ENVS 137 Chapter Notes - Chapter 8: National Park Service Organic Act, Wilderness Act, Ecosystem Services
16 Nov 2016
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Document Summary
Human activities increased rate of extinction. Relocation of species humans introduce non-native competitors, predators, and diseases. Worldwide, the single greatest threat to biodiversity is habitat loss . By 1900 over 95% of north america"s deciduous forests had been heavily logged/cleared for agriculture. Agriculture replaces grasslands only 3% of north america"s mixed and tall-grass prairies remain, and those that remain only in small isolated patches. Only 1% of longleaf pine savannas left provide habitat for diverse endemic flora and fauna now endangered. Dwindling tropical forests contain a lot of the world"s species today half these forests are gone. Tropical forests being cleared at a rate of million square miles every decade. Current global extinction rate in tropical forests 1,000 species per year. Species suffer from isolated populations in fragmented habitats. Coastal development and boating destroy sea grass beds in shallow coastal waters (provide habitat for shellfish, source of food for many endangered species)
