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Unformatted text preview: Sanctuary Approach Wildlife Refuges Zoos, Parks, Botanical Gardens Seed Banks, Gene Banks Sanctuary Approach National Wildlife Refuge System- 524 refuges in the USA- 20% of endangered species and their habitats Potential Use for abandoned military bases Mainly wetlands Controversy- allow oil and gas development Sanctuary Approach Gene banks, Botanical gardens
50 seed banks store 100 plant species that make up 90% of food supply 1600 Botanical Gardens- 30% of plant species Sanctuary Approach-Zoos, Aquariums Captive Breeding programs- intention to re-release into the wild- need 100500 individuals for genetic variability Artificial insemination, cloning Space for only half of threatened vertebrate species in the world Wildlife Management Regulation of fishing and hunting to manage populations- typically used to promote populations of wild game species, and regulate harvest quotas Manipulation of Vegetation and Water SuppliesEcological succession- species change over time in an area. Ecological Succession Gradual change in species composition in a given area Pioneer species- 1st to move in and colonize Climax community- most stable Secondary succession- follows a disturbance Ecological Succession Succession must be managed to maintain a particular habitat Planting seeds, tramsplanting, controlled burning all used Managing Land in USA 42% of land is public- 73% in Alaska, 22% in western states 20% of oil reserves, 30% natural gas reserves, 40% coal reserves, 40% commercial forests. National Forests- Multiple Use land Wildlife refuges-Moderately Restricted National Parks- Restricted Use land Managing Forest Land 32% of earth’s surface is forest, 30% in USA Old growth forests most ecologically diverse Secondary Forests- follow disturbance Tree plantations-managed with uniform species of same age Management Depends on use Short Rotation Cycles- pulp for paper, fuelwood 6-10 years in tropical forests, 20-30 years temperate forests Longer Rotation cycles required for higher quality wood Management Even Aged Management-same age and size- plantations Uneven Aged Management- Maintain variety of sizes, selective cuttingfoster biodiversity, long term sustainability, multiple uses Harvesting Techniques Build a Logging Road- opens accessdisqualifies land for protection as wilderness Clear cutting- remove all trees Selective cutting-cut older trees singly Shelterwood cutting- remove older trees in 2-3 cuttings over 10 years Seed-tree cutting- leave a few trees to reseed Clear cutting Clear cut forest in Oregon Tropical Forests 6% of world land area, 47% of forest cover 30% of species in Brazil tropical rain forest Half area has been cleared since 1950 Population growth, poverty, govt. policies encourage deforestation Commercial Logging- clear cutting Unsustainable farming Cash crops Mining Fuelwood-15% of fuel supply ...
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This note was uploaded on 01/26/2009 for the course BIOPL 2400 taught by Professor Silva,t. during the Fall '08 term at Cornell.
- Fall '08