Sustaining Biodiversity The Species Approach Chapter 9 Core
Sustaining Biodiversity: The Species Approach Chapter 9
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 9. 1 Lost natural capital: passenger pigeons have been extinct in the wild since 1900 because of human activities. The last known passenger pigeon died in the U. S. state of Ohio’s Cincinnati Zoo in 1914.
Core Case Study: The Passenger Pigeon: Gone Forever � Passenger pigeon hunted to extinction by 1900 � Commercial hunters used a "stool pigeon” � Geological record shows five mass extinctions � Human activities: hastening more extinctions?
9 -1 What Role Do Humans Play in the Premature Extinction of Species? �Concept 9 -1 A We are degrading and destroying biodiversity in many parts of the world, and these threats are increasing. �Concept 9 -1 B 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 of the earth’s land surface • Fills in wetlands • Converts grasslands and forests to crop fields and urban areas �Degraded aquatic biodiversity
Extinctions Are Natural but Sometimes They Increase Sharply � Background � Extinction extinction rate � Mass extinction: causes? • Poorly understood, but involve global changes in environmental conditions. � Levels of species extinction • Local extinction, or extirpation • Ecological extinction • Biological extinction
Define the terms extinction, extirpation and mass extinction. Extinction: The disappearance of an entire species from the face of the Earth. Extinction Rate: % or # of species that go extinct per unit time. i. e. 0. 00001 species/year Extirpation: The disappearance of a particular population from a given area, but not the entire species globally. Mass Extinction: The extinction of a large portion of the world’s species in a very short time period due to some extreme and rapid change or catastrophic event. The Earth has seen five mass extinction events in the past half-billon years. © 2011 Pearson Education, Inc.
Extinctions Are Natural But Sometimes They Increase Sharply § Background extinction and Mass extinction • Discussed in Chapter 4 § Extinction rate – the percent of species that go extinct in a given time period. • Background extinction • 1/1, 000 per year = 0. 00001% • Mass extinction • 50 – 95% of all living things on the planet
Extinctions Are Natural But Sometimes They Increase Sharply § Species can become extinct in three ways: • Local Extinction: • A species is no longer found in an area it once inhabited but is still found elsewhere in the world. • Typically the result of habitat destruction and affects more than one species. • Ecological Extinction: • Occurs when so few members of a species are left they no longer play its ecological role. • Biological Extinction (Global Extinction): • Species is no longer found on the earth. • Biological extinction is FOREVER.
Some Human Activities Cause Premature Extinctions; the Pace Is Speeding Up § Estimates of current annual extinction rate: • 0. 01 -1. 0% • 100 to 1, 000 times greater than the background extinction rate of 0. 0001% § Experts predict extinction rates will increase over the next 50 -100 years. § Reason = US!!
Animal Species Prematurely Extinct Due to Human Activities § Many animals have become prematurely extinct because of human activities. • Development, habitat destructions, hunting, etc.
Animal Species Prematurely Extinct Due to Human Activities “The first animal species to go are the big, the slow, the tasty, and those with valuable parts…” – Edward O. Wilson (biodiversity expert)
Some Human Activities Cause Premature Extinctions; the Pace Is Speeding Up (2) �Conservative estimates of extinction = 0. 01 -0. 1% • Growth of human population will increase this loss to 10 000 times (to 1%) • 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
Endangered Natural Capital: Species Threatened with Premature Extinction § Threatened (vulnerable) species: • Still abundant in its natural range but is likely to become endangered in the near future. § Endangered species: • So few individual survivors that it could soon become extinct.
Endangered Natural Capital: Species Threatened with Premature Extinction § Extinct Ex. : Dodo, Passenger Pigeon § Extinct in the wild Ex. : Alagoas Curassow • Captive individuals survive, but there is no free-living, natural population § Critically endangered Ex. : Ivory-billed Woodpecker, Javan Rhino • Faces an extremely high risk of extinction in the immediate future § Endangered Ex. : Cheetah, Blue Whale, Snow Leopard § Vulnerable Ex. : Lion, Wolverine § Conservation Dependent Ex. : Leopard Shark, Bristlecone Fir • Would be threatened without active conservation programs. § Near Threatened Ex. : California Red-legged Frog, Silvery Woolly Monkey • Likely to qualify as threatened soon. § Least Concern Ex. : Brown Rat, Rock Pigeon, Common Juniper • No immediate threat to the survival of the species.
