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Sustaining Biodiversity: The Ecosystem Approach Chapter 8
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Core Case Study: North American Gray Wolf Reduced to a few hundred Keystone species Restoration proposal angered ranchers, hungers, loggers 1995, reintroduced in Yellowstone, 136 by 2007 Positive ripple effect after reintroduction
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The Gray Wolf Fig. 8-1, p. 149
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8-1 How Are We Affecting the Earth’s Biodiversity and Why Should We Protect It? Concept 8-1A We are degrading and destroying biodiversity in many parts of the world and these threats are increasing. Concept 8-1B We should protect biodiversity because it exists and because of its usefulness to us and other species.
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Loss of Biodiversity Earth’s biodiversity depleted and degraded 83% land surface disturbed Degradation of aquatic biodiversity Ecological fishprint unsustainable
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Why Protect Biodiversity Intrinsic value Instrumental value Nonuse values Existence Aesthetic Bequest
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Endangered Orangutans Fig. 8-2, p. 152
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8-2 How Should We Manage and Sustain Forests? Concept 8-2 We can sustain forests by recognizing the economic value of their ecological services, protecting old-growth forests, harvesting trees no faster than they are replenished, and making most paper from fast- growing plants and agricultural residues instead of trees.
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Forest Services Forests 30% of earth’s land surface Economic services Ecological services
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Types of Forests Old-growth forests Second-growth forests Tree plantation
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Natural Capital: Forests Fig. 8-3, p. 153
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Old-growth Forest Fig. 8-4, p. 154
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Short Rotation Cycle Forestry
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Fig. 8-5, p. 154 Years of growth Weak trees removed Seedlings planted Clear cut 30 yrs 25 yrs 5 yrs10 yrs 15 yrs
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Loss of Original Forests 46% in 8,000 years, most since 1950 Most in tropical areas, developing countries Estimated loss of 40% intact forests within next 20 years
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Natural Capital Degradation: Deforestation Fig. 8-6, p. 155
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Science Focus: Putting a Price Tag on Nature’s Ecological Services Estimated value of earth’s ecological services $33.2 trillion per year $4.7 trillion per year for forests Need to start factoring values into land use
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Roads and Forests
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Fig. 8-7, p. 156 Cleared plots for agriculture New highway Old growth Highway Cleared plots for grazing
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Fig. 8-7, p. 156 New highway Old growth Cleared plots for agriculture Highway Cleared plots for grazing Stepped Art
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Good News on Forests 2000–2005 net total forested area stabilized or increased Most of the increase due to tree plantations Net loss of terrestrial biodiversity
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Return of Forests in the United States (1) U.S. forests Cover ~30% of land Contain ~80% of wildlife species Supply ~67% of nation’s surface water Forest cover greater now than in 1920 Secondary succession
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Return of Forests in the United States (2) Second- and third-growth forests fairly diverse More wood grown than cut 40% of forests in National Forest System Forests transformed into tree plantations
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Individuals Matter: Butterfly in a Redwood Tree Julia Hill – “Butterfly” – two years on a platform of California redwood tree Protest clear-cutting of the ancient trees Nonviolent civil disobedience Lost battle, but her tree was saved
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Controversy over the National Forests Forest service mandate Principle of sustainable yield Principle of multiple use Timber companies push for tree cutting to be primary goal
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Harvest Methods (1) Step one – build roads Erosion Invasive species Open up for human invasion Step two – logging operations Selective cutting Strip cutting Clear cutting
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Forest Harvesting Methods
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Fig. 8-8a, p. 156 Clear stream (a) Selective cutting
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Fig. 8-8b, p. 156 Muddy stream (b) Clear-cutting
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Fig. 8-8c, p. 156 Cut 1 year ago (c) Strip cutting Uncut Clear stream Uncut Cut 3–10 years ago Dirt road
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Clear-cut Logging Fig. 8-9, p. 157
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Trade-offs: Clear-cutting Forests Fig. 8-10, p. 157
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Forests and Fires Surface fires Burn undergrowth only Cool fire Ecological benefits Crown fires Burn the entire tree Hot fire Occur in forests with lack of surface fires
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Management of Forest Fires Fire suppression in all types of forests Some forests naturally fire adapted Restoration of fire’s natural role
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Forest Fires Fig. 8-11, p. 158
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Science Focus: Certifying Sustainably Grown Timber Forest Steward Council certification of forest operations Environmentally sound practices Sustainable yield harvest Minimal erosion from operations Retention of dead wood for wildlife habitat
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Solutions: Sustainable Forestry Fig. 8-12, p. 159
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Trees and Paper Many trees are cut for paper production Alternatives Pulp from rice straw and agricultural residues (China) Kenaf (U.S.)
