ENVIRONMENTAL SCIENCE 13e

CHAPTER 8:Sustaining Biodiversity: The Species Approach

Core Case Study: Polar Bears and Projected Climate Change

• 20,000 – 25,000 polar bears in Arctic

• Hunt seals on winter sea ice

• Global warming is quickly reducing the amount of sea ice and how long it lasts in winter

• Polar bears have less time to hunt and store fat for summer fasting

• Projected 30-35% decline by 2050

• Potentially extinct from wild by 2100

Fig. 8-1, p. 152

8-1 What Role Do Humans Play in the Premature Extinction of Species?

• Concept 8-1 Species are becoming extinct 100 to 1,000 times faster than they were before modern humans arrived on earth, and by the end of this century, the extinction rate is expected be 10,000 times higher than the background rate.

Human Activities and Extinction

• Background extinction rate

• Current rate is 100-1000 times background extinction

• Rate likely to rise to 10,000 times

• Is a mass extinction coming?

Current Extinction Rate Estimates Are Conservative

• Species and biodiversity decrease in next 50–100 years

• Biodiversity hotspot rates higher than global average

• Degrading, simplifying, and destroying diverse environments

Fig. 8-2, p. 154

Aepyornis(Madagascar)

Passenger pigeon Great auk Dodo Golden Toad

Fig. 8-2, p. 154

Science Focus: Estimating Extinction Rates (1)

• Three difficulties1. Not easy to document – takes a long

time

2. Only 2 million species of 8-100 million identified

3. Little is known about the 2 million species

Science Focus: Estimating Extinction Rates (2)

• Study records of post-human extinctions with previous extinctions from the fossil record

• DNA copying mistakes• How habitat reduction increases extinction• Mathematical models• Inadequate data and models• Normal: 1 million to 10 million years• Humans have greatly accelerated this

Ecological Smoke Alarms

• Endangered species

• Threatened species

• The first to go: large, slow, tasty, or have valuable parts

• Some behaviors make species prone to extinction

Fig. 8-3, p. 156

Siberian tiger

Grizzly bear Kirkland’s warbler

Knowlton cactus Florida manatee African elephant

Utah prairie dog Swallowtail butterfly

Humpback chub Golden lion tamarin

Fig. 8-3, p. 156

Fig. 8-3, p. 156

Black rhinoceros

Giant panda Black-footed ferret

Whooping crane Northern spotted owl

Blue whale

Mountain gorilla Florida panther California condor Hawksbill sea turtle

Fig. 8-3, p. 156

Fig. 8-4, p. 157

Large territories

Blue whale, giant panda, rhinoceros

Blue whale, giant panda, Everglades kite

Elephant seal, desert pupfish

Bengal tiger, bald eagle, grizzly bear

Blue whale, whooping crane, sea turtle

African violet, someorchids

Snow leopard, tiger, elephant, rhinoceros, rare plants and birds

California condor, grizzly bear, Florida panther

ExamplesCharacteristic

Low reproductiverate

Specializedniche

Narrowdistribution

Feeds at hightrophic level

Fixed migratorypatterns

Rare

Commerciallyvaluable

Fig. 8-4, p. 157

Stepped Art

Fixed migratory patterns

Blue whale, whooping crane, sea turtle

Feeds at high trophic level

Bengal tiger, bald eagle, grizzly bear

Narrow distribution

Elephant seal, desert pupfish

Commercially valuable

Snow leopard, tiger, elephant, rhinoceros, rare plants and birds

Low reproductive rate

Blue whale, giant panda, rhinoceros

Characteristic Examples

Rare African violet, some orchids

Large territoriesCalifornia condor, grizzly bear, Florida panther

Specialized niche

Blue whale, giant panda, Everglades kite

Fig. 8-4, p. 157

Fig. 8-5, p. 157

25%

Fish

Amphibians

Mammals

Reptiles

Plants

Birds

34% (51% of freshwater species)

32%

12%

14%

20%

Fig. 8-5, p. 157

Case Study: Extinction of the Passenger Pigeon

• Audubon, 1813: 3 days for a flock to pass over

• Extinct by 1900– Good to eat

– Feathers good for pillows

– Bones good for fertilizer

– Easy to kill

8-2 Why Should We Care about Preventing Species Extinction? • Concept 8-2 We should prevent the

premature extinction of wild species because of the economic and ecological services they provide and because they have a right to exist regardless of their usefulness to us.

