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Sustaining Biodiversity: The Ecosystem Approach

Sustaining Biodiversity: The Ecosystem Approach. Chapter 8. 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

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Sustaining Biodiversity: The Ecosystem Approach

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  1. Sustaining Biodiversity: The Ecosystem Approach Chapter 8

  2. 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

  3. The Gray Wolf Fig. 8-1, p. 149

  4. 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.

  5. Loss of Biodiversity • Earth’s biodiversity depleted and degraded • 83% land surface disturbed • Degradation of aquatic biodiversity • Ecological fishprint unsustainable

  6. Why Protect Biodiversity • Intrinsic value • Instrumental value • Nonuse values • Existence • Aesthetic • Bequest

  7. Endangered Orangutans Fig. 8-2, p. 152

  8. 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.

  9. Forest Services • Forests 30% of earth’s land surface • Economic services • Ecological services

  10. Types of Forests • Old-growth forests • Second-growth forests • Tree plantation

  11. Natural Capital: Forests Fig. 8-3, p. 153

  12. Old-growth Forest Fig. 8-4, p. 154

  13. Short Rotation Cycle Forestry

  14. Weak trees removed 25 yrs Clear cut 30 yrs 15 yrs Years of growth Seedlings planted 5 yrs 10 yrs Fig. 8-5, p. 154

  15. 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

  16. Natural Capital Degradation: Deforestation Fig. 8-6, p. 155

  17. 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

  18. Roads and Forests

  19. Cleared plots for grazing New highway Highway Cleared plots for agriculture Old growth Fig. 8-7, p. 156

  20. Cleared plots for grazing New highway Highway Cleared plots for agriculture Old growth Stepped Art Fig. 8-7, p. 156

  21. 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

  22. 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

  23. 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

  24. 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

  25. 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

  26. 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

  27. Forest Harvesting Methods

  28. (a) Selective cutting Clear stream Fig. 8-8a, p. 156

  29. (b) Clear-cutting Muddy stream Fig. 8-8b, p. 156

  30. (c) Strip cutting Cut 1 year ago Uncut Dirt road Cut 3–10 years ago Uncut Clear stream Fig. 8-8c, p. 156

  31. Clear-cut Logging Fig. 8-9, p. 157

  32. Trade-offs: Clear-cutting Forests Fig. 8-10, p. 157

  33. 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

  34. Management of Forest Fires • Fire suppression in all types of forests • Some forests naturally fire adapted • Restoration of fire’s natural role

  35. Forest Fires Fig. 8-11, p. 158

  36. 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

  37. Solutions: Sustainable Forestry Fig. 8-12, p. 159

  38. Trees and Paper • Many trees are cut for paper production • Alternatives • Pulp from rice straw and agricultural residues (China) • Kenaf (U.S.)

  39. Solutions: Kenaf Fig. 8-13, p. 159

  40. 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.

  41. 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 km2 per year

  42. Burning of a Tropical Forest Fig. 8-14, p. 160

  43. Destruction of Tropical Forests Fig. 8-15, p. 161

  44. Causes of Tropical Forest Deforestation and Degradation • Population growth and poverty • Government subsidies • International lending agencies encourage development

  45. Effects of Tropical Deforestation • Fragmentation of remaining patches • Remaining forests get drier and may burn • Degrades biodiversity • CO2 to the atmosphere • Accelerates climate change

  46. 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

  47. Solutions: Sustaining Tropical Forests Fig. 8-16, p. 162

  48. 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

  49. 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.

  50. 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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