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Solutions: Kenaf Fig. 8-13, p. 159
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8-3 How Serious Is Tropical Deforestation and How Can It Be Reduced? Concept 8-3 We can reduce tropical deforestation by protecting large forest areas, teaching settlers about sustainable agriculture and forestry, using government subsidies that encourage sustainable forest use, reducing poverty, and slowing population growth.
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Tropical Forests Cover 6% of earth’s land area Habitat for 50% of terrestrial plants and animals Vulnerable to extinction – specialized niches Rapid loss of 50,000–170,000 km 2 per year
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Burning of a Tropical Forest Fig. 8-14, p. 160
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Destruction of Tropical Forests Fig. 8-15, p. 161
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Causes of Tropical Forest Deforestation and Degradation Population growth and poverty Government subsidies International lending agencies encourage development
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Effects of Tropical Deforestation Fragmentation of remaining patches Remaining forests get drier and may burn Degrades biodiversity CO 2 to the atmosphere Accelerates climate change
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How to Protect Tropical Forests Teach settlers to practice small-scale sustainable agriculture Harvest renewable resources from the forests Debt-for-nature swaps Conservation concessions Gentler logging methods
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Solutions: Sustaining Tropical Forests Fig. 8-16, p. 162
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Individuals Matter: Wangari Maathai and Kenya’s Green Belt Movement Backyard small tree nursery Organized poor women Women paid for each surviving seedling planted Breaks cycle of poverty Reduces environmental degradation People walk less distance to get fuelwood Sparked projects in +30 African countries
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8-4 How Should We Manage and Sustain Grasslands? Concept 8-4 We can sustain the productivity of rangeland by controlling the number and distribution of livestock and by restoring degraded rangeland.
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Grasslands Provide important ecological services Second most used and altered ecosystem by humans 42% grazed by cattle, sheep, and goats – rangeland and pasture Overgrazing
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Manage Rangelands Sustainably Practice rotational grazing Fence out riparian zone areas Suppress invader plants Replant barren soil with seeds Employ controlled burns to control exotic vegetation
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San Pedro River Rangelands Fig. 8-17, p. 164
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8-5 How Should We Manage and Sustain Parks and Nature Reserves? Concept 8-5 Sustaining biodiversity will require protecting much more of the earth’s remaining undisturbed land area, starting with the most endangered biodiversity hot spots.
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National Parks >1,100 national parks in 120 countries Only 1% of parks in developing countries are protected Local people invade parks to survive
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Problems Protecting National Parks Illegal logging Illegal mining Wildlife poaching Most parks too small to protect large animals Invasion of nonnative species
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Stresses on U.S. National Parks Biggest problem popularity Damage from nonnative species Threatened islands of biodiversity
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Natural Capital Degradation: Off-road Vehicles Fig. 8-18, p. 165
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Nature Reserves Occupy a Fraction of Earth 12% of earth’s land protected Only 5% fully protected – 95% reserved for human use Need for conservation Minimum 20% of land in biodiversity reserves Protection for all biomes
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Solutions for Protection Requires action – bottom-up political pressure Nature Conservancy – world’s largest private system of reserves Buffer zones around protected areas Locals to manage reserves and buffer zones
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Solutions: National Parks Fig. 8-19, p. 166
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Case Study: Costa Rica Superpower of biodiversity Conserved 25% of its land, 8 megareserves Government eliminated deforestation subsidies Paid landowners to maintain and restore tree coverage Goal to make sustainable forestry profitable
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Model Biosphere Reserve Fig. 8-20, p. 167
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Biosphere Reserve Buffer zone 2 Human settlements Research station Visitor education center Core area Buffer zone 1
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Costa Rica’s Megareserve Network Fig. 8-21, p. 167
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Protecting Wilderness Protects Biodiversity Wilderness Minimum size >4,000 km 2 Preserves natural capital Centers for evolution
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Case Study: Controversy over Wilderness Protection in the U.S. 1964 Wilderness Act Roadless Rule protects 400,000 sq. miles Pressure from oil, gas, mining, and logging
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Protecting Global Biodiversity Hotspots 17 megadiversity countries in tropics and subtropics Two-thirds of biodiversity Developing countries economically poor and biodiversity rich Protect biodiversity hotspots
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34 Global Hotspots Fig. 8-22, p. 169
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Biodiversity Hotspots in the U.S. Fig. 8-23, p. 169
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8-6 What Is the Importance of Restoration Ecology? Concept 8-6 Sustaining biodiversity will require a global effort to rehabilitate and restore damaged ecosystems.
