sites such as this one at Queenstown, Tasmania can have a severe impact on biodiversity.

StateThe state of ecosystem diversity

Biogeographic regionalisations for AustraliaEcosystems can be defined at many scales becausethere are many ways of representing them,depending on the purpose and the particularecosystem components and processes that need tobe emphasised. The main reason for developing theterrestrial regionalisations discussed here was toprovide a framework for identifying gaps in thenational system of protected areas and to assist inallocating priorities for funding to projectsconcerned with conservation of biodiversity(Thackway and Cresswell, 1995). The rationale forthe marine regionalisation was similar. Quitedifferent classifications of ecosystems could beappropriate for different purposes.

The terrestrial ecosystems discussed here are thoseoutlined in the Interim BiogeographicRegionalisation for Australia (IBRA) (see Fig. 4.9),which divides the continent into 80 biogeographicregions representing major environmental units(Thackway and Cresswell, 1995). It is the onlycontinent-wide regionalisation agreed to by allStates and Territories and was initially developed inFebruary 1994 by combining State and Territoryland classifications at a scale appropriate for thewhole continent. The system is still evolving asmethods are developed to refine boundaries, makelevels of classification consistent between parts ofthe country and reconcile differences in approachbetween jurisdictions.

The biogeographic regions vary in size from 2372sq km (Furneaux, in Bass Strait) to 423 751 sq km

(Great Victoria Desert). The smaller regions occurwithin 300 km of the coastline, have relatively highrainfall in the growing season and, in many cases,are mountainous. Of the largest regions, most arein arid or semi-arid areas with broad climaticgradients and little topographic relief. The regionscan be progressively subdivided into smaller unitsbased on, for example, major vegetation structuraltypes, vegetation communities, local topographicvariations in communities and, at extremely finescales, water-filled tree hollows and small sectionsof the soil surface (see the box below). Any of thesescales of ecosystems can be characterised in termsof distinctive biological and physical patterns andprocesses.

In 1986, the Australian Committee for IUCNproposed the classification used here for majormarine regions (see Fig. 4.9), which is an interimone. The Department of the Environment, Sportand Territories (DEST) is reviewing the inshoreclassification with the States and the NorthernTerritory for waters under their jurisdiction — themarine areas within three nautical miles of thecoast. DEST has also commissioned CSIRO todevelop a new offshore regional classification thatwill integrate information on depth, type ofsubstratum, water column characteristics, such astemperature, salinity, currents and eddies, and thedistribution of more than 4000 species of fish (thebest known group of marine organisms). Of theinterim marine regions, 12 are predominantlycoastal or near-coastal, defined arbitrarily withinthe 200-m-depth contour, which is relatively closeto the coast in many areas but extends welloffshore in Bass Strait and the Great AustralianBight and along the Great Barrier Reef and muchof the northern coastline.


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. . . . . .

The New South Wales north coast (A) is one of the majorbiogeographic regions in eastern Australia (see Fig. 4.9).The region has been subdivided into six major vegetationstructural units (B) — rainforest, moist open forest, dryopen forest, woodland, and sclerophyll complexes on thecoast and tablelands. Each of these units can be consideredan ecosystem at a finer scale than the region as a whole. At a finer scale still, forest types (C) can be distinguishedwithin the major vegetation types. So rainforest in theDorrigo area can be subdivided into dry, warm temperate,cool temperate and subtropical and the open forest into

many more types. Each of these forest types can becharacterised by particular environmental variables andphysical processes and a distinctive flora and fauna. At another level of detail, the ground surface of any oneforest type can be mapped as a mosaic of surfaces (D),including the bases of trees, accumulated bark nearby, bare rock, disturbed bare soil, litter of leaves and smallbranches and fallen logs. The different surfaces also havedistinctive physical and biological characteristics and large populations of macro-invertebrates and micro-organisms.

Biogeographic regions — a closer look

A B C D

Source: compiled by NSW Parks and Wildlife Service.

Note: CL: areas of vegetation cleared (%) IP: areas affected by intensive production (%) IP is larger than CL in some

regions because some intensive production does not always require cleand because of discrepancies between the separate data sources.

GRd: average livestock densities on pastoral land (nos/ha) FO: areas used for commercial forestry on public land (%) MI: mineral deposits currently mined or potentially mined in the future (no.PR: protected areas (National Parks, nature reserves and equivalent tenuresSome small or irregularly shaped IBRA regions were merged for the analysis intensive production and grazing because the data for these enterprises areavailable only for Statistical Local Areas (SLAs). Merging produced the follow12 combinations of regions: Australian Alps and South Eastern Highlands; Noand eastern Tasmania: Ben Lomond, Central Highlands, D’Entrecasteaux, FreyFurneaux, Tasmanian Midlands and Woolnorth; Burt Plain and MacDonnell RaCentral Arnhem, Daly Basin, and Pine Creek–Arnhem; Esperance Plains and MGulf Fall and Uplands and Gulf Coastal; Hampton and Nullarbor; Jarrah ForestSwan Coastal Plain and Warren; Murchison and Yalgoo; Nandewar and NewEngland Tableland; Naracoorte Coastal Plain, Victorian Midlands, and VictorianVocanic Plain; South East Coastal Plain and South East Corner.Data compiled by ANCA.


4-24

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9

Figure 4.9 Australian marine regions and terrestrial bioregions

Marine regions1 North Coast2 North West Coast3 Central West Coast4 Lower West Coast5 South West Coast6 Great Australian Bight7 South Gulfs Coast8 Bass Strait9 Tasmanian Coast10 North East Coast11 Central East Coast12 Lower East Coast13 Great Barrier Reef14 Gulf of Carpentaria15 North West Oceanic16 West Oceanic17 South Oceanic18 South East Oceanic19 North East Oceanic

Terrestrial bioregions(see table opposite)

19

10

5

1

29

28

41

5545

51

60 64

64

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78

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72


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. . . . . .

The most extensive clearing has been in regions that are bothtopographically and climatically suitable for large-scale cropping orimproved grazing. These form a band from east to west in the southernhalf of the continent and include Nandewar, New England Tablelands,New South Wales South-Western Slopes, Riverina, Victoria Midlands,Victoria Volcanic Plain, Naracoorte Coastal Plain, Lofty Block, Eyre andYorke Blocks and the Avon Wheatbelt. Source: estimates of cleared areas are derived from two sources. Themajor one is the Australian Heritage Commission wilderness inventorywhich is a compilation of information supplied by the States andTerritories, except Western Australia. For south-western Australia,clearing data come from interpretation of satellite imagery by theEnvironmental Resources Information Network.

Commercial forestry affects far fewer regions than clearing or grazingand is strongly concentrated in the south-east and south-west. Itsoverall effects on biodiversity can, however, still be substantial becauseforests are richer biologically than other terrestrial habitats.

CL IP GRd FO MI PR1 Australian Alps 38 35 2.08 27 3 18.92 Avon Wheatbelt 88 81 0.96 0 26 0.53 Brigalow Belt North 60 17 0.76 2 29 1.24 Brigalow Belt South 64 16 1.01 9 28 2.05 Ben Lomond 37 19 44 29 9.36 Broken Hill Complex 0 0 0.15 8 1.47 Burt Plain 0 0 0.09 5 2.38 Central Arnhem 2 1 0.14 2 7.69 Carnarvon 0 7 0.08 3 6.910 Central Highlands 37 19 18 4 9.311 Channel Country 0 0 0.15 0 3 6.612 Central Kimberley 0 0 0.15 8 0.013 Central Mackay Coast 34 63 1.12 9 2 6.614 Coolgardie 3 13 0.08 1 325 7.615 Cobar Peneplain 33 25 0.50 1 14 0.916 Central Ranges 0 0 0.06 3 0.017 Cape York Peninsula 0 0 0.10 1 4 11.718 Daly Basin 2 1 0.14 6 7.619 D’Entrecasteaux 37 19 42 9.320 Desert Uplands 15 19 0.44 4 1.621 Dampierland 0 0 0.17 3 0.322 Darling Riverine Plains 51 28 0.85 0 0.523 Einasleigh Uplands 7 4 0.34 1 72 0.824 Esperance Plains 43 47 1.41 0 17 19.325 Eyre and Yorke Blocks 76 48 0.59 0 6 6.626 Finke 0 0 0.6 2 0.027 Flinders and Olary Ranges 7 4 0.18 25 10.128 Freycinet 37 19 28 9.329 Furneaux 37 19 9.330 Gascoyne 0 0 0.04 31 1.931 Gawler 0 11 0.06 5 9.932 Gibson Desert 0 0 0.0 12.033 Gulf Fall and Uplands 0 0 0.07 15 0.934 Geraldton Sandplains 52 56 0.73 4 14.035 Great Sandy Desert 0 0 0.10 12 1.936 Gulf Coastal 0 1 0.07 12 0.037 Gulf Plains 0 1 0.25 0.038 Great Victoria Desert 0 2 0.04 8 17.139 Hampton 0 1 0.04 28.640 Jarrah Forest 44 55 2.82 34 25 8.141 Lofty Block 81 64 1.58 1 6 4.942 Little Sandy Desert 0 0 0.03 2 4.943 MacDonnell Ranges 0 0 0.09 1 2.344 Mallee 43 47 1.41 32 19.345 Murray–Darling Depression 39 33 0.55 2 7 12.846 Mitchell Grass Downs 3 2 0.28 9 0.347 Mount Isa Inlier 0 0 0.21 0 52 2.348 Mulga Lands 8 5 0.30 1.649 Murchison 2 4 0.05 0 393 1.150 Nandewar 74 45 2.41 1 2 2.151 Naracoorte Coastal Plain 78 73 2.52 6 4.752 New England Tablelands 74 45 2.41 6 9 2.153 Northern Kimberley 0 0 0.15 1 12.054 NSW North Coast 37 21 1.78 21 64 8.055 NSW South Western Slopes 80 55 2.16 1 30 1.256 Nullarbor 0 1 0.04 28.657 Ord-Victoria Plains 0 1 0.18 7 5.458 Pine-Creek Arnhem 2 1 0.14 47 7.659 Pilbara 0 0 0.08 224 5.660 Riverina 72 38 1.05 2 4 0.261 Sydney Basin 26 22 1.22 6 33 32.462 South East Coastal Plain 41 37 0.97 4 16.663 South East Corner 41 37 0.97 53 4 16.664 South Eastern Highlands 38 35 2.08 25 46 18.965 South Eastern Queensland 60 23 1.33 12 26 3.066 Simpson-Strzelecki Dunefields 0 0 0.09 1 26.767 Stony Plains 0 0 0.05 5 4.968 Sturt Plateau 0 0 0.15 0.069 Swan Coastal Plain 44 55 2.82 5 33 8.170 Tanami 0 0 0.11 33 0.071 Top End Coastal 1 1 0.19 4 9.872 Tasmanian Midlands 37 19 4 9.373 Victorian Bonaparte 1 1 0.17 4 11.274 Victorian Midlands 78 73 2.52 9 44 4.775 Victoria Volcanic Plain 78 73 2.52 2 4.776 Warren 44 55 2.82 36 14 8.177 Woolnorth 37 19 29 12 9.378 West and South West 5 7 2.95 18 19 49.079 Wet Tropics 23 22 0.93 35 16.180 Yalgoo 2 4 0.05 0 13 1.1

Table 4.5 State of terrestrial biogeographic regions indicated by extent ofmajor threatening processes and coverage by conservation reserve

Figure 4.11 Percentage areas of vegetationcleared in terrestrial biogeographic regions

Figure 4.10 Percentages of terrestrialbiogeographic regions used for commercialforestry on public land

42 – 56 28 – 42 14 – 28 1 – 14 0 – 1

forestry area (%)

75 – 100 50 – 75 25 – 50 1 – 25 0 – 1

area cleared (%)



Marine regions, like terrestrial ones, can be definedat many scales. For example, the Gulf ofCarpentaria is a large marine region with muchinternal variation in physical and biologicalcharacteristics. The eastern side contains largeestuaries with extensive mangroves, fine sediments,high turbidity and lowered salinity in the monsoonseason. On the western side, much of the coastlineis rocky, sediments are mainly coarse, the water isrelatively clear and extensive beds of seagrassesgrow in sheltered areas. Further subdivision ofthese large areas is also possible using biologicaland physical data.

Ecosystem diversityResearchers have used satellite imagery to examinechanges in land cover on the Australian continent(Graetz et al., 1995). They found that 39 per centof the continent was in the intensive-land-use zone(characterised by clearing for cropping, pasture,plantation and urban development) and 61 percent in the extensive-land-use zone (the centralcore of the continent characterised by pastoralactivities on native vegetation and unallocated land).

The extent of clearing of native vegetation in theintensive-land-use zone ranged from 30 to 99 percent with a mean value of 47 per cent. Within thiszone, the remaining land cover was highlyfragmented. In the extensive-land-use zone, 26 percent of the area had significant disturbance to landcover and 15 per cent had been substantiallydisturbed. Land cover over 48 per cent of thecontinent is either significantly or substantiallydisturbed and no vegetation types remaincompletely unaffected by human activities.

Processes threatening major terrestrial ecosystems In contrast to species, ecosystems have nonationally agreed classification system and, moreimportantly for this report, no agreed listing of theextent to which they are threatened. It is alsodifficult to specify when an ecosystem is extinct.How many of the components have to be lost andwhat degree of alteration of processes is necessary

to make such a proclamation? This report uses theextent of various threatening processes in eachbiogeographic region to summarise the state of ourecosystems. In this way, it is possible to make somenational generalisations about the patterns ofimpacts on major Australian ecosystems and toaugment these with some examples of alteredecosystems at finer scales than the nationalclassification.

Figures 4.10 and 4.11 illustrate the continentalpatterns of two threatening processes in terrestrialenvironments — forestry and clearing/intensiveproduction. The overall extent of both issummarised in Table 4.5. Clearing combines theimpacts of human settlements and transportsystems, cropping and the mechanical removal ofwoody vegetation for increased carrying capacity ofstock. Of these, clearing for human settlementsand associated activities is relatively minor inextent and strongly concentrated on the south-eastern seaboard, with smaller areas in the south-west and north-east. Human settlements, therefore,affect mainly the biogeographic regions in coastalparts of the continent and cover small percentagesof their total areas. Nevertheless, urbanisation canhave severe impacts on ecosystems defined at finerscales than IBRA regions. For example, some of thevegetation types in the Sydney region have beenlargely eliminated by the expansion of themetropolitan area while others are still extensive(Benson and Howell, 1990).

By far the largest proportion of clearing has beenfor cropping and grazing, either on improved orunimproved pastures. The extent of these impactsis demonstrated by the fact that 49 of the 80biogeographic regions are affected to some extent(see Table 4.5). Incentives for clearing are largelydetermined by rainfall, soil type and availablestream flow for irrigation. Clearing is thereforeconcentrated in the south-west, the east and themonsoonal north (see Figs 4.11 and 6.6). Large variations in the percentage of area clearedexist between biogeographic regions. The highestpercentages are in regions that are bothtopographically and climatically suitable for large-scale cropping or improved grazing. Overall, mostof the southern half of the continent is highlydisturbed by clearing.

Percentages of biogeographic regions cleared give anational picture but hide variation in land use atfiner scales. In the Avon Wheatbelt of WesternAustralia, clearing has avoided the more ruggedoutcrops (see the box on page 4-13). Similarly, inthe New South Wales North Coast biogeographicregion, overall clearing is about 37 per cent butthis has been highly selective (see the image onpage 4-27). Some ecosystems such as the ‘BigScrub’, formerly the largest tract of subtropicalrainforest in Australia, are almost completelycleared because they possess rich soils and gentletopography. Other large parts of the region are still trackless wilderness because they aretopographically unsuitable for intensive land uses.

The national patterns of clearing arecomplemented by accounts of clearing in other


4-26

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. . . . . . . . . .

A snapshot of change to some ofAustralia’s ecosystems: 1788–1995• Seagrass beds in temperate areas have

declined significantly.

• About 43 per cent of forests have beencleared.

• More than 60 per cent of coastal wetlands insouthern and eastern Australia have beenlost.

• Nearly 90 per cent of temperate woodlandsand mallee have been cleared.

• More than 99 per cent of temperate lowlandgrasslands in south-eastern Australia havebeen lost.

