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Sustaining Biodiversity: The Ecosystem Approach
Chapter 8 Sections 1-4
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Key Concepts Human impacts on biodiversity Public lands and their use
Use and management of forest resources Temperate and Tropical Deforestation Problems associated with parks Establishing and managing natural reserves Protecting and sustaining aquatic biodiversity Importance of ecological restoration Sustaining the Earth’s biodiversity Part 1 Part 2
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Reintroducing Wolves to Yellowstone (1995)
Why wolves were killed- 2 million killed to “make the west safe for livestock and big-game animals” Wolf protection 1974 listed as endangered species Ecological importance- Keystone predator- culled herds of bison, elk, caribou and mule deer, keep coyote pop low, … Yellowstone controversy- ranchers, hunters, miners all opposed Importance of biodiversity- ecological success- willow & aspen re-growth in riparian areas, more beavers, elk carcasses feed grizzlies, coyote population reduced, squirrel & fox pop increase = more food for eagles & hawks Fig. 8-1, p. 154
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Human Impacts on Biodiversity
Human “footprint” Disturbing the land- humans have disturbed % of Earth Destruction of wetlands half world’s wetlands lost in past 100 yrs Deforestation Aquatic biodiversity- 27% coral reefs severely damaged- 75% fish are fished at or above limit Premature extinctions- current extinction rate likely 1, ,000 times greater than before humans Fig. 8-2, p. 155
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Human Impacts on Biodiversity
The Ecosystem Approach The Species Approach Human Impacts on Biodiversity Goal Protect populations of species in their natural habitats Protect species from premature extinction Strategy Preserve sufficient areas of habitats in different biomes and aquatic systems • Identify endangered species • Protect their critical habitats Tactics • Protect habitat areas through private purchase or government action • Eliminate or reduce populations of nonnative species from protected areas • Manage protected areas to sustain native species • Restore degraded ecosystems • Legally protect endangered species • Manage habitat • Propagate endangered species in captivity • Reintroduce species into suitable habitats Stepped Art Fig. 8-3, p. 156
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Natural Capital Degradation: Orangutans
< 20,000 Organutans left- disappear at a rate >2,000 per year
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Natural Capital: Scarlet Macaw
Fig. 8-5, p. 157
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Types of US Public Lands (35% of US is public land)
Multiple-use lands: National Forest System; Natural Resource Lands (BLM) Moderately restricted-use lands: Natural Wildlife Refuges Restricted-use lands: Natural Park System; Natural Wilderness Preservation System
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What percent of U.S. land is federally-owned public land?
35% 7% c. 55% 3% 0%
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US Federal Public Lands
National parks and preserves National forests (and Xs) National wildlife refuges Fig. 8-6b, p. 158
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Managing US Public Lands principles of public land use
Conservationists Developers Protecting biodiversity is a primary goal No subsidies or tax breaks for use of resources Public should get fair compensation for use Users are responsible for environmental damage Alternative views from developers and industry Sell public lands / less than market value Slash funding for regulation Cut old growth forests in national forests and replace with tree plantations Open all public land to oil, mining, off-roading and commercial development Eliminate Nat. Park Service, mine without royalties, repeal Endangered Species Act, …
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Which of the following is a major problem of U.S. national parks?
wildfires too much land area to manage Popularity lack of management plans attack from vicious wildlife on humans
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It is permissible to trap animals in most national wildlife refuges.
a. True b. False
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a. roads b. fishing c. camping d. sailboats e. APES students
The National Wilderness Preservation System forbids the introduction of: a. roads b. fishing c. camping d. sailboats e. APES students
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Arctic National Wildlife Refuge (CNN Video) 2 min
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Types of Forests Old-growth- not seriously disrupted for at least several hundred years Second-growth - results from secondary succession Tree plantation or tree farm - managed tract of uniformly aged trees of one or two species. Clear cut when commercially valuable, then replanted.
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Major Services of Forests
Natural Capital Ecological services of world’s forests valued at $4.7 trillion per year Forests Value of ecological services much greater than value of economic services Ecological Services >>> Much greater than Economic Services Support energy flow and chemical cycling Reduce soil erosion Absorb and release water Purify water Purify air Influence local and regional climate Store atmospheric carbon Provide numerous wildlife habitats Fuelwood Lumber Pulp to make paper Mining Livestock grazing Recreation Jobs Fig. 8-7, p. 160
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Types of Forest Management
Even-aged management (industry forestry) trees about same age and size- simplified tree plantation- 1-2 fast-growing species harvested on rotation cycle. EX: Clear cutting EX: Seed tree method: In the seed-tree method, 2-12 seed trees per acre (5-30/ha) are left standing in order to regenerate the forest. EX: Shelter wood method: The method's objective is to establish new forest reproduction under the shelter of the retained trees. Rotation cycles: years (temperate), 6-10 years (tropical) EX: Strip cutting Uneven-aged management- variety of species w/ range of ages & sizes. Goals: biodiversity, sustainable high quality timber EX: Selective cutting Sustainable management intensive management of as little as 20% of world’s forests could meet current and future demand for commercial wood / fiber EX: Combine aspects of a number of these management techniques.
