March 4th Ecology Notes - March 4th Ecology Notes Human...

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March 4 th Ecology Notes Human Domination of the earths ecosystems -Vitousek et al 1997 Science -Nearly ½ of land surface area modified by humans -over half of surface water used by humans - carbon dioxide increased by over 30 percent -global nitrogen inputs to soil and water have doubled with human activities Land use and Land Cover -Land Cover: habitat or vegetation type (croplands, forest, grassland) - Land Use: way humans use/employ the land and its resources (logging, housing, recreation, agriculture) - Leading cause of species extinction is habitat loss Why do forests matter? -logging is decreasing spotted owl population -there is a conflict over old growth forests -it is not jobs versus the environment but jobs because of environment -Columbia River -Salmon catch is diminishing, 75 pecent of these 2.5 million salmon are actually from fish hatcheries, therefore the real number is lower -streams are still there but they are smothered -salmon migrate up to 2000 miles to spawn -return to the same spot to spawn -once the most common fish in north America -sea lice latch onto salmon and suck the resources out of them, leave wounds on them -deforestation is 2 nd leading cause of carbon dioxide increase from land use change -missing carbon sink: going into oceans, and terrestrial forest ecosystems 15 million hectares,37 million acres being logged/cut per year globally -Net Impact of Tropical Deforestation -about 1 percent lost per year globally FAO 1999 -conversion to agriculture/ranching. Some commercial logging -source of 20-25% of C emissions -loss of significant sink March 6 th Notes Forest use in the US -Pre European settlement- 50 percent of us covered by forest E and NW -general trends-loss of forest and grasslands, increased agriculture -1730 forest clearing began -1800 half open land -1850 85 percent of land open -after 1850 farms abandoned forests ruined -1920-1990 forest cover and residential development -northeast forest cover greater than southeast, Midwest forests were cleared later -urban sprawl, ATL
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Forest policy and management in the US -plantation forestry, pine plantations, popular for producing timber very quickly -approximate timber harvested from California, relevant to staff in the white house, drop occurred when Jimmy Carter was in white house, increase when regan was in white house - with a change in administrations, there was a change in the cutting of old growth forests -Bush Administration “Healthy Forest Initiative” 2002 -this would reduce threat of destructive forest fires -this allows for construction of fire roads in old growth forests -allows timber companies to cut the largest/old growth trees -not require removal of underbrush -The larges trees do not promote fires -underbrush does -bills favored the logging industry -land management policies and land protection policies -when we cut the last of the old growth forest in the us, because of the length of the time necessary to grown an old growth forest no human alive today will ever see one again -given reality, it is likely that no human alive in the next century will see an old growth
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March 4th Ecology Notes - March 4th Ecology Notes Human...

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