• About 75 per cent of rainforests have beencleared.

ecosystems. Forests, for example, are among theleast-extensive ecosystems in Australia, but are richbiologically. Of the original nine per cent of thecontinent that was once forested, only five per centremains (AUSLIG, 1990) (see Chapter 6).Rainforests are thought to have once covered morethan 80000 sq km, but are now reduced to 20000sq km. Much of the remaining rainforest is in steepand inaccessible areas, on infertile soils, whereasmost of that cleared was in lowland and tablelandareas with more fertile soils (Winter et al., 1987).Given the often specific requirements and limiteddistribution of rainforest organisms, there is a realpossibility that clearances have already resulted inmassive loss of biological diversity.

Until recently, the importance of grasslands to theconservation of biodiversity has been neglected.For a long time, graziers have regarded manygrasslands as natural pastures. Only about 10000ha of the original grassland vegetation of south-eastern Australia is still intact, which representsonly 0.5 per cent of the original area (Kirkpatricket al., 1995). Less than 0.2 per cent of Victoria’soriginal grasslands now remain in fragmentedremnants, mostly restricted to roadsides, railwaylines, cemeteries and lightly grazed unimprovedpastures. Some 21 species of vertebrates originallyfound in grasslands in Victoria are no longerpresent in that State and six are extinct (VictorianDepartment of Conservation and NaturalResources, 1992). More than 83 per cent of theoriginal lowland grasslands and grassy woodlandsin Tasmania have been destroyed or greatlymodified.

Only about five per cent of the more than sixmillion hectares of brigalow (Acacia harpophylla) inQueensland still remain (Biodiversity Unit, DEST,1995). Other woodland communities have beenentirely eliminated. For example, no natural standsremain of Eucalyptus crenulata, a Victorianendemic. Others are close to elimination: grassywoodlands of white box (E. albens) on the centraland western slopes of New South Wales have only0.01 per cent of their original area inapproximately natural condition — these survive infour small sites on roadsides and in cemeteries(Prober and Thiele, 1993).

Grazing by domestic stock is the most widespreadof the threatening processes listed in the Table 4.5.It affects most of the continent to some extent,occurring in almost all of the 80 biogeographicregions. While grazing often involves clearing inwetter regions, the most extensive grazing in thecountry is on native vegetation in the arid andsemi-arid zones. Low densities of livestock in aridareas can be at least as damaging to soil, vegetationand fauna as higher densities in wetter regions.This is because the arid rangelands are lessproductive and so have a much lower carryingcapacity for stock. It is also possible that stockgrazing in the arid zone has serious impacts onsome restricted ecosystems such as the isolated,relatively moist refugia on which many native aswell as introduced animals rely during droughts(Morton, 1990; Morton et al., 1995).

Commercial forestry affects relatively fewbiogeographic regions and relatively small areas ofthe continent (see Fig. 4.10 and Table 4.5),although the high biological diversity of forestscalls for careful management of logging andassociated activities. Forestry alters hydrology(increasing erosion and sedimentation), removesthe major structural components of the ecosystemsuch as foliage, canopy and root systems andreduces the availability of suitable habitat for manyanimals including forest-dependent endangeredspecies, particularly arboreal mammals.

No national figures are available on the extent ofmining, but the overall distribution of thisthreatening process is indicated by the number ofmajor mines and potentially exploitable mineraldeposits (see Table 4.5 and Fig. 6.3). Althoughsome mines are extensive, the total area of landdirectly affected by mining in Australia is smallrelative to the other threatening processes shown inthe table. Much progress has been made in recentdecades with techniques for rehabilitation of minedsites, although serious impacts from some minedareas persist. These include long-term changes tosoil profiles and topography after sand-mining incoastal dunes. Sand-mining on the coast of NewSouth Wales and Queensland has also destroyedextensive areas of coastal forest, heathland andswamps. Processing of minerals has led to pollutionwith heavy metals in areas such as estuaries inTasmania, with unknown effects on marineorganisms. On land, smelter gases have devastatedvegetation in places such as Queenstown inTasmania (see photograph on page 4-22).

Other threatening processes discussed earlier in thischapter and not covered in Table 4.5 are pollution,introduced species and climate change. Thesepressures do not lend themselves to geographicanalyses in the same way as those in the table and,in the case of climate change, the potential effectsat the ecosystem level are still uncertain.

The important threatening processes in eachterrestrial biogeographic region are summarised inFig. 4.12 (Thackway and Cresswell, 1995). Theresults support the analyses in Table 4.5 regarding


4-27

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. . . . . .

HLandsat image of part of the New

South Wales North Coastbiogeographic region; altogether,about 37 per cent of the region iscleared, but, as the image shows,

clearing has been highlyselective. Some environments are

still completely forested whileothers have almost no natural

vegetation remaining.

the relative extent of clearing, grazing, forestry andmining. They also emphasise the widespreadproblem of feral animals and weeds for natureconservation at the regional level and indicate thatland managers in many regions perceive altered fireregimes as an important issue.

The information indicates that all biogeographicregions have been affected to some extent by oneor more threatening processes. Some have beenlargely altered from their pre-European conditionand others severely changed over small areas. Whileit is not possible to create a reliable index ofecosystem condition from these data, several piecesof information help to illustrate the condition ofterrestrial ecosystems in Australia.

A general recognition that some ecosystems aremore prone to serious impacts than others has ledto a process for proposing and listing endangeredecological communities under the EndangeredSpecies Protection Act 1992. In New South Wales,Benson (1991) has rated major vegetation groupsaccording to reservation status and degree of threatin a similar way to previous ratings for plantspecies (Briggs and Leigh, 1988). Of 432vegetation groups, he considered 27 (six per cent)to be endangered and 84 (19 per cent) to bevulnerable. A national view comes from assess-ments by State and Territory conservation agenciesof the overall condition of each biogeographicregion (Thackway and Cresswell, 1995) (see Table4.6). Only five regions (six per cent) are consideredto be largely natural with no significant impacts.Alteration is widespread in 56 (70 per cent) andalmost complete in 16 (20 per cent).

Analysis of major threatening processes gives noindication of the extent of impacts on fresh-waterhabitats. Large areas of Australian wetlands havebeen seriously altered by factors such as drainage,filling, alteration of stream flows, changed burningregimes and invasion by weeds and introducedanimals (Pressey and Adam, 1995). Overall, thegreatest loss and degradation of wetlands andimpacts on flowing waters have occurred inagricultural districts (see Chapter 7).

Table 4.7 summarises the condition of marineecosystems for each interim marine region. Formore detail on marine and estuarine habitats, seeChapter 8.

Protected areasThe condition of ecosystems can sometimes also beinferred from the extent to which they arerepresented in protected areas. Like threateningprocesses, the patterns of protected-area coveragevary widely between biogeographic regions. Thereis no clear geographical pattern (see Table 4.5 andFig. 4.13), but many biogeographic regions arebelow the 10 per cent level of representationrecommended by the IUCN. This assessment sayssomething about the need for more protected areasand the degree to which regions are separated fromthreatening processes. However, the figures need tobe qualified carefully. Extent is not equivalent toeffectiveness for protecting biodiversity for anumber of reasons.


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. . . . . . . . . .

0 10 20 30 40 50 60Agriculture

Clearing

Ferals

Fire

Forestry

Grazing

Mining

Salinisation

Tourism

Urbanisation

Weeds

Number of terrestrial bioregions

Figure 4.12 Number of terrestrial biogeographic regions in which each of 11threatening processes are considered important by State and Territoryconservation agencies

Source: Thackway and Cresswell, 1995.

Figure 4.13 Percentage of biogeographic regions covered by natureconservation reserves

Source: AUSLIG; compiled by ANCA. Tenure coverage at a scale of 1:5 million.

Assessment by State and Territory conservation agencies No. of regions

Natural ecosystems dominant with no known risk 5

Natural ecosystems dominant with no widespread degrading land uses but processes of disturbance present 19

Natural ecosystems present but coexisting with pastoral or timber industries 40

Modified ecosystems dominant with natural ecosystems occupying a very small proportion of the regions 16

Source: Derived from Thackway and Cresswell, 1995.

Table 4.6 Assessments of the condition of terrestrial biogeographic regions

45 – 60 30 – 45 15 – 30 1 – 15 0 – 1

area of conservation reserves (%)

Major ecosystems are heterogeneous in terms ofphysical and biological characteristics. High overallpercentages in reserves can mask the fact that muchinternal variation is unprotected. In north-easternNew South Wales, for example, about seven percent of the region is covered by national parks andnature reserves but some environments areprotected poorly or not at all (Pressey, 1995). High levels of bias in the distribution of reserveswithin ecosystems are common in Australia(Thackway and Cresswell, 1995). Within manyecosystems, protected areas are concentrated inenvironments least prone to disturbance fromintensive land uses while the most vulnerableenvironments are missed (see the box on page 4-52).

The effectiveness of protected areas also dependson the types of threatening processes operating,funding for management and the size andboundaries of the areas. Strict reserves are generallygood at preventing the effects of clearing, grazing

by domestic stock, forestry and mining. For otherthreatening processes, they are less useful. Reservesdo not protect against introduced species withoutintensive management to control weeds and feralanimals. They can be subject to run-off andsedimentation from surrounding land uses if theirboundaries are not aligned with catchments. Nomatter how well managed the reserve itself, speciescan be lost if their food sources in one season areoutside the reserve and lost to clearing. Species canalso be lost if reserves are too small to maintainpopulations of sufficient size to escape theproblems of chance population changes that leadto extinction. In fragmented landscapes, onlyrelatively small areas of natural habitats remain.Although this limits the viability of some species,many others will persist. Fragments offer the onlychance of protecting parts of ecosystems that areheavily cleared and are vitally important forconserving biodiversity.


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. . . . . .

North CoastEstuaries and coast generally in good condition. Impact of prawntrawling not known but large amounts of bycatch are discarded.

North West CoastCoast and estuaries generally in good condition. Some wetlandsdestroyed for salt production. Significant traffic in bulk carriers for gasand iron ore. Impact of prawn trawling not known. Offshore, the seabedis recovering from damage from fish trawling.

Central West CoastCoast generally in good condition. Impact of prawn trawling and lobsterfishing not known.

Lower West CoastEstuaries in the south are eutrophic. Inshore waters generally in goodcondition, especially in the north. The impacts of a large commercialrock lobster fishery and extensive recreational fisheries are not known.A natural predator (Drupella) is damaging corals.

South West CoastLocalised pollution, severe in some places, has been reduced in recentyears. Impacts of fisheries for shark and abalone as well as a purseseining fishery are not known. Inshore waters in good condition.

Great Australian BightCoastal waters generally in pristine condition.

South Gulfs CoastGulf St Vincent and northern parts of Spencer Gulf are polluted bynutrients and heavy metals. Major loss of seagrasses associated withsewage discharges. Heavy recreational and commercial fishing pressurein finfish, abalone and lobster. This pressure is exacerbated by large-scale illegal fishing for high value shellfish. Impacts of the prawn trawlfishery are unknown.

Bass StraitBass Strait has exceptionally high biodiversity of seabed organismswhich, in the case of Port Phillip Bay, appear to be crucial in preventingeutrophication from the high input of nutrients. Extensive seagrass losshas occurred in Westernport Bay, possibly through siltation or pollution.Other impacts include introduced marine pests and scallop dredging.Effects of the large recreational and commercial fisheries on finfish andabalone are not known but populations of rock lobsters have declinedand poaching of shellfish is increasing the pressure of harvesting.

Tasmanian CoastSome inshore areas such as the Derwent estuary are badly polluted byheavy metals. Introduced species such as starfish, macroalgae anddinoflagellates are posing threats to a large aquaculture industry. Thehigh wave energy coasts are in good condition. Impacts of largeabalone and lobster fisheries are not known.

North East CoastMuch of the coast is adversely affected by run-off of nutrients and siltfrom coastal catchments. Extensive urban development in the south andcentral areas have affected coastal habitats. There has been a majorloss of wetlands through ponding of coastal flats for pastures. Impactsof the large trawl fishery for prawns and scallops are not known.

Lower East CoastExtensive impacts from urban and tourist developments, agriculture,and commercial and recreational fishing on the estuaries which aresubject to pollution. The coast is mainly in good condition except nearcentres of population. Impacts of fish and prawn trawling are notknown.

Central East CoastExtreme impacts from urban and tourist developments, agriculture,andcommercial and recreational fishing on the estuaries which are subjectto pollution. Acid sulfate soils are a problem for water quality caused bydrainage of the coastal floodplains. Impacts of prawn trawling notknown.

Great Barrier ReefSubject to an overall management plan with zoning for conservation,tourism, fishing and research. Generally in good condition but therehas been loss of coastal coral reefs, apparently from nutrientenrichment of coastal waters due to nearby land use. Impacts of prawntrawling and recreational and commercial line fishing are not known.

Gulf of CarpentariaGenerally pristine but localised impacts from dredging for port access.Impacts from prawn trawling in coastal waters are not known but largeamounts of bycatch are discarded.

North West OceanicGenerally pristine. Adverse impacts could come from the offshoreextraction of gas and petroleum

West OceanicApparently pristine

South OceanicLongline fishery in the south affecting seabirds. Impacts of finfish trawlfishery in the Bight are not known.

South East OceanicDeepwater seabed in the northern section is generally pristine.Deepwater trawl fisheries (up to 1000 m depth) in the south onseamounts could have adverse impacts on seabed fauna. Longlinefishery around the edge of the continental shelf adversely affectingseabirds.

North East OceanicPristine.

Table 4.7 Summary of condition of marine regions

The state of species diversityOf the 12 nations in the world that contain majorrepositories of species diversity, Australia is the onlydeveloped country. Others include Indonesia withits wealth of islands and different habitats, Zaire inequatorial Africa and Brazil with its expanses ofrich tropical rainforests, rivers and mountains. Thestate of species diversity in Australia — particularlythe large proportions of some groups that arethreatened by the pressures outlined earlier — iscause for national concern.

The species is the basic unit of biologicalclassification. It is defined as a group ofinterbreeding (or potentially interbreeding) naturalpopulations that are reproductively isolated fromother such groups. Certainly for organisms likelarger plants and animals this is a useful definition.For micro-organisms, however, it posesconsiderable problems with identification. Thespecies concept is difficult to apply to organismswith different modes of reproduction from the‘higher’ organisms. Even some larger life formssuch as algae and lichens are under-represented incensuses of biodiversity because of problems ofidentification.

Species inventoryDespite these difficulties, we still need to estimatethe extent of biodiversity. To do this, we usuallycount published, recognised species. For groupsthat are poorly collected and described, we useestimates of species richness based on the rate atwhich new species are being discovered anddescribed (see Fig. 4.14). This rate is high and notdiminishing. Table 4.8 illustrates the strong bias inknowledge towards large, conspicuous life formsand shows that most biodiversity is either invertebrateor microbial. Australian flowering plants arereasonably well known, as are the vertebrateanimals, but many of our invertebrate groups arepoorly known — both poorly collected and not yetadequately described. However, even forconspicuous life forms, new species are still beingdiscovered (see the box on the Wollemi pine).

The outlook is not good for those groups oforganisms where scientists estimate only a smallfraction have been described. Many of these speciesmay become extinct before they are collected anddescribed. This lack of information (highlighted onpage 4-51) about something as basic as inventorypoints out one of the most important issuesrelating to biodiversity — our ignorance. It isextremely difficult to respond to changes in thestate of biodiversity if we do not possess the basicinformation about what it is and how it isdistributed. The best approach may be to selectgroups for study that have known biologicalsignificance rather than trying to catalogue parts ofall groups.

Australia is one of the world’s six floristic realms —regions of the world supporting a characteristicflora. Most of our plant species are found naturallyonly here. However, the special nature of our florais not limited to its global uniqueness. We havesome of the world’s most primitive plants, nowfound only in the rainforests of northern Australia.

Much of our terrestrial vegetation is dominated byeucalypts and acacias. Most forests and woodlandsfeature several species of eucalypts, while acaciasdominate the extensive shrublands of the inland.Each genus has more than 700 species, almost allof which occur naturally only here. Neither groupis distributed evenly across the continent. Theacacias are particularly abundant in the semi-aridregion of southern Western Australia while theeucalypts are richest in the south-eastern region.The recent assessment of the Blue Mountains inNew South Wales for World Heritage Listingshowed that parts of this area contain the greatestvariety of eucalypt species anywhere.

