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Chapter 12 Sustaining Biodiversity: The Species Approach. Extinction: Local – species is extinct in one area, but still found in other locations Ecological – so few left that it no longer plays its ecological role in the communities in which it is found
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Extinction: Local – species is extinct in one area, but still found in other locations Ecological – so few left that it no longer plays its ecological role in the communities in which it is found Biological extinction – completely gone from the planet
Review: Biodiversity at Risk Extinction is a natural process Mass extinction – when more than half the existing species go extinct over a period of 1000’s or tens of thousands of years Are we heading for a sixth mass extinction? Predicted time to completion: 100 years Cause: human activity
Extinction rates Review – 99.9% of all species that have existed have gone extinct Estimated annual extinction rate before humans: 0.0001% Estimated annual extinction rate since humans: 0.1-1%
Extinct species – due to human activities Passenger pigeon Dusky seaside sparrow Great auk Dodo Aepyornis (Madagascar)
Think about this… Name some characteristics of species that make them especially likely to go extinct: List on the next slide….
Characteristic Examples Low reproductive rate (K-strategist) Blue whale, giant panda, rhinoceros Specialized niche Blue whale, giant panda, Everglades kite These are characteristics that increase the risk of extinction, along with examples of each Narrow distribution Many island species, elephant seal, desert pupfish Bengal tiger, bald eagle, grizzly bear Feeds at high trophic level Fixed migratory patterns Blue whale, whooping crane, sea turtles Rare Many island species, African violet, some orchids Commercially valuable Snow leopard, tiger, elephant, rhinoceros, rare plants and birds Large territories California condor, grizzly bear, Florida panther
The Species Approach The Ecosystem Approach Goal Goal Protect populations of species in their natural habitats Protect species from premature extinction Strategies Strategy • Identify endangered species • Protect their critical habitats Preserve sufficient areas of habitats in different biomes and aquatic systems Tactics Tactics • Protect habitat areas through private purchase or government action • Eliminate or reduce populations of alien species from protected areas • Manage protected areas to sustain native species • Restore degraded ecosystems • Legally protect endangered species • Manage habitat • Propagate endangered species in captivity • Reintroduce species into suitable habitats
Benefits of Biodiversity • Biodiversity can affect the stability of ecosystems When even one species is lost, it affects the entire ecosystem
Keystone species – species that are critical to the survival of an entire ecosystem Example: sea otter
Benefits of Biodiversity 2.Healthy ecosystems provide good ecosystem services – the benefits that people obtain from ecosystems
Ecosystem Services: the benefits people obtain from ecosystems Regulating Benefits obtained from regulation of ecosystem processes • climate regulation • disease regulation • flood regulation Provisioning Goods produced or provided by ecosystems • food • fresh water • fuel wood • genetic resources Cultural Non-material benefits from ecosystems • spiritual • recreational • aesthetic • inspirational • educational Supporting Services necessary for production of other ecosystem services • Soil formation • Nutrient cycling • Primary production
Benefits of Biodiversity • Humans need biodiversity for medical, industrial, and agricultural purposes (existing uses and genetic information for new uses) Foxglove Digitalis purpurea, Europe Digitalis for heart failure Pacific yew Pacific Northwest Ovarian cancer
Potential new food crops may be lost forever Source: FAO
Ethics, aesthetics, and recreation E.O. Wilson: there is “spiritual, religious and psychological value” in preserving biodiversity Ecotourism – tourism that supports conservation and sustainable development of ecologically unique areas
How do humans cause extinction?HIPPCO • Habitat destruction – may be complete destruction or habitat fragmentation Habitat destruction is the number one threat to biodiversity
How do humans cause extinction?HIPPCO • Introduction of invasive species Example: Mites, called Verroa destructor, introduced from Asia have seriously reduced the wild honeybee population in the U.S.
1918 2000 Spread of fire ants
Kudzu • Fast-growing climbing vine from Asia • Introduced to control erosion
European Starling • Released into New York City in the late1800’s by a man who wanted to introduce to the U.S. all of the birds mentioned in Shakespeare • Now widespread across North America • Outcompetes many native birds, such as bluebirds, for nest holes
How do humans cause extinction?HIPPCO 3. Population growth – root of the problem? Food for thought: What native species could live in these conditions?