Endangered Natural Capital: Species Threatened with Premature Extinction
Endangered Natural Capital: Species Threatened with Premature Extinction
Some Human Activities Cause Premature Extinctions; the Pace Is Speeding Up (1) �Premature extinctions due to • Habitat destruction • Overhunting, or overexploitation
Animal Species Prematurely Extinct Due to Human Activities
Figure 9. 3 Effects of a 0. 1% extinction rate.
Endangered and Threatened Species Are Ecological Smoke Alarms � Endangered species • International Union for the Conservation of Nature (IUCN), or the World Conservation Union. Red List �Since 1960, published �In 2007, listed 16, 306 animals and plants that are in danger of extinction— 60% higher than in 1995. � Threatened species, vulnerable species • Characteristics of such species
Figure 9. 4 Endangered natural capital. Some species that are endangered or threatened with premature extinction largely because of human activities. Almost 30, 000 of the world’s species and roughly 1, 300 of those in the United States are officially listed as being in danger of becoming extinct. Kirkland’s warbler Knowlton Florida manatee African Grizzly bear. Kirkland’s elephant cactus Utah prairie dog Swallowtail Humpback chub. Golden lion tamarin butterfly Siberian tiger Giant panda Black-footed. Whooping crane Northern Blue whale spotted owl ferret Most biologists believe the actual number of species at risk is much larger. Mountain gorilla Florida California condor Black rhinoceros Hawksbill sea panther turtle
Figure 9. 5 Characteristics of species that are prone to ecological and biological extinction. Question: Which of these characteristics helped lead to the premature extinction of the passenger pigeon within a single human lifetime? Characteristic Examples Low reproductive rate (K-strategist) Blue whale, giant panda, rhinoceros Specialized niche Narrow distribution Blue whale, giant panda, Everglades kite Elephant seal, desert pupfish Feeds at high trophic level Bengal tiger, bald eagle, grizzly bear Fixed migratory patterns Blue whale, whooping crane, sea turtle African violet, some orchids Rare Commercially valuable Large territories Snow leopard, tiger, elephant, rhinoceros, rare plants and birds California condor, grizzly bear, Florida panther
Figure 9. 6 Endangered natural capital: percentage of various types of species threatened with premature extinction because of human activities
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 • Suggests species survive for 1 to 10 million years before going extinct. � Use species–area relationship • On average, 90% loss of habitat results in a 50% loss of species living in that habitat. � 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. � “It will take 5 -10 million years for natural speciation to rebuild the biodiversity we are likely to destroy during your lifetime. ”
Species Are a Vital Part of the Earth’s Natural Capital � Instrumental value – usefulness to us in providing ecological and economic services.
Species Are a Vital Part of the Earth’s Natural Capital �Ecotourism: wildlife tourism
Species Are a Vital Part of the Earth’s Natural Capital • Use value Genetic information �Loss in diversity of crop species is cause for concern. http: //www. ted. com/talks/cary_fowler_one_se ed_at_a_time_protecting_the_future_of_food. html
Extrinsic Value � Food crops, recreation, scientific information, lumber, paper, etc.
Aesthetic value
Ecological value • Energy flow, nutrient cycling, and population control—the scientific principles of sustainability that sustain and support life on earth.
Intrinsic Value �Plants and animals have a right to exist!
Figure 9. 7 Natural capital degradation: endangered orangutans in a tropical forest. In 1900, there were over 315, 000 wild orangutans. Now there are less than 20, 000 and they are disappearing at a rate of over 2, 000 per year because of illegal smuggling and clearing of their forest habitat in Indonesia and Malaysia to make way for oil palm plantations. An illegally smuggled orangutan typically sells for a street price of $10, 000. According to 2007 study by the World Wildlife Fund (WWF), projected climate change will further devastate remaining orangutan populations in Indonesia and Malaysia. Question: How would you go about trying to set a price on the ecological value of an orangutan?
Figure 9. 8 Natural capital: nature’s pharmacy. Parts of these and 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. Nine of the ten leading prescription drugs originally came from wild organisms. About 2, 100 of the 3, 000 plants identified by the National Cancer Institute as sources of cancer-fighting chemicals come from tropical forests. Despite their economic and health potential, fewer than 1% of the estimated 125, 000 flowering plant species in tropical forests (and a mere 1, 100 of the world’s 260, 000 known plant species) have been examined for their medicinal properties. Once the active ingredients in the plants have been identified, they can usually be produced synthetically. Many of these tropical plant species are likely to become extinct before we can study them.