The animal kingdom provides similar strikingexamples. Australia has two of the only threespecies of monotremes (egg-laying mammals), ithas a large proportion of the living marsupials(pouched mammals) and it is the only nation tohave the large arid-adapted kangaroos.

The numbers of taxa listed in different families ofplants depend on the extent to which they havebeen studied. Recent research on eucalypts forexample, has doubled the known number of


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. . . . . . . . . .

Major group Estimated no. Percentage of species described

Micro-organisms

Protozoans 65 000 40

Fungi 160 000 5

Bacteria 40 000 0.1

Invertebrates

Arthropods

Coleoptera (beetles) 30 000 67

Lepidoptera (moths and butterflies) 20 000 53

Hymenoptera (ants, wasps and bees) 23 000 33

Diptera (flies and mosquitoes) 11 000 75

Other insects 15 000 20

Arachnids (e.g. spiders and mites) 39 000 14

Crustaceans (e.g. crabs and prawns) 18 000 5

Springtails 2 500 14

Other arthropods ? ?

Molluscs (e.g. snails, oysters, squid) 19 000 ?

Sponges 1 400 28

Nematodes 150 000 1

Other invertebrates ? ?

Vertebrates 5588 90+

Plants

Higher plants 20 000 90+

Algae 22 000 50

Estimates were taken from several published sources, each of which is not comprehensive. For somegroups the level of knowledge is so poor that estimates are unavailable and are indicated by ‘?’. Sources are Kennedy, 1990; Williams, 1990; Castles, 1992 and Biodiversity Unit, DEST, 1994. Updated information was obtained from CSIRO Division of Entomology, Australian Museum, QueenslandMuseum and ABRS.

Table 4.8 Estimated extent of Australia’s species diversity and of thoseformally described

species. Our knowledge of the distribution ofspecies is also incomplete; for some groups, a mapat one degree resolution is unreliable. Even forwell-known groups, the data become patchy as wemove to finer scales. In one of the best surveyedparts of Australia, the south-east forests of NewSouth Wales, all the survey plots add up to only0.1 per cent of the landscape.

Number and distribution of speciesOf the four groups of vertebrate animals for whichdata are available, bird species are most numerousalong the east coast and in the south-easternregion; their numbers diminish in the arid interior(see Fig. 4.15). In contrast, reptile species-richnessis high in the arid zone and the tropics. Thepattern for mammals is different again, with highnumbers along the eastern margin of the continentand in the far north, the south-west and part of thearid zone. Lastly, amphibian species-richness ishighest for parts of the eastern region and acrossthe north, with some pockets in the south-west.

Our seas also support many forms of life unique tothis region. For example, Australia has an extremelydiverse flora of macroalgae (seaweed). Temperatewaters alone contain nearly 1200 species, of which62 per cent are endemic. Bass Strait has more than500 species. The introduction of Japanese kelp toTasmania, probably in ballast water, appears to bethreatening indigenous macroalgae because it growsrapidly and smothers other species. This invader isspreading along the Tasmanian coast at a rate ofbetween four and 40 km a year.

Australia has about 30 species of seagrasses (seepage 8-24 and Table 8.8). They form rich beds inshallow water and are important as nurserygrounds for the juvenile stages of many species ofcrustaceans and fish. Seagrasses have suffered severereductions in recent years from a variety of causes,including pollution and siltation as well as naturalcauses such as floods and cyclones. The mostrecent major loss resulted from the construction ofthe third runway at Sydney Airport, whichdestroyed an important seagrass bed in New SouthWales by filling part of Botany Bay.

Although a high proportion of our temperatemarine plants and animals are endemic, mosttropical marine fauna are Indo-West Pacific. Thismeans that many species are also found in theIndian and Western Pacific Oceans. For example,the blue swimmer crab (Portunus pelagicus), alsoknown as the manna or sand crab, occurs in thePacific and Indian Oceans and the Red Sea and haseven extended into the eastern Mediterranean bymigrating through the Suez Canal. Such widedistributions have, however, not lessened the threatto many species. Massive clearance of mangroves inSouth-East Asia for aquaculture as well asdestructive fishing practices, including the use ofexplosives on coral reefs, have severely depletedmany tropical marine habitats in the Indo-Pacific.

Australia now has the largest intact coral reef in theworld and some of the best-preserved mangroveforests. Some species, such as turtles and dugongs


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. . . . . .

fish

spiders

flies

nematodes

beetles

1979 1980 1981 1982 1983 1984 1985 1986 1987 19880

500

1000

1500

2000

2500

3000Number of new species described

Figure 4.14 The number of new species described each year world-wide forfive groups

The Wollemi pine — a relic from the age of dinosaursThe discovery in December 1994 of a new kind of tree near Sydneycaused great excitement, as Australia’s flora is considered to be wellknown. The Wollemi pines (Wollemia nobilis) reach about 35 m inheight with a main trunk up to one metre in diameter. The discoveryof a new species of tree, especially one that grows to such animpressive height, is extremely unusual. The habitat of the trees —protected steep-sided canyons north-west of Sydney, which acted asrefuges from fires that frequently burn the adjacent plateaus —contributed to their continued existence. The tree, given thecommon name of ‘pine’, is a conifer but is closer to the NorfolkIsland pine than to the true pines. The discovery is a dramaticdemonstration that parts of our biological heritage remain unknown.

Source: derived from World Conservation Monitoring Centre, 1992.

(Dugong dugon), may eventually survive only inAustralian waters. Hence, the conservation ofAustralia’s tropical marine flora and fauna is ofglobal significance.

Some of the sea’s most-threatened species are edibleones that, unlike most marine species, are (or were)abundant. Modern fishing techniques are extremelyefficient and overseas experience shows it ispossible to fish formerly abundant species to nearextinction. Many exploited marine species are nowsubject to management plans that seek to exploitthem at sustainable levels or try to rebuild depletedstocks. Nevertheless, several formerly abundantanimals have been reduced to seriously low levels.They include eastern gemfish and eastern rocklobster off New South Wales, school shark andsouthern rock lobster off Victoria, King Georgewhiting off South Australia and southern bluefintuna in the Southern Ocean.

Status of speciesAll groups of higher plants and vertebrates havespecies that are highly threatened. The realsituation is worse than indicated in Table 4.9because many groups include species in decline.The cumulative effect on birds of the threateningprocesses will be accelerated loss of bird speciesparalleling the loss of mammal species (Recher and


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. . . . . . . . . .

Figure 4.15 The distributions of species-richness for four vertebrate groups

Amphibians Reptiles

Birds Mammals

Cape York Peninsula

Atherton Plateau

Eastern Queensland

Arnhem Land

Kimberley Plateau

Northern Desert

Eastern Desert

Western Desert

Pilbara

South Western Forest

Eyre Peninsula

Adelaide

Tasmania

South Eastern Forest

Figure 4.16 Areas of endemism based on distribution patterns of birds

Each of the 14 recognised areas has a unique assemblage of bird species. Source: Cracraft, 1991.

33 – 48 25 – 36 13 – 24 1 – 12

no. of species 91 – 120 61 – 90 31 – 60 1 – 30

no. of species

286 – 380 191 – 285 96 – 190 1 – 95

no. of species 67 – 80 41 – 60 21 – 40 1 – 20

no. of species

RGrid cells (one degree of latitudeby one degree of longitude). The

boundaries indicate InterimBiogeographic Regions for

Australia.

Source: compiled by ANCA

Lim, 1990). Many species of frogs are declining inpart of their range and several, including theunique gastric brooding frog (Rheobatrachus silus),have disappeared in recent years (Tyler, 1994).Tables 4.9 to 4.18 and Fig. 4.18 indicate thecurrent conservation status of various groups ofAustralian plants and animals.

Australia’s record of mammal species extinctions isthe worst for any country. In the past twocenturies, the country has lost ten species of theoriginal marsupial fauna of 144 species and eightof the 53 species of native rodents (see Table 4.17).More than one hundred mammal species areconsidered endangered, vulnerable or potentiallyvulnerable. This number includes marine mammalssuch as dugong. Some marine species, like whalesand seals, which were hunted in Australian watersuntil recently, now show signs of recovery. Thesightings of whales close to the coast, even withinSydney Harbour, herald a positive response toembargos imposed on harvesting.

Many species were illustrated or evenphotographed before becoming extinct. Forexample: the Tasmanian tiger (Thylacinuscynocephalus) — last specimen died in 1936; thepig-footed bandicoot (Chaeropus ecaudatus) — lastrecorded sighting 1907; the desert rat kangaroo —

(Caloprymnus campestris) — 1935; lesser bilby(Macrotis leucura) — 1931; long-tailed hopping-mouse (Notomys longicaudatus) — 1901; lesserstick-nest rat (Leporillus apicalis) — 1933; AliceSprings mouse (Pseudomys fieldi) — 1895; DarlingDowns hopping-mouse (Notomys mordax) —1840s.

Not surprisingly, the main regions containingthreatened species coincide with those of highspecies-richness. However, there are some


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. . . . . .

Figure 4.17 Number of species of fish, seagrasses, prawns and mangroves by marine region

Fish Seagrasses

Prawns Mangroves

421 – 560 281 – 420 141 – 280 0 – 140

no. of species

> 10 5 – 9 1 – 4 zero

no. of species

27 – 35 18 – 26 9 – 17 0 – 8

no. of species

24 – 35 12 – 23 1 – 11 zero

no. of species


The lesser bilby (Macrotisleucura) was last recorded in

1931.

P


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. . . . . . . . . .

Conservation Number of Percentage of status species estimated total

Presumed extinct 0 0

Endangered 9 4.1

Vulnerable 8 3.7

Poorly known 19 8.8

Rare 36 16.6

Approximately one-third of the species are either threatened orrare. Source: derived from Wager and Jackson, 1993.

Table 4.10 The conservation status of Australia’sfreshwater fish

Conservation Number of Percentage of status species estimated total

Presumed extinct 3 1.5

Endangered 10 4.9

Vulnerable 19 9.4

Indeterminate 2 1.0

A total of 203 species of Australian amphibians has been identifiedfrom a world total of approximately 4000. It is estimated that afurther 25–30 species in Australia await discovery.Source: derived from Tyler, 1994.

Table 4.12 The conservation status of Australia’samphibians

Major group Estimated Percentage Number Number of Number of Number ofnumber of endemic presumed endangered vulnerable naturalised

of species species extinct species species (introduced) (since 1788) species

Flowering plants 20 000 85 76 301 708 1500– 2000

Fish

freshwater 195 90 0 9 8 21

marine 4000 13 0 0 - 8(tropical inshore)

85 (temperate inshore)

Amphibians 203 93 3 10 19 1

Reptiles 770 89 0 11 40 2

Birds 777 45 201 25 25 32(1074 species and

subspecies)

Mammals (terrestrial) 268 84 19 25 18 25

1. Nineteen once existed on Australian territorial islands, including Lord Howe and Norfolk Islands; only one is extinct on the mainland.

Conservation Number of Percentage ofstatus species estimated total

Presumed extinct 0 0

Endangered 11 1.4

Vulnerable 40 5.2

Rare or insufficientlyknown 148 19.2

A total of 770 species of Australian reptiles has been identifiedfrom a world total of approximately 6500 species. Source: derived from Cogger et al., 1993; H.G. Cogger (pers.comm.).

Table 4.11 The conservation status of Australia’sreptiles

Table 4.9 The status of flowering plants and vertebrate animals

The meaning of rarity and threatRarity, while it can predispose some species toextinction, can be a natural, inherentcharacteristic that has nothing to do with thepressures discussed earlier in this chapter. Insome cases species are rare because of humanpressures, particularly habitat destruction.However, rarity may be the result of a naturalcondition such as specialised habitatrequirements. Most marine species, forexample, are rare. A large proportion of theflora of south-western Western Australia isendemic to the region and many of thesespecies are rare. Threat, on the other hand, isexplicitly the result of pressures. Theconjunction of large numbers of species(including many rare ones) and manythreatening processes — especially vegetationclearance for intensive agriculture — leadsinevitably to large numbers of threatenedspecies.


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. . . . . .


Presumed extinct 3 ?

Endangered 40 ?

Vulnerable 78 ?

Indeterminate or insufficiently known 291 ?

The number of non-marine invertebrates is unknown, hence nopercantage of total can be calculated.

Table 4.13 The conservation status of Australia’snon-marine invertebrates

Table 4.17 The conservation classification of Australian terrestrial nativemammals recorded since 1778

Major group No. of described Extinct Endangered Endangered asextant species a percentage of

total extant

Monotremes 2 0 0 0

Marsupials 144 10 19 13.2

Placentals

Dingo 1 0 0 0

Rodents 53 8 6 11.3

Bats 68 1 0 0

Principal sources: derived from Kennedy, 1990 and 1992; Williams, 1990; Castles, 1992; EndangeredSpecies Protection Act, 1992, schedules 1, 2 & 3, July 1994; Biodiversity Unit, 1994 and Census ofAustralian Vertebrate Species, 1994.

Conservation Lichens Bryophytes Algaestatus

Presumed extinct* 2 12 -

Endangered 94 83 -

Vulnerable 74 43 1

Potentially vulnerable 31 12 6

*Not found during recent surveys.Information on the conservation status of these groups is poorand there is insufficient information to nominate any species orcommunities as endangered or rare.Source: ‘Overview of the Conservation of Non-Marine Lichens,Bryophytes, Algae and Fungi’, report for the Endangered SpeciesProgram, ANCA, 1994.

Table 4.14 The preliminary conservation status ofAustralia’s algal, lichen and bryophyte species

Conservation Number of Percentage of status species* estimated total


Endangered 301 1.5

Vulnerable 708 3.5

Rare 1570 7.9

Poorly known 2376 11.9

*The numbers of species of vascular plants listed in the 1995CSIRO Rare and Threatened Plants (ROTAP) publication.

Table 4.15 The conservation status of Australia’shigher plants

Major group Total Presumed Endangered Vulnerable Insufficientlyextinct known

Monotremes 2 - - 1 -

Dasyurids 51 1 6 12 1

Bandicoots and bilbies 11 3 2 4 -

Marsupial mole 1 - - 1 -

Wombats, possums koala and kangaroos 81 6 11 23 1

Australian marsupials are facing many threats. The bandicoots and bilbies are particularly vulnerable. Source: derived from Kennedy, 1992.

Table 4.16 The conservation status of Australiannative rodents



Endangered 6 11.3

Vulnerable 5 9.4

Rare 4 7.5

Insufficiently known 7 13.2

Rodents, along with marsupials, have taken the brunt of mammalextinctions in Australia since European settlement. Source: derivedfrom Lee, 1995.

(566)

(4)(21)

(21)(12)

(19)(97)(41)(94)(26)(20)(21)(30)(21)(20)(3)(4)

(49)(5)

(total no. of subspecies) percentage of total no.

Source: Garnett, 1992b.

0 10 20 30 40 50 60 70 80

insufficiently knownrarevulnerableendangeredextinct

Passerines

SwiftsKingfisher & allies

OwlsFrogmouths & nightjars

Cuckoos & coucalsParrots & cockatoos

Pigeons & dovesShore birds

Rails & alliesGame birds

WaterfowlHawks & falcons

RaptorsPelicans & allies

GrebesPenguins

Albatrosses & alliesRatites

Figure 4.18 The proportion of Australia’s birds (by sub-species) that areextinct, endangered, vulnerable, rare or insufficiently known

Table 4.18 The conservation status of Australian monotremes and marsupials

exceptions. For birds, threatened species are mainlyconcentrated in the south-east, the north and thefar south-west. Reptile species are richest in thearid interior, although threatened species are mostnumerous in the high-rainfall forested south-east ofthe continent. A strong pattern emerges formammal species, with arid Central Australia clearlythe zone of pressure. The amphibian pattern is acluster of discrete regions along the eastern margin.

Figure 4.18 shows the proportions of Australianbirds (by Order) that are presumed extinct,endangered, vulnerable, rare or insufficientlyknown. A similar situation exists for Australia’smammals (see Table 4.17). Alarmingly highproportions of each Order are in one of the threatcategories. Similarly, 17 species of freshwater fish(see Table 4.10) and 29 species of amphibians (seeTable 4.12) are either endangered or vulnerable.Many and varied pressures or threats have led tothis situation. One study has been made of thecurrent and former threats affecting Australianbirds (see Table 4.2). The main differences betweenthe perceived current threats and those thatoperated earlier are: altered fire regime, grazing,forestry operations and shortage of nest hollows.

