Sustaining Biodiversity: The Species Approach

Sustaining Biodiversity: The Species Approach
Chapter 11 Sustaining Biodiversity: The Species Approach

Chapter Overview Questions
How do biologists estimate extinction rates, and how do human activities affect these rates? Why should we care about protecting wild species? Which human activities endanger wildlife? How can we help prevent premature extinction of species? What is reconciliation ecology, and how can it help prevent premature extinction of species?

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. 3

Core Case Study: The Passenger Pigeon - Gone Forever
Once the most numerous bird on earth. In 1858, Passenger Pigeon hunting became a big business. By 1900 they became extinct from over-harvest and habitat loss. Figure 11-1

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? 5

SPECIES EXTINCTION Species can become extinct:
Locally: A species is no longer found in an area it once inhabited but is still found elsewhere in the world. Ecologically: Occurs when so few members of a species are left they no longer play its ecological role. Globally (biologically): Species is no longer found on the earth.

Global Extinction Some animals have become prematurely extinct because of human activities. Figure 11-2

Human Activities Are Destroying and Degrading Biodiversity
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 8

Extinctions Are Natural but Sometimes They Increase Sharply
Background extinction: steady rate of extinctions is normal Extinction rate: number of extinctions in a given time period Mass extinction: extinction rate increases dramatically above background level – fossil record shows 5 major mass extinctions Most famous is Cretaceous extinction that wiped out the dinosaurs Biggest was Permian extinction that killed about 90% of all life, just before the dinos took over We are currently in a human-caused mass extinction 9

Some Human Activities Cause Premature Extinctions; the Pace Is Speeding Up (1)
Premature extinctions due to Habitat destruction (#1 cause) Overhunting (commercial, sport, & poaching) Pollution Invasive Species Global Warming 10

Conservative estimates of extinction = 0.01-1.0% per year
Some Human Activities Cause Premature Extinctions; the Pace Is Speeding Up (2) Conservative estimates of extinction = % per year 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: evolution of new species is too slow to make up for current extinction rate 11

Endangered and Threatened Species: Ecological Smoke Alarms
Endangered species: so few individual survivors that it could soon become extinct. Threatened species: still abundant in its natural range but is likely to become endangered in the near future. Figure 11-3

Swallowtail butterfly Humpback chub Golden lion tamarin Siberian tiger
Grizzly bear Kirtland’s warbler Knowlton cactus Florida manatee African elephant Figure 11.3 Endangered natural capital: species that are endangered or threatened with premature extinction largely because of human activities. Almost 30,000 of the world’s species and 1,260 of those in the United States are officially listed as being in danger of becoming extinct. Most biologists believe the actual number of species at risk is much larger. Utah prairie dog Swallowtail butterfly Humpback chub Golden lion tamarin Siberian tiger Fig. 11-3, p. 224

Giant panda Black-footed ferret Whooping crane Northern spotted owl
Blue whale Figure 11.3 Endangered natural capital: species that are endangered or threatened with premature extinction largely because of human activities. Almost 30,000 of the world’s species and 1,260 of those in the United States are officially listed as being in danger of becoming extinct. Most biologists believe the actual number of species at risk is much larger. Mountain gorilla Florida panther California condor Hawksbill sea turtle Black rhinoceros Fig. 11-3, p. 224

SPECIES EXTINCTION Some species have characteristics that make them vulnerable to ecological and biological extinction. Figure 11-4

SPECIES EXTINCTION Scientists use measurements and models to estimate extinction rates. The International Union for the Conservation of Nature and Natural Resources (IUCN) publishes an annual Red List, listing the world’s threatened species. The 2004 Red List contains 15,589 species at risk for extinction. Figure 11-5

SPECIES EXTINCTION Percentage of various species types threatened with premature extinction from human activities. Figure 11-5

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 Mathematical models 18

SPECIES EXTINCTION Scientists use models to estimate the risk of particular species becoming extinct or endangered. Figure 11-6

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. 20

IMPORTANCE OF WILD SPECIES
We should not cause the premature extinction of species because of the economic and ecological services they provide. Some believe that each wild species has an inherent right to exist. Some people distinguish between the survival rights among various types of species (plants vs. animals).

