Sustaining Biodiversity:

The Species ApproachChapter 9

Core Case Study: The Passenger Pigeon: Gone

Forever• Passenger pigeon hunted to extinction by 1900

• Commercial hunters used a "stool pigeon”• Archeological record shows five mass

extinctions• Human activities: hastening more

extinctions?

SELF - STUDY

9-1 What Role Do Humans Play in the Premature Extinction of Species?• Concept 9-1A We are degrading and

destroying biodiversity in many parts of the world, and these threats are increasing.

• Concept 9-1B Species are becoming extinct 100 to 1,000 times faster than they were before modern humans arrived on the earth (the background rate), and by the end of this century, the extinction rate is expected to be 10,000 times the background rate.

Human Activities Are Destroying and Degrading

Biodiversity• Human activity has disturbed at least half to 83%* of the earth’s land surface– Filling in wetlands– Converting grasslands and forests to

crop fields and urban areas• Degraded aquatic biodiversity*2005 Millennium Ecosystem Assessment

Extinctions Are Natural but Sometimes They Increase

Sharply• Background extinction estimated = 0.0001%

• Extinction rate Can be #/million/year or %/yr.

• Mass extinction: causes?• Levels of species extinction

– Local extinction – extinct in one area, but not others

– Ecological extinction – so few individuals that species can’t fill their ecological role

– Biological extinction – none anywhere on earth… this is forever.

Human Activities Cause Premature Extinctions: Pace

Is Speeding Up• Premature extinctions due to

– Habitat destruction– Overhunting

• Where are the golden toads?

Human Activities Cause Premature Extinctions:

Pace Is Speeding Up• Conservative estimates of extinction = 0.01-1%– Growth of human population will increase this

loss– Rates are higher where there are more

endangered species– Tropical forests and coral reefs, wetlands and

estuaries—sites of new species—being destroyed

• Speciation crisis – “death is one thing. The lack of births is another.” (loss of genetic biodiversity and diverse habitats can cause speciation to slow)

Effects of a 0.1% Extinction Rate

Endangered and Threatened Species Are Ecological Smoke Alarms• Endangered species – so few indiv. left that it could soon become extinct over all or part of natural range.

• Threatened species (vulnerable species) – likely to become endangered soon… declining numbers

Endangered

Natural Capital: Species

Threatened with

Premature

Extinction

Characteristics of

Species That Are Prone to

Ecological and

Biological Extinction

The big, the slow, the tasty, those with

valuable parts.

Percentage of Various Species Threatened with

Premature Extinction

IUCN• International Union for the

Conservation of Nature and Natural Resources – World Conservation Union

• Red lists – in 2007: 16,306 species of plant and animals listed as in danger of extinction.

Science Focus: Estimating Extinction

Rates Is Not Easy• Three problems– Hard to document due to length of time– Only 1.8 million species identified– Little known about nature and ecological

roles of species identified• Document little changes in DNA• Use species–area relationship -

90% habitat loss causes 50% of species to become extinct

• Mathematical models

9-2 Why Should We Care about Preventing Premature

Species Extinction?• Concept 9-2 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.

Species Are a Vital Part of the Earth’s Natural Capital

• Instrumental value (2 forms)– 1) Use value

• Ecotourism: wildlife tourism• Genetic information

– 2) Nonuse value • Existence value – appreciate that it exists• Aesthetic value – it’s pretty• Bequest value – willing to pay so it will be

there for future generations• Ecological value – plays a role in

ecosystem

Natural Capital Degradation: Endangered Orangutans in

Tropical Forest

Natural Capital: Nature’s Pharmacy

Science Focus: Using DNA to Reduce Illegal Killing of Elephants for Their Ivory

• 1989 international treaty against poaching elephants (although, poaching is on the rise)

• Track area of poaching through DNA analysis of elephants

• WWF - Wildlife crime scorecard• Elephants damaging areas

of South Africa: Should they be culled?

Are We Ethically Obligated to Prevent

Premature Extinction?• Intrinsic value: existence value • Edward O. Wilson: biophilia

phenomenon• Biophobia

Science Focus: Why Should We Care about

Bats?• Vulnerable to extinction– Slow to reproduce– Human destruction of habitats

• Important ecological roles– Feed on crop-damaging nocturnal

insects– Pollen-eaters– Fruit-eaters

• Unwarranted fears of bats

Be afraid of this one

9-3 How do Humans Accelerate

Species Extinction?• Concept 9-3 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.

Loss of Habitat Is the Single Greatest Threat to

Species: Remember HIPPCO• Habitat destruction, degradation,

and fragmentation• Invasive (nonnative) species• Population and resource use growth• Pollution• Climate change• Overexploitation

Causes of Depletion and Premature Extinction of

World Species

Natural Capital

Degradation:

Reduction in the

Ranges of Four

Wildlife Species

Science Focus: Studying the Effects of Forest

Fragmentation on Old-Growth Trees• Tropical Biologist Bill Laurance, et al.

• How large must a forest fragment be in order to prevent the loss of rare trees?

• Within 100m of the edge of plots, 36% of old-growth biomass is lost.

Case Study: A Disturbing Message

from the Birds• 70% of species declining• Habitat loss and fragmentation of the

birds’ breeding habitats– Forests cleared for farms, lumber

plantations, roads, and development• Intentional or accidental introduction

of nonnative species– Eat the birds– Everglades!