Looking at the continental distribution ofthreatened plant species (see Fig. 4.20), the south-western region and parts of eastern Australia areclearly regions for concern but action is neededover most of the continent to offset threateningprocesses. Of Australia’s presumed extinct andendangered plant species the overwhelmingnumber are from woodland habitats (Leigh andBriggs, 1994). This reflects both the pressures onthis habitat and its vast geographic extent.Combining woodland and scrub reveals 97instances of endangered plant species — almosthalf the national total for all habitat types.

Figure 4.19 Australia’s threatened vertebrate species

Amphibians Reptiles

Birds Mammals


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. . . . . . . . . .

2 1

no. of species 2 1

no. of species

5 – 6 3 – 4 1 – 2 zero

no. of species

7 – 8 5 – 6 3 – 4 1 – 2 zero

no. of species

Figure 4.20 Numbers of threatened plant species

37 – 48 25 – 36 13 – 24 1 – 12 zero

no. of species

RNumbers of threatened species

from each of the four groupsfor which data are available are

shown. The various threatcategories are combined.Grid cells (one degree oflatitude by one degree of

longitude). The boundariesindicate Interim Biogeographic

Regions for Australia.


RGrid cells (one degree oflatitude by one degree of

longitude). The boundariesindicate Interim Biogeographic

Regions for Australia.


Genetic diversityOne measure of the degree of genetic diversitywithin a species is the recognition of identifiablesubspecies. For example, the dingo (Canis familiarisdingo) is a subspecies of the domestic dog(C. familiaris ). Although most inventories are madeat the species level, the full diversity may be betterexpressed at the subspecies level. For example,worldwide the number of butterfly species isthought to total about 17500; however, thenumber of currently recognised subspecies is closerto 100000. The genus Calyptorhynchus containsfour species of black cockatoo in Australia, but ithas nine recognised subspecies.

Good scientific evidence now exists that, aspopulations decline, the amount of geneticdiversity that remains in them is crucial to theirsurvival. Very often, small populations lose geneticdiversity and, consequently, suffer lowered fertilityand lowered ability to adapt to changingenvironments. Because populations of manyAustralian species have declined through habitatloss or fragmentation, genetic issues are crucial tothe management of biodiversity for conservation.Although there are relatively few Australianexamples, some studies do provide clearillustrations of the genetic effects of habitatdestruction and the consequent declines inpopulation size.

Habitat loss and degradationWhen habitats shrink, populations decline and losegenetic diversity. This reduces their ability tocompete, fight disease or adapt to changingconditions.

Northern hairy-nosed wombatUnlike the more abundant southern hairy-nosedwombat (Lasiorhinus latifrons), which is distributedin forests and grasslands in southern Australia, thenorthern hairy-nosed wombat (L. krefftii ) is anexample of a rare Australian animal that hasexperienced severe loss and degradation of habitatand consequent loss of genetic diversity. It is one ofAustralia’s rarest mammals, existing as a singlecolony of about 65 individuals in Epping Forest,central Queensland.

By using a genetic technique known asmicrosatellite technology, scientists can detectlosses in genetic diversity with astonishing accuracyusing a tiny amount of DNA — the amountcontained in a single wombat hair is enough. Everyindividual or population has a distinct complementof microsatellite labels and scientists have strongevidence that the northern species has lostsignificant amounts of the genetic diversity it oncepossessed (Taylor et al., 1994). The geneticdiversity of the northern species is less than halfthat of the southern hairy-nosed wombat. Becausethe two species are closely related and fill similarecological niches, it is reasonable to expect thatthey should have similar measures of geneticdiversity, especially heterozygosity. The fact thatthey don’t is most likely a direct result of the steepdecline in the number of animals, together with a

process known as genetic drift, which occurs whenthe breeding population is so small that too fewoffspring are born in each generation tosuccessfully carry all of the genetic variability in theparent population.

The population at Epping Forest cannot regain thelost genetic variability except by the long-termprocess of random mutation, but it is hoped thatthe problems associated with inbreeding andgenetic drift can be overcome through carefulmanagement.

KoalaThe koala (Phascolarctos cinereus ) in south-easternAustralia has suffered severe population declinessince European settlement due to loss of habitat.An extensive but ad hoc program of restocking hasled to recolonisation of many regions throughoutits original range. Many of the animals have comefrom the island populations of Westernport Bay inVictoria. These colonies were themselves foundedartificially with low numbers and represent anarrow genetic base.

Comparisons of mainland populations derivedfrom island colonies (restocked populations) andundisturbed mainland populations have shownthat genetic diversity is severely reduced in therestocked populations (Taylor et al., 1991). Thiswork highlights the need to be cautious when re-establishing locally extinct or depleted populationsof endangered species. Thorough characterisationof the genetic variability of remaining colonies willhelp to ensure that diversity is maximised to givenew populations their best hope of survival.

Habitat fragmentationMany kinds of habitats have become greatlyfragmented and, without suitable connectinghabitat, the movement of organisms and themixing of genes are slowed down or stopped. Theresulting isolated gene pools may follow differentevolutionary paths. If they are too small, they losegenetic variability, especially heterozygosity, morerapidly than if they were connected with eachother. Very often small populations isolated fromeach other are like islands, frequently surroundedby inhospitable ‘seas’ of urban or ruraldevelopment (see page 4-13).

Sleepy lizardsThe sleepy lizard (Trachydosaurus rugosus) is a largelizard that bears live young and is found over muchof southern Australia. It experienced a large-scalenatural experiment on the genetic effects offragmentation. As sea levels rose 6000 to 8000years ago, populations were isolated on offshoreislands, preventing gene flow with the mainland.Comparisons of the genetic diversity of island andmainland populations have shown that sufficienttime has elapsed to allow significant geneticdivergence between them (Sarre et al., 1990). Theisland populations lack some rare mainland genes— probably because of genetic drift. Changes inthe smaller island populations have been greaterthan those between mainland populations.


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. . . . . .


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. . . . . . . . . .

Cryptic speciesAnimals that look the same may be a complex of cryptic orhidden species distinguished only by genetic means.

Rock wallabiesThe rock wallabies (genus Petrogale) are found throughoutAustralia. They live in rocky habitats such as cliffs, gorges andboulder outcrops. Researchers have investigated the problemof distinguishing those that are merely races, between whichgene flow can still occur, from those that are true species,where it does not. The most informative genetic techniqueused so far has been cytogenetics, the study of chromosomes.In mammals, all individuals within the same species have thesame number of chromosomes. Also, genes lie along thechromosomes in the same order. Individuals with differentchromosome numbers and different gene orders usuallycannot reproduce. They may mate but their offspring aresterile. This is one of the mechanisms that separates species.

Rock wallabies inhabiting the east coast were thought tobelong to eight races, several of which cannot be distinguishedmorphologically. Each race has distinctive genetic markers,but where their ranges overlap hybridisation has occurred andhybrid animals can be found. However, genes found in thesecontact zones have not spread into the populations outside thezone; thus the races are maintaining their genetic identitydespite these ‘mixed marriages’. In addition, the offspring ofthe hybrids are sterile. The chromosome and sterility datastrongly suggest that these similar-looking animals are, in fact,eight distinct species (Eldridge and Close, 1992).

Two wallabies that look alike but belong to two species: Petrogale assimilus and P. sharmani.

Velvet wormsThe velvet worms or peripatus live in moist habitats such asrotting logs and leaf litter in forests around the southernhemisphere. Peripatus look like caterpillars but they haveantennae and ‘glue guns’ on either side of the jaw with whichthey capture prey. In Australia they occur in the forests ofeastern Australia, Tasmania and south-western Australia.

Velvet worms show little variation in body structure and, untilrecently, Australia was thought to have only eight species, oreight per cent of the world’s species. However, genetictechniques, such as allozyme electrophoresis, have shown thatat least 100 species occur in this country (Briscoe and Tait,1995).

Consequently, the number of recorded velvet worm species inthe world has doubled. Almost everywhere a suitable habitatoccurs, a new species unique or endemic to that area is found.

Single speciesA single species can harbour a broad range of genetic diversityacross its range.

Barramundi The barramundi perch (Lates calcarifer) is a large fish whoserange extends from the Persian Gulf in the west to Australiaand Papua New Guinea in the east. It inhabits fresh-waterponds and rivers, tidal swamps and estuaries and coastal reefs.It can live to 20 years of age and weigh over 50 kg. InAustralia and Papua New Guinea it spends the first six orseven years as a male then metamorphoses into a female,producing 15–45 million eggs per year.

Genetic analysis using allozyme electrophoresis has uncoveredgreat genetic diversity across Australian waters (Shaklee andSalini, 1993). More than 14 genetically distinct stocks havebeen identified so far: seven in Queensland, six in theNorthern Territory and one in Western Australia, and thereare likely to be many more as surveys continue into the moreremote populations of north-western Australia.

A number of factors have contributed to the high degree ofpopulation subdivision. Large gaps between its habitats alongthe Australian coast have restricted dispersal between isolatedbreeding populations. Offshore dispersal of larval and juvenileforms is also limited because the females spawn at the mouthsof estuaries, not offshore.

The degree of genetic variation across the range of thebarramundi and its partitioning into distinct genetic stocksmakes it important that local populations are properlymanaged. If genetic differentiation has occurred, it could wellbe because the local environment requires that the stock inthat region have their own particular set of adaptations.Allowing stocks to mix or moving individuals from one regionto another (for aquaculture or restocking, for example) coulddisrupt a delicate equilibrium brought about by evolution.

Some patterns of genetic diversity

Genetic variation within a single species: Sturt’s desert pea.

Papilionid butterfliesAnother important genetic consequence of habitatfragmentation is known as inbreeding depression.As a population declines and numbers dwindle,matings between related individuals becomeunavoidable. This leads to inbreeding and in manycases a reduction in fitness — inbreedingdepression. The decline in health and inreproductive output causes the population toshrink further, often leading to extinction.

Papilionid butterflies in the rainforests of northernAustralia illustrate the phenomenon. Thesenorthern rainforests persist today as highlyfragmented remnants. Normally wide-rangingspecies of large and beautiful swallowtail butterfliesare now often confined within the remnantpatches. Experimental breeding between relatedindividuals in captivity showed inbreedingdepression in three species (Orr, 1994). Theproportion of eggs hatching, the number ofcaterpillars surviving to adulthood and growth rateswere all severely affected in offspring from relatedparents. These results show that even wide-rangingspecies can be susceptible to the effects ofinbreeding depression and reserves must be largeenough to prevent it.

Other processes that lead to steep declines in the sizeof populations are excessive harvesting, as in somefisheries, and the presence of introduced predatorssuch as foxes and cats and of introduced diseases.

Introduction of exotic genesMating between organisms that are related butgenetically distinct may result in hybrids and theloss of the identity of the original gene pools. Theescape of domestic dogs into the Australian bushand their mating with the dingo has led to avariety of hybrids. Changes in the patterns ofgenetic diversity of the dingo have probablyoccurred in some areas of Australia as a result.

Changes in gene-flow vectorsAnimals feed on many Australian plants andpollinate them. After brushing against flowers andreceiving a dab of pollen, many kinds of animalsfunction as pollen vectors, depositing pollen onneighbouring flowers. Animal pollinators includehoneyeaters, pygmy possums, fruit bats and nativebees. Likewise, animals that feed on fruit spreadseeds in their droppings, and many seeds havespecial adaptations that prevent them from beingdestroyed during digestion.

The effects of changes in or losses of pollen andfruit vectors are not well understood. Theintroduced honeybee appears to compete withnative bees, removing nectar and monopolisingflowers. However, it is not known whether theeffects on native bees are serious. Australianrainforest plants depend heavily on fruit bats forboth pollination and seed dispersal, but there islittle information on the effects of changes in theirnumbers and distribution on forest plant species.However, elsewhere in the world, losses of pollenand seed vectors have had drastic effects on plantpopulations.

ResponseSince the 1980s a number of major internationalagreements (briefly outlined below) have addressedbiodiversity. The United Nations has declared anInternational Day for Biological Diversity(29 December). As a result, biodiversity has becomethe focus for a number of national policy statementsand is now influencing decisions being made atnational, State and local levels. This increases thescope for integrating biodiversity with social andeconomic considerations. It is also being institution-alised in Australia through legislation such as theQueensland Nature Conservation Act 1992 and theSouth Australian Native Vegetation Act 1992.

In 1987, the General Assembly of the UnitedNations adopted a report from the WorldCommission on Environment and Development(1987) (the Brundtland Report or Our CommonFuture). This inspired the National Strategy forEcologically Sustainable Development, agreed toby all Australian governments in November 1992(see the box on page 4-40). One of the three coreaims of the Strategy is to ‘protect biologicaldiversity and maintain essential ecological processesand life support systems’. A key strength of thisstrategy is its potential to bring together the social,economic and environmental aspects of society’sgoals and aspirations.

The Brundtland Report fostered the concept ofsustainable development and paved the way for theEarth Summit in Rio de Janeiro in June 1992. Oneof the outcomes of the summit was thepresentation for signature of the Convention onBiological Diversity. The key aims of thisconvention are:

‘The conservation of biological diversity, thesustainable use of its components and the fair andequitable sharing of the benefits arising out of theutilization of genetic resources, including byappropriate access to genetic resources and byappropriate transfer of relevant technologies, takinginto account all rights over those resources and totechnologies, and by appropriate funding.’

The spirit of this convention is reflected in theNational Strategy for the Conservation ofAustralia’s Biological Diversity (Commonwealth ofAustralia, 1996) that has been developed byCommonwealth, State and Territory governments.Its aim is to bridge the gap between currentactivities and the effective identification,conservation and management of Australia’sbiological diversity.

The strategy recognises the significant cultural,economic, educational, environmental, scientificand social benefits of biodiversity and the need formore knowledge and understanding of ourbiodiversity. It contains nine principles to be usedfor its implementation. These note thatbiodiversity is best conserved in situ and that,although levels of government have clearresponsibility for the conservation of biodiversity,the cooperation of conservation groups, resourceusers, indigenous peoples and the community ingeneral is critical to its successful conservation.


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. . . . . .

Types of responsesResponses to pressures on Australia’s biodiversityare generally based on the assumption that naturalresources can be managed sustainably to balanceconservation and development. However, much isyet to be learned in order to achieve this ideal (seethe box below). Societal responses to themanagement of biodiversity can be grouped intothree broad categories: government, communityand industry. Many responses involve feedback andcollaboration between different sections of societyand there is considerable overlap. Although someof the responses discussed in this section are notspecifically targeted at biodiversity, they all affect it.

Government responses Australia is a party to numerous majorinternational agreements (see the box opposite).

National approaches by governmentsIn 1989, the Prime Minister committed theCommonwealth Government to preparing anational strategy for the conservation ofbiodiversity. Subsequently, conservation ofbiodiversity has become a major focus for policy. Itis a core aim of the National Strategy forEcologically Sustainable Development and aprinciple of the Intergovernmental Agreement on

the Environment (IGAE, see Chapter 2 fordetails). A number of policy frameworks fordifferent sectors have included conservation ofbiodiversity; for example, the National ForestPolicy Statement, the draft National RangelandManagement Strategy and the NationalEcotourism Strategy.

The National Strategy for the Conservation ofAustralia’s Biological Diversity has been signed bythe Commonwealth and all State and Territorygovernments (Commonwealth of Australia, 1996).It provides an integrated framework of actions tostrengthen conservation efforts across Australiawith the object of protecting biological diversityand maintaining ecological processes and systems.It covers six main areas:

• Conserving biological diversity across Australia

• Integrating biological diversity conservationand natural resource management

• Managing threatening processes

• Improving our knowledge

• Involving the community

• Australia’s international role

The Commonwealth established the BiodiversityUnit in the Department of the Environment, Sportand Territories to coordinate the development andimplementation of the strategy. Ultimateresponsibility for the strategy at the national levelrests with the Australian and New ZealandEnvironment and Conservation Council. TheBiological Diversity Advisory Council has beenestablished to report to governments on issuesrelated to the conservation of biodiversity and thefurther development and implementation of thestrategy. Its aim is to ensure governments receivetimely advice from sources such as relevantindustries, the scientific community and non-government organisations.

