chapter 9 sustaining biodiversity: the species approach 5... · chapter 9 . sustaining...

Chapter 9 Sustaining Biodiversity: The Species Approach

The last word in ignorance is the person who says of an animal or plant: “What good is it?”… If the land mechanism as a whole is good, then every part of it is good, whether we understand it or not. Harmony with the land is like harmony with a friend; you cannot cherish his right hand and chop off his left. - Aldo Leopold

Core Case Study: Polar Bears and Global Warming

• 20,000-25,000 in the Arctic

• Most calories in winter from seals on sea ice

• Environmental impact on polar bears • Less summer sea ice from global

warming • Could be gone from wild by 2100

• 2008: Threatened species list

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Presentation Notes

Figure 9.1: On floating ice in Svalbard, Norway, a polar bear feeds on its seal prey. Polar bears in the Arctic could become extinct sometime during this century if projected atmospheric warming melts much of the floating sea ice on which they hunt seals. Question: What do you think about the possibility that the polar bear might become extinct mostly because of human activities? Explain.

9-1 What Role Do Humans Play in the Extinction of Species?

Concept 9-1 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.

Extinctions Are Natural but Sometimes They Increase Sharply (1)

Biological extinction • No species member alive

Background extinction

• Natural low rate of extinction

Extinction rate • Percentage or number of species that go extinct in a

certain time period

Extinctions Are Natural but Sometimes They Increase Sharply (2)

Mass extinction • 3-5 events • 50-95% of species became extinct • From global changes in environmental conditions:

major climate change, volcanoes, asteroid impacts Levels of species extinction

• Local extinction • Ecological extinction • Biological extinction

Some Human Activities Are Causing Extinctions

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 • Pollution of land and water

Extinction Rates Are Rising Rapidly • Current extinction rate is at

least 100 times higher than typical background rate of .0001%

• Will rise to 10,000 times the background rate by the end of the century Rate will rise to 1% per year ¼ to ½ of the world’s plant

and animal species

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

Extinction Rates Are Rising Rapidly

Endangered and Threatened Species Are Ecological Smoke Alarms

• Endangered species • So few members that the species could soon become

extinct

• Threatened species (vulnerable species) • Still enough members to survive, but numbers

declining -- may soon be endangered

Endangered and Threatened Species What Are There Characteristics?

• Big • Slow • Tasty • Valuable parts • Behaviors that make them easy

to kill

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Presentation Notes

Figure 9.3: This diagram shows the characteristics of species that can put them in greater danger of becoming extinct. Question: Which of these characteristics might possibly contribute to the extinction of the polar bear (Core Case study) during this century?

Fig. 9-2, p. 193

Endangered Natural Capital: Species Threatened with Premature Extinction

Sumatran Tiger: < 60 Mexican Gray Wolf: 60

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Presentation Notes

Figure 9.2: Endangered natural capital: These four critically endangered species are threatened with extinction, largely because of human activities. More than 17,300 of the world’s species, including 1,318 species in the United States, were officially listed in 2009 as endangered or threatened species. The number below each photo indicates the estimated total number of individuals of that species remaining in the wild. These and thousands of other species may disappear forever during your lifetime. According to most biologists, the actual number of species at risk is much larger. Question: What kinds of human activities to you think are putting these four animals in danger? (a) Sumatran tiger: less than 60 in Sumatra, Indonesia

Fig. 9-2, p. 193

Endangered Natural Capital: Species Threatened with Premature Extinction

California Condor: 172 Whooping Crane: 210

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Presentation Notes

Figure 9.2: Endangered natural capital: These four critically endangered species are threatened with extinction, largely because of human activities. More than 17,300 of the world’s species, including 1,318 species in the United States, were officially listed in 2009 as endangered or threatened species. The number below each photo indicates the estimated total number of individuals of that species remaining in the wild. These and thousands of other species may disappear forever during your lifetime. According to most biologists, the actual number of species at risk is much larger. Question: What kinds of human activities to you think are putting these four animals in danger? (a) Sumatran tiger: less than 60 in Sumatra, Indonesia

Fig. 9-4, p. 194

Percentage of Various Species Threatened with Premature Extinction

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Presentation Notes

Figure 9.4: Endangered natural capital. This graph shows the estimated percentages of various types of known species that are threatened with extinction because of human activities (Concept 9-1). Question: Why do you think plants (see Photo 4 in the Detailed Contents) and fish species top this list? (Data from International Union for Conservation of Nature, Conservation 2009)