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Tree Plantation Fig. 8-8, p. 160
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Degradation of Forests from Logging Roads
Increased erosion and sediment runoff Habitat fragmentation Biodiversity loss Pathways for pests, diseases, and invasive species More accessible for humans
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Degradation of Forests
Cleared plots for grazing Highway Cleared plots for agriculture Fig. 8-10b, p. 161
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Degradation from Clear-cut Logging
Fig. 8-12, p. 163
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Tradeoffs of Clear-cutting Forests
Advantages Disadvantages Higher timber yields Maximum economic return in shortest time Can reforest with genetically improved fast-growing trees Short time to establish new stand of trees Needs less skill and planning Best way to harvest tree plantations Good for tree species needing full or moderate sunlight for growth Reduces biodiversity Disrupts ecosystem processes Destroys and fragments some wildlife habitats Leaves moderate to large openings Increases soil erosion Increases sediment water pollution and flooding when done on steep slopes Eliminates most recreational value for several decades Fig. 8-13, p. 163
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Harmful Effects of Deforestation
© 2006 Brooks/Cole - Thomson Natural Capital Degradation Deforestation Decreased soil fertility from erosion Runoff of eroded soil into aquatic systems Premature extinction of species with specialized niches Loss of habitat for migratory species such as birds and butterflies Regional climate change from extensive clearing Releases CO2 into atmosphere from burning and tree decay Accelerates flooding Fig. 8-14, p. 164
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Deforestation has all of the following effects except:
a. increase in soil fertility. b. regional climate change. c. flooding. d. extinction of species with specialized niches. e. increase in soil erosion.
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Sustainable Forestry Conserves biodiversity, water & soil resources
© 2006 Brooks/Cole - Thomson Solutions Sustainable Forestry Conserves biodiversity, water & soil resources Grow more timber on long rotations Rely more on selective cutting and strip cutting No clear-cutting, seed-tree, or shelterwood cutting on steeply sloped land No fragmentation of remaining large blocks of forest Sharply reduce road building into uncut forest areas Leave most standing dead trees and fallen timber for wildlife habitat and nutrient recycling Certify timber grown by sustainable methods Include ecological services of trees and forests in estimating economic value Fig. 8-15, p. 164
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Surface and Crown Forest Fires
Ground fire = underground surface fire, common in northern peat bogs Fig. 8-16, p. 166
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Minimizing Forest Damage from Fire
Prescribed burning- reduce underbrush Allow small fires in National Parks, forests & wilderness to burn (if people & property not threatened) Defensible space- clear 200 feet around buildings Effects of the Healthy Forests Initiative Timber Co. allowed to take large/medium trees in Nat. Forests if they clear away smaller, fire-prone trees- criticized by fire scientists (large tree most fire resistant, logging creates slash)
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Healthy Forests Initiative (CNN Video)
Read more about this!
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Managing US National Forests
Status of US forests- 30% of USA forested, more wood grown than cut more forests now than in 1920 (old growth forests decreasing) Importance of national forests Management of forests Lost revenue from timber sales- timber sales from US federal land lost taxpayer money in 97 of past 100 years Controversies of logging national forests- 10x more $ and 7x more jobs added to economy by using national forests for recreation, hunting & fishing Tree-free fibers and paper- agricultural residues, kenaf & industrial hemp
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Logging in U.S. National Forests
Trade-Offs Logging in U.S. National Forests Advantages Disadvantages Helps meet country’s timber needs Cut areas grow back Keeps lumber and paper prices down Provides jobs in nearby communities Promotes economic growth in nearby communities Provides only 4% of timber needs Ample private forest land to meet timber needs Has little effect on timber and paper prices Damages nearby rivers and fisheries *Recreation in national forests provides more local jobs and income for local communities than logging Decreases recreational opportunities Fig. 8-17, p. 168
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Kenaf Holds potential to greatly reduce pressure to cut trees for paper End Part 1 Fig. 8-18, p. 169
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