While the strategy takes a broad approach to theconservation of biodiversity, it has also beennecessary to provide a specific focus on endangeredand vulnerable species, and on ecologicalcommunities and the threats acting on them.Commonwealth, State and Territory governmentshave finalised the Conservation of AustralianSpecies and Ecological Communities Threatenedwith Extinction: The National Strategy.

Funding The cost of conserving biodiversity forms part ofthe overall cost of environmental protection. Thisincludes funds spent on activities as varied asimproving water quality, waste management,preventing and mitigating soil erosion, combatingweeds, pests and feral animals, rehabilitation ofmine and industrial sites, research and educationand programs such as Landcare. Australian andoverseas studies show a high benefit-to-cost ratiofor money spent on the environment, with benefitscoming, for example, from enhanced tourismopportunities, improved land values and publichealth as well as reduced costs of land managementand agriculture (Driml, 1994).


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. . . . . . . . . .

Ecologically sustainable development and biodiversity: theneed for researchOne of the core objects of the National Strategy for EcologicallySustainable Development (ESD) is to protect biological diversity andmaintain essential ecological processes and systems. However, therelationships between ESD and the protection of biodiversity are not wellunderstood and it is widely assumed that, once a human activity appearssustainable, biodiversity will be protected. Some support for thisassumption comes from conservation practices such as the reforestation offarmland, the establishment of wildlife corridors and the introduction offorestry and fishery practices sympathetic to wildlife. Although theseinitiatives are important, we still need research to measure their success inachieving conservation of biodiversity.

Two examples illustrate the need for research. First, some of the species ofsoil bacteria required to produce leguminous crops are well known, butthe contributions of most soil fungi and invertebrate species to the successof these crops are less well understood. In the second case, many nativeinsects are required for crop pollination, but the ecological processes thatsustain them and the other species that contribute to their availability arerarely known in any detail. In these contexts, it is likely that once thosecomponents of biodiversity necessary to grow a particular crop areworking, and apparently sustainable, other components that do not appearto be necessary for growing it will be ignored. This would meansustainable development without biodiversity conservation.

Sustainability anticipates the needs of Australians many generations intothe future. The only way to determine whether new production methodsare sustainable is to establish well-designed experiments now, which, whenmonitored in the future, will identify the improvements and changesrequired to meet both production and conservation goals. Knowledge ofsustainability, by definition, comes only with time. To obtain the baselinedata requires an immediate start on the research and monitoring requiredto ensure that ESD and biodiversity conservation really are achievedtogether.

However, despite the benefits, only a smallproportion of government expenditure isspecifically directed to the environment. Forexample, only 0.52 per cent of the CommonwealthGovernment’s budget in 1994–95 was allocated tothe Department of the Environment, Sport andTerritories and of the DEST budget, only 29 percent was allocated to the environment(Commonwealth of Australia, 1994). Evenallowing for funds spent on the environment bythe States, Territories and other Commonwealthbodies such as the Department of PrimaryIndustries and Energy, the total spent on theenvironment is a small proportion of the totalCommonwealth, State and Territory budgets.

Policy responsesGovernments have a range of policy instrumentsfor the conservation of biodiversity. These includelegislative, economic and social instruments.

LegislationNo broad Commonwealth, State or Territorylegislation for the conservation of biodiversitycurrently exists. However, governments have, overmany years, recognised the need to manage andconserve the environment and natural resourcesthrough legislation. Laws relevant to themanagement of fauna and flora date back morethan 100 years, although only since the late 1960shas legislation increased significantly . Fewexamples, however, specifically identify theconservation of biodiversity. Some key legislation isgiven in the box on page 4-43.

The effectiveness of legislation varies widely and, ingeneral, depends on the capacity and willingness ofthe responsible agency to administer the powersprovided by the legislation together with thepolitical agenda of the government of the day. Thebox on page 4-43 clearly shows the central role ofthe States and Territories in conservation ofbiodiversity.

One example of Commonwealth legislation toassist in the conservation of particular species andecological communities is the Endangered SpeciesProtection Act, which came into force in 1993.This Act lists endangered species and commits thegovernment to producing recovery plans for theirprotection. The total annual budget of theEndangered Species Program in 1994–95 was $5.5million. This level of funding is inadequate giventhat the recovery plan for one species alone, thewestern swamp tortoise (Pseudemydura umbrina),will require about $100 000 per year. With 148recovery plans in operation and more planned (seeTable 4.19), the Endangered Species Program isgrossly underfunded.

Individual States and Territories have their ownprotection programs. In Western Australia, forexample, the Department of Conservation andLand Management is using poisoned baits tocontrol foxes that prey on native animals as part ofa 10-year recovery plan aimed at protecting thechuditch (Dasyurus geoffroyi), the numbat(Myrmecobius fasciatus) and other native animals.

Research and educationMany organisations are involved in research relatedto biodiversity. The Commonwealth funds suchresearch through CSIRO and the Environmentportfolio. CSIRO has established a multi-divisionalprogram to improve coordination and focus forresearch on biodiversity. Research on biodiversityhas focused on:

• strengthening knowledge of the role ofbiodiversity in ecosystem function

• planning and management regimes that betterintegrate biodiversity conservation considerations


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. . . . . .

International and regionalbiodiversity agreements to whichAustralia is a party

• International Convention for the Regulationof Whaling (1946)

• Ramsar Convention on Wetlands ofInternational Importance (1971)

• Washington Convention on InternationalTrade in Endangered Species of Wild Faunaand Flora (CITES) (1973)

• International Convention for the Preventionof Pollution from Ships (1973 and its 1978protocol) (MARPOL 73/78)

• Convention Concerning the Protection ofthe World Cultural and Natural Heritage(1974)

• Japan Australia Migratory Bird Agreement(JAMBA) (1974)

• Convention on Conservation of Nature inthe South Pacific (Apia) (1976)

• Bonn Convention on Conservation ofMigratory Species of Wild Animals (1979)

• Convention on the Conservation ofAntarctic Marine Living Resources (1980)

• London Convention on the Prevention ofMarine Pollution by Dumping of Wastes andOther Matter (1985)

• China Australia Migratory Bird Agreement(CAMBA) (1986)

• Convention for the Protection of the NaturalResources and Environment of the SouthPacific Region (SPREP) (1986 and relatedprotocols)

• Basel Convention on the Control ofTransboundary Movement of HazardousWastes and their Disposal (1989)

• Convention on Biological Diversity (1992)

• Framework Convention on Climate Change(1992)


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Australia’s biodiversity includes species of birds, marinemammals and fish that depend on areas outside Australia forpart of their life cycle.

Migratory species are subject to pressures in areas other thanthose under Australian jurisdiction, and so theCommonwealth Government has negotiated several bilateralagreements, for example the Japan and Australia MigratoryBird Agreement and the China and Australia Migratory BirdAgreement. Following meetings between Australia, China andJapan in 1995, the Migratory Waterbird ConservationStrategy and the Shorebird Reserve Network are beingdeveloped. A trilateral agreement between Australia, Japanand New Zealand is designed to protect stocks of southernbluefin tuna mainly through imposition of quotas to restrictcatches.

Of the 50 species of wading or shorebirds that regularly occurin Australia, 33 (66 per cent) breed outside Australia andmigrate in autumn and spring between Australia and placessuch as central Asia, Siberia and the Arctic zone of NorthAmerica (Blakers et al., 1984). The red-necked stint (Calidrisruficollis), for example, is a small (about 30g) wading birdthat breeds in eastern Siberia and western Alaska, spends thenon-breeding season in Australia and migrates to and from itsbreeding grounds via Indonesia, the South China Sea,Vietnam, China, Japan and probably up the east coast ofAsia. About two million waders of various species avoidwinter each year by making the 20 000 km round trip to

Australia. Of the 71 species of coastal or seabirds thatregularly occur in Australian waters, 25 (35 per cent) breedelsewhere — mainly on islands in the Southern Ocean, in theAntarctic or around New Zealand (Blakers et al., 1984). Aswell as the migratory waders and sea birds, at least 36terrestrial species of bird that breed in Australia seasonallymigrate between Australia and Papua New Guinea. Largechanges in species diversity occur locally on a seasonal basisbecause of north south migrations undertaken by many birdswithin Australia.

Migratory species also enhance the species diversity of marinemammals. Southern right whales (Eubalaena australis) andhumpback whales (Megaptera novaeanglieae) migrate from theSouthern Ocean to Australian coastal waters to calve (seeChapter 8). Whaling reduced the numbers of whales todangerously low levels worldwide. Commercial whaling wasbanned in 1978 in Australian waters and in 1986 in allinternational waters. Southern right and humpback whalesare listed as endangered under the CommonwealthEndangered Species Protection Act and their numbers appearto be increasing. Estimates indicate that nearly 1000humpbacks migrate to eastern Australia where they havebecome a popular tourist attraction. Regulations have beenintroduced to prevent boats and divers harassing them.

Some of Australia’s highly diverse fish fauna are migatoryspecies. Marlin (Family Istiophoridae) and tuna (FamilyScombridae) are fast-swimming fish that range over large

areas in the Pacific, Indian and Southern Oceansand spend part of their life in Australian waters.Southern bluefin tuna for example, spawn in theIndian Ocean south of Indonesia and the youngfish migrate southwards along the coast of WesternAustralia. Some then swim westwards to the watersoff South Africa while others swim eastwards acrossthe Great Australian Bight to south of Tasmaniaand New Zealand. Many species of shark also travellarge distances; school shark (Galeorhinus galeus)tagged in New Zealand have been caught inAustralian waters.

Migratory species are subject to pressures in manyof the places they visit. In Australia, migratory birdsface a range of pressures including loss of habitatthrough processes such as urbanisation of the coast,drainage of wetlands and agricultural development.However the main threats come during theirbreeding migration. Large numbers are shot ortrapped in the northern hemisphere each year.Illegal hunting in China is also a serious problem asis habitat loss.

Seabirds also face threats in Australia. Longlinefishing in Australian and international watersthreatens populations of some species such as thewandering albatross (Diomedea exulans) (see page 8-33). Others, such as the brown booby (Sulaleucogaster), are harvested illegally (Blakers et al.,1984). Most of our pelagic species of fish appear tobe in a healthy condition but stocks of southernbluefin tuna have been greatly reduced throughfishing by Australian and Japanese fleets (see Fig.8.13).

Migratory species

probable mating area

occasional sightings

occasional sightings

southern migration

southern migration

northern migration

northern migration

The humpback whale migrates northwards in winter to calve. It feeds in Antarctic waters.Source: Marsh et al., 1995.

• elucidating trends on the state of Australia’s biotaresulting from various impacts and thedevelopment of geographic information systemsto assess terrestrial biodiversity at the scale oflandscapes, biogeographic regions andecosystems

Research by Australian Biological Resources Studyconcentrates on the systematics of a wide variety ofgroups of organisms, especially the lesser-knownones. Several universities and most major museumssponsor research and educational programs. Theseinclude: the Cooperative Research Centre forTropical Rainforest Management in northQueensland, the Commonwealth Key Centre forBiodiversity and Bioresources at MacquarieUniversity, and the Invertebrate BiodiversityConservation Program at the Museum of Victoria.

Biodiversity is increasingly a focus for tertiary andsecondary curricula. For example, in Victoria,biodiversity now forms one of the majorcomponents of the Year 12 course inenvironmental studies. Professional developmentcourses for teachers include one on biodiversityand ecologically sustainable development beingprepared by the Australian Association forEnvironmental Education.

A range of information and education materials hasalso become available recently. These include aprimer on biodiversity produced by the ResearchUnit for Biodiversity and Bioresources atMacquarie University (Beattie, 1995), a CD-ROMon insect biodiversity produced by CSIRO’sDivision of Entomology, a series of reports onbiodiversity, the State of the Marine EnvironmentReport (Zann, 1995; Zann and Kailola, 1995)(see Chapter 8) and other materials produced bythe Commonwealth Department of theEnvironment, Sport and Territories.

Community responsesOver the last two decades, public awareness ofenvironmental issues has grown rapidly. Since the1970s, many surveys of public attitudes to theenvironment have been conducted. Of these, onlyeight have identified specific environmentalconcerns and the priority that people attach tothem (Lothian, 1994). Although a study by ANOPResearch Pty Ltd into public attitudes to theenvironment (commissioned by DEST) found thatfew people have a good understanding of the termbiodiversity, the Lothian study indicates that thepublic are concerned about many of the issuessurrounding it, such as species loss, deforestation,vegetation clearance, logging, harvesting kangaroosand the role of national parks. Overall, biodiversityissues ranked second in the eight surveys behindpollution and waste production/disposal.

In recent years, concern for the long-termecological sustainability of Australia’s naturalresources has led to the rapid growth of local andregional environmental community groups. Manygroups have changed from being passive recipientsand distributors of information to taking aproactive role. They are demanding to be involved

in planning and decision-making processesundertaken by governments for management ofbiodiversity.

Public awareness of native flora and fauna issymbolised by community support for replacingtraditional symbols such as the Easter bunny withnative species like the endangered bilby (Macrotislagotis).

Community involvementThe National Strategy for the Conservation ofAustralia’s Biological Diversity relies on communitysupport and community-based actions for itssuccessful implementation. The Commonwealth ofAustralia House of Representatives StandingCommittee on Environment, Recreation and theArts (1992) stressed the need to develop innovativestrategies for increasing community awareness and


4-43

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. . . . . .

Commonwealth Environment Protection (Impact ofProposals) Act 1974

Australian Heritage Commission Act1975

Great Barrier Reef Marine Park Act1975

National Parks and WildlifeConservation Act 1975

Antarctic Treaty (EnvironmentProtection) Act 1980

Whale Protection Act 1980

Antarctic Marine Living ResourcesConservation Act 1981

Wildlife Protection (Regulation ofExports and Imports) Act 1982

Protection of the Sea (prevention ofpollution from ships) Act 1983

World Heritage PropertiesConservation Act 1983

Endangered Species Protection Act1992

Australian Capital TerritoryNature Conservation Act 1980

New South WalesNational Parks and Wildlife Act1974

Heritage Act 1977

Environmental Planning andAssessment Act 1979

Wilderness Act 1987

Threatened Species Conservation Act1995

QueenslandMarine Parks Act 1982

Nature Conservation Act 1992

South AustraliaNational Parks and Wildlife Act1972

Native Vegetation Act 1992

TasmaniaNational Parks and Wildlife Act1970

State Policies and Projects Act 1993

VictoriaWildlife Act 1975

National Parks Act 1975

Planning and Environment Act1987

Flora and Fauna Guarantee Act1988b

National Parks (Alpine NationalPark) Act 1989

National Parks (Wilderness) Act1992

Western AustraliaSoil and Land Conservation Act1945

Wildlife Conservation Act 1950

Conservation and LandManagement Act 1984

Northern TerritoryTerritory Parks and WildlifeConservation Act 1977

Source: DEST, Biodiversity Unit.

Conservation of biodiversity: relevant legislationThe fragmented approach to the conservation of biodiversity is illustratedby the range of legislation for the management of fauna and flora.


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A number of legislative and administrative actions haveoccurred in response to the decline and extinction of anumber of species.

The Commonwealth enacted The Endangered SpeciesProtection Act 1992, which came into force on 30 April 1993.It introduced a statutory process for the listing of nationallythreatened species, communities and key threateningprocesses. It also led to the establishment of two ministeriallyappointed committees: the Endangered Species AdvisoryCommittee and the Endangered Species ScientificSubcommittee. These bodies provide advice to the FederalMinister for the Environment on a range of mattersprescribed in the Commonwealth Act, including priorities forpreparation of plans, scientific advice on listings, andsignificant statutory responsibilities and powers that affectCommonwealth agencies and areas. The Australian and NewZealand Environment and Conservation Council hasdeveloped a strategy titled ‘The Conservation of AustralianSpecies and Ecological Communities Threatened withExtinction: The National Strategy’.