Science Focus: Estimating Extinction Rates

• Three problems 1. Hard to document due to length of time 2. Only 1.9 million species identified 3. Little known about nature and ecological roles of species

identified

• Approaches 1. Study extinction rates over last 10,000 years and then

compare with the fossil record 2. Use species–area relationship 3. Mathematical models

Case Study: The Passenger Pigeon: Gone Forever

• Once one of the world’s most abundant birds

• Audubon: flock took 3 days to fly over

• Passenger pigeon hunted to extinction by 1900 • Habitat loss • Commercial hunting • Easy to kill: flew in large flocks

and nested in dense colonies

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Presentation Notes

Figure 9.5: Because of human activities, the North American passenger pigeon became extinct in the wild in 1900. In 1914, the world’s last known passenger pigeon died in a zoo in the U.S. city of Cincinnati, Ohio.

9-2 Why Should We Care about the Rising Rate of 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.

Why Should We Prevent Extinctions? TOP 4 REASONS

1. Species provide natural resources and natural services • Insects for pollination • Birds for pest control

2. Most species contribute economic services

• Plants for food, fuel, lumber, medicine • Ecotourism

3. It will take 5-10 million years to regain species biodiversity

4. Many people believe species have an intrinsic right to exist

Fig. 9-6, p. 195

Natural Capital Degradation: Endangered Orangutans in a Tropical Forest

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Figure 9.6: Natural capital degradation. These endangered orangutans are shown in their rapidly disappearing tropical forest habitat. In 1900, there were over 315,000 wild orangutans, which are found only in the tropical forests of Indonesia and Malaysia. According to the WWF, today there are fewer than 56,000 left in the wild (90% of them in Indonesia). These highly intelligent animals are disappearing at a rate of more than 1,000–2,000 per year because of illegal smuggling and the clearing of their tropical forest habitat to make way for plantations that supply palm oil used in cosmetics, cooking, and the production of biodiesel fuel. An illegally smuggled, live orangutan sells for a street price of up to $10,000. Without urgent protective action, the endangered orangutan may be the first great ape species to become extinct, primarily because of human activities. Question: What difference will it make if human activities cause the extinction of the orangutan?

Fig. 9-7, p. 196

Natural Capital: Nature’s Pharmacy

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Presentation Notes

Figure 9.7: Natural capital. These plant species are examples of nature’s pharmacy. Their scientific names (see Supplement 5, p. S18–S19) and some of their medicinal uses are shown as well. Parts of these plants as well as a number of other plant and animal species (many of them found in tropical forests) are used to treat a variety of human ailments and diseases. Once the active ingredients in the plants have been identified, scientists can usually produce them synthetically. The active ingredients in nine of the ten leading prescription drugs originally came from wild organisms. Many of the world’s tropical plant species are likely to become extinct before we can even study them. Question: Which of these species, if any, might have helped you or people you know to deal with health problems?

Fig. 9-8, p. 197

Endangered Hyacinth Macaw is a Source of Beauty and Pleasure

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Figure 9.8: Many species of wildlife such as this endangered hyacinth macaw are sources of beauty and pleasure. This species of parrot is found in fairly open woodlands and swamps in several areas of Brazil, Bolivia, and Paraguay. This and other colorful species of parrots have become endangered because many birds have been removed from the wild and sold (sometimes illegally) as pets.

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.

Pilot Whale Hunt, Faeroe Island

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

Habitat Fragmentation • Habitat fragmentation

• Large intact habitat divided by roads, crops, urban development

• Leaves habitat islands • Blocks migration routes • Divides populations • Inhibits migrations and colonization • Inhibits finding food

• National parks and nature reserves as habitat islands

Fig. 9-9, p. 198

Causes of Depletion and Premature Extinction of World Species

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Figure 9.9: This figure illustrates both the underlying and direct causes of depletion and extinction of wild species resulting from human activities (Concept 9-3) (see Figure 1-9, p. 13). The biggest cause is habitat loss, degradation, and fragmentation. This is followed by the deliberate or accidental introduction of harmful invasive (nonnative) species into ecosystems. Question: What are two direct causes that are specifically related to each of the underlying causes?

Fig. 9-9, p. 198

Natural Capital Degradation

Causes of Depletion and Extinction of Wild Species

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

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Presentation Notes

Figure 9.9: This figure illustrates both the underlying and direct causes of depletion and extinction of wild species resulting from human activities (Concept 9-3) (see Figure 1-9, p. 13). The biggest cause is habitat loss, degradation, and fragmentation. This is followed by the deliberate or accidental introduction of harmful invasive (nonnative) species into ecosystems. Question: What are two direct causes that are specifically related to each of the underlying causes?