Species Are a Vital Part of the Earth’s Natural Capital
Instrumental value Use value Ecotourism: wildlife tourism Genetic information Medical compounds Nonuse value Existence value Aesthetic value Bequest value Ecological value: keystone species, etc. 22

1989 international treaty against poaching elephants
Science Focus: Using DNA to Reduce Illegal Killing of Elephants for Their Ivory 1989 international treaty against poaching elephants Poaching on the rise, since the low supply of ivory has made it more valuable Track area of poaching through DNA analysis of elephants Elephants damaging areas of South Africa – especially gardens: Should they be culled? Some evidence suggests that legal elephant hunts lead to increased elephant populaions, since local people protect them as an economic resource 23

Elephant shot with machine gun, then its face removed with chain saw
Stack of confiscated ivory and rhino horn $22,000 ivory cell phone cover

Are We Ethically Obligated to Prevent Premature Extinction?
Intrinsic value: existence value Edward O. Wilson: biophilia phenomenon – many people express a love for living things, nature, animals, etc. (bio = life, philia = to love, phobia = to fear) Biophobia 25

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 26

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. 27

HABITAT LOSS, DEGRADATION, AND FRAGMENTATION
Conservation biologists summarize the most important causes of premature extinction as “HIPPCO:” Habitat destruction, degradation, and fragmentation Invasive species Population growth Pollution Climate Change Overharvest

The greatest threat to a species is the loss, degradation, and fragmentation of where it lives. Figure 11-7

Commercial hunting and poaching Climate change
Habitatloss Overfishing Pollution Habitat degradation and fragmentation Commercial hunting and poaching Climate change Introducing nonnative species Sale of exotic pets and decorative plants Predator and pest control Secondary Causes • Population growth • Rising resource use • No environmental accounting • Poverty Figure 11.7 Natural capital degradation: underlying and direct causes of depletion and premature extinction of wild species. The major direct cause of wildlife depletion and premature extinction is habitat loss, degradation, and fragmentation. This is followed by the deliberate or accidental introduction of harmful invasive (nonnative) species into ecosystems. Basic Causes Fig. 11-7, p. 229

Reduction in ranges of four wildlife species, mostly due to habitat loss and overharvest. Figure 11-8

Indian Tiger Range 100 years ago Range today (about 2,300 left)
Figure 11.8 Natural capital degradation: reductions in the ranges of four wildlife species, mostly as the result of habitat loss and hunting. What will happen to these and millions of other species when the world’s human population doubles and per capita resource consumption rises sharply in the next few decades? (Data from International Union for the Conservation of Nature and World Wildlife Fund) Range 100 years ago Range today (about 2,300 left) Fig. 11-8a, p. 230

Black Rhino Range in 1700 Range today (about 3,600 left)
Figure 11.8 Natural capital degradation: reductions in the ranges of four wildlife species, mostly as the result of habitat loss and hunting. What will happen to these and millions of other species when the world’s human population doubles and per capita resource consumption rises sharply in the next few decades? (Data from International Union for the Conservation of Nature and World Wildlife Fund) Range in 1700 Range today (about 3,600 left) Fig. 11-8b, p. 230

African Elephant Probable range 1600 Range today Fig. 11-8c, p. 230
Figure 11.8 Natural capital degradation: reductions in the ranges of four wildlife species, mostly as the result of habitat loss and hunting. What will happen to these and millions of other species when the world’s human population doubles and per capita resource consumption rises sharply in the next few decades? (Data from International Union for the Conservation of Nature and World Wildlife Fund) Probable range 1600 Range today Fig. 11-8c, p. 230

Asian or Indian Elephant
Figure 11.8 Natural capital degradation: reductions in the ranges of four wildlife species, mostly as the result of habitat loss and hunting. What will happen to these and millions of other species when the world’s human population doubles and per capita resource consumption rises sharply in the next few decades? (Data from International Union for the Conservation of Nature and World Wildlife Fund) Former range Range today (34,000–54,000 left) Fig. 11-8d, p. 230

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? 36

Case Study: A Disturbing Message from the Birds (1)
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 (cats, rats, snakes…) Compete for nest sites Spread diseases (West Nile virus) 37

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 38

Greatest new threat: Climate change Environmental indicators: birds are great indicator species, since they are widespread, react quickly to environmental changes, are relatively easy to study, etc. Economic and ecological services 39

Case Study: A Disturbing Message from the Birds
Human activities are causing serious declines in the populations of many bird species. Figure 11-9

