Chapter 10 Sustaining Terrestrial Biodiversity: The Ecosystem Approach

Chapter 10Chapter 10

Sustaining Terrestrial Sustaining Terrestrial Biodiversity: The Biodiversity: The

Ecosystem ApproachEcosystem Approach

Core Case Study: Core Case Study: Reintroducing Wolves to YellowstoneReintroducing Wolves to Yellowstone

Endangered SpeciesEndangered Species 1850-1900 two million 1850-1900 two million

wolves were destroyed.wolves were destroyed. Keystone SpeciesKeystone Species

Keeps prey away from open Keeps prey away from open areas near stream banks.areas near stream banks.

Vegetation reestablishes.Vegetation reestablishes. Species diversity expands.Species diversity expands.

Figure 10-1Figure 10-1

HUMAN IMPACTS ON HUMAN IMPACTS ON TERRESTRIAL BIODIVERSITYTERRESTRIAL BIODIVERSITY

We have depleted We have depleted and degraded some and degraded some of the earth’s of the earth’s biodiversity and these biodiversity and these threats are expected threats are expected to increase.to increase.


Why Should We Care About Why Should We Care About Biodiversity?Biodiversity?

Use ValueUse Value: For the : For the usefulness in terms usefulness in terms of economic and of economic and ecological services.ecological services.

Nonuse ValueNonuse Value: : existence, aesthetics, existence, aesthetics, bequest for future bequest for future generations.generations.


MANAGING AND SUSTAINING MANAGING AND SUSTAINING FORESTSFORESTS

Forests provide a Forests provide a number of ecological number of ecological and economic services and economic services that researchers have that researchers have attempted to estimate attempted to estimate their total monetary their total monetary value.value.


Types of ForestsTypes of Forests

Old-growth forestOld-growth forest: uncut : uncut or regenerated forest that or regenerated forest that has not been seriously has not been seriously disturbed for several disturbed for several hundred years.hundred years. 22% of world’s forest.22% of world’s forest. Hosts many species with Hosts many species with

specialized niches.specialized niches.


Types of ForestsTypes of Forests

Second-growth forestSecond-growth forest: a stand of trees : a stand of trees resulting from natural secondary succession.resulting from natural secondary succession.

Tree plantationTree plantation: planted stands of a : planted stands of a particular tree species.particular tree species.


Global Outlook: Global Outlook: Extent of DeforestationExtent of Deforestation

Human activities Human activities have reduced the have reduced the earth’s forest cover earth’s forest cover by as much as half.by as much as half.

Losses are Losses are concentrated in concentrated in developing developing countries.countries.


Case Study: Deforestation and the Case Study: Deforestation and the Fuelwood CrisisFuelwood Crisis

Almost half the people in the developing Almost half the people in the developing world face a shortage of fuelwood and world face a shortage of fuelwood and charcoal.charcoal. In Haiti, 98% of country is deforested.In Haiti, 98% of country is deforested. MIT scientist has found a way to make charcoal MIT scientist has found a way to make charcoal

from spent sugarcane.from spent sugarcane.

Harvesting TreesHarvesting Trees

Building roads into previously inaccessible Building roads into previously inaccessible forests paves the way for fragmentation, forests paves the way for fragmentation, destruction, and degradation.destruction, and degradation.



Trees can be harvested Trees can be harvested individually from diverse individually from diverse forests (selective cutting), forests (selective cutting), an entire forest can be cut an entire forest can be cut down (clear cutting), or down (clear cutting), or portions of the forest is portions of the forest is harvested (e.g. strip harvested (e.g. strip cutting).cutting).


Fig. 10-9a, p. 198

(a) Selective cutting

Fig. 10-9b, p. 198

(b) Clear-cutting

Fig. 10-9c, p. 198

Uncut(c) Strip cutting

Stream

Uncut

Cut 3–10years ago

Dirt road

Cut 1year ago


Effects of clear-cutting in the Effects of clear-cutting in the state of Washington, U.S.state of Washington, U.S.

Figures 10-10 and 10-11Figures 10-10 and 10-11

SolutionsSolutions

We can use forests We can use forests more sustainably by more sustainably by emphasizing:emphasizing: Economic value of Economic value of

ecological services.ecological services. Harvesting trees no Harvesting trees no

faster than they are faster than they are replenished.replenished.

Protecting old-growth Protecting old-growth and vulnerable areas.and vulnerable areas.


CASE STUDY: CASE STUDY: FOREST RESOURCES AND FOREST RESOURCES AND MANAGEMENT IN THE U.S.MANAGEMENT IN THE U.S.

U.S. forests cover more area than in 1920.U.S. forests cover more area than in 1920. Since the 1960’s, an increasing area of old Since the 1960’s, an increasing area of old

growth and diverse second-growth forests growth and diverse second-growth forests have been clear-cut.have been clear-cut. Often replace with tree farms.Often replace with tree farms. Decreases biodiversity.Decreases biodiversity. Disrupts ecosystem processes.Disrupts ecosystem processes.

