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Case Study: Remember Wolves In Yellowstone Endangered Species – 1850-1900 two million wolves were destroyed Keystone Species – Keeps herbivore population in check (elk, moose) – Vegetation reestablishes – Species diversity expands (beavers & ducks return) Figure 10-1 Types of “Protected” Lands in U.S. Multiple-use lands National Forest (U.S.F.S.) sustainable yield multiple use used for logging, mining, grazing, farming, oil, recreation, hunting and conservation National Resource lands (BLM) mostly out west and Alaska multiple use used for mineral and oil extraction/ grazing Types of “Protected” Lands Moderately Restricted-Use Lands National Wildlife Refuges (USFWS) 522 refuges 24% designated as wilderness protect habitats oil, farming, hunting, mineral extraction are allowed as long as Dept. of Interior says OK Types of Protected Lands Restricted-Use lands National Park System (NPS) 55 National Parks and 324 recreation areas, battlefields, memorials, etc. Preserve and interpret the country’s historic and cultural heritage and protect wilderness areas Parks can be used for camping, hiking, fishing and boating Rec areas: also mining and oil 49% of National Park system is wilderness Locations of Parks, Preserves, Forests and Refuges Types of Forests Old-growth forest: uncut or regenerated forest that has not been seriously disturbed for several hundred years – 22% of world’s forest – Hosts many species with specialized niches Due to human activities over 50% of the earth’s original forests have been removed. Figure 10-5 Types of Forests Second-growth forest: a stand of trees resulting from natural secondary succession Tree plantation: planted stands of a particular tree species Figure 10-6 Impact of Deforestation Figure 10-7 Case Study: Deforestation and the Fuelwood Crisis • Almost half the people in the developing world face a shortage of fuelwood and charcoal – In Haiti, 98% of country is deforested – MIT scientist has found a way to make charcoal from spent sugarcane Harvesting Trees Increased erosion and runoff Habitat fragmentation Pathways for exotic species Accessibility to humans Figure 10-8 Harvesting Trees • Trees can be harvested individually from diverse forests (selective cutting) • an entire forest can be cut down (clear cutting) • portions of the forest is harvested (strip cutting) Figure 10-9 Harvesting Trees Effects of clear-cutting in the state of Washington, U.S. Figures 10-10 and 10-11 Types and Effects of Forest Fires • Depending on their intensity, fires can benefit or harm forests – Burn away flammable ground material – Release valuable mineral nutrients Figure 10-13 Fire Surface fires Surface fire Crown fires Crown fire Solutions: Controversy Over Fire Management • To reduce fire damage: – Set controlled surface fires – Allow fires to burn on public lands if they don’t threaten life and property – Clear small areas around property subject to fire Controversy over Logging in U.S. National Forests • There has been an ongoing debate over whether U.S. national forests should be primarily for: – – – – Timber Ecological services Recreation Mix of these uses Figure 10-14 Solutions: Reducing Demand for Harvest Trees • Tree harvesting reduced by wasting less wood, making paper and charcoal fuel from fibers that don’t come from trees – Kenaf is promising plant for paper production Figure 10-15 American Forests in a Globalized Economy • Timber from tree plantations in temperate and tropical countries is decreasing the need for timber production in the U.S. – This could help preserve the biodiversity in the U.S. by decreasing pressure to clear-cut old-growth and second-growth forests – This may lead to private land owners to sell less profitable land to developers – Forest management policy will play a key role CASE STUDY: TROPICAL DEFORESTATION • Large areas of ecologically and economically important tropical forests are being cleared and degraded at a fast rate Figure 10-16 CASE STUDY: TROPICAL DEFORESTATION • At least half of the world’s terrestrial plant and animal species live in tropical rain forests • Large areas of tropical forest are burned to make way for cattle ranches and crops Figure 10-17 Why Should We Care about the Loss of Tropical Forests? • About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancerfighting chemicals come from tropical forests. Figure 10-18 MANAGING AND SUSTAINING GRASSLANDS • Almost half of the world’s livestock graze on natural grasslands (rangelands) and managed grasslands (pastures) • We can sustain rangeland productivity by controlling the number and distribution of livestock and by restoring degraded rangeland MANAGING AND SUSTAINING GRASSLANDS • Overgrazing (left) occurs when too many animals graze for too long and exceed carrying capacity of a grassland area. Figure 10-21 MANAGING AND SUSTAINING GRASSLANDS • Example of restored area along the San Pedro River in Arizona after 10 years of banning grazing and off-road vehicles. Figure 10-22 Case Study: Grazing and Urban Development in the American West • Ranchers, ecologists, and environmentalists joining together to preserve grasslands on cattle ranches – Paying ranchers conservation easements (barring future owners from development) – Pressuring government to zone land to prevent development of ecologically sensitive areas NATIONAL PARKS • Countries established more than 1,100 national parks, but most threatened by human activities – Local people invade park for wood, cropland, & other natural resources – Loggers, miners, & wildlife poachers also deplete natural resources – Many are too small to sustain large-animal species – Many suffer from invasive species Case Study: Stresses on U.S. National Parks • Overused due to popularity • Inholdings (private ownership) within parks threaten natural resources • Air pollution Figure 10-23 NATURE RESERVES • Ecologists call for protecting more land to help sustain biodiversity, but powerful economic and political interests oppose doing this. – Currently 12% of earth’s land is protected – Only 5% strictly protected from harmful human activities – Conservation biologists call for full protection of at least 20% of earth’s land area representing multiple examples of all biomes NATURE RESERVES • Large and medium-sized reserves with buffer zones help protect biodiversity and can be connected by corridors. • Costa Rica has consolidated its parks and reserves into 8 megareserves designed to sustain 80% if its biodiversity. Figure 10-10B NATURE RESERVES • A model biosphere reserve that contains a protected inner core surrounded by two buffer zones that people can use for multiple use. Figure 10-25 • 34 hotspots identified by ecologists as important and endangered centers of biodiversity. Figure 10-26 NATURE RESERVES • Wilderness is land legally set aside in a large enough area to prevent or minimize harm from human activities. • Only a small percentage of the land area of the United States has been protected as wilderness.