Two major Commonwealth programs: the EndangeredSpecies and Feral Pests Programs, address the conservation ofthreatened species and communities, and the major threats totheir conservation. The Endangered Species Program, whichwas established in 1989, seeks to prevent further extinctionsof Australian biota and to restore endangered species andecological communities to secure status in the wild. Fundingfor the program in 1994–95 was $5.5 million and cumulativefunding since its inception has been $23 million. The FeralPests Program began in 1992–93 with annual funding of $2.2million. Foxes, feral cats, feral rabbits and goats are listed askey threatening processes under the CommonwealthEndangered Species Act, as is dieback caused by the fungusPhytophthora cinnamomi and longline fishing which poses athreat to albatross.

Action plans have been prepared for birds, marsupials,freshwater fish, reptiles, rodents and vascular plants, and arein preparation for amphibians, bats, cetaceans, seals anddugongs. Conservation overview statements have beenprepared for non-vascular plants, and non-marineinvertebrates including butterflies. These plans and statementsare commissioned to help identify endangered and vulnerablespecies and nationally agreed priorities for action. The statusof recovery action on individual species listed in the schedulesto the Commonwealth Endangered Species Act is summarisedin Table 4.19. No ecological communities are listed in theCommonwealth Act, however, a discussion paper waspublished by the Endangered Species Scientific Subcommitteein January 1995 to stimulate comment from the scientificcommunity, conservation organisations, industry groups andinterested individuals.

Examples of recovery plansThe western swamp tortoise (Pseudemydura umbrina), whichis listed as endangered, consists of one wild population ofabout 48 individuals in Ellen Brook Nature Reserve nearPerth and 112 captive individuals that form part of a captivebreeding program. The recovery plan aims to increase thepopulation in Ellen Brook Nature Reserve and to establish asecond population of up to 40 at a nearby nature reserve thatformerly had a population of tortoises. It also aims to

maintain a captive breeding population of at least 50individuals (Burbidge and Kuchling, 1994). The estimatedcost of implementation of the recovery plan to 2002 is $1.7million.

At present, the main threats to the tortoise come from thesurrounding agricultural matrix and the availability of water.Conservation of the species depends on the management oftwo small swamp nature reserves surrounded by extensiveagricultural development. Winter water levels need to bemaintained. Since 1990, Ellen Brook Nature Reserve has beensurrounded by a fox-proof fence and extensive predatorcontrol is conducted within the reserve. However, unless thesurrounding land is managed to remove any threats to thetortoise population, the plan may still fail in the long term.This case highlights the need for management plans tointegrate conservation of biodiversity as an essential part oftotal landscape management (see page 4-53).

The western swamp tortoise

The Lord Howe Island woodhen (Tricholimnas sylvestris) is aflightless rail (Family Rallidae) occurring only on Lord HoweIsland, off the coast of New South Wales. Its nearest relativewas the wood rail of New Caledonia, which is now extinct.Before human settlement, the woodhen occurred over most ofthe island. Estimates based on known habitat requirementsand the original area of preferred habitat suggest an originalpopulation of several hundred. By the mid 19th century thewoodhen was confined to the summit regions of MountsGower and Lidgbird and between 1974 and 1980 thepopulation had been reduced to about 30 individuals,including at most 10 breeding pairs. The decline was probablyinitially due to hunting pressure but subsequently topredation and habitat alteration by introduced animals.

An extensive study of the ecology of the remaining birdsbegan in 1971, followed by management to offset theidentified threats, and a program of captive breeding and re-introduction. By 1984, more than 80 birds had been bred andreleased and the wild population had grown to an apparentlystable level of 200 individuals, including 50 breeding pairs.Further increases appear to be limited by lack of suitablehabitat for more breeding territories. Twice-yearly countingcontinues for early detection of any further problems, andthere is a proposal to establish a captive colony off the islandin case of a catastrophic impact on the native population.

Response to species endangerment

involvement. The committee identified severalstrategies for facilitating community involvementat the grassroots level:

• provision of seeding funds for projects

• government involvement and encouragement incommunity projects

• extension and dissemination of practicaltechnical advice based on scientific research andknowledge

• bioregional planning and management tocoordinate and direct local community actionswithin a broader perspective

• practical equipment to facilitate on-groundactions

Many mechanisms exist for obtaining input fromthe community on specific environmental matters.For example, most planning legislation requiresopportunity for public comment. Governmentshave created a range of advisory bodies to betterinform people involved in the policy developmentprocess. Many non-government groups alsoprovide advice to government through theirparticipation in government committees, such asthe Biological Diversity Advisory Council and theEndangered Species Advisory Committee.However, feedback from community groupsindicates a need for increased government support,since community input generally relies on the workof volunteers.

Many community groups regularly monitor theenvironment and undertake field activities to eitherprotect or restore biodiversity (Saunders et al.,1995). Programs such as Worm Watch, FrogWatch and NatureSearch collate information aboutspecies collected by members of the public.Community groups monitor organisms as diverseas orchids, birds, frogs, earthworms, dung beetlesand butterflies on a nationwide basis. Theinformation collected by these groups has greatlyincreased our knowledge of the diversity oforganisms such as earthworms in Australia. Animportant example of the role of the community ingathering data is The Atlas of Australian Birds(Blakers et al., 1984), which is based oninformation provided by bird-watchers all overAustralia.

The public also donate money towards researchrelated to biodiversity. In New South Wales, forexample, the New England community establisheda ‘dieback fund’ for research into the causes ofdieback killing native trees in the district. Trees forLife provides two million indigenous trees annuallyfree of charge to landholders to assist in therehabilitation of farmland in South Australia. Therestoration of native bush in urban areas is apopular and rapidly growing community activitythat seeks to re-establish local species.

Community–government initiativesCommunity groups, conservation and governmentbodies often collaborate on environmental projects.

A successful example of a community–governmentinitiative is the Land for Wildlife scheme run bythe Victorian Department of Conservation andNatural Resources and the Bird Observers Club ofAustralia. Private landholders are encouraged toconserve flora and fauna and given support by theprogram. The scheme does not require landholdersto enter into agreements with the government, butinstead provides a structural framework for thesupport of voluntary management of wildlifehabitat on private land.

Greening Australia and the One Billion Treescampaigns are collaborative projects betweengovernment, conservation groups and thecommunity, which have arisen in direct response toloss of native vegetation. The establishment of anumber of community networks such as theCommunity Biodiversity Network, the Marine andCoastal Community Network and the NationalThreatened Species Network are other examples ofcollaborative projects. The latter is an activecommunity-based network that increases publicsupport and involvement in the protection ofthreatened species and their habitats throughoutAustralia.

The Landcare movement has the potential to bethe most important mechanism for integratingconservation of biodiversity into agricultural and


4-45

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. . . . . .

Species No. of endangered Recovery Recovery planor vulnerable species plan prepared being

or in preparation implemented

Mammals 48 13 11

Birds 50 12 8

Amphibians 9 7 2

Reptiles 21 2 1

Freshwater fish 13 6 2

Vascular plants 890 224 124

Total 1031 264 148

*As listed in the schedules to the Commonwealth Endangered Species Act.No ecological communities are listed in the Act, however, the endangered species scientificsubcommittee published a discussion paper in January 1995 to stimulate comment from the scientificcommunity, conservation organisations, industry groups and interested individuals.

HPlanting trees as part of a

community–governmentinitiative, Greening Australia.

Table 4.19 Status of recovery action on individual species*

pastoral production. Landcare was originallyestablished by the National Farmers Federation andthe Australian Conservation Foundation in the1980s (see page 6-43). More than 2000 Landcaregroups now exist across Australia, involved in awide range of activities aimed at improvingproduction, land and water restoration andconservation. Some of these activities contributedirectly or indirectly to conservation of biodiversity(Commonwealth House of RepresentativesStanding Committee on Environment, Recreationand the Arts, 1992).

Industry responsesAs the Australian public’s attitudes toenvironmental issues change, so do those ofindustry. The agricultural sector is increasinglyincorporating nature conservation into landscapeprograms. Some industry responses are driven byconsumer demand — that is, the desire to buymore ‘environmentally friendly’ products.Conservation groups such as WWF, for example,endorse some products. In many cases industrieshave failed to respond of their own accord topressures on biodiversity and have only acted in


4-46

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. . . . . . . . . .

A range of economic instruments is being developed to helpachieve the sustainable use of natural resources. However, few‘economic’ instruments have been introduced specifically formanaging biodiversity.

Environmental pricingCharges, levies and the setting of prices to fund conservationof biodiversity are rare in Australia — beyond fees for parkuse, trail access and other uses within reserves. The GreatBarrier Reef Marine Park Authority has introduced a one-dollar visitor fee that is expected to raise about one milliondollars per year. Most of the funds are being allocated to theCooperative Research Centre concentrating on the ecologicalmanagement of the reef.

Some local authorities, such as the Brisbane City Council,have introduced environmental levies on ratepayers. Fundsraised in this way are used to buy environmentally sensitiveland in order to protect habitats and their associated flora andfauna.

Conservation easements Conservation easements, like South Australia’s heritageagreements, bind owners to a set of conditions, such asprohibition of clearing or cropping an area of land. OtherStates and Territories also have legislation that facilitates theuse of conservation easements, but their limited budgets meanprogress has been slow.

Funding arrangementsA revolving fund is one of several ways to maximise the effectof funds for managing biodiversity. This involves buying landand placing a permanent covenant on it to manage part or allof it for conservation. The land is then sold to someone whoagrees to abide by the covenant and the money used to buymore land. The Victorian Conservation Trust has established arevolving fund, and other environmental organisations, likethe Australian Bush Heritage Fund have expressed a desire todo likewise.

TaxationSome income-tax deductions are available for control of landdegradation, but they are narrowly defined and do not reflectconcerns for the conservation of biodiversity. Localgovernments grant rate relief for land maintained forbiodiversity conservation purposes. Rate reimbursementsapply in South Australia under the Native Vegetation Act 1992and further reductions are available under a heritageagreement. In Victoria, new financial provisions in the Local

Government Act 1991 allow local authorities to charge ratesunder a method of capital improvement valuation. Thiswould reduce the tax burden associated with a decision tolease undeveloped land. However, these provisions have notyet been used.

Transferable development rightsThis mechanism is designed to limit development inconservation areas without affecting the underlying value ofindividual assets. Transferable development rights enablepeople who own valuable habitat to sell clearing rights toothers who own land of lesser biological importance and needa development right in order to proceed with a proposeddevelopment. The use of transferable development rights isallowed under the Resource Management Act 1991 in NewZealand and opportunities exist for its application inAustralia.

Performance bondsEnvironmental performance bonds are best suited tosituations where there is one source of potentialenvironmental damage that can reasonably be estimated.Apart from their use for land rehabilitation in the miningindustry, bonds are used as a permit condition for aquaculturein South Australia and New South Wales and by the GreatBarrier Marine Park Authority for tourist development.

Financial assistanceFinancial assistance forms part of many voluntarymanagement schemes offered by the States and Territories andusually takes the form of payment to assist with the cost ofpurchasing material associated with the work required. Forexample, a 50 per cent fencing subsidy exists under theremnant vegetation protection scheme in Western Australiaand the Victorian action statement program also payssubsidies.

Land management funding schemes such as the NationalLandcare Program and the Murray–Darling ManagementStrategy’s Investigations and Education and IntegratedCatchment Management programs, while broadly directedtowards activities of significance to the conservation ofbiodiversity, do not contain any explicit biodiversityconservation requirements. The Commonwealth Departmentof Housing and Regional Development Program (establishedin 1994 with funding of $15 million over four years) fundsthree major regional development programs, none of whichcontains biodiversity conservation criteria.

Economic mechanisms for conserving biodiversity

response to government legislation. However, someresponses are based on industry’s need to preservenatural resources. Commercial fishing organisationsin several States employ environmental officers andtake active roles in widening the debate on issuessuch as coastal development and protection ofseagrasses. In response to industry lobbying,governments have legislated to protect seagrassesand mangroves over much of northern Australia.

A number of industries have introduced initiatives,such as codes of practice, cleaner production andbest practice environmental management, toreduce the impacts of their operations byminimising use of materials and energy and byreducing wastes. These initiatives focus onpollution control and reduction of environmentaldegradation and do not specifically addressbiodiversity.


4-47

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. . . . . .

Technological advances since World War II have made large-scale clearance of native vegetation easier. As a consequence,more land has been cleared in the last 50 years than in thepreceding 150 years, bringing associated problems of landdegradation and loss of biodiversity. These problems havearoused concern in many sectors of the community, and anumber of responses have evolved to address the impacts ofclearance.

Since the early 1980s, governments and key communitysectors have increasingly recognised the economic, ecologicaland social benefits of remnant native vegetation and haveinitiated programs, not only to ensure the protection andmanagement of remnants, but to re-establish large areas ofvegetation.

This has resulted in a number of community-based projectssupported by programs like the National Landcare Program,whose components include Save the Bush and One BillionTrees. However, while the enthusiasm for ‘tree planting’ hasgenerated activity on many fronts, this activity has proceededwithout any underlying ecological rationale or planningframework. Concern is now being expressed about theplanning and preparation for revegetation activities, theappropriateness of plantings and the species selected(Commonwealth House of Representatives StandingCommittee on Environment, Recreation and the Arts 1992).Many of the plantings have had a single purpose (such ascontrol of soil erosion or salinisation) and planned solelywithin the confines of one property. Clearly, it is better toensure that tree-planting has potential multiple benefits (forexample plantings for soil erosion control can be designed toprovide habitat) and is placed within a broader planningframework.

Some schemes now advocate the concepts of integratedlandscape ecology and bioregional planning as a basis fordeveloping an integrated approach to landscape management.These approaches offer the potential to place previously adhoc community activities within a regional framework. Usingcatchments as a basis for designing National LandcareProgram projects and planting along corridors — for exampleCorridors of Green by Greening Australia — are indicative ofmoves towards an integrated landscape management approach.

The way in which the landscape has been managed isillustrated in a study by Hobbs et al. (1993) using ahypothetical section of the Western Australian wheat belt.Individual segments in the landscape, such as road verges,paddocks and patches of remnant vegetation, are usuallymanaged in isolation. The landholder is mainly concernedwith individual paddocks and the conservation authority withnature reserves, while the authority responsible for the

roadside verges — usually the local council — is unlikely toshare much interest in either of these. While resourcemanagers and landholders manage their own piece of land inisolation, landscape segments are unlikely to operate as aninterconnected system. Landscape linkages can be establishedby planning and planting in line with landscape features. Thisapproach, applied on a regional scale, offers opportunities toenhance the benefits from tree-planting activities at aproperty/local level.

The benefits of extensive networks of vegetation for theprotection of water and soils and for the maintenance ofbiodiversity now have wide recognition. However, few dataare available to either support or refute the value ofinterconnecting areas of vegetation (corridors) forconservation and maintenance of biodiversity, and their meritcontinues to be hotly debated in the scientific literature (Noss, 1987; Simberloff et al., 1992). Despite this, it isgenerally accepted that corridors serve to ameliorate theprocess and consequences of fragmentation, which constitutea serious threat to biodiversity.

Community actions to integrate the landscape

��

��

��

��

��

��

��

��

��

Drainage channels

Road vergeFence lines

Pasture/crop

Nature reserve

Revegetation

Remnant vegetation (privately owned)

Landscape linkages. A – A hypothetical section of an agricultural landscapeshowing remnant vegetation, reserves, roads, paddocks and drainage lines. B – Revegetation plan that provides linkages along road verges and drainage lines to connect remnant vegetation.

Source: Hobbs et al., 1993.

A

B

Responses to key issuesOn the basis of the preceding sections, thefollowing key issues for management ofbiodiversity emerge:

• human population patterns

• land clearance

• harvesting of native species

• introduced species

• pollution

• mining

• climate change

• lack of knowledge

• integrated ecosystem-based management ofnatural resources

The state of Australia’s biodiversity is ultimately aconsequence of the number of people, our patternsof movement and the resources required to fulfilour desires and to maintain our living standards.Without limiting human population growth anddeveloping management systems that recognise thecritical role of biodiversity in human economicsthe pressures on biodiversity will continue.