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Ecological Restoration Ecological Restoration Restoration Rehabilitation Replacement Creating artificial ecosystems
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Science-based Principles for Restoration Identify cause of degradation Stop abuse by reducing factors Reintroduce species if necessary Protect area from further degradation
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Case Study: Ecological Restoration of Tropical Dry Forest in Costa Rica One of world’s largest ecological restoration projects Restore a degraded tropical dry forest and reconnect it to adjacent forests Involve 40,000 people in the surrounding area – biocultural restoration Ecotourism
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Will Restoration Encourage Further Degradation Some worry environmental restoration suggests any harm can be undone Scientists disagree Restoration badly needed Altered restored site better than no restoration
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What Can You Do? Fig. 8-24, p. 171
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8-7 How Can We Help Sustain Aquatic Biodiversity? Concept 8-7 We can sustain aquatic biodiversity by establishing protected sanctuaries, managing coastal development, reducing water pollution, and preventing overfishing.
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Three Patterns of Aquatic Biodiversity Greatest biodiversity in coral reefs, estuaries, and deep-ocean floor Higher near the coast than in open sea Higher in the bottom region of ocean than in surface layer
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Human Impacts on Aquatic Ecosystems Destroyed or degraded by human activities Ocean floor degradation 150 times larger than area clear-cut annually 75% of most valuable fish species overfished Likely extinction 34% marine fish species 71% freshwater species
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Effects of Bottom Trawling Fig. 8-25, p. 172
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Why Is Protection of Marine Biodiversity So Difficult? Human aquatic ecological footprint expanding Not visible to most people Viewed as an inexhaustible resource Most ocean areas outside jurisdiction of a country
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Solutions for Marine Ecosystems Protect endangered and threatened species Establish protected marine sanctuaries Marine reserves – work well and quickly Integrated coastal management Protect existing coastal wetlands
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Solutions: Managing Fisheries Fig. 8-26, p. 173
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8-8 What Should Be Our Priorities for Protecting Biodiversity? Concept 8-8 Sustaining the world’s biodiversity requires mapping terrestrial and aquatic biodiversity, protecting terrestrial and aquatic hotspots and old-growth forests, initiating ecological restoration projects worldwide, and making conservation profitable.
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Priorities for Protecting Biodiversity Map terrestrial and aquatic biodiversity Immediately preserve biodiversity hotspots Keep old-growth forests intact Protect and restore lakes and rivers Initiate ecological restoration Make conservation profitable
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Animation: Ocean Provinces PLAY ANIMATION
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Animation: Humans Affect Biodiversity PLAY ANIMATION
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Animation: Habitat Loss and Fragmentation PLAY ANIMATION
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Animation: Area and Distance Effects PLAY ANIMATION
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Animation: Succession PLAY ANIMATION
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Animation: Hubbard Brook Experiment PLAY ANIMATION
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Animation: Effects of Air Pollution in Forests PLAY ANIMATION
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Animation: Effects of Deforestation PLAY ANIMATION
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Animation: Biodiversity Hot Spots PLAY ANIMATION
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Animation: Resources Depletion and Degradation PLAY ANIMATION
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Animation: Species Diversity By Latitude PLAY ANIMATION
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Video: Easter Island PLAY VIDEO
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Video: New Species Found PLAY VIDEO
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Video: Bachelor Pad at the Zoo PLAY VIDEO
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Video: Desertification in China PLAY VIDEO
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Video: U.S. Forests PLAY VIDEO
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Video: Marine Sanctuary PLAY VIDEO
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Video: Sea Turtle Release PLAY VIDEO
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