Types and Effects of Forest FiresTypes and Effects of Forest Fires

Depending on their intensity, fires can benefit or Depending on their intensity, fires can benefit or harm forests.harm forests. Burn away flammable ground material.Burn away flammable ground material. Release valuable mineral nutrients.Release valuable mineral nutrients.


Solutions: Solutions: Controversy Over Fire ManagementControversy Over Fire Management To reduce fire damage:To reduce fire damage:

Set controlled surface fires.Set controlled surface fires. Allow fires to burn on public lands if they don’t Allow fires to burn on public lands if they don’t

threaten life and property. threaten life and property. Clear small areas around property subject to fire.Clear small areas around property subject to fire.

Solutions: Solutions: Controversy Over Fire ManagementControversy Over Fire Management In 2003, U.S. Congress passed the In 2003, U.S. Congress passed the Healthy Healthy

Forest Restoration ActForest Restoration Act:: Allows timber companies to cut medium and Allows timber companies to cut medium and

large trees in 71% of the national forests.large trees in 71% of the national forests. In return, must clear away smaller, more fire-In return, must clear away smaller, more fire-

prone trees and underbrush.prone trees and underbrush. Some forest scientists believe this could increase Some forest scientists believe this could increase

severe fires by removing fire resistant trees and severe fires by removing fire resistant trees and leaving highly flammable slash.leaving highly flammable slash.

Controversy over Logging in U.S. National Controversy over Logging in U.S. National ForestsForests

There has been an There has been an ongoing debate over ongoing debate over whether U.S. whether U.S. national forests national forests should be primarily should be primarily for:for: Timber.Timber. Ecological services.Ecological services. Recreation.Recreation. Mix of these uses.Mix of these uses.


Solutions: Solutions: Reducing Demand for Harvest TreesReducing Demand for Harvest Trees

Tree harvesting can Tree harvesting can be reduced by be reduced by wasting less wood wasting less wood and making paper and making paper and charcoal fuel and charcoal fuel from fibers that do from fibers that do not come from trees.not come from trees. Kenaf is a promising Kenaf is a promising

plant for paper plant for paper production.production.


American Forests in a Globalized American Forests in a Globalized EconomyEconomy

Timber from tree plantations in temperate Timber from tree plantations in temperate and tropical countries is decreasing the need and tropical countries is decreasing the need for timber production in the U.S.for timber production in the U.S. This could help preserve the biodiversity in the This could help preserve the biodiversity in the

U.S. by decreasing pressure to clear-cut old-U.S. by decreasing pressure to clear-cut old-growth and second-growth forests.growth and second-growth forests.

This may lead to private land owners to sell less This may lead to private land owners to sell less profitable land to developers.profitable land to developers.

Forest management policy will play a key role.Forest management policy will play a key role.

CASE STUDY: TROPICAL CASE STUDY: TROPICAL DEFORESTATIONDEFORESTATION

Large areas of ecologically and Large areas of ecologically and economically important tropical forests are economically important tropical forests are being cleared and degraded at a fast rate.being cleared and degraded at a fast rate.


CASE STUDY: TROPICAL CASE STUDY: TROPICAL DEFORESTATIONDEFORESTATION

At least half of the At least half of the world’s terrestrial plant world’s terrestrial plant and animal species live and animal species live in tropical rain forests.in tropical rain forests.

Large areas of tropical Large areas of tropical forest are burned to forest are burned to make way for cattle make way for cattle ranches and crops.ranches and crops.


Why Should We Care about the Loss Why Should We Care about the Loss of Tropical Forests?of Tropical Forests?

About 2,100 of the 3,000 plants identified by About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of the National Cancer Institute as sources of cancer-fighting chemicals come from tropical cancer-fighting chemicals come from tropical forests.forests. Figure 10-18Figure 10-18

Causes of Tropical Deforestation and Causes of Tropical Deforestation and DegradationDegradation

Tropical Tropical deforestation deforestation results from a results from a number of number of interconnected interconnected primary and primary and secondary causes.secondary causes.


Fig. 10-20, p. 207

Protect most diverse and endangered areas

Educate settlers about sustainable agriculture and forestry

Phase out subsidies that encourage unsustainable forest use

Add subsidies that encourage sustainable forest use

Protect forests with debt-for-nature swaps and conservation easements

Certify sustainably grown timber

Reduce illegal cutting

Reduce poverty

Slow population growth

Restoration

Reforestation

Rehabilitation of degraded areas

Concentrate farming and ranching on already-cleared areas

Solutions

Sustaining Tropical Forests

Prevention

Kenya’s Green Belt Movement:Kenya’s Green Belt Movement:Individuals MatterIndividuals Matter

Wangari Maathai Wangari Maathai founded the Green Belt founded the Green Belt Movement.Movement.

The main goal is to The main goal is to organize poor women to organize poor women to plant (for fuelwood) and plant (for fuelwood) and protect millions of trees.protect millions of trees.

In 2004, awarded Nobel In 2004, awarded Nobel peace prize.peace prize.