Figure 9. 9 Many species of wildlife, such as this endangered scarlet macaw in Brazil’s Amazon rain forest, are a source of beauty and pleasure. These and other colorful species of parrots can become endangered when they are removed from the wild and sold (sometimes illegally) as pets.
Are We Ethically Obligated to Prevent Premature Extinction? �Intrinsic value, or existence value • Species have an inherent right to exist and play their ecological roles, regardless of their usefulness to us. �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
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 (1) �Habitat destruction, degradation, and fragmentation �Invasive (nonnative) species �Population and resource use growth �Pollution �Climate change �Overexploitation
Figure 9. 10 Underlying and direct causes of depletion and premature extinction of wild species (Concept 9 -3). The major direct causes of wildlife depletion and premature extinction are habitat loss, degradation, and fragmentation. This is followed by the deliberate or accidental introduction of harmful invasive (nonnative) species into ecosystems. NATURAL CAPITAL DEGRADATION Causes of Depletion and Premature 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
Figure 9. 11 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? Question: Would you support expanding these ranges even though this would reduce the land available for people to grow food and live on? Explain. (Data from International Union for the Conservation of Nature and World Wildlife Fund)
Loss of Habitat Is the Single Greatest Threat to Species: Remember HIPPCO (2) �Globally, habitat loss, greatest in temperate biomes, pace picking up in tropics. �Endemic species – Habitat is restricted to one area • Hawaii, the extinction capital of America— 63% of species at risk. The Bali Mynah is distributed and endemic to the island of Bali, where it is the island's only surviving endemic species. This rare bird was discovered in 1910 and is one of the world's most critically endangered birds. In fact, it has been hovering immediately above extinction in the wild for several years.
Habitat Islands �Habitat Islands - an area of habitat surrounded by an area of unsuitable habitat. Can be treated like an island. Examples of habitat islands: 1. Man made: forest surrounded by area that has been converted to grassland 2. Natural: alpine habitat on mountaintops, isolated from other alpine habitat by lower land 3. Natural, very small scale: dung piles, habitat for dung beetles. 4. Islands generally hold fewer species than an area of the same size in continuous habitat. � This is true for genuine oceanic islands and for habitat islands.
Habitat Fragmentation �Habitat fragmentation involves alteration of habitat resulting in spatial separation of habitat units from a previous state of greater continuity. Habitat Fragmentation of Great Apes
Underlying Causes of Species Extinction �Population growth �Overconsumption �Pollution �Climate change
Other Causes of Species Extinction (2) �Pesticides • DDT: Banned in the U. S. in 1972 �Bioaccumulation �Biomagnification
Case Study: A Disturbing Message from the Birds (1) � 70% of the worlds 10, 000 birds are declining; 12% are threatened with extinction. � 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
One in every eight bird species (12%) is threatened with extinction. Three-fourths live in forests. Numbers Location Reason(s) 75% of birds species Sumatra’s lowland forests Lumber and palm plantations, used for biofuels 115 bird species Brazil Burning/clearing of rainforests for farms and ranches; 93% loss of Atlantic coastal rainforest; clearing of savannah-like cerrado for soybean plantations 30% of bird species, 70% of grassland species North America Habitat loss and fragmentation of breeding habitat; replaced by roads and other developments. 28% of species Worldwide Introduction of non-native bird-eating species 52 of 388 parrot species Worldwide Pet trade 23 Seabirds Worldwide Bycatch from commercial fishing; pollution 40% of waterbirds Worldwide Loss of wetlands
Case Study: A Disturbing Message from the Birds (2) � 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
Case Study: A Disturbing Message from the Birds (3) �Greatest new threat: Climate change �Environmental indicators • Live in every climate and biome • Respond quickly to environmental changes • Easy to track �Economic and ecological services
Figure 9. 12 Distribution of bird species in North America and Latin America. Question: Why do you think more bird species are found in Latin America than in North America? (Data from The Nature Conservancy, Conservation International, World Wildlife Fund, and Environment Canada).