A few endangered US songbirds
Cerulean warbler Sprague’s pipit Bichnell’s thrush Black-capped vireo Golden-cheeked warbler Figure 11.10 Threatened natural capital: the 10 most threatened species of U.S. songbirds, according to a 2002 study by the National Audubon Society. Most of these species are vulnerable because of habitat loss and fragmentation from human activities. An estimated 12% of the world’s known bird species may face premature extinction from human activities during this century. (Data from National Audubon Society) Florida scrub jay California gnatcatcher Kirtland’s warbler Henslow’s sparrow Bachman’s warbler Fig , p. 232

Case Study: A Disturbing Message from the Birds
The majority of the world’s bird species are found in South America. Threatened with habitat loss and invasive species. Figure 11-10

Vultures poisoned from diclofenac in cow carcasses
Science Focus: Vultures, Wild Dogs, and Rabies: Unexpected Scientific Connections Vultures poisoned from diclofenac in cow carcasses More wild dogs eating the cow carcasses More rabies spreading to people 43

INVASIVE SPECIES Many nonnative species provide us with food, medicine, and other benefits but a a few can wipe out native species, disrupt ecosystems, and cause large economic losses. Kudzu vine was introduced in the southeastern U.S. to control erosion. It has taken over native species habitats. Figure 11-A

Some Deliberately Introduced Species Can Disrupt Ecosystems
Most species introductions are beneficial Food Shelter Medicine Aesthetic enjoyment However, nonnative species may have no natural Predators Competitors Parasites Pathogens 45

Case Study: The Kudzu Vine
Imported from Japan in the 1930s “ The vine that ate the South:” grew wildly, covering other plants, buildings, etc. with a green blanket Could there be benefits of kudzu? 46

Case Study: The European Starling
Less than 100 starlings brought to Central Park, New York from England by a man who believed that every bird mentioned in Shakespeare should be brought to the New World Millions-billions of starlings now found across the continent Aggressive competitors for nest sites in tree cavities – will kick out other birds and their eggs Many people find them noisy and dirty 47

Deliberately Introduced Species
Purple loosestrife European starling African honeybee (“Killer bee”) Nutria Salt cedar (Tamarisk) Figure 11.11 Threats to natural capital: some of the more than 7,100 harmful invasive (nonnative) species that have been deliberately or accidentally introduced into the United States. Marine toad (Giant toad) Japanese beetle European wild boar (Feral pig) Water hyacinth Hydrilla Fig a, p. 234

Some Accidentally Introduced Species Can Also Disrupt Ecosystems
Argentina fire ant: 1930s Pesticide spraying in 1950s and 1960s worsened conditions Burmese python – now spreading through the Everglades and displacing native species like alligators Brown tree snake – climbs up in aircraft landing gear, and has spread to new islands in the South Pacific. Has destroyed entire species of birds in Samoa, and Hawaiian officials are very concerned about it getting to the Aloha State. 49

Accidentally Introduced Species
Sea lamprey (attached to lake trout) Argentina fire ant Brown tree snake Eurasian ruffe Common pigeon (Rock dove) Figure 11.11 Threats to natural capital: some of the more than 7,100 harmful invasive (nonnative) species that have been deliberately or accidentally introduced into the United States. Formosan termite Zebra mussel Asian long-horned beetle Asian tiger mosquito Gypsy moth larvae Fig b, p. 234

INVASIVE SPECIES The Argentina fire ant was introduced to Mobile, Alabama in 1932 from South America. Most probably from ships. No natural predators. Figure 11-12

INVASIVE SPECIES Prevention is the best way to reduce threats from invasive species, because once they arrive it is almost impossible to slow their spread. Figure 11-13

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 53

• Do not allow wild animals to escape.
What Can You Do? Invasive Species • Do not allow wild animals to escape. • Do not spread wild plants to other areas. • Do not dump the contents of an aquarium into waterways, wetlands, or storm drains. • When camping use wood near your campsite instead of bringing firewood from somewhere else. • Do not dump unused bait into the water. • After dogs visit woods or the water brush them before taking them home. • After each use clean your vehicle, mountain bike, surfboard, kayaks, canoes, boats, tent, hiking boots, and other gear before heading for home. • Empty all water from canoes, kayaks, dive gear, and other outdoor equipment before heading home. • Plant a variety of trees, shrubs, and other plants in your yard to reduce losses from invasive species. • Do not buy plants from overseas or swap them with others using the Internet. Figure 11.14 Individuals matter: ways to prevent or slow the spread of harmful invasive species. QUESTIONS: Which two of these actions do you think are the most important? Which of these actions do you plan to take? Fig , p. 236

