Sustaining Terrestrial Biodiversity: The Ecosystem Approach

1. Sustaining Terrestrial Biodiversity: The Ecosystem Approach Chapter 10

2. 10-1 What Are the Major Threats to Forest Ecosystems? • 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. • 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.

3. Forests Vary in Their Make-up, Age, and Origins • Old-growth forest: Original forests that have not been disturbed for logging, road building, or development • Sometimes called primary, ancient, virgin, or primeval forests • 36% of world’s forest • High biodiversity because of many specialized niches

4. Forests Vary in Their Make-up, Age, and Origins Remaining Old-Growth Forests in the U.S.

5. Forests Vary in Their Make-up, Age, and Origins Second-growth forest: • Area which has re-grown after a major disturbance such as fire, insect, or timber harvest • 60% of world’s forest • The area is reclaimed by the natural process of secondary succession • Small shrubs and trees followed by the larger trees

6. Forests Vary in Their Make-up, Age, and Origins • Tree plantation (tree farm): Planted stands of a particular tree species that are maintained, harvested, and replanted • Typically used for paper or particle board

7. Forests Provide Important Economic and Ecological Services Estimated annual value: Economic services $1.8 trillion Ecological services $4.7 trillion

8. Unsustainable Logging is a Major Threat to Forest Ecosystems • Building roads into previously inaccessible forests paves the way for increased erosion, habitat fragmentation, loss of biodiversity, and invasion by non-native species. • For this reason, many federal wilderness areas do not allow the construction of roads.

9. Unsustainable Logging is a Major Threat to Forest Ecosystems • Three major tree harvesting methods: • Selective cutting • Clear-cutting • Strip cutting

10. Unsustainable Logging is a Major Threat to Forest Ecosystems • Selective Cutting: • Mature trees are harvested individually from diverse forests • Younger trees left to harvest later • Reduces crowding • Removes diseased trees • Encourages growth of younger trees

11. Unsustainable Logging is a Major Threat to Forest Ecosystems Clear-cutting: • Removing all trees in a single pass.

12. Unsustainable Logging is a Major Threat to Forest Ecosystems Clear-cutting

13. Unsustainable Logging is a Major Threat to Forest Ecosystems • Strip-cutting: • A type of clear cutting that involves clear trees along the contours of the land. • Less erosion

14. Fire, Insects, and Climate Change Can Threaten Forest Ecosystems • Forest fires can either benefit or harm forests • Burn away flammable ground material • Prevent larger, more destructive fires • Release valuable mineral nutrients • Stimulate new forest growth

15. 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, jump from treetop to treetop • Fierce and hard to control

16. Fire, Insects, and Climate Change Can Threaten Forest Ecosystems • Accidental or deliberate introduction of foreign diseases and insects are also a major threat to forests.

17. We Have Cut Down Almost Half of the World’s Forests • Human activities have reduced the earth’s forest cover by as much as half. • Deforestation – temporary or permanent removal of large areas of forests • Results from unsustainable cutting of trees • Losses are concentrated in developing countries. • Use it for fuel – heating and/or cooking • Tropical forests • Especially in Latin America, Indonesia, and Africa • Boreal forests • Especially in Alaska, Canada, Scandinavia, and Russia

18. We Have Cut Down Almost Half of the World’s Forests

19. Tropical Forests Are Disappearing Rapidly • Large areas of ecologically and economically important tropical forests are being cleared and degraded at a rapid rate.

20. Tropical Forests Are Disappearing Rapidly

21. Tropical Forests Are Disappearing Rapidly • Large areas of tropical forest are burned to make way for cattle ranches and crops. • Soil in the rainforest is very poor • Farmers burn the trees down to provide nutrients for the soil • Heavy rain leaches away the nutrients so they move to another area and burn again

22. Tropical Forests Are Disappearing Rapidly • At least half of the world’s terrestrial plants and animals live in tropical rain forests. • About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer-fighting chemicals come from tropical rain forests.

23. Tropical Forests Are Disappearing Rapidly

24. 10-2 How Should We Manage and Sustain Forests? • Concept 10-2 We can sustain forests by emphasizing the economic value of their ecological services, protecting old-growth forests, harvesting trees no faster than they are replenished, and using sustainable substitute resources.