Human population patterns

UrbanisationAustralia is the most highly urbanised society inthe world (see Chapter 3). The National Strategyfor the Conservation of Australia’s BiologicalDiversity has identified a number of goals to

minimise the impact of urbanisation onbiodiversity, including the following:

• encouraging habitat retention

• improving strategic planning to enhancebiodiversity

• reducing fringe development

• encouraging use of indigenous species

• integrating biodiversity conservation intorelevant policies and programs such as theBetter Cities program

Tourism and recreationTourism is a relatively unregulated activity inAustralia and consequently government bodieshave made little response to the pressuresassociated with it. However, the CommonwealthGovernment has responded to growth in theecotourism industry with the National EcotourismStrategy designed to provide guidelines to ecotouroperators.

All States and Territories have produced policydocuments on ecotourism or tourism. Some havealso recognised the value of tourism-based activitiesand contribute some of the revenue gained fromusing natural resources into the management ofthose resources. However, the challenge remains todesign and implement systems that will link thegrowth of tourism with conservation ofbiodiversity (Preece et al., 1995). One example isthe Northern Territory Tourism Masterplan, underwhich the Northern Territory tourism industry andthe Northern Territory Conservation Commissionare working together to investigate the touristpotential of protected areas.

The growth of ecotourism itself reflects thecommunity’s desire to participate in moresustainable types of tourism and to learn moreabout the natural environment. However, sinceanyone can call him- or herself an ecotour operatorthere is no proof that the activities of ecotouristsare any more sustainable than other forms oftourism. To overcome this problem a number ofaccreditation schemes have recently beenintroduced and the Commonwealth Departmentof Tourism is investigating the merits of a nationalscheme (Preece et al., 1995).

Some forms of recreation, such as fishing (see page8-12), require intensive management to ensuretheir sustainability. Intertidal rock platforms nearlarge cities such as Sydney and Perth are easilyaccessible and so shellfish may be over-collected.Recreational abalone fishers near Perth, for example,take between 80 and 100 tonnes each season —about 40 per cent of the available stocks and oneand a half times the tightly controlled commercialcatch. Controls have been introduced to protectthe resource. These include a limit of 20 abaloneper person, size limits for common species andregulations on collecting methods (scuba diving,for example, is banned). Fishing is also restricted totwo hours a day on eight weekends each year.

Many States and Territories have restrictions onshell collecting — usually a limit on the numbers


4-48

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. . . . . . . . . .

The Bubbler Mound Springsnear Lake Eyre South,northern SA. Visitor impact onsensitive sites is oftenunwitting, highlighting theimportance of public educationand adequate signage.

P

French Track, SimpsonDesert, SA. Use of four-wheeldrive vehicles enables peopleto appreciate remote parts ofAustralia but can also lead to

disturbance of sensitiveecosystems.

R

that can be collected — to reduce the harvest byamateur collectors.

Recreational fishing is an important leisure activityfor more than 4.5 million Australians. However,increasing fishing pressure on inshore stocks fromrecreational and commercial fishing, coupled withenvironmental damage, is causing the decline ofmany fish stocks. A working group set up underthe Australian and New Zealand Fisheries andAquaculture Council has developed a nationalpolicy on recreational fishing. The key principlesfor sustainable fishing include protecting theresource and habitat, and involving governmentand the community. The policy seeks responsibleland use and farming practices, protection ofshoreline and floodplain areas and wetlands, andcareful use of chemicals and fertilisers that have animpact, direct or indirect, on aquatic habitats orfish stocks (National Recreational FisheriesWorking Group, 1994).

Land clearanceThe clearance of native vegetation is the singlegreatest threat to terrestrial biodiversity and asignificant threat to aquatic and some inshoremarine biodiversity. Thus it is extraordinary thatnobody has accurately assessed its extent over thelast one to two decades, despite the availability ofthe appropriate technology (Graetz et al., 1992).The Department of Environment, Sport andTerritories is supporting a number of projects torectify this gap in knowledge. One recentlycompleted project, undertaken by CSIRO, usedsatellite imagery to assess landcover disturbance ata continental scale (Graetz et al., 1995). TheDepartment has also released a compilation thatprovides an overview of the pattern of recentvegetation clearance (Biodiversity Unit, DEST,1995).

Reserves have only limited value as an antidotebecause most of the land set aside is in small blocksthat are infertile and/or steep. Fertile land is lesslikely to be preserved (see the box on page 4-52).The problem will continue without changes topolicies on land clearance and reserve selection.

About 70 per cent of Australia’s land mass is underthe control of private landholders and resourcemanagers, including indigenous peoples.Vegetation clearance on lands under freehold andleasehold tenure is a major concern. Controls onnative vegetation clearance and the provision ofincentives for native vegetation retention varybetween States and Territories. In South Australia,vegetation clearance is tightly controlled, but otherStates and Territories have less stringent rules (seepage 6-39 and Table 6.8). New South Wales,Queensland and Western Australia are in theprocess of strengthening measures to control nativevegetation clearance. In 1995, the QueenslandGovernment released a package of measuresincluding draft tree-clearing guidelines thatdemand 30 per cent retention of trees on mostleasehold properties throughout the State andprohibit large-scale clearing of mulga (Acaciaaneura).

Governments have also implemented a range ofeconomic mechanisms to address the issue of landclearance (see the box on page 4-46). For example,all the 1950 taxation provisions designed toencourage it have now been removed from theIncome Tax Assessment Act 1936, although farmerscan still deduct the full cost of clearing in the yearof expenditure by using their own equipment andemployees.

The removal of incentives that encouragedeforestation or land degradation is an effectiveresponse to conservation of biodiversity. In thepast, it has been argued that drought policy hasencouraged land degradation, including the loss ofbiodiversity values. Recent changes to droughtpolicy at both State and federal levels are makingfarmers more self reliant in a way that may reducethreats to biodiversity values during time ofbiological stress.

Environmental lobby groups have focused on issuesof native vegetation clearance, especially thoseresulting from logging operations, conversion toagricultural land and mining activities. The powerof large-scale environmental protests over the pasttwo decades to influence government policy andchange public perception should not beunderestimated. Community groups have alsoresponded to removal of forests by cooperatingwith government–community initiatives such asLandcare, Greening Australia and Save the Bushprograms.

Harvesting native speciesRights to harvest and/or use Australia’s flora andfauna vary between States and Territories. In recentyears the Commonwealth, several States and theNorthern Territory have increased the marketorientation of harvesting licences, such as in thekangaroo- and timber-harvesting industries.

The Commonwealth, States and Territories requirea permit or licence to take, kill, trade or exportprotected flora and fauna. These licences, however,are usually issued for a short period with noguarantee of renewal. Beyond these provisions,Australia is a party to the CITES convention whichrestricts the international trade in endangeredspecies and bans trade in most threatened species.There is continuing debate on the conservationbenefit, economics and ethics of using wildlifecommercially.

In the fishing industry, measures have beenintroduced to reduce fishing pressure. Theseinclude reductions in the number of trawlers insome prawn fisheries and the number of pots inlobster fisheries, smaller quotas for finfish in thesouth-east trawl fisheries and controls on mesh sizeof nets, sizes of animals caught and fishing times.New Commonwealth, State and Territory fisherieslegislation emphasises the importance of managingfisheries to achieve ecological sustainabilityincluding maintenance of biodiversity (see Chapter8). Research is being conducted to reduce thequantity of bycatch in prawn trawl fisheries.


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. . . . . .

Recreational fisheries have generally had few limitsapart from controls on the type of equipment usedfor fishing and minimum size of fish caught. MostStates and Territories now limit the number of fishthat can be caught each day. Despite thesemeasures, some species are still declining or theirnumbers are not recovering and it is likely thatcontrols will be increased in the future.

Introduced speciesThe devastation caused by introduced plants andanimals has elicited a number of government,community and industry responses. TheCommonwealth Government established theCooperative Research Centre for Vertebrate PestControl, which involves five research groups in

developing humane methods to combat vertebratepests such as rabbits and foxes. Their mainapproach is to investigate methods of fertilitycontrol in vertebrate pests. The Feral Pests Programwas set up in 1992–93 to address threats toendangered species posed by feral pests (see the boxon page 4-44).

Growing public awareness of the effects of feralanimals and introduced plants on native fauna andflora has led to numerous community-basedprojects. Bush-regeneration groups are common inurban areas, where remnant vegetation is especiallyprone to invasion by exotic weeds. Individuals andcommunity organisations such as Landcare groupsshoot or poison feral cats, rabbits and foxes.

In 1991, the Australian Quarantine and InspectionService introduced voluntary controls on thedischarge of ballast water. These guidelines providea number of options — the most common beingexchange of ballast water offshore to prevent waterloaded in foreign ports from being discharged here.In this way, many shallow-water organisms fromother ports are dumped at sea in deep water wherethey are unlikely to survive. Despite modern anti-fouling paints, many organisms are still beingtransported on the hulls of ships on parts notprotected by the paint or on sections where thepaint has been scraped off. The Centre forResearch on Introduced Marine Pests establishedby CSIRO under the auspices of the AustralianBallast Water Management Advisory Council,established by the Commonwealth Government in1994, is researching ways of dealing with marinepests. However, it is unlikely that introducedmarine organisms will be eradicated.

PollutionThe National Environment Protection Council is asignificant initiative being established jointlythrough legislation by the Commonwealth, Statesand Territories to develop harmonised goals,standards and guidelines for the protection of theenvironment. The areas it covers include: ambientair and water, assessment of contaminated sites,impacts of hazardous wastes and recycling.

Although the amount of government legislation onpollution control has grown steadily in recentyears, its effectiveness has been limited by thedispersal of responsibility for enforcing pollutionlaws across many government departments. Thissituation has changed recently with thecentralisation of responsibility under Stateenvironmental protection authorities (EPAs). InNew South Wales and Victoria, for example, EPAscan impose fines of up to one million dollars oncompanies that pollute illegally and in WesternAustralia the head of one company was gaoled as aresult of pollution by the company.

Government legislation generally dictates industryresponses to pollution. For example, the AustralianMaritime Safety Authority has recently prepared anational plan to combat pollution of the sea by oil.However, industry also reflects changing attitudestowards environmental issues in society generally.Many companies are using a variety of waste-


4-50

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. . . . . . . . . .

Fraser IslandFraser Island, the largest sand island in the world, supports rainforest,freshwater lakes, coastal heathland and sand dunes. Over the years it hasfaced a number of threats, including sand-mining, logging, feral animalsand (being only four hours drive from a region supporting two millionpeople) tourism and recreation — especially recreational angling.

Numbers of visitors to the island have increased from 50 000 in 1985 to250 000 in 1994. Following a long public campaign, the CommonwealthGovernment — against the wishes of the then Queensland Government— refused to issue export licences for minerals produced on the island andso sand-mining was stopped. In response to continuing public pressure,the Queensland Government banned the logging of the island’srainforests. The Commonwealth subsequently obtained listing of FraserIsland as a World Heritage Area and now the island — together with themainland immediately to its south — has been incorporated into anational park. This park (and areas outside it) are subject to the GreatSandy Region Management Plan, which covers an area of about 840 000ha.

The plan provides for protection of natural and cultural features of theregion, while allowing for provision of services for residents and visitorsand ensuring that development is sustainable. It contains a range ofstrategies, including rehabilitation of degraded areas, removal of feralanimals, catchment management, controls on recreational and commercialfishing, rationalisation of vehicle access — including use of four-wheeldrive vehicles on beaches — and development and control of tourist areas.If the plan meets its targets, it will provide substantial protection andrestoration of the island’s biodiversity.

minimisation measures and recycling programs toincrease profits and improve their image with anincreasingly critical public. Consumer demand for‘greener’, ‘cleaner’ products has generated a flurryof activity and competition in companies todevelop products that are seen to be moreenvironmentally friendly. Products are increasinglymade from, or packaged in, recycled materials andfrequently contain less non-biodegradablechemicals.

The Cooperative Research Centre for WasteManagement and Pollution Control involves 18different research and industry groups and isresponsible for research into all aspects of wastemanagement and minimisation. Although it coversall elements of waste, the Centre’s research focus ison the treatment of liquid waste.

MiningWhen planning new mining developments,companies now must carry out environmentalimpact assessments that include plans forrehabilitation. In most States, mining leases includea condition requiring the holder to lodge a securitydeposit, which may be forfeited if therehabilitation conditions are not met. In 1990, theAustralian Mining Industry Council published ahandbook that lists standard rehabilitationprocedures (AMIC, 1990). These includelandscaping, management of topsoil, revegetation,managing waste dumps, acid, alkaline and salinesites, heavy metals and toxic chemicals as well asremoval of access roads and constructions.Considerable effort is now applied to rehabilitationof sand-mining areas. However, thousands ofabandoned mine sites remain with norehabilitation apart from natural processes.

In South Australia, mining operators are requiredunder the Mining Act to pay a royalty (presently10 cents per tonne) on all materials produced. TheExtractive Areas Rehabilitation Fund is used tofinance approved rehabilitation projects. Some ofthe larger mining companies employ horticulturaladvisers or rehabilitation consultants.

Climate changeCommonwealth, State and Territory governmentsand the Australian Local Government Associationon behalf of local governments have accepted theNational Greenhouse Response Strategy.

Under the United Nations Framework Conventionon Climate Change, the OECD countries arecommitted to stabilising gas emissions at their1990 levels by the year 2000. Australia’sgreenhouse gas emissions in 1990 have beenestimated at 572 megatonnes of carbon dioxideequivalent and at present rate of growth wouldincrease by 14 per cent by the year 2000.Vegetation clearing for agricultural purposes in1990 was estimated to have contributed about 27per cent of Australia’s total net emissions in carbondioxide equivalent (National Greenhouse GasInventory Committee, 1994).

The National Greenhouse Gas Inventory aims toassemble a comprehensive information base ofhuman-induced net emissions of greenhouse gasesin Australia. As part of the long-term program todevelop an improved capacity to compile thisnational inventory, about $1.1 million has beendirected to scientific research over the three years1995–97 (see also Chapter 5).

Lack of knowledgeMajor research programs are required in three keyareas to improve knowledge of Australianbiodiversity and its conservation and management.

InventoryAustralian biodiversity consists of hundreds ofecosystems, more than one million species andmillions of genes.

Although the country has been divided intobiogeographic regions (see Fig. 4.9), each of thesecontains undescribed ecosystems. Thus, we have along way to go before we understand ecosystemdiversity. Commonwealth, State and Territoryagencies are using Geographic Information Systems(GISs) to establish a national inventory ofecosystems. In the future, GISs should enable us topredict, for any given area, how many species livethere, species turnover from one habitat to anotherand numbers of rare, vulnerable and endangeredspecies.

Like the rest of the world, Australia has describedonly a small proportion of its species (see Table4.8). While most flowering plants and vertebratesare known, the ‘lower’ plants (mosses and theirrelatives) are relatively unexplored. Less than halfof the invertebrates are described and the micro-organisms remain little known. We have too fewtaxonomists to carry out a full inventory ofAustralian species.

The establishment of the Australian BiologicalResources Study (now incorporated in theAustralian Nature Conservation Agency) provides amajor incentive for the documentation ofAustralia’s species diversity. Funding has beenprovided, under the aegis of the Commonwealthagency, for the scientific investigation of majorgroups of animals and plants. Researchers publishtheir findings in the Flora of Australia and theZoological Catalogue of Australia and ancillarypublications.

The massive task of understanding genetic diversityis being directed towards two goals. The first is tounderstand the genetics of species in decline orgoing extinct and to manage their threatenedpopulations to retain the genetic diversity requiredfor recovery. The second is to locate and bring intothe laboratory genes that are commerciallyimportant, including those from the wild relativesof crop plants (see the box on page 4-5), bacteriaand fungi for industrial use and invertebrates forbiological control and biological monitoring.


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. . . . . .


4-52

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. . . . . . . . . .

Conservation areas are parts of the land or sea where specialmanagement is applied for nature conservation. Managementis intended to separate elements of biodiversity (ecosystems,communities, species, populations, genes) from processes thatthreaten their persistence. National assessments ofconservation areas have been limited to ‘strict’ reserves (thosein IUCN, 1994 Categories I–IV). Regional studies haveshown that other types of formal protection measures can bevery extensive, but we lack information on these for largeparts of the continent. Because of the sheer number andextent of these other formal protection measures and the lackof computerised data bases, it is not possible to examine theirdistribution and coverage of elements of biodiversity.

