Chapter 12Chapter 12

Sustaining Biodiversity:Sustaining Biodiversity:

The Species Approach The Species Approach

Key ConceptsKey Concepts

Human effects on biodiversityHuman effects on biodiversity Importance of biodiversityImportance of biodiversity How human activities affect How human activities affect

wildlifewildlife Management of wildlifeManagement of wildlife

67%Secure orapparently

secure

1%Other

16%Vulnerable

8%Imperiled

7%Critically imperiled

1% Probably extinct

US Diversity

What Increases What Increases Biodiversity?Biodiversity?

Physically diverse habitatPhysically diverse habitatModerate environmental Moderate environmental

disturbancedisturbanceSmall variations in conditionsSmall variations in conditionsMiddle stages of ecological Middle stages of ecological

successionsuccession

What Decreases What Decreases Biodiversity?Biodiversity?

Environmental stressEnvironmental stress Large environmental disturbanceLarge environmental disturbance Extreme environmental conditionsExtreme environmental conditions Severe limiting factorsSevere limiting factors Introduction of alien (exotic) Introduction of alien (exotic)

speciesspecies Geographic isolationGeographic isolation

Projected Status of Biodiversity1998–2018

Critical and endangered Threatened Stable or intact

ANTARCTICA

NORTHAMERICA

EUROPE

AFRICA

ASIA

SOUTHAMERICA AUSTRALIA

PacificOcean

Antarctic Circle

PacificOcean

Tropic of Cancer

Tropic of CapricornIndianOcean

AtlanticOcean

150°90°60°E0°30°W90°120°150°0°

60°

30°N

30°S

60°

Arctic CircleArctic Circle

Strategies for Protecting Species

Species ExtinctionSpecies Extinction

Local ExtinctionLocal Extinction: when a species is no : when a species is no longer found in the area that it once longer found in the area that it once inhabited (but is still found elsewhere inhabited (but is still found elsewhere in the world)in the world)

Ecological ExtinctionEcological Extinction: so few members : so few members of a species are left that it can’t play of a species are left that it can’t play its ecological roleits ecological role

Biological ExtinctionBiological Extinction: species is not : species is not found anywhere on earth (permanent)found anywhere on earth (permanent)

Endangered and Threatened Endangered and Threatened SpeciesSpecies

Endangered SpeciesEndangered Species: so few : so few survivors that the species could soon survivors that the species could soon become extinctbecome extinct

Threatened SpeciesThreatened Species: still abundant in : still abundant in its natural range but is likely to its natural range but is likely to become endangered due to declining become endangered due to declining numbersnumbers

Extinction RisksExtinction Risks

Low reproductive rateLow reproductive rate (K-strategists): (K-strategists): blue whale, giant pandablue whale, giant panda

Specialized nicheSpecialized niche: giant panda: giant panda Narrow distributionNarrow distribution: island species: island species Feeds at high trophic levelFeeds at high trophic level: Bengal : Bengal

tiger, bald eagletiger, bald eagle RareRare: island species, orchids: island species, orchids Commercially valuableCommercially valuable: elephant: elephant

How Do We Estimate Extinction How Do We Estimate Extinction Risks?Risks?

Population viability analysis (PVAPopulation viability analysis (PVA): ): risk assessment to predict whether a risk assessment to predict whether a population will persist for a certain # population will persist for a certain # of generationsof generations

PVA is based onPVA is based on: resource needs, : resource needs, current and predicted habitat current and predicted habitat conditions, genetic variability, conditions, genetic variability, interactions with other species, interactions with other species, reproductive ratesreproductive rates

Continued…Continued…

Minimum viable population (MVP)Minimum viable population (MVP): : smallest number of individuals smallest number of individuals necessary for the survival of a necessary for the survival of a population in a regionpopulation in a region

Minimum dynamic area (MDA)Minimum dynamic area (MDA): the : the minimum area of habitat needed to minimum area of habitat needed to maintain the MVPmaintain the MVP

Why Should We Care About Why Should We Care About Biodiversity?Biodiversity?

Humans value nature in different Humans value nature in different waysways

Instrumental valueInstrumental value: usefulness to us: usefulness to us Intrinsic valueIntrinsic value: because they exist, : because they exist,

regardless of useregardless of use UtilitarianUtilitarian (use): goods, services, (use): goods, services,

recreationrecreation NonutilitarianNonutilitarian (nonuse): aesthetic (nonuse): aesthetic

Value of Nature

Instrumental Intrinsic

Utilitarian Nonutilitarian

(human centered) (species orecosystemcentered)

Goods

Ecological services

Information

Recreation

Existence

Aesthetic

Causes of Depletion of Wild Causes of Depletion of Wild SpeciesSpecies

Human population growthHuman population growthFailure to value the Failure to value the

environmentenvironment Increasing resource useIncreasing resource usePovertyPoverty

