F.ConserveSu11 - Conservation Ecology Millennium Ecosystem...

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Conservation Ecology Heyer 1 Millennium Ecosystem Assessment 2005 Landmark study by 1300 experts from 95 countries. Reports that humans have disrupted ~60% of earth’s ecological systems to meet demands for food, water, timber and fuel. http://www.millennium assessment.org Millennium Ecosystem Assessment “Any progress achieved in addressing . . . poverty and hunger, health and environmental protection is unlikely . . . if most of the ecosystem services on which humanity relies continue to be degraded.” “Human activity is putting such strain on the natural functions of earth that the ability of the planet’s ecosystems to sustain future generations can no longer be taken for granted.” Slowing this trend “will require radical changes in the way nature is treated at every level of decision- making.” http://www.millennium assessment.org Real and potential human insults to the integrity of the biosphere Regional & global Regional & global Loss of biodiversity Loss of biodiversity Loss of overall life support Real and potential human insults to the integrity of the biosphere 1. Global contamination (pollution) Global contamination (pollution) 2. Disrupted biogeochemical cycles 3. Lost biodiversity [HIPPO] Lost biodiversity [HIPPO] 4. 4. Global warming 5. Destruction of the ozone layer 6. Nuclear winter Ecology and Environmentalism • The precautionary principle Basically states that humans need to be concerned with how their actions affect the environment It is a lot more plausible to prevent environmental degradation than to try to remediate it Disrupted biogeochemical cycles Water cycle –Desertification; contamination; saltwater intrusion Nitrogen cycle –Nutrient depletion; cultural eutrophication; nitrite contamination; acid rain Carbon cycle: –Excessive CO 2 ; depleted fossil pools • Soils: –Erosion; nutrient depletion; fire suppression
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Conservation Ecology Heyer 2 Biodiversity Crisis Birds 13% of known bird species worldwide are threatened with extinction. Density of songbird populations has dropped by 50% in the US in the last 40 years. Biodiversity Crisis Plants In the US, 200 species of plants have disappeared within the past 100 years. Another 730 species are endangered. Biodiversity Crisis Fish About 20% of the known freshwater fishes in the world became extinct during historical times, or are now threatened. About 200 of the 300 species of cichlids in lake Victoria are gone due to introduction of the exotic Nile perch. Since 1900, Since 1900, 123 freshwater vertebrate and vertebrate and invertebrate species have become extinct in North America, and North America, and hundreds more are hundreds more are threatened. Extinction rates of aquatic species are five times that of terrestrial. Biodiversity Crisis Biodiversity Crisis Biodiversity Crisis Since 1900, the current rate of extinction is 100 to 1000 times “background” rates of prior centuries This past century may represent the greatest This past century may represent the greatest extinction event of Earth extinction event of Earth’ s history!
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