Figure 9. 13 The 10 most threatened species of U. S. songbirds. 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 due mostly to human activities during this century. (Data from National Audubon Society) Cerulean warbler Sprague’s pipit Florida scrub jay California gnatcatcher Bichnell’s thrush Black-capped vireo Kirtland's warbler Golden-cheeked warbler Henslow's sparrow Bachman's warbler
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
Some Deliberately Introduced Species Can Disrupt Ecosystems � Most species introductions are beneficial. • Food • Shelter • Medicine • Aesthetic enjoyment � Nonnative species may have no natural enemies. • • Predators Competitors Parasites Pathogens
Figure 9. 14 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 1930 s to control soil erosion. �“ The vine that ate the South” �Could there be benefits of kudzu?
Kudzu Taking Over an Abandoned House in Mississippi, U. S.
Some Accidentally Introduced Species Can Also Disrupt Ecosystems �Argentina fire ant: 1930 s • Pesticide spraying in 1950 s and 1960 s worsened conditions �Wiped out competitor ant species and made them more pesticide resistant. �Burmese python
Figure 9. 16 The Argentina fire ant, introduced accidentally into Mobile, Alabama, in the 1930 s from South America (green area), has spread over much of the southern United States (red area). This invader is also found in Puerto Rico, New Mexico, and California. Question: How might this accidental introduction of fire ants have been prevented? (Data from S. D. Porter, Agricultural Research Service, U. S. Department of Agriculture)
Prevention Is the Best Way to Reduce Threats from Invasive Species � Prevent them from becoming established � Learn the characteristics of the successful invader species and the types of ecosystems that are vulnerable to invasion. � Inspection of imports. � Ballast water from cargo ships. � Set up research programs to try to find natural ways to control them: predators, parasites, bacteria and viruses. � Ground surveys and satellite observations to detect and monitor invasions to develop better models for predicting spread.
Figure 9. 17 Some general characteristics of successful invader species and ecosystems vulnerable to invading species. Question: Which, if any, of the characteristics on the right-hand side could humans influence?
Figure 9. 18 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? Why? Which of these actions do you plan to take?
DDT in fish-eating birds (ospreys) 25 ppm DDT in large fish (needle fish) 2 ppm DDT in small fish (minnows) 0. 5 ppm DDT in zooplankton 0. 04 ppm DDT in water 0. 000003 ppm, or 3 ppt
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
Case Study: Polar Bears and Global Warming � Environmental impact on polar bears • Less summer sea ice • PCBs and DDT �Can adversely affect their development, behavior, and reproduction. � IUCN • 2006 Study: Population projected to decline by 30 - 35%, and may be found only in zoos by end of century. • 2007 listed as threatened species � 2008 listed as threatened species under US ESA.
Figure 9. 20 Polar bear with seal prey on floating ice in Svalbard, Norway. Polar bears in the Arctic are likely to become extinct sometime during this century because global warming is melting the floating sea ice on which they hunt seals.
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 � When commercially valuable species become endangered, black market prices soar. � Prevention: research and education
Figure 9. 21 White rhinoceros killed by a poacher for its horn in South Africa. Question: What would you say if you could talk to the poacher of this animal?
The hyacinth macaw, Anodorhynchus hyacinthinus, may be worth $10 000 to an exotic bird collector, but worth $165 00 in tourist revenues left in the wild.
Individuals Matter: Jane Goodall �Primatologist and anthropologist � 45 years understanding and protecting chimpanzees • Chimps have tool-making skills
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 � US Agency for International Development, trying to introduce alternatives in some areas. • Fish farms • Breeding large rodents, like cane rats.
Figure 9. 22 Bush meat, such as this severed head of a lowland gorilla in the Congo, is consumed as a source of protein by local people in parts of West Africa and sold in the national and international marketplace. You can find bush meat on the menu in Cameroon and the Congo in West Africa as well as in Paris, London, Toronto, New York, and Washington, D. C. It is often supplied by poaching. 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?
9 -4 How Can We Protect Wild Species from Premature Extinction? (1) �Concept 9 -4 A 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 -4 B We can help to prevent species extinction by creating and maintaining wildlife refuges, gene banks, botanical gardens, zoos, and aquariums.
9 -4 How Can We Protect Wild Species from Premature Extinction? (2) �Concept 9 -4 C 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 (1) �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 (2) �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 (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
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
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?
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 (1) �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 (2) �Limited space and funds �Critics say these facilities are prisons for the organisms
What Can You Do? Protecting Species
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
The Precautionary Principle �Species: primary components of biodiversity �Preservation of species �Preservation of ecosystems
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