Sustaining Terrestrial Biodiversity: The Ecosystem Approach

1. Sustaining Terrestrial Biodiversity: The Ecosystem Approach Chapter 10

2. Core Case Study: Reintroducing Gray Wolves to Yellowstone • Around 1800 • 1850–1900: decline due to human activity • U.S. Endangered Species Act: 1973 • 1995–1996: relocation of gray wolves to Yellowstone Park • 2008: Gray wolf no longer protected

3. Natural Capital Restoration: the Gray Wolf

4. 10-1 What Are the Major Threats to Forest Ecosystems? (1) • Concept 10-1A Forest ecosystems provide ecological services far greater in value than the value of raw materials obtained from forests. • Concept 10-1B Unsustainable cutting and burning of forests, along with diseases and insects, are the chief threats to forest ecosystems.

5. 10-1 What Are the Major Threats to Forest Ecosystems? (2) • Concept 10-1C Tropical deforestation is a potentially catastrophic problem because of the vital ecological services at risk, the high rate of tropical deforestation, and its growing contribution to global warming.

6. Forests Vary in Their Make-Up, Age, and Origins • Old-growth or primary forest • 36% of world’s forests • Second-growth forest • 60% of world’s forests • Tree plantation, tree farm or commercial forest • 4% of world’s forests • May supply most of the industrial wood in the future

7. Natural Capital: An Old-Growth Forest and an Old-Growth Tropical Forest

8. Rotation Cycle of Cutting and Regrowth of a Monoculture Tree Plantation

9. Fig. 10-3a, p. 216

10. Weak trees removed 25 yrs Clear cut 30 yrs 15 yrs Years of growth Seedlings planted 5 yrs 10 yrs Fig. 10-3a, p. 216

11. Fig. 10-3b, p. 216

12. Forests Provide Important Economic and Ecological Services (1) • Support energy flow and chemical cycling • Reduce soil erosion • Absorb and release water • Purify water and air • Influence local and regional climate • Store atmospheric carbon • Habitats

13. Forests Provide Important Economic and Ecological Services (2) • Wood for fuel • Lumber • Pulp to make paper • Mining • Livestock grazing • Recreation • Employment

14. Natural Capital: Major Ecological and Economic Services Provided by Forests

15. Science Focus: Putting a Price Tag on Nature’s Ecological Services • Forests valued for ecological services • Nutrient cycling • Climate regulation • Erosion control • Waste treatment • Recreation • Raw materials • $4.7 Trillion per year

16. Estimated Annual Global Economic Values of Ecological Services Provided by Forests

17. 400 350 300 250 200 Worth (billions of dollars) 150 100 50 0 Nutrient cycling Climate regulation Erosion control Waste treatment Recreation Raw materials Ecological service Fig. 10-A, p. 218

18. Unsustainable Logging is a Major Threat to Forest Ecosystems (1) • Increased erosion • Sediment runoff into waterways • Habitat fragmentation • Loss of biodiversity

19. Unsustainable Logging is a Major Threat to Forest Ecosystems (2) • Invasion by • Nonnative pests • Disease • Wildlife species • Major tree harvesting methods: • Selective cutting • Clear-cutting • Strip cutting

20. Natural Capital Degradation: Building Roads into Previously Inaccessible Forests

21. Cleared plots for grazing Highway New highway Cleared plots for agriculture Old growth Fig. 10-5, p. 218

22. Major Tree Harvesting Methods

23. Fig. 10-6a, p. 219

24. (a) Selective cutting Clear stream Fig. 10-6a, p. 219

25. Fig. 10-6b, p. 219

26. (b) Clear-cutting Muddy stream Fig. 10-6b, p. 219

27. Fig. 10-6c, p. 219

28. (c) Strip cutting Uncut Cut 1 year ago Dirt road Cut 3–10 years ago Uncut Clear stream Fig. 10-6c, p. 219

29. (a) Selective cutting (b) Clear-cutting Clear stream Muddy stream Uncut (c) Strip cutting Cut 1 year ago Dirt road Cut 3–10 years ago Uncut Clear stream Stepped Art Fig. 10-6a, p. 219

30. Clear-Cut Logging in Washington State, U.S.

31. Trade-offs: Advantages and Disadvantages of Clear-Cutting Forests

32. TRADE-OFFS Clear-Cutting Forests Advantages Disadvantages Higher timber yields Reduces biodiversity Destroys and fragments wildlife habitats Maximum profits in shortest time Can reforest with fast-growing trees Increases water pollution, flooding, and erosion on steep slopes Good for tree species needing full or moderate sunlight Eliminates most recreational value Fig. 10-8, p. 220

33. Fire, Insects, and Climate Change Can Threaten Forest Ecosystems (1) • Surface fires • Usually burn leaf litter and undergrowth • May provide food in the form of vegetation that sprouts after fire • Crown fires • Extremely hot: burns whole trees • Kill wildlife • Increase soil erosion

34. Fire, Insects, and Climate Change Can Threaten Forest Ecosystems (2) • Introduction of foreign diseases and insects • Accidental • Deliberate • Global warming • Rising temperatures • Trees more susceptible to diseases and pests • Drier forests: more fires • More greenhouse gases

35. Surface and Crown Fires

36. U.S. Forest Invading Nonnative Insect Species and Disease Organisms

37. White pine blister rust Pine shoot beetle Beech bark disease Sudden oak death Hemlock woolly adelgid Fig. 10-10, p. 221

38. We Have Cut Down Almost Half of the World’s Forests • Deforestation • Tropical forests • Especially in Latin America, Indonesia, and Africa • Boreal forests • Especially in Alaska, Canada, Scandinavia, and Russia

39. Natural Capital Degradation: Extreme Tropical Deforestation in Thailand

40. Natural Capital Degradation: Harmful Environmental Effects of Deforestation

41. Case Study: Many Cleared Forests in the United States Have Grown Back • Forests of the eastern United States decimated between 1620 and 1920 • Grown back naturally through secondary ecological succession • Biologically simplified tree plantations reduce biodiversity

42. Tropical Forests are Disappearing Rapidly • Majority of loss since 1950 • Brazil and Indonesia tropical forest loss • Role of deforestation in species’ extinction

43. Satellite Images of Amazon Deforestation between 1975 and 2001

44. Species Diversity

45. Causes of Tropical Deforestation Are Varied and Complex • Primary • Secondary

46. Major Causes of the Destruction and Degradation of Tropical Forests

47. NATURAL CAPITAL DEGRADATION Major Causes of the Destruction and Degradation of Tropical Forests Basic Causes Secondary Causes • Not valuing ecological services • Roads • Cattle ranching • Fires • Logging • Crop and timber exports • Settler farming • Tree plantations • Government policies • Cash crops • Poverty • Population growth Cattle ranching Tree plantations Logging Cash crops Settler farming Fires Roads Fig. 10-15, p. 225

48. NATURAL CAPITAL DEGRADATION Major Causes of the Destruction and Degradation of Tropical Forests • Not valuing ecological services Basic Causes Secondary Causes • Government policies • Roads • Cattle ranching • Fires • Logging • Crop and timber exports • Poverty • Settler farming • Tree plantations • Population growth • Cash crops Cattle ranching Tree plantations Logging Cash crops Settler farming Fires Roads Stepped Art Fig. 10-15, p. 225

49. Natural Capital Degradation: Large Areas of Brazil’s Amazon Basin Are Burned

50. Animation: Hubbard Brook experiment