Overfishing

Habitatloss

Habitatdegradation

Introducingnonnativespecies

Commercialhunting

Sale ofexotic pets

anddecorative

plants

Predatorandpest

control

Pollution

Climatechange

Basic Causes

• Population growth• Rising resource use• No environmental

accounting• Poverty

Type of Nonnative Organism Annual Losses and DamagesCrop disease

Crop weeds

Rats

Feral cats and outdoor pet cats

Crop insects

Livestock diseases

Forest insects and diseases

Zebra mussels

Common pigeon

Formosan termite

Fishes

Asian clam

Feral pigs

Starlings

Fire ant

$23.5 billion

$23.4 billion

$19 billion

$17 billion

$14 billion

$9 billion

$4.8 billion

$3 billion

$1.1 billion

$1.1 billion

$1.1 billion

$1.1 billion

$0.8 billion

$0.8 billion

$0.6 billion

Damage from

NonnativeSpecies

Characteristics ofSuccessful

Invader Species

• High reproductive rate, short generation time (r-selected species)

• Pioneer species

• Long lived

• High dispersal rate

• Release growth- inhibiting chemicals into soil

• Generalists

• High genetic variability

Characteristics ofEcosystems Vulnerable

to Invader Species

• Similar climate to habitat of invader

• Absence of predators on invading species

• Early successional species

• Low diversity of native species

• Absence of fire

• Disturbed by human activities

What Can Be Done to Reduce What Can Be Done to Reduce Threat from Nonnative Threat from Nonnative

Species?Species? Identify characteristics that make Identify characteristics that make

species successful invaders and use species successful invaders and use this information to screen out this information to screen out invadersinvaders

Increase inspections of goods coming Increase inspections of goods coming into a countryinto a country

Pass laws to ban the transfer of Pass laws to ban the transfer of harmful invader speciesharmful invader species

Biome % of Area Disturbed

Temperate broadleaf forests

Temperate evergreen forests

Temperate grasslands

Mixed mountain systems

Tropical dry forests

Subtropical and temperate rain forests

Cold deserts and semideserts

Mixed island systems

Warm deserts and semideserts

Tropical humid forests

Tropical grasslands

Temperate boreal forests

Tundra

94%

94%

72%

71%

70%

67%

55%

53%

44%

37%

26%

18%

0.7%

HabitatDisturbance

by Biome

Hunting and PoachingHunting and Poaching

Wild African ElephantWild African Elephant

1970: 2.5 million1970: 2.5 million Today: 300,000Today: 300,000 Killed for tusks (worth about $500-1500)Killed for tusks (worth about $500-1500) Bleed to deathBleed to death 1989 ban on sale of ivory from 1989 ban on sale of ivory from

elephantselephants Caused increased killing of walruses Caused increased killing of walruses

and hippos for ivoryand hippos for ivory

DO NOT POST TO INTERNET

Protecting Wild Species IProtecting Wild Species I

BioinformaticsBioinformatics: managing, analyzing, : managing, analyzing, and communicating biological and communicating biological informationinformation

Involves: 1. building computer Involves: 1. building computer databases 2. developing computer tools databases 2. developing computer tools to analyze the information 3. to analyze the information 3. communicating the informationcommunicating the information

Example: Example: Species 2000- Species 2000- global research global research project with the goal of providing project with the goal of providing information about all species on earthinformation about all species on earth

Protecting Wild Species IIProtecting Wild Species II

International TreatiesInternational Treaties Convention on International Trade in Convention on International Trade in

Endangered SpeciesEndangered Species (CITES) 1972 (CITES) 1972 Signed by 152 countriesSigned by 152 countries Lists 900 species that cannot be Lists 900 species that cannot be

commercially tradedcommercially traded Restricts international trade of Restricts international trade of

29,000 other at-risk species29,000 other at-risk species

Protecting Wild Species IIIProtecting Wild Species III

National LawsNational Laws Lacey Act of 1900Lacey Act of 1900: prohibits : prohibits

transportation of live or dead animals transportation of live or dead animals (or their parts) across state borders (or their parts) across state borders without a permitwithout a permit

Endangered Species Act of 1973Endangered Species Act of 1973: : illegal for Americans to import or illegal for Americans to import or trade any product made from an trade any product made from an endangered or threatened speciesendangered or threatened species

Protecting Wild Species IVProtecting Wild Species IV

Habitat Conservation PlansHabitat Conservation Plans Compromise between endangered Compromise between endangered

species and private landownersspecies and private landowners Landowners are allowed to kill a certain Landowners are allowed to kill a certain

# of endangered species on private land # of endangered species on private land in exchange for taking steps to protect in exchange for taking steps to protect the speciesthe species

Possible stepsPossible steps: setting aside a preserve for : setting aside a preserve for the species, paying to relocate the the species, paying to relocate the species, paying for government buy species, paying for government buy habitat elsewherehabitat elsewhere

Other Approaches to Protecting Other Approaches to Protecting Wild SpeciesWild Species

Wildlife refuges and protected Wildlife refuges and protected areasareas

Gene banks (storing plant seeds), Gene banks (storing plant seeds), botanical gardens (cultivation of botanical gardens (cultivation of rare and endangered plants), and rare and endangered plants), and farms (raise for commercial sale)farms (raise for commercial sale)

Zoos and aquariumsZoos and aquariums

Wildlife ManagementWildlife Management

Laws regulating hunting and Laws regulating hunting and fishingfishing

Harvest quotasHarvest quotasPopulation management plansPopulation management plans Improving habitatImproving habitatLaws for migrating speciesLaws for migrating species