Sustaining Biodiversity: The Species Approach

Chapter 9

Passenger pigeon hunted to extinction by 1900

Commercial hunters used a "stool pigeon”

Archeological record shows five mass extinctions

Human activities: hastening more extinctions?

Core Case Study: The Passenger Pigeon: Gone Forever

Passenger Pigeon

Degrading and destroying biodiversity in many parts of the world and these threats are increasing : 83% of the earth’s land surface

filling in wetlands, converting grasslands and forests to crop fields and urban areas

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 role in premature extinction…….

Human activity has disturbed at least half of the earth’s land surface◦ Fills in wetlands◦ Converts grasslands and forests to crop fields

and urban areas

Degraded aquatic biodiversity

Human Activities Are Destroying and Degrading Biodiversity

continuous low level of extinction extinction rate : expressed as a percentage or

number of species that go extinct/per million species per year 1/1,000,000=.000001 or .0001% ( estimated extinction rate before humans came on the scene)

Background Extinction……….

Premature extinctions due to◦Habitat destruction◦Overhunting

Some Human Activities Cause Premature Extinctions; the Pace Is Speeding Up

Conservative estimates of extinction = 0.01-1.0%◦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

Some Human Activities Cause Premature Extinctions; the Pace Is Speeding Up

Animal Species Prematurely Extinct Due to Human Activities

Lost Natural capital

Fig. 9-2, p. 185

Passenger pigeon

Great auk Dodo Golden toad Aepyornis (Madagascar)

Effects of a 0.1% Extinction Rate

Fig. 9-3, p. 186

Number of species existing Effects of a 0.1% extinction rate

5 million 5,000 extinct per year

14 million 14,000 extinct per year

50 million 50,000 extinct per year

100 million 100,000 extinct per year

Number of years until one million species are extinct

2000 50 100 150

Endangered species – has so individual survivors that the species could soon become extinct over all or most of it’s natural range

Threatened species - abundant in natural range , but numbers declining

Endangered and Threatened Species Are Ecological Smoke Alarms

Endangered Natural Capital: Species Threatened with Premature Extinction

Fig. 9-5, p. 188

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 (K-strategist)

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

Percentage of Various Species Threatened with Premature Extinction

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

Mathematical models

Science Focus: Estimating Extinction Rates Is Not Easy

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.

Why Should We Care about Preventing Premature Species Extinction?

Instrumental value◦Use value Ecotourism: wildlife tourism Genetic information

◦Nonuse value Existence value Aesthetic value Bequest value

Ecological value

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

Natural Capital Degradation: Endangered Orangutans in a Tropical Forest

Endangered Scarlet Macaw is a Source of Beauty and Pleasure

Natural Capital: Nature’s Pharmacy

1989 international treaty against poaching elephants

Poaching on the rise

Track area of poaching through DNA analysis of elephants

Elephants damaging areas of South Africa: Should they be culled?

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

Intrinsic value: existence value

Edward O. Wilson: biophilia (inherent kinship with the natural world)

Biophobia – against certain organisms

Are We Ethically Obligated to Prevent Premature Extinction?

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

Science Focus: Why Should We Care about Bats?

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.

How do Humans Accelerate Species Extinction?

Habitat destruction, degradation, and fragmentation

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

Loss of Habitat Is the Single Greatest Threat to Species: Remember HIPPCO

Causes of Depletion and Premature Extinction of World Species

Fig. 9-10, p. 193

NATURAL CAPITAL DEGRADATION

Underlying Causes

• Population growth

• Rising resource use

• Undervaluing natural capital

• Poverty

Direct Causes

• Habitat loss • Pollution • Commercial hunting and poaching

• Habitat degradation and fragmentation

• Climate change • Sale of exotic pets and decorative plants

• Introduction of nonnative species

• Overfishing• Predator and pest control

Causes of Depletion and Premature Extinction of Wild Species

Natural Capital Degradation: Reduction in the Ranges of Four Wildlife Species

Tropical Biologist Bill Laurance, et al.- edges of forest fragments invaded by vines which take over

How large must a forest fragment be in order to prevent the loss of rare trees? – within 100 meters of the edge of a forest fragment 36% of the biomass of old growth trees is lost within 10-17 years