How do humans cause extinction?HIPPCO 4. Pollution Example: Use of DDT almost caused the extinction of the Bald Eagle and other predatory birds
Biomagnification Also called biological magnification Accumulation of pollutants in higher order trophic levels
How do humans cause extinction?HIPPCO • Climate change polar bear– loss of sea icebleaching of coral reefs
Males • Golden toads were discovered in 1964, in Monteverde, Costa Rica • The mountainous cloud forest has a perfect climate for amphibians • Extreme sexual dimorphism • Unfortunately, they became extinct within 25 years • Causes: • Changes in habitat – drying of cloud forest due to global warming, ENSO • Narrow window of time for reproduction – breed in temporary ponds which dried up early • Limited range • Disease Female
How do humans cause extinction?HIPPCO 6. Overharvesting, hunting, poaching Both legal and illegal collecting of organisms has had a negative impact
Areas of Critical Biodiversity • Biodiversity “hotspots” • High numbers of endemic species • Threatened by human activities • Tropical rainforests • Coral reefs and coastal ecosystems • Islands
U.S. Biodiversity Hotspots 2 4 3 5 Top Six Hot Spots 6 1 Hawaii 2 San Francisco Bay area 3 Southern Appalachians 4 Death Valley 5 Southern California 6 Florida Panhandle Concentration of rare species 1 Low Moderate High
Efforts to Preserve Biodiversity • Efforts to save individual species • Captive-breeding programs – California condor population went from 9 in 1986 to 58 in 2002 • Zoos, aquariums, parks, gardens – for many, there is now more emphasis on preservation and less on entertainment • Gene banks and seed banks
Efforts to Preserve Biodiversity • Efforts to save habitats and ecosystems (more on this in Chapters 11 and 13) Reconciliation ecology – finding ways to share spaces with other species Restoration ecology – science devoted to repairing, restoring damaged ecosystems It is important to save the entire ecosystem, not just an isolated species Example: Vermillion Darter The vermilion darter is found only in the Turkey Creek drainage, a tributary of the Locust Fork of the Black Warrior River, Jefferson County, Alabama.
Efforts to Preserve Biodiversity Legal protection – exists in many countries U.S. has Endangered Species Act (ESA), passed in 1973 Main Provisions: U.S. Fish and Wildlife Service (USFWS) compiles a list of endangered and threatened species on land and in freshwater, National Marine Fisheries Service (NMFS) is responsible for marine species End./Thr. Species may not be killed, caught, sold (penalties include fines and jail, enforced mainly by USFWS, also Coast Guard) Fed. Govt. may not carry out projects that jeopardize listed species Dept. of Interior should designate and protect critical habitat necessary for survival of listed species USFWS must develop a recovery plan for each listed species
ESA terminology Endangered species – a species that is likely to become extinct unless some protective measures are enacted immediately Threatened species – species with declining populations, likely to become endangered if not protected Critical habitat – areas that are critical to the conservation of the species, may be where it lives or where it migrates Alabama endangered species: Red-cockaded woodpecker Watercress darter Gray bat Green pitcher plant Green sea turtle Gopher tortoise
Successful recoveries • Species which increased in population size since being placed on the endangered list include: • Bald Eagle (increased from 417 to 11,040 pairs between 1963 and 2007); removed from list 2007 • Whooping Crane (increased from 54 to 436 birds between 1967 and 2003) • Kirtland's Warbler (increased from 210 to 1,415 pairs between 1971 and 2005) • Peregrine Falcon (increased from 324 to 1,700 pairs between 1975 and 2000); removed from list • Gray Wolf (populations increased dramatically in the Northern Rockies, Southwest, and Great Lakes) • Gray Whale (increased from 13,095 to 26,635 whales between 1968 and 1998); removed from list • Grizzly bear (increased from about 271 to over 580 bears in the Yellowstone area between 1975 and 2005); removed from list 3/22/07 • California’s Southern Sea Otter (increased from 1,789 in 1976 to 2,735 in 2005) • San Clemente Indian Paintbrush (increased from 500 plants in 1979 to more than 3,500 in 1997) • Red Wolf (increased from 17 in 1980 to 257 in 2003) • Florida's Key Deer (increased from 200 in 1971 to 750 in 2001) • Hawaiian Goose (increased from 400 birds in 1980 to 1,275 in 2003) • (increased from 3,500 in 1979 to 18,442 in 2004)
Controversy over ESA • How successful has it been? • Does it trample individual rights by prohibiting certain uses of critical habitat owned by private citizens (limits on logging, mining, development, etc.)? • Does it hinder economic development by such prohibitions?
Efforts to Preserve Biodiversity International efforts IUCN – International Union for the Conservation of Nature and Natural Resources; organization that publishes the “red list” of endangered species, promotes preservation of species and habitats (http://www.iucnredlist.org/) CITES treaty – first effort to stop killing of African elephants for ivory tusks, prohibits trade of many species
International efforts: Biodiversity Convention 1993 • First international treaty to recognize that biodiversity is "a common concern of humankind“ and is important to the development of countries • Works to protect entire ecosystems • Works for sustainable use of resources to provide significant environmental, economic and social benefits • Uses the precautionary principle as a guide • Covers the rapidly developing field of biotechnology • Not ratified by the U.S.
Efforts to Preserve Biodiversity Private organizations Examples: World Wildlife Fund, Nature Conservancy, Greenpeace International