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Chapter 23

Chapter 23. Sustaining Terrestrial Biodiversity. Biodiversity. …different life forms and life-sustaining processes found on the earth. Examples: Genetic diversity (variety of genes among individuals) Species diversity (types of living things on the planet)

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Chapter 23

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  1. Chapter 23 Sustaining Terrestrial Biodiversity

  2. Biodiversity • …different life forms and life-sustaining processes found on the earth. Examples: • Genetic diversity (variety of genes among individuals) • Species diversity (types of living things on the planet) • Ecological diversity (variety of communities and habitats) • Functional diversity (processes and functions which allow for survival)

  3. World Forest – 32% Desert – 20% Tundra/wetlands – 9% Urban – 2% Cropland – 11% Range/pasture – 26% U.S. Forest – 30% Desert/tundra/wetland – 13% Parks/wilderness – 9% Urban – 2% Cropland – 17% Range/pasture – 29% Land Use

  4. Conservationists: Protect wildlife, habitats, ecosystems. No extra $ gain for resource use/responsible for damage from extraction. Belongs to American people. Developers: Sell land/resources to private groups. Open areas to logging, mining, drilling, etc. Privatize natl parks. Decrease govt rules and fines. Management of Federal Public Lands (35%)

  5. Forests • …can be tropical, boreal, temperate, or subtropical. • Old-growth or Primary: uncut, undisturbed. (36% of world’s forests) • Second-growth: recovering from disturbance. (60% of world’s forests) • Tree farms/commercial: uniform tree age and species; clear-cut/replant cycles. (4% of world’s forests)

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

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

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

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

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

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

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

  13. Major Tree Harvesting Methods

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

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

  16. Fire, Insects, and Climate Change Can Threaten Forest Ecosystems • 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

  17. Surface and Crown Fires

  18. 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

  19. Natural Capital Degradation: Extreme Tropical Deforestation in Thailand

  20. Harmful Environmental Effects of Deforestation

  21. Satellite Images of Amazon Deforestation between 1975 and 2001

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

  23. Solution: Sustainable Forestry

  24. Management of Forest Fires • The Smokey Bear educational campaign • Prescribed fires • Allow fires on public lands to burn • Protect structures in fire-prone areas • Thin forests in fire-prone areas

  25. 2003 Healthy Forests Restoration Act (Healthy Forests Initiative) Pros • With the new cutting of timber, many new jobs would be available • Wood fuel is acquired • With new jobs would come a rise in the economy • May help thin forests and minimize the chances of disease and catastrophic fires

  26. 2003 Healthy Forests Restoration Act (Healthy Forests Initiative) Cons • Supposed to cut forests with a high risk of forest fire; only a fraction of acreage being reducing near threatened homes. • Thinning selected forests is a good idea, but opponents thought President was more interested in large-scale logging. • Many animals displaced and perhaps become in danger of dying out. • Further erosion and loss of topsoil in logged areas. Flooding and mudslides could occur .

  27. Solutions: Sustaining Tropical Forests

  28. Preservation/Restoration • National Parks: restricted-use areas for recreation and preservation. • Nature Reserves: protected wilderness areas. • Problems – not protected, too small, over-use, etc. • Restoration, rehabilitation, replacement -- can be costly and ineffective.

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