Fig. 9-10, p. 199

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

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Figure 9.10: Natural capital degradation. These maps reveal the reductions in the ranges of four wildlife species, mostly as the result of severe habitat loss and fragmentation and illegal hunting for some of their valuable body parts. What will happen to these and millions of other species during the next few decades when the human population grows by at least 2 billion—the equivalent of more than 6 times the current U.S. population and almost twice the current population of China—as is projected by scientists? See an animation based on this figure at CengageNOW. Question: Would you support expanding these ranges even though this would reduce the land available for human habitation and farming? Explain. (Data from International Union for the Conservation of Nature and World Wildlife Fund)

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

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Presentation Notes

Figure 9.11: These are some of the more than 7,100 harmful invasive (nonnative) species that have been deliberately or accidentally introduced into the United States.

Case Study: The Kudzu Vine • Imported from Japan in the

1930s

• “ The vine that ate the South” • Could there be benefits of

kudzu? • Fiber for making paper • Kudzu powder reduces desire

for alcohol

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Presentation Notes

Figure 9.12: Kudzu has taken over this abandoned house in the U.S. state of Mississippi. The vine, which can grow 5 centimeters (2 inches) per hour, was deliberately introduced into the United States for erosion control. Digging it up and burning it do not halt its spread. Grazing goats and repeated doses of herbicides can destroy it, but goats and herbicides also destroy other plants, and herbicides can contaminate water supplies. Scientists have found a common fungus that can kill kudzu within a few hours, apparently without harming other plants, but they need to investigate any harmful side effects it may have.

Some Accidentally Introduced Species Can Also Disrupt Ecosystems

• Argentina fire ant: 1930s Reduced populations of native ants Painful stings can kill Pesticide spraying in 1950s and 1960s worsened

conditions 2009: tiny parasitic flies may help control fire ants

• Burmese python Florida Everglades

Fig. 9-13, p. 202

Fight Between a Python and Alligator

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Presentation Notes

Figure 9.13: This huge python and an American alligator were in a life-or-death struggle in the Florida Everglades. After a 10-hour battle the alligator killed the snake by taking it underwater and drowning it. However, in some struggles, these snakes kill and eat the alligators—their only natural predator in the Everglades.

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

• International treaties

• Public education

Fig. 9-14, p. 203

What Can You Do? Controlling Invasive Species

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Figure 9.14: Individuals matter. Here is a list of some ways to prevent or slow the spread of harmful invasive species. Questions: Which two of these actions do you think are the most important? Why? Which of these actions do you plan to take?

Other Causes of Species Extinction

• Human population growth

• Overconsumption • Pollution

• Climate change

• Pesticides

• DDT: Banned in the U.S. in 1972 • Bioaccumulation • Biomagnification

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Presentation Notes

Figure 9.15: Bioaccumulation and biomagnification: DDT is a fat-soluble chemical that can accumulate in the fatty tissues of animals. In a food chain or web, the accumulated DDT is biologically magnified in the bodies of animals at each higher trophic level. (Dots in this figure represent DDT.) The concentration of DDT in the fatty tissues of organisms was biomagnified about 10 million times in this food chain in an estuary near Long Island Sound in the U.S. state of New York. If each phytoplankton organism takes up and retains one unit of DDT, a small fish eating thousands of zooplankton (which feed on the phytoplankton) will store thousands of units of DDT in its fatty tissue. Each large fish that eats ten of the smaller fish will ingest and store tens of thousands of units, and each bird (or human) that eats several large fish will ingest hundreds of thousands of units. Question: How does this story demonstrate the value of pollution prevention?

Case Study: Where Have All the Honeybees Gone?

• Honeybees responsible for 80% of insect-pollinated plants and nearly 1/3 human food

• 2006: 30% drop in honeybee populations

• Dying due to • Pesticides? • Parasites? • Viruses, fungi, bacteria? • Microwave radiation – cell phones? • Bee colony collapse syndrome

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

Fig. 9-16, p. 205

Mountain Gorilla in Rwanda

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Figure 9.16: This male mountain gorilla inhabits the bush of the African country of Rwanda. Mountain gorillas feed mostly on the leaves, shoots, and stems of a variety of plants. Only about 700 individuals of this critically endangered species remain in the wild.

Fig. 9-17, p. 205

White Rhinoceros Killed by a Poacher

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Presentation Notes

Figure 9.17: This white rhinoceros was killed by a poacher in South Africa solely for its horns. Question: What would you say if you could talk to the person who killed this animal?