Value of Species

• Instrumental value of biodiversity – Food crops– Genetic information– Medicine– Bioprospectors– Ecotourism

• Do not know what we lose when species go extinct

Fig. 8-6, p. 158

Fig. 8-7, p. 158

Cathranthus roseus,MadagascarHodgkin's disease,lymphocytic leukemia

Rauvolfia

Rauvolfia sepentina,Southeast AsiaAnxiety, highblood pressure

Foxglove

Digitalis purpurea,EuropeDigitalis for heart failure

Pacific yew

Taxus brevifolia,Pacific NorthwestOvarian cancer

Cinchona

Cinchona ledogeriana,South AmericaQuinine for malaria treatment

Neem tree

Azadirachta indica,IndiaTreatment of manydiseases, insecticide,spermicide

Rosy periwinkle

Fig. 8-7, p. 158

Ethical Obligations

• Intrinsic (existence) value

• Stewardship viewpoint

8-3 How Do Humans AccelerateSpecies Extinction?

• Concept 8-3 The greatest threats to any species are (in order) loss or degradation of its habitat, harmful invasive species, human population growth, pollution, climate change, and overexploitation.

Fig. 8-8, p. 160

Fig. 8-8, p. 160

Causes of Depletion and Premature Extinction of Wild Species

• Population growth

• Rising resource use

• Undervaluing natural capital

• Poverty

• Habitat loss

• Habitat degradation and fragmentation

• Introduction of nonnative species

• Commercial hunting and poaching

• Sale of exotic pets and decorative plants

• Predator and pest control

• Pollution

• Climate change

• Overfishing

Underlying Causes

Direct Causes

Natural Capital Degradation

Causes of Endangerment and Premature Extinction (HIPPCO)

• Habitat destruction

• Invasive species

• Population growth

• Pollution

• Climate change

• Overexploitation

Habitat Loss

• Deforestation of tropical areas greatest eliminator of species

• Endemic species

• Habitat fragmentation

Fig. 8-9, p. 161

Fig. 8-9, p. 161

Stepped Art

Indian Tiger

Range 100 years agoRange today

Black Rhino

Range in 1700

Range today

African Elephant

Probable range 1600Range today

Asian or Indian Elephant

Former rangeRange today

Fig. 8-9, p. 161

Case Study: Declining BirdSpecies (1)

• Decline of ~70% of ~10,000 known species

• 12% threatened with extinction

• Birds around humans benefited, but forest species declined

• Long-distance migrants – greatest decline

Case Study: Declining BirdSpecies (2)

• Reasons – Habitat loss

– Habitat fragmentation

– Climate change

• Birds are environmental indicators

• Perform economic and ecological services

Species Introductions

• Most beneficial – food crops, livestock, pest control

• 500,000 alien invader species globally

• 50,000 nonnative species in the U.S.