Science Focus: Studying the Effects of Forest Fragmentation on Old-Growth Trees

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

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

◦ Climate Change

Case Study: A Disturbing Message from the Birds

Distribution of Bird Species in North America and Latin America

Loss of 93% of Brazil’s coastal rain forest

Vultures poisoned from diclofenac in cow carcasses

More wild dogs eating the cow carcasses

More rabies spreading to people

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

Most species introductions are beneficial◦Food◦Shelter◦Medicine◦Aesthetic enjoyment

Nonnative species may have no natural◦Predators◦Competitors◦Parasites◦Pathogens

Some Deliberately Introduced Species Can Disrupt Ecosystems

Some Harmful Nonnative Species in the United States

Fig. 9-14a, p. 199

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)

7100 harmful invasive species introduced into the US

Fig. 9-14b, p. 199

Fig. 9-14b, p. 199

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. 9-14, p. 199

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

Imported from Japan in the 1930s

“ The vine that ate the South” – might spread as far as the Great Lakes by 2040 if climate change (global warming) occurs

Could there be benefits of kudzu? – source of food, for making paper

Case Study: The Kudzu Vine

Kudzu Taking Over an Abandoned House in Mississippi, U.S.

Argentina fire ant: 1930s◦Pesticide spraying in 1950s and 1960s worsened

conditions

Burmese python –imported as a pet from Southeast Asia. Dumped in the Everglades. By 2100 in most of southern US

Some Accidentally Introduced Species Can Also Disrupt Ecosystems

Argentina Fire Ant Accidentally Introduced into Mobile, Alabama,

U.S.

Prevent them from becoming established

Learn the characteristics of the species

Set up research programs

Try to find natural ways to control them

Prevention Is the Best Way to Reduce Threats from Invasive Species

Characteristics of Invader Species and Ecosystems Vulnerable to Invading Species

What Can You Do to Control Invasive Species ?

Population growth Overconsumption Pollution Climate change

Other Causes of Species Extinction

Pesticides◦DDT: Banned in the U.S. in 1972

Bioaccumulation

Biomagnification

Other Causes of Species Extinction

Bioaccumulation and Biomagnification

Honeybees responsible for 80% of insect-pollinated plants; 110 commercially grown crops; 1/3 US fruit and vegetable crops

30% drop in population

Dying due to?◦Pesticides◦Parasites◦Bee colony collapse syndrome

Case Study: Where Have All the Honeybees Gone?

Environmental impact on polar bears◦Less summer sea ice◦PCBs and DDT

2007: Threatened species list

Case Study: Polar Bears and Global Warming

Polar Bear with Seal Prey

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

Prevention: research and education

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

White Rhinoceros Killed by a Poacher

Indigenous people sustained by bush meat

More hunters leading to local extinction of some wild animals

Rising Demand for Bush Meat Threatens Some African Species

Bush Meat: Lowland Gorilla

Wealthy patrons of some restaurants regard gorilla meat as a source of power and status

We can use existing environmental laws and treaties and work to enact new laws designed to prevent species extinction and protect overall biodiversity.

We can help to prevent species extinction by creating and maintaining wildlife refuges, gene banks, botanical gardens, zoos, and aquariums.

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

How Can We Protect Wild Species from Premature Extinction?

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.)

International Treaties Help to Protect Species

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

Case Study: The U.S. Endangered Species Act

Confiscated Products Made from Endangered Species

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

Science Focus: Accomplishments of the Endangered Species Act

1903: Theodore Roosevelt- Pelican Island , Florida – brown pelican

Wildlife refuges -547◦Most are wetland sanctuaries- trumpeter swan◦More needed for endangered plants◦Could abandoned military lands be used for

wildlife habitats?

We Can Establish Wildlife Refuges and Other Protected Areas

Gene or seed banks◦Preserve genetic material of endangered plants by

storing their seeds in refrigerated, low humidity environments

Botanical gardens and arboreta◦Living plants- 1/3 rd of the world’s species

Farms to raise organisms for commercial sale

Gene Banks, Botanical Gardens, and Wildlife Farms Can Help Protect 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

What Can You Do? Protecting Species

Largest North American bird

Nearly extinct◦Birds captured and breed in captivity

By 2007, 135 released into the wild◦Threatened by lead poisoning

Case Study: Trying to Save the California Condor

Species: primary components of biodiversity

Preservation of species

Preservation of ecosystems

The Precautionary Principle