Presentation on theme: "Sustaining Terrestrial Biodiversity: The Ecosystem Approach"— Presentation transcript:
1Sustaining Terrestrial Biodiversity: The Ecosystem Approach Chapter 10
2Core Case Study: Reintroducing Gray Wolves to Yellowstone Around 18001850–1900: decline due to human activityU.S. Endangered Species Act: 19731995–1996: relocation of gray wolves to Yellowstone Park2008: Gray wolf no longer protected
4Science Focus: Effects of Reintroducing the Gray Wolf to Yellowstone National Park Gray wolves prey on elk and push them to a higher elevationRegrowth of aspen, cottonwoods, and willowsIncreased population of riparian songbirdsReduced the number of coyotesFewer attacks on cattleWolf pups susceptible to parvovirus carried by dogs4
5HUMAN IMPACTS ON TERRESTRIAL BIODIVERSITY We have depleted and degraded some of the earth’s biodiversity and these threats are expected to increase.
610-1 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.
710-1 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.
8Forests Vary in Their Make-Up, Age, and Origins Old-growth or primary forest36% of world’s forestsSecond-growth forest60% of world’s forestsTree plantation, tree farm or commercial forest4% of world’s forestsMay supply most of the industrial wood in the future
9Natural Capital: An Old-Growth Forest and an Old-Growth Tropical Forest
10Rotation Cycle of Cutting and Regrowth of a Monoculture Tree Plantation Fig 10-3
11Natural Capital: Major Ecological and Economic Services Provided by Forests Fig 10-4
12Science Focus: Putting a Price Tag on Nature’s Ecological Services Forests valued for ecological servicesNutrient cyclingClimate regulationErosion controlWaste treatmentRecreationRaw materials$4.7 Trillion per year
13Estimated Annual Global Economic Values of Ecological Services Provided by Forests Fig 10a
14Natural Capital Degradation: Building Roads into Previously Inaccessible Forests Fig 10-5
15Unsustainable Logging is a Major Threat to Forest Ecosystems (1) Increased erosionSediment runoff into waterwaysHabitat fragmentationLoss of biodiversity
16Unsustainable Logging is a Major Threat to Forest Ecosystems (2) Invasion byNonnative pestsDiseaseWildlife speciesMajor tree harvesting methods:Selective cuttingClear-cuttingStrip cutting
18(a) Selective cutting(c) Strip cuttingClear stream(b) Clear-cuttingMuddy streamUncutCut 1 year agoDirt roadCut 3–10 years agoClear streamFigure 10.6Major tree harvesting methods. Question: If you were cutting trees in a forest you owned, which method would you choose and why?Stepped ArtFig. 10-6a, p. 219
20TRADE-OFFS Clear-Cutting Forests Advantages Disadvantages Higher timber yieldsReduces biodiversityDestroys and fragments wildlife habitatsMaximum profits in shortest timeFigure 10.8Advantages and disadvantages of clear-cutting forests. Question: Which single advantage and which single disadvantage do you think are the most important? Why?Can reforest with fast-growing treesIncreases water pollution, flooding, and erosion on steep slopesGood for tree species needing full or moderate sunlightEliminates most recreational valueFig. 10-8, p. 220
21Controversy over Logging in U.S. National Forests There has been an ongoing debate over whether U.S. national forests should be primarily for:Timber.Ecological services.Recreation.Mix of these uses.
22Fire, Insects, and Climate Change Can Threaten Forest Ecosystems (1) Surface firesUsually burn leaf litter and undergrowthMay provide food in the form of vegetation that sprouts after fireCrown firesExtremely hot: burns whole treesKill wildlifeIncrease soil erosion
23Fire, Insects, and Climate Change Can Threaten Forest Ecosystems (2) Introduction of foreign diseases and insectsAccidentalDeliberateGlobal warmingRising temperaturesTrees more susceptible to diseases and pestsDrier forests: more firesMore greenhouse gases
25U.S. Forest Invading Nonnative Insect Species and Disease Organisms Fig 10-10
26Solutions: Controversy Over Fire Management In 2003, U.S. Congress passed the Healthy Forest Restoration Act:Allows timber companies to cut medium and large trees in 71% of the national forests.In return, must clear away smaller, more fire-prone trees and underbrush.Some forest scientists believe this could increase severe fires by removing fire resistant trees and leaving highly flammable slash.
27We Have Cut Down Almost Half of the World’s Forests DeforestationTropical forestsEspecially in Latin America, Indonesia, and AfricaBoreal forestsEspecially in Alaska, Canada, Scandinavia, and Russia
28Natural Capital Degradation: Extreme Tropical Deforestation in Thailand
29Natural Capital Degradation: Harmful Environmental Effects of Deforestation Fig 10-12
30Satellite Images of Amazon Deforestation between 1975 and 2001
31Major Causes of the Destruction and Degradation of Tropical Forests Fig10-15
32NATURAL CAPITAL DEGRADATION • Not valuing ecological services• Government policies• Poverty• Population growthNATURAL CAPITAL DEGRADATIONMajor Causes of the Destruction and Degradation of Tropical ForestsBasic Causes• Crop and timber exportsCattle ranchingTree plantationsLoggingCash cropsSettler farmingFiresRoadsSecondary Causes• Roads• Cattle ranching• Fires• Logging• Settler farming• Tree plantations• Cash cropsFigure 10.15Major interconnected causes of the destruction and degradation of tropical forests. The importance of specific secondary causes varies in different parts of the world. Question: If we could eliminate the basic causes, which if any of the secondary causes might automatically be eliminated?Stepped ArtFig , p. 225
33Natural Capital Degradation: Large Areas of Brazil’s Amazon Basin Are Burned
34Why Should We Care about the Loss of Tropical Forests? About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer-fighting chemicals come from tropical forests.Figure 9-8
3510-2 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.