It seems obvious that strict reserves should be located so thatthe elements of biodiversity most needing this type ofprotection are able to persist in the landscape. However, thisdoes not occur. The location of reserves in Australia has beenlargely shaped by a process of ad hoc acquisition of land thatis determined by its availability for conservation purposes, itscost, and a wide variety of aims, some of which lead to verydifferent priorities for protection. Only recently have moresystematic approaches to establishing protected areas hadsome effect on acquisition priorities. Several decades ofad hoc protection have led to two serious limitations of thenational reserve system.

The first is that reserves often do not effectively represent thenatural features (such as ecosystems or species) withinregions. Some features are represented many times and othersnot at all. This means that the total area needed to representall the features in a region, starting with the existing reservesystem, is greater than if a whole new reserve system weredesigned from scratch. An example of this tendency occurs inthe Western Division of New South Wales (see figure below).The same results have emerged wherever similar analyses havebeen done in other parts of Australia. The upward trend inrequired area as more ad hoc reserves are added to the systemindicates a steadily increasing cost of reserving all the naturalfeatures in a region and a decline in the likelihood ofachieving a fully representative reserve system.

The second limitation is that reserves tend to be a ‘residual’land use, with more extensive protection given to land that isleast useful for intensive commercial purposes (see thediagram above). In many areas, this means that reserves donot occur where threatening processes are greatest. Forexample, ecosystems most in danger of outright replacementby crops and pastures often receive zero or minimalprotection. The major conservation battles tend to be foughtin a small subsection of the environments in need ofprotection. In eastern and southern Australia, this is typicallyon areas of Crown land where the main alternatives areforestry or reservation. Crown land itself is usually theresidual tenure after freehold land has been released forintensive land use. A residual reserve system is a poor startingpoint for regional-based planning, which requires a mix ofprotection measures with the strictest protection applied tothose areas least able to persist under any form of extractiveuses — particularly intensive ones like agriculture. A residualreserve system provides the opposite starting point.

Ad hoc reservation consumes limited conservation resourcesand often gives the appearance of conservation progress (forexample, increasing area of reserves) without genuinelycontributing to the protection of biodiversity. Two criticalquestions should be asked in a regional context aboutproposals for new reserves.

• Will the proposed reserve represent features that are poorlyprotected?

• Will it cover features that most need this form ofprotection?

If the answer to one of these questions is ‘no’, conservationresources will not be spent in the most effective way forconserving biodiversity. Source: Pressey, 1990.

Location and effectiveness of conservation reserves

19881971

area of region (%)

0

2

4

6

8

10

existing reserves

total area needed

0.0

1.0

2.0

3.0

4.0

LowModerateHigh

Land reserved (%)

Suitability for agriculture

Existing reserves and total area of reserves required to represent all land types inthe Western Division of New South Wales. In 1971, before any reserves werededicated, all land types could have been represented in 5.7 per cent of the region.In 1988, following acquisition of reserves totalling 3.3 per cent of the region, theminimum area of reserve needed to represent all land types, starting with existingreserves, was 8.3 per cent.

Reservation in relation to three classes of agricultural suitability in the Mt LoftyRanges of South Australia.Source: Department of Housing and Urban Development, SA, GIS Unit.

MonitoringMonitoring reveals the success or failure ofstrategies designed to conserve biodiversity and thesustainability or otherwise of industrial practices.Three types of monitoring correspond to the threelevels of biodiversity: ecosystems, species and genes.

Australia is a world leader in ecosystem monitoringby GIS. Satellite imagery can reveal the extent ofclearing, deforestation, over-grazing, urbanisation,siltation of rivers or coasts or reef dieback from oneperiod to another. Much work remains to be doneon ‘ground-truthing’— that is, making sure thatthe interpretation of satellite data corresponds towhat is really happening on the ground or in thesea.

Scientists commonly use the distribution andabundance of flowering plant and selectedvertebrate species for environmental monitoring.However, they are also increasingly usinginvertebrates and micro-organisms. Freshwater andmarine environments are routinely monitored byassessing the responses of selected vertebrate andinvertebrate species to disturbance such aspollution. Research is required to test the reliabilityof indicator species when monitoring naturalresource management, industrial pollution andconservation practices in all kinds of environments.

Declines in genetic variation need to be monitoredin populations of endangered species so that, wherepossible, they can be managed to stabilise lossesand reverse the trend. Australian conservationgeneticists have contributed to the management ofmany endangered plants and animals in the fieldand to captive breeding programs of species on theverge of extinction in the wild.

Reserve systemsThe box opposite highlights the problems andshortcomings of Australia’s reserve system. Toooften the reservation of a piece of land has been foreconomic or political rather than biologicalreasons, with the result that ecosystems that areunproductive — for example, because they are onpoor soils — are well reserved while those on moreproductive land or at highly desirable locationsmay not be reserved at all. Australian ecologists aredeveloping the criteria and guidelines forestablishing reserve systems representative ofterrestrial and marine ecosystems. Muchinformation and some software are alreadyavailable, but much needs to be done to integratethe scientific criteria and guidelines intomainstream political and legislative procedures.

Integrated ecosystem-based management ofnatural resourcesPlanning and management should be integratedand regionally based to overcome a number ofproblems. These include large numbers of publicagencies involved in management decisions;administrative boundaries that do not reflect anyparticular physical, geographic or ecologicalfeature; and the cumulative effects of multiple andcontinuous developments.

One of the principles of the national biodiversitystrategy states that ‘biological diversity is bestconserved in situ’. In view of the limitations of thereserve system, bioregional planning is one way ofintegrating options for conservation of biodiversity.Bioregional planning has been defined as anecological and social framework within whichgovernment, business and community interestsshare responsibility for coordinating land useplanning and formulating and implementingdevelopment options which meet human needs ina sustainable way (World Resources Institute,1992). However, the boundaries of a region canvary depending on the context for which they arebeing established. To date, commonly usedregionalisations include local governmentboundaries, catchment boundaries and the InterimBiogeographic Regionalisation for Australiaregions.

Traditional planning, while it is effective forcontrolling site-specific development proposals, hasproved ineffective for addressing cumulative, off-site and incremental impacts such as habitatfragmentation and soil salinisation that result fromland clearance. Bioregional planning can be used tointegrate the often ad hoc approaches in planningdecisions, as it facilitates a system-based approach.The move towards greater integration across alllevels of government, the community and industryin regional planning is indicative of a movetowards a more holistic approach.

It is generally agreed that we will not reconcileproduction and conservation values simply byexpanding the national system of reserves andnational parks. Many ecosystems and species willbe sustainable only if the environment is managedin accordance with natural rather than economic orpolitical boundaries. For example, it makes littleenvironmental sense if an endangered species isprotected under one jurisdiction but not in anadjacent one, or a land-use practice is illegal on oneside of a political boundary but not on the other.

Bioregional planning and management is a vehicledesigned to overcome problems of fragmenteddecision-making or the tyranny of small decisions.Many Australians, including landholders,government agencies, industries and conservationgroups, are already involved, but much knowledge(not only biological) is required to implement it.While scientific knowledge of the biodiversity of aregion is essential, ways of creating theinfrastructure to include all interested parties andto resolve their conflicts are, in most cases, still tobe worked out. Planners also have yet to evaluateadequately existing knowledge of the effects of onetype of activity upon others and upon theenvironment. Where they do not yet exist, datashould be gathered so that facts remain the basisfor planning and for dispute resolution.


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. . . . . .


4-54

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. . . . . . . . . .

Key issue

E c o s y s t e m d i v e r s i t yNorthern rainforestsHabitat destruction

Southern rainforestsHabitat destruction

Tall open forests (wet sclerophyll)Altered fire regimes; land clearance;logging

Acacia forests, woodlands andshrublandsClearance; grazing

Eucalypt scrubs and shrublandsClearance; grazing

HeathlandsClearance, altered fire regimes,urbanisation, agriculture and sand-mining

Chenopod shrublandsGrazing

Native grasslandsGrazing

Alpine and subalpine vegetationGrazing; tourism; predicted to bevulnerable to global warming

Salt marshes and mangrovesHabitat destruction and degradation

S p e c i e s d i v e r s i t yMicro-organismsHabitat modification and loss

Marine invertebratesHabitat modification and loss; harvestingof edible species; competition frommarine pests

Freshwater invertebratesHabitat modification and loss

Land invertebratesHabitat modification and loss

Marine fishHarvesting of edible species

Freshwater fishHabitat modification and loss;competition and predation fromintroduced species

AmphibiansSubstantial habitat loss but oftenpressures not identified

State

Highly fragmented; many areasdegraded

Highly fragmented

Extensive losses in area andalteration of species composition

Habitat loss and degradation;species diversity reduced

Extreme fragmentation; possibleinability to regenerate

Widespread habitat loss;fragmentation

Widespread habitat degradation;many plant species endangered

Many areas highly degraded oraltered by introduction of exoticspecies

Some areas highly degraded

Extensive loss near urban areas

Unknown but population composi-tion and size likely to be affected

Reduction in population size ofexploited species

Insufficient information to assess

Massive reduction in populationsize of affected species

Many important speciesoverexploited but majority in goodcondition

Generally in poor condition; manyspecies endangered

Several species have disappeared orare declining

AdequateInfo.

YY

YYY

YYY

YY

YY

YY

YYY

YYY

YYY

YY

Y

YY

Y

YY

YY

YY

YY

Response

Listing as protected areas, includingWorld Heritage Register; improved landmanagement

Listing as protected areas

Improved management; reservation

Improved land management

Reservation; restoration

Reserves

Improved land management; reserves

Improved land management/legislation;reservation

Reservation; improved landmanagement

Protected areas; development controls;community awareness

Little direct response

Management plans for exploitedspecies; controls on illegal harvesting

Integrated catchment management;waste-water treatment; restoration ofwetlands; control of introduced pests

Little direct response; protected areas

Management plans for most of themajor species

Integrated catchment management;waste-water treatment; restoration ofwetlands; control of introduced pests

Protected areas; community-initiatedprotection

Effectiveness of response

Limited; some unique areas notprotected; clearing, fire management,grazing and weeds still problematic

Adequate in some areas only

Reserve system inadequate;management practices still indevelopment

Locally effective

Very limited; reserves inadequate

Limited and only locally effective

Locally effective only

Locally effective; reservesinadequate

Many areas now in national parks;others remain degraded andvulnerable

Limited; loss and degradationcontinue in many areas

Not known

Pressures are continuing; very fewsuccesses

Little known

Little known

Pressures are continuing on mostspecies

Very limited effect because ofdifficulty of controlling introducedspecies and long time needed torehabilitate habitat

Lack of knowledge of causes ofdeclines prevents effective action

Table 4.20 Summary

ConclusionAustralia has a world-class heritage of uniqueecosystems, species and genes. Although thecountry was already occupied by Aboriginal people,recent colonisation by people predominantly fromEuropean countries has resulted in theintroduction of many practices that, whileappropriate in their land of origin, have radicallyaltered and degraded much of the Australianlandscape, initiating widespread changes withmany flow-on effects still to appear. We are nowdealing with a continent-wide ecologicalexperiment, the results of which we are strugglingto understand and manage.

Australia has a biodiversity comparable to that ofmany equatorial countries covered in rainforestbut, unlike those countries, is industrialised andhas a comparatively small human population.Consequently, we have the opportunity to balanceconservation of biodiversity, human populationgrowth and economic development. This will comeabout only with substantial changes in the way thatland and oceans are managed. Clearly, manycurrent practices are not sustainable and

biodiversity-based industries such as agriculture,pastoralism, forestry, fisheries and tourism oftenerode the resources upon which they depend.Biodiversity is also a source of profound inspirationto Australians and an essential part of our culture.It is a reservoir of resources that as yet remainrelatively untapped. All these issues demonstratethe urgency of establishing major, often nation-wide, coordinated programs for the discovery,monitoring, management and sustainable use ofbiodiversity.

The use of new management strategies, particularlyecologically sustainable development and theprecautionary principle, if implemented, wouldenable this country to provide world leadership forthe wise use of natural resources for futuregenerations. Our Commonwealth, State, Territory,and local governments have a central role to play inbalancing conservation of biodiversity andeconomic production. Future generations areunlikely to forgive further losses of biodiversitythrough bad management or lack of commitment,especially now that its precarious state isrecognised.


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. . . . . .

Key issue

ReptilesHabitat loss

BirdsHabitat modification and loss; predationfrom feral animals

MammalsHabitat modification and loss;competition with and predation by feralanimals

Marine plantsHabitat modification and loss; pollution;natural events - floods and cyclones

Freshwater plantsHabitat modification and loss

Land plantsClearance; habitat modification and loss

G e n e t i c d i v e r s i t yHabitat fragmentation and loss

State

Massive reduction in numbers inurban and agricultural areas

Some species disappearing, othersthreatened; a few increasing theirrange

Several species lost, othersthreatened; a few increasing innumbers and range

Extensive loss of seagrasses;localised loss of mangroves

Species threatened

Many species endangered orvulnerable

Some species show reduced geneticdiversity

AdequateInfo.

YYY

YYY

YYY

YYY

YY

YYY

Y

Response

Protected areas; protection of marineand freshwater turtles

General protection; protected areas

General protection, protected areas

Protection for seagrasses andmangroves but destruction still allowedin some areas by permit

Limitation on water licences; protectedareas

Protected areas

Protected areas; captive breedingprograms; reintroductions; regulation ofexploitation

Effectiveness of response

Partially effective

Partially effective

Partially effective; pressure fromferal cats and foxes continues

Effective for mangroves; loss ofseagrass likely to continue throughcoastal development and naturalevents

Little known

Effective in some areas

Little known; research in progress.

Table 4.20 Summary (continued)

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Zann, L.P. (1995). ‘Our Sea, Our Future. MajorFindings of the State of the Marine EnvironmentReport for Australia.’ Published by the Great BarrierReef Marine Park Authority for DEST, Ocean Rescue2000 Program, pp. 1–112.

Zann, L.P., and Kailola, P. (1995). ‘The State of theMarine Environment Report for Australia. TechnicalAnnex 1: the Marine Environment.’ Published by theGreat Barrier Reef Marine Park Authority for DEST,Ocean Rescue 2000 Program, pp. 1–193.


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AcknowledgmentsThe following people reviewed the chapter in draft formand provided constructive comments.

Professor Rhonda Jones (James Cook University)Dr Sam Lake (Monash University)Dr Judith Lambert (Community Solutions)Professor Henry Nix (Australian National University)Professor Harry Recher (Edith Cowan University)

A number of people from government departments,private industry and voluntary organisations providedinformation. We especially thank the following whoassisted in the preparation of this chapter:

Jim Crennan (Australian Nature Conservation Agency)Rohan Fernando (Australian Nature Conservation Agency)Andreas Glanznig (Community Biodiversity Network)Andrew Taplin (Australian Nature Conservation Agency)

In addition, Commonwealth Government departmentsand members of the Commonwealth/State ANZECCState of the Environment Reporting Taskforce alsohelped identify errors of fact or omission. Theirassistance is also gratefully acknowledged.

Photo creditsPage 4-1: Richard WeatherlyPage 4-4: (from top) CSIRO Division of Fisheries;

D. McKillop (GBRMPA); GBRMPAPage 4-5: (top) Kathie Atkinson; (bottom) Beth SeviourPage 4-6: (top) Kathie Atkinson; (bottom) CSIROPage 4-7: Denis Saunders (CSIRO Division of Wildlife

& Ecology)Page 4-8: Kathie AtkinsonPage 4-10: CSIRO Division of FisheriesPage 4-12: Kathie AtkinsonPage 4-15: Kathie AtkinsonPage 4-18: Ian MorrisPage 4-20: CSIRO Division of FisheriesPage 4-21: Denis Saunders (CSIRO Division of Wildlife

& Ecology)Page 4-22: Kathie AtkinsonPage 4-27: Land Information Centre, Bathurst; from

data captured by ACRESPage 4-31: (from left) Michael Sharp (NSW Parks &

Wildlife Service); Wyn Jones (NSW Parks & WildlifeService)

Page 4-33: Painting by Oldfield Thomas (ANT PhotoLibrary)

Page 4-38: (left column) Robert Close; (right column)Manfred Jusaitis (Botanic Gardens of Adelaide)

Page 4-44: D. Whitford (ANT Photo Library)Page 4-45: Greening Australia, VictoriaPage 4-48: Colin Harris (Dept E&NR SA)Page 4-50: Nick Alexander (Oryx Films)


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