• Some definitely not beneficial

Fig. 8-10, p. 163

European wild boar(Feral pig)

Deliberately Introduced Species

Purple loosestrife European starling African honeybee(“Killer bee”)

Nutria Salt cedar(Tamarisk)

Marine toad(Giant toad)

Water hyacinth Japanese beetle Hydrilla

Fig. 8-10, p. 163

Fig. 8-10, p. 163

Gypsy moth larvae

Accidentally Introduced Species

Sea lamprey(attached to lake trout)

Argentina fire ant

Brown tree snake

Eurasian ruffe Common pigeon(Rock dove)

Formosan termite

Zebra mussel Asian long-horned beetle

Asian tiger mosquito

Fig. 8-10, p. 163

Stepped Art

Deliberately introduced species

Purple loosestrife

European starling

African honeybee (“Killer bee”)

Nutria Salt cedar (Tamarisk)

Marine toad (Giant toad)

Water hyacinth

Japanese beetle

Hydrilla European wild boar (Feral pig)

Accidentally introduced species

Sea lamprey (attached to lake trout)

Argentina fire ant

Brown tree snake

Eurasian ruffe

Common pigeon (Rock dove)

Formosan termite

Zebra mussel

Asian long-horned beetle

Asian tiger mosquito

Gypsy moth larvae Fig. 8-10, p. 163

Case Study: The Kudzu Vine

• Kudzu introduced to control erosion• Prolific growth• Uses

– Asians use powdered starch in beverages

– Edible – Source of tree-free paper– Japanese kudzu farm in Alabama

Fig. 8-11, p. 164

Disruptions from AccidentallyIntroduced Species

• Downside of global trade

• Downside of traveling

• Argentina fire ant

• Burmese python

• Zebra mussel

Fig. 8-12, p. 165

Prevention of Nonnative Species (1)

• Identify characteristics of successful invaders

• Detect and monitor invasions

• Inspect imported goods

• Identify harmful invasive species and ban transfer

Prevention of Nonnative Species (2)

• Ships discharge ballast waters at sea

• Introduce natural control organisms of invaders

Fig. 8-13, p. 165

Fig. 8-14, p. 166

Human Choices Drive Extinction

• Human population growth

• Excessive, wasteful consumption

• Use of pesticides

• Climate change

DDT and Bioaccumulation

• 1950s–1960s fish-eating bird populations drop

• DDT biologically magnified in food webs

• Bird’s eggshells thin and fragile

• Leads to unsuccessful reproduction

Fig. 8-15, p. 166

DDT in water0.000003 ppm,or 3 ppt

DDT in fish-eatingbirds (ospreys)

25 ppm

DDT in largefish (needle fish)2 ppm

DDT in smallfish (minnows)0.5 ppm

DDT inzooplankton0.04 ppm

Fig. 8-15, p. 166

Stepped Art

DDT in water 0.000003 ppm, or 3 ppt

DDT in small fish (minnows) 0.5 ppm

DDT in zooplankton 0.04 ppm

DDT in fish-eating birds (ospreys)

25 ppm

DDT in large fish (needle fish) 2 ppm

Fig. 8-15, p. 166

Case Study: Where Have All the Honeybees Gone?

• Honeybees responsible for 80% of pollination of insect-pollinated plants

• Population down 30% since the 1980s– Pesticides– Parasitic mites– Invasive African honeybees

• 2008: 36% of honeybee colonies lost– Colony collapse disorder– New nicotine-based pesticides to blame?

Illegal Killing and Trading of Wildlife

• Poaching endangers many larger animals, rare plants

• Over two-thirds die in transit

• Illegal trade: $1.1 million per hour

• Wild species depleted by pet trade

• Exotic plants often illegally gathered

Fig. 8-16, p. 168

Fig. 8-A, p. 168

The Value of Wild Rare Species

• Declining populations increase black market values

• Rare species valuable in the wild – eco-tourism

• Some ex-poachers turn to eco-tourism

Rising Demand for Bush Meat

• Demand increasing with population growth

• Increased road access

• Loggers, miners, ranchers add to pressure

• Local and biological extinctions

• Spread of HIV and Ebola virus

Fig. 8-17, p. 169

8-4 How Can We Protect Wild Species from Premature Extinction?

• Concept 8-4 We can reduce species extinction and help to protect overall biodiversity by establishing and enforcing national environmental laws and international treaties, creating a variety of protected wildlife sanctuaries, and taking precautionary measures to prevent such harm.