Fig. 9-B, p. 206

The Rare Rhinoceros Hornbill

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Presentation Notes

Figure 9.B: The rare Rhinoceros hornbill is found in tropical and subtropical forest habitats in parts of Asia. It emits a loud honking squawk and uses its long bill to defend itself from predators such as snakes and monkeys. Its habitat is threatened by agricultural development and logging, and in some areas, the hornbill is threatened by local tribesmen who kill it for food and for its feathers. It is also captured and sold live as part of the illegal wildlife trade.

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

• West and Central Africa

• Helps spread HIV/AIDS and Ebola from animals to humans

Bush Meat: Lowland Gorilla

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Presentation Notes

Figure 9.18: Bush meat such as this severed head of an endangered lowland gorilla in the Congo is consumed as a source of protein by local people in parts of West and Central Africa and is sold in national and international marketplaces. You can find bush meat on the menu in Cameroon and the Democratic Republic of the Congo in West Africa as well as in Paris, London, Toronto, New York, and Washington, DC. Poachers are often the suppliers of bush meat. Wealthy patrons of some restaurants regard gorilla meat as a source of status and power. Question: How, if at all, is this different from killing a cow for food?

Case Study: A Disturbing Message from the Birds (1)

• 1/3 of 800 bird species in U.S. are endangered or threatened

• 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


• 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


• Greatest new threat: Climate change • Environmental indicators • Economic and ecological services

Fig. 9-19, p. 208

Endangered Black-Browed Albatross

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Presentation Notes

Figure 9.19: The IUCN reports that 82% of albatrosses are threatened. The black-browed albatross shown here is endangered because of a drastic reduction in its population, due largely to long-line and trawler fishing fleets whose hooks and nets ensnare and drown these birds when they dive into the water for food.

9-4 How Can We Protect Wild Species from Premature Extinction?

Concept 9-4 We can reduce the rising rate of 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 and National Laws 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.)

Endangered Species Act (ESA) 1973 (amended 1982, 1985, 1988)

• Identify and protect endangered species in the U.S. and abroad 2010: 1,370 species officially listed

• National Marine Fisheries Service for ocean species, U.S. Fish and

Wildlife Service for all others USFWS and NMFS prepare recovery plans

• Forbids federal agencies (except Defense) from funding or

authorizing projects that jeopardize endangered or threatened species

• Incentives for private property owners

Why Is ESA NOT a Failure?

• Even if only 46 species were removed from endangered list 1. Species listed only when in serious danger 2. Takes decades to help endangered species 3. Conditions for more than half of listed species are

stable or improving 4. 2010: spend only 9 cents per American

How Can ESA Be Improved? 1. Greatly increase funding 2. Develop recovery plans

more quickly 3. When a species is first

listed, establish the core of its habitat that’s critical for survival

• New law needed to focus on sustaining biodiversity and ecosystem health

Fig. 9-20, p. 210

Confiscated Products Made from Endangered Species

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Presentation Notes

Figure 9.20: These confiscated products were made from endangered species. Because of a scarcity of funds and inspectors, probably no more than one-tenth of the illegal wildlife trade in the United States is discovered. The situation is even worse in most other countries.

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?

Fig. 9-21a, p. 211

Pelican Island National Wildlife Refuge

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Presentation Notes

Figure 9.21: The Pelican Island National Wildlife Refuge in Florida was America’s first National Wildlife Refuge. It was established in 1903 to help protect the brown pelican (see photo insert) and other birds from extinction. In 2009, the brown pelican was removed from the U.S. endangered species list.

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

• Goal of ultimately releasing/reintroducing populations to the wild

• Limited space and funds

Fig. 9-22, p. 213

What Can You Do? Protecting Species

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Presentation Notes

Figure 9.22: Individuals matter. You can help prevent the extinction of species. Questions: Which two of these actions do you believe are the most important? Why?

Case Study: Trying to Save the California Condor

• Largest North American bird

• Nearly extinct • Birds captured and breed in captivity

• By 2009, 180 in the wild

• Threatened by lead poisoning

The Precautionary Principle • Precautionary principle: act to prevent or reduce

harm when preliminary evidence indicates acting is needed

Three Big Ideas

1. We are greatly increasing the extinction of wild species by destroying and degrading their habitats, introducing harmful invasive species, and increasing human population growth, pollution, climate change, and overexploitation.

2. We should avoid causing the extinction of wild species because of the ecological and economic services they provide and because their existence should not depend primarily on their usefulness to us.

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

chapter 9 sustaining biodiversity: the species approach 5... · chapter 9 . sustaining...

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