Conservation Biology Chapter 59 Biodiversity Crisis Extinction is a fact of life: all species become extinct eventually More than 99% of species known to science are now extinct Current accelerating loss of habitat 20% of present day species will be extinct by the middle of this century
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Why have African mega fauna survived ?
Some species under imminent extinction threat
Hotspots: areas where species have high endemism and are disappearing at a rapid rate. Red areas are hotspots.
25 hotspots have been identified
Contain nearly half of all terrestrial
species in the world
Why are species going extinct in hotspots ?
Cancer-fighting drugs like taxol, have been developed from the bark of the Pacific yew
Thailand are more
Tropical rainforests provide more economic benefits if they are left standing than if they are destroyed and the land used for other purposes
Case Study: New York City watershed
New York City’s water source
Why worry about amphibian declines ?
Rain forest covering the eastern coast of Madagascar:
Extinction and Island Area
Case Study: songbird declines
Case Study: whales
Introduced species threaten native species and habitats
Two thirds of Hawaiian birds are extinct or have reduced populations
Disruption of ecosystems can cause an extinction cascade
Heath hen and dusky seaside sparrow
Case Study: Prairie chickens
Prairie chicken, male mating ritual
Destroyed habitats can sometimes be restored
Removing introduced species
Cleanup and rehabilitation
Case Study: Peregrine falcon