37We Can Improve the Management of Forest Fires (1) The Smokey Bear educational campaignPrescribed firesAllow fires on public lands to burnProtect structures in fire-prone areasThin forests in fire-prone areas
38We Can Reduce the Demand for Harvested Trees Improve the efficiency of wood useMake tree-free paperKenafHemp
40Governments and Individuals Can Act to Reduce Tropical Deforestation Reduce fuelwood demandPractice small-scale sustainable agriculture and forestry in tropical forestDebt-for-nature swapsConservation concessionsUse gentler logging methodsBuy certified lumber and wood products
4210-3 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.
43Some Rangelands Are Overgrazed (1) Important ecological services of grasslandsSoil formationErosion controlNutrient cyclingStorage of atmospheric carbon dioxide in biomassMaintenance of diversity
44Some Rangelands are Overgrazed (2) Overgrazing of rangelandsReduces grass coverLeads to erosion of soil by water and windSoil becomes compactedEnhances invasion of plant species that cattle won’t eat
45Natural Capital Degradation: Overgrazed and Lightly Grazed Rangeland
46We Can Manage Rangelands More Sustainably (1) Rotational grazingSuppress growth of invasive speciesHerbicidesMechanical removalControlled burningControlled short-term trampling
47We Can Manage Rangelands More Sustainably (2) Replant barren areasApply fertilizerReduce soil erosion
48Restoration of Grazing Lands Example of restored area along the San Pedro River in Arizona after 10 years of banning grazing and off-road vehicles.Figure 10-21
4910-4 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.
50National Parks Face Many Environmental Threats Worldwide: 1100 major national parksParks in developing countriesGreatest biodiversity1% protected againstIllegal animal poachingIllegal logging and mining
51Natural Capital Degradation: Damage From Off-Road Vehicles
53National Parksin CaliforniaClick for National Park Atlas
54Nature Reserves Occupy Only a Small Part of the Earth’s Land Conservationists’ goal: protect 20% of the earth’s landCooperation between government and private groupsNature ConservancyEco-philanthropistsDevelopers and resource extractors opposition
59Public Land in the United States Private land = 60%, Federal = 28%, State = 9%Wilderness: around 110 million acres (half in Alaska)National Parks: around 85 million acres. Click for Na ParksNational Wildlife Refuges: around 100 million acres. Around half in Alaska. Click for US Fish and Wildlife ServiceNational Forests: around 200 million acres. Around 155 million acres are forest, 20 million grasslands. Click for US Forest ServiceBureau of Land Management: around 260 million acres million acres subsurface. Click for BLM
60Southern Los Padres National Forest Click for Wilderness Society
6110-5 What is the Ecosystem Approach to Sustaining Biodiversity? (1) 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.
6210-5 What is the Ecosystem Approach to Sustaining Biodiversity? (2) 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.
63We Can Use a Four-Point Strategy to Protect Ecosystems Map global ecosystems; identify speciesLocate and protect most endangered speciesRestore degraded ecosystemsDevelopment must be biodiversity-friendlyAre new laws needed?
65Endangered Natural Capital: Biodiversity Hotspots in the U.S. Fig 10-27
66ECOLOGICAL RESTORATION Restoration: trying to return to a condition as similar as possible to original state.Rehabilitation: attempting to turn a degraded ecosystem back to being functional.Replacement: replacing a degraded ecosystem with another type of ecosystem.Creating artificial ecosystems: such as artificial wetlands for flood reduction and sewage treatment.
67ECOLOGICAL RESTORATION Five basic science-based principles for ecological restoration:Identify cause.Stop abuse by eliminating or sharply reducing factors.Reintroduce species if necessary.Protect area form further degradation.Use adaptive management to monitor efforts, assess successes, and modify strategies.
68WHAT CAN WE DO? Eight priorities for protecting biodiversity: Take immediate action to preserve world’s biological hot spots.Keep intact remaining old growth.Complete mapping of world’s biodiversity for inventory and decision making.Determine world’s marine hot spots.Concentrate on protecting and restoring lake and river systems (most threatened ecosystems).
69WHAT CAN WE DO?Ensure that the full range of the earths ecosystems are included in global conservation strategy.Make conservation profitable.Initiate ecological restoration products to heal some of the damage done and increase share of earth’s land and water allotted to the rest of nature.
70What Can You Do? Sustaining Terrestrial Biodiversity Fig 10-29
71Active Figure: Biodiversity hot spots Click for animationClick for Conservation International