25. 10-2 How Should We Manage and Sustain Forests? • We can use forests more sustainably by emphasizing: • Economic value of ecological services • Harvesting trees no faster than they are replenished • Protecting old-growth and vulnerable areas

26. We Can Improve the Management of Forest Fires • Fire prevention programs have been very effective…too effective. • Large amounts of highly flammable underbrush have accumulated • Leads to larger, more destructive crown fires • To reduce fire damage: • Set controlled surface fires (Prescribed Fires). • Allow fires to burn on public lands if they don’t threaten life and property. • Clear small areas around property subject to fire.

27. 10-3 How Should We Manage and Sustain Grasslands? • Concept 10-3 We can sustain the productivity of grasslands by controlling the number and distribution of grazing livestock and restoring degraded grasslands.

28. 10-3 How Should We Manage and Sustain Grasslands? • Important ecological services of grasslands: • Soil formation • Erosion control • Nutrient cycling • Storage of atmospheric carbon dioxide in biomass • Maintenance of diversity

29. 10-3 How Should We Manage and Sustain 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.

30. Some Rangelands Are Overgrazed • Overgrazing occurs when too many animals graze for too long and exceed carrying capacity of a grassland area. • Grass/shrubs are damaged beyond repair • Reduces grass cover • Leads to erosion of soil by water and wind

31. Some Rangelands Are Overgrazed • Desertification - The degradation of land that results in a desert • Caused by overgrazing, deforestation, or overuse • The worlds deserts are getting bigger • Prevention of overgrazing: • Rotational grazing • Replant barren areas • Apply fertilizer • Reduce soil erosion

32. 10-4 How Should We Manage and Sustain Parks and Natural Reserves? • Concept 10-4 Sustaining biodiversity will require protecting much more of the earth’s remaining undisturbed land area as parks and nature reserves.

33. 10-4 How Should We Manage and Sustain Parks and Natural Reserves? Important Definitions: • Conservation Focuses on the proper use of nature • Seeks to regulate the human use of wilderness and its resources • Preservation Focuses on the protection of nature from use • Seeks to eliminate the human use of wilderness and its resources

34. 10-4 How Should We Manage and Sustain Parks and Natural Reserves? • National park –a reserve of land, usually, but not always declared and owned by a national government, protected from most human development and pollution. • Countries have established more than 1,100 national parks, but most are threatened by human activities. • Local people invade park for wood, cropland, and other natural resources. • Loggers, miners, and wildlife poachers also deplete natural resources. • Many are too small to sustain large-animal species. • Many suffer from invasive species.

35. 10-4 How Should We Manage and Sustain Parks and Natural Reserves? • 58 Major national parks in the U.S. • Overused due to popularity – litter, trampling, off road vehicles, etc. • Many species are isolated and fragmented from the ecosystems around them • Air pollution from areas outside of park

36. 10-4 How Should We Manage and Sustain Parks and Natural Reserves? • Nature Reserves(Nature Preserves) Protected areas of importance for wildlife, geological features, or other special interests, which are reserved and managed for conservation. • Nature reserves may be designated by government institutions, by private landowners, or by charities and research institutions. • Currently 12% of earth’s land area is protected. • Only 5% is strictly protected from harmful human activities • Conservation biologists call for full protection of at least 20% of earth’s land area

37. 10-4 How Should We Manage and Sustain Parks and Natural Reserves? • Wildernessis 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. • Wilderness Act of 1964 • Established 9.1 million acres of federally protected wilderness in national forests

38. Federally protected Wilderness

39. 10-5 What is the Ecosystem Approach to Sustaining Biodiversity? • Concept 10-5A We can help sustain biodiversity by identifying severely threatened areas and protecting those with high plant diversity and those where ecosystem services are being impaired. • Concept 10-5B Sustaining biodiversity will require a global effort to rehabilitate and restore damaged ecosystems. • Concept 10-5C Humans dominate most of the earth’s land, and preserving biodiversity will require sharing as much of it as possible with other species.

40. 10-5 What is the Ecosystem Approach to Sustaining Biodiversity? • We can prevent or slow down losses of biodiversity by concentrating efforts on protecting global “biodiversity hot spots” where significant biodiversity is under immediate threat.

41. 10-5 What is the Ecosystem Approach to Sustaining Biodiversity?

42. 10-5 What is the Ecosystem Approach to Sustaining Biodiversity?