Ecosystems Vulnerable
Characteristics of Successful Invader Species Characteristics of Ecosystems Vulnerable to 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 • Climate similar to habitat of invader • Absence of predators on invading species • Early successional systems • Low diversity of native species • Absence of fire • Disturbed by human activities Figure 11.13 Threats to natural capital: some general characteristics of successful invasive species and ecosystems vulnerable to invading species. Fig , p. 236

POPULATION GROWTH, POLLUTION, AND CLIMATE CHANGE
Population growth, affluenza (overconsumption of resources), and pollution have promoted the premature extinction of some species. Projected climate change threatens a number of species with premature extinction.

Pollution and Biomagnification
Pollutants can build up in the food chain, since each larger animal eats many smaller animals, resulting in an increase in the concentration of the pollution in the top trophic levels. Called biomagnification or bioaccumulation

DDT in fish-eating birds (ospreys)
25 ppm DDT in large fish (needle fish) 2 ppm DDT in small fish (minnows) 0.5 ppm Figure 11.15 Natural capital degradation: 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 can be biologically magnified in the bodies of animals at each higher trophic level. 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 New York. If each phytoplankton organism takes up from the water 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 10 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. Dots represent DDT, and arrows show small losses of DDT through respiration and excretion. DDT in zooplankton 0.04 ppm DDT in water ppm, or 3 ppt Fig , p. 237

Pollution Each year pesticides:
Kill about 1/5th of the U.S. honeybee colonies. 67 million birds. 6 -14 million fish. Threaten 1/5th of the U.S.’s endangered and threatened species. DDT is a pesticide which bioaccumulates, resulting in egg-shell thinning in top predators such as eagles and pelicans. Banned for use in the US in 1972, but we still make it and sell it to other countries. And most US citizens have measurable levels of it in their bodies, since we buy produce from countries that use it! Figure 11-15

Case Study: Polar Bears and Global Warming
Environmental impact on polar bears Less summer sea ice makes it hard for them to capture seals PCBs and DDT found in polar bear tissues, even though these chemicals are not used anywhere near their habitat! 2007: Threatened species list 60

OVEREXPLOITATION Some protected species are killed for their valuable parts or are sold live to collectors. Killing predators and pests that bother us or cause economic losses threatens some species with premature extinction. Legal and illegal trade in wildlife species used as pets or for decorative purposes threatens some species with extinction.

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 62

OVEREXPLOITATION Rhinoceros are often killed for their horns and sold illegally on the black market for decorative and medicinal purposes. Figure 11-16

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 Population growth, political unrest, crop failures, all force people to eat bush meat, including chimps, gorillas, and more 64

Case Study: Rising Demand for Bushmeat in Africa
Bushmeat hunting has caused the local extinction of many animals in West Africa. Can spread disease such as HIV/AIDS and ebola virus. Figure 11-17

Individuals Matter: Jane Goodall
Primatologist and anthropologist 45 years understanding and protecting chimpanzees Recorded life histories of many individuals chimps, making new discoveries about their behavior Chimps have tool-making skills Chimps behave in many ways like people: laughing, fighting, showing anger, planning ahead… 66

9-4 How Can We Protect Wild Species from Premature Extinction? (1)
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. 67

9-4 How Can We Protect Wild Species from Premature Extinction? (2)
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. 68

PROTECTING WILD SPECIES: LEGAL AND ECONOMIC APPROACHES
International treaties have helped reduce the international trade of endangered and threatened species, but enforcement is difficult. One of the most powerful is the 1975 Convention on International Trade of Endangered Species (CITES). Signed by 169 countries, lists 900 species that cannot be commercially traded.