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Case Study: A Disturbing Message

from the Birds• Seabirds caught and drown in fishing equipment

• Migrating birds fly into power lines, communication towers, and skyscrapers

• Other threats– Oil spills– Pesticides– Herbicides– Ingestion of toxic

lead shotgun pellets

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Case Study: A Disturbing Message

from the Birds• Greatest new threat: Climate change• Environmental indicators• Economic and ecological servicesSELF - STUDY

Distribution of Bird Species in North America and Latin AmericaSELF - STUDY

The 10 Most Threatened Song Birds

in the United States

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Science Focus: Vultures, Wild Dogs, and Rabies: Unexpected Scientific

Connections• Vultures poisoned from diclofenac in cow carcasses

• More wild dogs eating the cow carcasses (increases milk production in cows)

• Increase in wild dog population• More rabies spreading to people –

more than ½ of rabies cases in the world

SELF – STUDYBut see

Cats of Borneo

Some Deliberately Introduced Species Can

Disrupt Ecosystems• Most species introductions are beneficial– Food– Shelter– Medicine– Aesthetic enjoyment

• Nonnative species may have no natural– Predators– Competitors– Parasites– Pathogens

Case Study: The Kudzu Vine

• Imported from Japan in the 1930s • “ The vine that ate the South”• Could there be benefits of kudzu?

Some Accidentally Introduced Species Can Also Disrupt Ecosystems

• Argentina fire ant: 1930s– Pesticide spraying in 1950s and 1960s

worsened conditions • Burmese python

Argentina Fire Ant

Accidentally

Introduced into

Mobile, Alabama,

U.S.

Prevention Is the Best Way to Reduce Threats from

Invasive Species• Prevent them from becoming

established• Learn the characteristics of the

species• Set up research programs• Try to find natural ways to control

them

Other Causes of Species Extinction

• Population growth• Overconsumption• Pollution• Climate change

Other Causes of Species Extinction

• Pesticides– DDT: Banned in the U.S. in 1972

• Bioaccumulation- increase in concentration of a pollutant from the environment to the first organism in a food chain

• Biomagnification-increase in concentration of a pollutant from one link in a food chain to another

Bioaccumulation and Biomagnification

Case Study: Where Have All the Honeybees Gone?• Honeybees responsible for 80% of

insect-pollinated plants• Dying due to?

– Pesticides– Parasites– Bee colony collapse syndrome

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Case Study: Polar Bears and

Global Warming• Environmental impact on polar bears– Less summer sea ice– PCBs and DDT

• 2007: Threatened species listSELF - STUDY

Illegal Killing, Capturing, and Selling of Wild Species Threatens Biodiversity

• Poaching and smuggling of animals and plants– Animal parts– Pets– Plants for landscaping and enjoyment

• Prevention: research and education

Animals Killed by a Poacher

Individuals Matter: Jane Goodall

• Primatologist and anthropologist• 45 years understanding and

protecting chimpanzees– Chimps have tool-making skillsSELF - STUDY

Rising Demand for Bush Meat Threatens Some

African Species• Indigenous people sustained by bush meat

• More hunters leading to local extinction of some wild animals

9-4 How Can We Protect Wild Species from

Premature Extinction? • Concept 9-4A We can use existing environmental laws and treaties and work to enact new laws designed to prevent species extinction and protect overall biodiversity.

• Concept 9-4B We can help to prevent species extinction by creating and maintaining wildlife refuges, gene banks, botanical gardens, zoos, and aquariums.

• Concept 9-4C According to the precautionary principle, we should take measures to prevent or reduce harm to the environment and to human health, even if some of the cause-and-effect relationships have not been fully established, scientifically.

International Treaties Help to

Protect Species• 1975: Convention on International Trade in Endangered Species (CITES)– Signed by 172 countries

• Convention on Biological Diversity (BCD)– Focuses on ecosystems– Ratified by 190 countries (not the U.S.)

Case Study: The U.S. Endangered Species Act

• Endangered Species Act (ESA): 1973 and later amended in 1982, 1983, and 1985

• Identify and protect endangered species in the U.S. and abroad

• Hot Spots• Habitat Conservation Plan (HCP)

colony

Case Study: The U.S. Endangered Species Act

• Mixed reviews of the ESA– Weaken it– Repeal it– Modify it– Strengthen it– Simplify it– Streamline it

Confiscated Products Made from Endangered

Species

Science Focus: Accomplishments of the Endangered

Species Act • Species listed only when serious

danger of extinction• Takes decades for most species to

become endangered or extinct• More than half of the species listed

are stable or improving• Budget has been small

Science Focus: Accomplishments of the Endangered

Species Act • Suggested changes to ESA

– Increase the budget– Develop recovery plans more quickly– Establish a core of the endangered

organism’s survival habitat

We Can Establish Wildlife Refuges

and Other Protected Areas• 1903: Theodore Roosevelt• Wildlife refuges

– Most are wetland sanctuaries– More needed for endangered plants– Could abandoned military lands be used

for wildlife habitats? (UXO at Big Oaks in Southeastern Indiana)

Gene Banks, Botanical Gardens, and Wildlife

Farms Can Help Protect Species• Gene or seed banks

– Preserve genetic material of endangered plants

• Botanical gardens and arboreta– Living plants

• Farms to raise organisms for commercial sale

Zoos and Aquariums Can Protect

Some Species• Techniques for preserving endangered terrestrial species– Egg pulling– Captive breeding– Artificial insemination– Embryo transfer– Use of incubators– Cross-fostering

Zoos and Aquariums Can Protect

Some Species • Limited space and funds• Critics say these facilities are prisons

for the organisms

Case Study: Trying to Save the

California Condor• Largest North American bird• Nearly extinct

– Birds captured and breed in captivity• By 2007, 135 released into the wild

– Threatened by lead poisoningSELF - STUDY

The Precautionary Principle

• Species: primary components of biodiversity

• Preservation of species• Preservation of ecosystemsSELF - STUDY