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Chapter 55 ~ Conservation Biology Three Levels of Biodiversity Loss of Genetic diversity: Loss of Species Diversity: endangered vs. threatened Loss of Ecosystem Diversity Biodiversity crisis Extinction ~ natural phenomenon, however, rate is of concern….. 50% loss of species when 90% of habitat is lost Major Threats: Habitat destruction ~ single greatest threat; cause of 73% of species designation as extinct, endangered, vulnerable, rare; 93% of coral reefs Competition by exotic (non-native) species ~ cause of 40% of species designation as extinct. Overexploitation ~ commercial harvest or sport fishing; illegal trade Biodiversity: Human welfare 25% of all medical prescriptions Genetic variability Aesthetic and ethical reasons Species survival Conservation at the Population and Species Level Small Population Approach: study process that causes very small pop. To become extinct. Extinction Vortex How small is too small? – Minimum Viable Population (MVP) – Effective Population Size (Ne) breeding potential Conservation biology focus Preservationism: setting aside select areas as natural and underdeveloped Resource conservation: public lands to meet the needs of agriculture and extractive industries, i.e., ”multiple use” Evolutionary / ecological view: natural systems result from millions of years of evolution and ecosystem processes are necessary to maintain the biosphere Declining Population Approach Action oriented Focuses on threatened and endangered pop. Case by Case process Steps – – – – – – Confirm species is in decline Study history to determine environmental needs Determine all possible causes of decline List prediction of each hypothesis for the decline Test most likely hypothesis Apply results of diagnosis Case Study Red-Cockaded Woodpecker •Build nest in Heartwood of •Logging/Agriculture live pines. destroyed habitate. •Center rotten •Fire prevention •Space •Caused •Resin repels insect and other pred. •Overgrowth of forest undergrowth •Under-story must be low cover/profile Ecologist construct cavities in pines at 20 sites. 18 of 20 were occupies Breeding pairs w/ helpers for inhabitating incubation ofarea eggsbecause Woodpeckers were not Occupy nests b/c takes several years to make nest ofabandoned lack of breeding cavities Prevents dispersion of species Population & species level conservation Biodiversity hot spot: small area with an exceptional concentration of species Endemic species: species found nowhere else Endangered species: organism “in danger of extinction” Threatened species: likely to become endangered in the foreseeable future Bioremediation: use of living organisms to detoxify polluted systems Conservations Protected of world’s land is a form of reserve. EdgedArea: and 7% corridors: Biodiversity Hotspot: small area w/ high concentration of natural and created, endemic species and large # of endangered/threatened species define an ecosystem La Fin El Extremo Das Ende L’ estremita The End