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. Tree plantations
Tree plantations are much less biologically diverse and probably less sustainable than old-growth and second-growth forest.
They deplete the soil of nutrients and can hinder the growth of any type of forest on the land.
Also controversy over the increased use of genetically engineered tree species whose seed could spread to other areas an threaten their diversity.

8. Old-Growth Forest
The following countries have more than tree-fourths of the world´s remaining old-growth forest:
Russia
Canada
Brazil
Indonesia
Papua New Guinea

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

10. 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.

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

12. 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

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

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

15. 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

16. Unsustainable Logging is a Major Threat to Forest Ecosystems
Biodiversity experts are alarmed at the growing practice of illegal, uncontrolled and unsustainable logging taking place in 70 countries, especially in Africa and Southeast Asia.
Global trade in timber and wood products.

17. 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

18. 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

19. Fire, insects and climate change can threaten forest ecosystems
As part of a natural cycle, forest fires are not a major threat to forest ecosystems. They are threats in parts of the world where people intentionally burn forests to clear the land, mostly to make way for crop plantations.

20. 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.

21. Ways to reduce the impacts of tree diseases and insect pests on forests
Banning imported timber (diseases and insects)
Removing or clear-cut infected and infested trees.
Developing tree species that are genetically resistant to common diseases.
Controling insect pests by applying conventional pesticides.
Biological control (bugs) combined with small amounts of pesticides.

22. Climate Change
Projected climate change from global warning could harm many forests:
Could kill trees sensitives to heat such as sugar maple.
Rising temperatures would also make many forst areas more suitable for insect pests and increase the size of pest populations.
Drier forests and more dead trees could increase the incidence and intensity of forest fires.

23. 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
Human activities have reduced the earth´s original forest cover by about 46%.
The world´s forests are being cleared or degraded at a rate of % per year, with much higher rates in some areas.

24. We Have Cut Down Almost Half of the World´s Forests
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
Are the world´s greatest terrestrial storehouse of organic carbon and play a major role in the carbon cycle and in climate regulation for the entire planet.

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

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

27. Tropical Forests Are Disappearing Rapidly

28. 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

29. 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.

30. Tropical Forests Are Disappearing Rapidly

31. Causes of Tropical Deforestation Are Varied and Complex
Population growth and poverty combine: they try to grow food to survive.
Reduce of costs of timber harvesting, cattle grazing.
Vast plantations of crops such as soybeans.

32. Road is cut deep into the forest
Loggers remove the best timber and other trees fall with them.
Once the forests are gone, the companies move on to another country (leaving devastation and importation) and sell the land to ranchers (overgrazing)

33. 10-2 How Should We Manage and Sustain Forests?
Concept 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.

34. 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

35. 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.

36. 10-3 How Should We Manage and Sustain Grasslands?
Concept We can sustain the productivity of grasslands by controlling the number and distribution of grazing livestock and restoring degraded grasslands.

37. 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

38. 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.

39. 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

40. 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

41. 10-4 How Should We Manage and Sustain Parks and Natural Reserves?
Concept Sustaining biodiversity will require protecting much more of the earth’s remaining undisturbed land area as parks and nature reserves.

42. 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

43. 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.

44. 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

45. 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

46. 10-4 How Should We Manage and Sustain Parks and Natural Reserves?
Wilderness is 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

47. 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.

48. 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.

49. 10-5 What is the Ecosystem Approach to Sustaining Biodiversity?

50. 10-5 What is the Ecosystem Approach to Sustaining Biodiversity?