International Treaties

• Convention on International Trade of Endangered Species (CITES)

• Convention on Biological Diversity (CBD)

U.S. Endangered Species Act (1)

• National Marine Fisheries Services – ocean species

• U.S. Fish and Wildlife Service – other species

• Listings based on biological factors

• Forbids federal agency projects that jeopardize listed species or habitats

U.S. Endangered Species Act (2)

• Fines violations on private land

• Illegal to sell or buy listed species

• 1,318 species listed

• USFWS and NMFS supposed to prepare recovery plan – 86% species in 2009

U.S. Endangered Species Act (3)

• Successful recovery plans include American alligator, grey wolf, and bald eagle

• Lax enforcement of imports and exports

• Amended to give private landowners economic incentive to save species

Science Focus: Accomplishments of the Endangered Species Act

• Biologists defend limited success– Species listed only when gravely threatened– Takes long time for species to recover– >50% endangered species improving

• Need more funding

• Develop recovery plans more quickly

• Core habitat established when listed

Protection of Marine Species

• ESA and international treaties protect endangered marine reptiles and mammals

• Challenges to protecting marine species– Limited knowledge of species

– Difficulty in monitoring and enforcing treaties – open oceans

Sea Turtles Threatened

• Six species critically endangered

• Loss or degradation of habitat

• Illegal harvest of eggs

• Threats from fishing methods

• Protection measures have helped

Fig. 8-18, p. 171

Case Study: Protecting Whales (1)

• Easy to kill

• International Whaling Commission– Sets quotas

– Often ignored

– No enforcement powers

• 1986: Whaling ban, although violated, greatly decreased whale kills

Case Study: Protecting Whales (2)

• Key countries that violate whaling ban– Japan

– Norway

– Iceland

Fig. 8-19, p. 172

Establish Wildlife Refuges

• National Wildlife Refuge System• Wetland refuges: ~75%• 40 million American visitors• 20% of listed species in refuge system• Many refuges in disrepair, and many

allow mining, oil drilling, and off-road vehicles

Storing Genetic Information

• Gene or seed banks

• Botanical gardens and arboreta

• Farms – commercial sale of endangered species removes pressure

Zoos and Aquariums for Protection

• Collect species with long-term goal of returning them into habitat

• Egg pulling• Captive breeding• 100–500 captive individuals to avoid

extinction• 10,000 individuals to maintain

capacity for biological evolution

Case Study: Trying to Save the California Condor

• Last 22 individuals captured

• Released a few at a time

• 2009: 167 condors in the wild

• Threatened by lead poisoning from animal carcasses and gut piles

The Precautionary Principle

• When substantial preliminary evidence indicates an activity could harm humans or the environment, we should take precautionary measures to prevent or reduce the harm

• Do even if cause-and-effect relationships are not yet clearly established

• “Better safe than sorry”

Three Big Ideas from This Chapter - #1

We are greatly increasing the premature extinction of wild species by destroying and degrading their habitats, introducing harmful invasive species, and increasing human population growth, pollution, contributing to projected climate change, and over-exploitation.

Three Big Ideas from This Chapter - #2

We should prevent the premature extinction of wild species because of the economic and ecological services they provide and because they have a right to exist regardless of their usefulness to us.

Three Big Ideas from This Chapter - #3

We can work to prevent the premature extinction of species and to protect overall biodiversity by using laws and treaties, protecting wildlife sanctuaries, and making greater use of the precautionary principle.

Animation: Species Diversity By Latitude

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Animation: Area and Distance Effects

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Animation: Humans Affect Biodiversity

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Animation: Resources Depletion and Degradation

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Animation: Biodiversity Hot Spots

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Animation: Habitat Loss and Fragmentation

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Video: New Species Found

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Video: Hsing Hsing Dies

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Video: Penguin Rescue

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Video: Bachelor Pad at the Zoo

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Video: Sea Turtle Release

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Video: Human Zoo

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