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Apes ch 9 species approach Key Concepts Human effects on extinction rates Understanding biodiversity and extinction How human activities endanger wildlife Preventing extinction Reconciliation ecology 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? Species Extinction Local extinction: A species is extinct in one area but still lives elsewhere Ecological extinction: A few members are left but no longer play a role in the biological community Biological extinction: The species is no longer found anywhere on the planet 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 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 Extinction Rates Background (natural) rate of extinction: 99.9% of all species that have existed have goon extinct Mass extinction: 25% - 70% or more Extinction spasm: Large number of species go extinct in a very short time (less than 1000 years) Problems Estimating Extinction Rates Extinction not easily documented over time Many species remain unidentified Little is known about most identified species Estimating Extinction Rates Species-area relationships: 90% loss of habitat results in 50% species loss Population viability analysis (PVA): Species specific calculation on how many years before the population will become extinct Minimum viable population (MVP): Minimum number a population can have and survive in the wild Minimum dynamic area (MDA): minimum amount of area a species needs to survive Endangered and Threatened Endangered species: So few individuals that the species could soon become extinct over all or part of its natural range Threatened (vulnerable) species: Still abundant but numbers are dropping and likely to become endangered Causes of Depletion of Wild Species Human population growth Increasing per capita resource use Endangered centers of biodiversity Environmental destruction Spread of opportunistic species Importance of Wild Species Rebuilding biodiversity is slow Instrumental value Genetic information Eco-tourism Ecological value Intrinsic value Species Are a Vital Part of the Earth’s Natural Capital Instrumental value Use value Ecotourism: wildlife tourism Genetic information Nonuse value Existence value Aesthetic value Bequest value Ecological value Science Focus: Using DNA to Reduce Illegal Killing of Elephants for Their Ivory 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? Are We Ethically Obligated to Prevent Premature Extinction? Intrinsic value: existence value Edward O. Wilson: biophilia phenomenon Biophobia Science Focus: Why Should We Care about Bats? Vulnerable to extinction Slow to reproduce Human destruction of habitats Important ecological roles Feed on crop-damaging nocturnal insects Pollen-eaters Fruit-eaters Unwarranted fears of bats Causes of Premature Extinction of Wild Species Habitat Loss and Degradation Greatest threat to species “HIPPO” Habitat destruction Invasive species Population (humans) growth Pollution Overharvesting Case Study: A Disturbing Message from the Birds 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 Case Study: A Disturbing Message from the Birds Greatest new threat: Climate change Environmental indicators Economic and ecological services 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 Threats from Nonnative Species Case Study: The Kudzu Vine Imported from Japan in the 1930s “ The vine that ate the South” Could there be benefits of kudzu? Prevention Is the Best Way to Reduce Threats from Invasive Species Prevent them from becoming established Learn the characteristics of the species Set up research programs Try to find natural ways to control them Other Extinction Threats Hunting and Poaching Predators and Pest Control Exotic Pets and Decorative Plants Climate Change and Pollution Other Causes of Species Extinction Pesticides DDT: Banned in the U.S. in 1972 Bioaccumulation Biomagnification Case Study: Where Have All the Honeybees Gone? Honeybees responsible for 80% of insect-pollinated plants Dying due to? Pesticides Parasites Bee colony collapse syndrome Case Study: Polar Bears and Global Warming Environmental impact on polar bears Less summer sea ice PCBs and DDT 2007: Threatened species list 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 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 Hunting of bush meat is connected to the spread of AIDS Protecting Wild Species: The Research and Legal Approaches International Treaties: CITES and CBD Convention on International Trade in Endangered Species (CITES) 1975 Convention on Biological Diversity (CBD) U.S. National Laws: Lacey Act (1900) Prohibits transport of live or dead animals across state line without a federal permit Endangered Species Act (1973, 82, 85, 88) Identifies and lists endangered and threatened species Endangered Species Act Private versus public poverty rights Win-win compromises Habitat conservation plans (HCPs) Voluntary candidate conservation agreements Weaken or strengthen the act? Science Focus: Accomplishments of the Endangered Species Act Species listed only when serious danger of extinction Takes decades for most species to become endangered or extinct More than half of the species listed are stable or improving Budget has been small Protecting Wild Species: The Sanctuary Approach Wildlife refuges and protected areas Gene banks, botanical gardens, and farms Zoos and Aquariums U.S. has 542 federal refuges for wildlife; most are suffering from environmental degradation 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 Reconciliation Ecology Establishing and maintaining new habitats Being good neighbors to wildlife Reward voluntary conservation efforts The Precautionary Principle Species: primary components of biodiversity Preservation of species Preservation of ecosystems