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.) 70

Endangered Species Because of scarcity of inspectors, probably no more than 1/10th of the illegal wildlife trade in the U.S. is discovered. Figure 11-19

Case Study: The U.S. Endangered Species Act
One of the world’s most far-reaching and controversial environmental laws is the 1973 U.S. Endangered Species Act (ESA). ESA forbids federal agencies (besides defense department) to carry out / fund projects that would jeopardize an endangered species. ESA makes it illegal for Americans to engage in commerce associated with or hunt / kill / collect endangered or threatened 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: areas with extra-high diversity that need protecting Habitat Conservation Plan (HCP) colony 73

Biodiversity hotspots in relation to the largest concentrations of rare and potentially endangered species in the U.S. Figure 11-18

3 Southern Appalachians 4 Death Valley 5 Southern California
Top Six Hot Spots 1 Hawaii 2 San Francisco Bay area 3 Southern Appalachians 4 Death Valley 5 Southern California 6 Florida Panhandle Figure 11.18 Threatened natural capital: biodiversity hot spots in the United States. The shaded areas contain the largest concentrations of rare and potentially endangered species. Compare these areas with those on the map of the human ecological footprint in North America shown in Figure 4 on pp. S14–S15 in Supplement 4. (Data from State Natural Heritage Programs, the Nature Conservancy, and Association for Biodiversity Information) Concentration of rare species Low Moderate High Fig , p. 241

Science Focus: Accomplishments of the Endangered Species Act (1)
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 Very small percentage (<5%) of economic activities have been blocked by the ESA – most go forward with no changes, some are approved with slight modifications, others with major changes, but few prevented completely 76

Science Focus: Accomplishments of the Endangered Species Act (2)
Suggested changes to ESA Increase the budget Develop recovery plans more quickly Establish a core of the endangered organism’s survival habitat 77

Endangered Species Congress has amended the ESA to help landowners protect species on their land. Some believe that the ESA should be weakened or repealed while others believe it should be strengthened and modified to focus on protecting ecosystems. Many scientists believe that we should focus on protecting and sustaining biodiversity and ecosystem function as the best way to protect species.

How Would You Vote? Should the Endangered Species Act be modified to protect and sustain the nation's overall biodiversity? a. No. Protecting entire habitats will only further interfere with the rights of landowners. b. Yes. Protecting endangered habitats is more efficient and effective than saving individual species.

We Can Establish Wildlife Refuges and Other Protected Areas
1903: Theodore Roosevelt was an avid hunter and outdoorsman, and he created the first wildlife refuges Wildlife refuges Most are wetland sanctuaries More needed for endangered plants Could abandoned military lands be used for wildlife habitats? 80

PROTECTING WILD SPECIES: THE SANCTUARY APPROACH
The U.S. has set aside 544 federal refuges for wildlife, but many refuges are suffering from environmental degradation. Many refuges focus on providing habitat for waterfowl (ducks and geese), since hunting them is big business Pelican Island was the nation’s first wildlife refuge. Figure 11-20

Botanical gardens and arboreta
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 82

PROTECTING WILD SPECIES: THE SANCTUARY APPROACH
Gene banks, botanical gardens and using farms to raise threatened species can help prevent extinction, but these options lack funding and storage space. Zoos and aquariums can help protect endangered animal species by preserving some individuals with the long-term goal of reintroduction, but suffer from lack of space and money.

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 But Limited space and funds Critics say these facilities are prisons for the organisms 84

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 poisoning 85

Tagged Condor #19 Condor Puppet used to feed condor chicks without them becoming dependent on humans

RECONCILIATION ECOLOGY
Reconciliation ecology involves finding ways to share places we dominate with other species. Replacing monoculture grasses with native species. Maintaining habitats for insect eating bats can keep down unwanted insects. Reduction and elimination of pesticides to protect non-target organisms (such as vital insect pollinators).

Using Reconciliation Ecology to Protect Bluebirds
Putting up bluebird boxes with holes too small for (nonnative) competitors in areas where trees have been cut down have helped reestablish populations. Figure 11-B

The Precautionary Principle
Species: primary components of biodiversity Preservation of species Preservation of ecosystems 89

What Can You Do? Protecting Species
• Do not buy furs, ivory products, and other materials made from endangered or threatened animal species. • Do not buy wood and paper products produced by cutting remaining old-growth forests in the tropics. • Do not buy birds, snakes, turtles, tropical fish, and other animals that are taken from the wild. • Do not buy orchids, cacti, and other plants that are taken from the wild. • Spread the word. Talk to your friends and relatives about this problem and what they can do about it. Figure 11.21 Individuals matter: ways to help premature extinction of species. QUESTIONS: Which two of these actions do you think are the most important? Which of these actions do you plan to take? Fig , p. 246

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