Figure 10-10AFigure 10-10A

MANAGING AND SUSTAINING MANAGING AND SUSTAINING GRASSLANDSGRASSLANDS

Almost half of the world’s livestock graze on Almost half of the world’s livestock graze on natural grasslands (rangelands) and natural grasslands (rangelands) and managed grasslands (pastures).managed grasslands (pastures).

We can sustain rangeland productivity by We can sustain rangeland productivity by controlling the number and distribution of controlling the number and distribution of livestock and by restoring degraded livestock and by restoring degraded rangeland.rangeland.


Overgrazing (left) Overgrazing (left) occurs when too occurs when too many animals many animals graze for too long graze for too long and exceed and exceed carrying capacity carrying capacity of a grassland of a grassland area.area.



Example of restored area along the San Example of restored area along the San Pedro River in Arizona after 10 years of Pedro River in Arizona after 10 years of banning grazing and off-road vehicles.banning grazing and off-road vehicles.


Case Study: Grazing and Urban Case Study: Grazing and Urban Development in the American WestDevelopment in the American West

Ranchers, ecologists, and environmentalists Ranchers, ecologists, and environmentalists are joining together to preserve the are joining together to preserve the grasslands on cattle ranches.grasslands on cattle ranches. Paying ranchers conservation easements Paying ranchers conservation easements

(barring future owners from development).(barring future owners from development). Pressuring government to zone the land to Pressuring government to zone the land to

prevent development of ecologically sensitive prevent development of ecologically sensitive areas.areas.

NATIONAL PARKSNATIONAL PARKS

Countries have established more than 1,100 Countries have established more than 1,100 national parks, but most are threatened by national parks, but most are threatened by human activities.human activities. Local people invade park for wood, cropland, Local people invade park for wood, cropland,

and other natural resources.and other natural resources. Loggers, miners, and wildlife poachers also Loggers, miners, and wildlife poachers also

deplete natural resources.deplete natural resources. Many are too small to sustain large-animal Many are too small to sustain large-animal

species.species. Many suffer from invasive species.Many suffer from invasive species.

Case Study: Stresses on U.S. Case Study: Stresses on U.S. National ParksNational Parks

Overused due to Overused due to popularity.popularity.

Inholdings (private Inholdings (private ownership) within ownership) within parks threaten parks threaten natural resources.natural resources.

Air pollution.Air pollution.


Suggestions for Suggestions for sustaining and sustaining and expanding the expanding the national park national park system in the system in the U.S.U.S.


NATURE RESERVESNATURE RESERVES

Ecologists call for protecting more land to Ecologists call for protecting more land to help sustain biodiversity, but powerful help sustain biodiversity, but powerful economic and political interests oppose doing economic and political interests oppose doing this.this. Currently 12% of earth’s land area is protected.Currently 12% of earth’s land area is protected. Only 5% is strictly protected from harmful human Only 5% is strictly protected from harmful human

activities.activities. Conservation biologists call for full protection of Conservation biologists call for full protection of

at least 20% of earth’s land area representing at least 20% of earth’s land area representing multiple examples of all biomes.multiple examples of all biomes.


Large and medium-sized reserves with buffer Large and medium-sized reserves with buffer zones help protect biodiversity and can be zones help protect biodiversity and can be connected by corridors.connected by corridors.

Costa Rica has Costa Rica has consolidated its parks consolidated its parks and reserves into 8 and reserves into 8 megareserves megareserves designed to sustain designed to sustain 80% if its biodiversity.80% if its biodiversity.

Figure 10-10BFigure 10-10B


A model biosphere A model biosphere reserve that reserve that contains a protected contains a protected inner core inner core surrounded by two surrounded by two buffer zones that buffer zones that people can use for people can use for multiple use.multiple use.



Geographic Information System (GIS) Geographic Information System (GIS) mapping can be used to understand and mapping can be used to understand and manage ecosystems.manage ecosystems. Identify areas to establish and connect nature Identify areas to establish and connect nature

reserves in large ecoregions to prevent reserves in large ecoregions to prevent fragmentation.fragmentation.

Developers can use GIS to design housing Developers can use GIS to design housing developments with the least environmental developments with the least environmental impact.impact.


We can prevent or slow down losses of We can prevent or slow down losses of biodiversity by concentrating efforts on biodiversity by concentrating efforts on protecting global hot spots where significant protecting global hot spots where significant biodiversity is under immediate threat.biodiversity is under immediate threat.

Conservation biologists are helping people in Conservation biologists are helping people in communities find ways to sustain local communities find ways to sustain local biodiversity while providing local economic biodiversity while providing local economic income.income.

34 hotspots identified by ecologists as important and 34 hotspots identified by ecologists as important and endangered centers of biodiversity.endangered centers of biodiversity.



Wilderness is land legally set aside in a large Wilderness is land legally set aside in a large enough area to prevent or minimize harm enough area to prevent or minimize harm from human activities.from human activities.

Only a small percentage of the land area of Only a small percentage of the land area of the United States has been protected as the United States has been protected as wilderness.wilderness.

ECOLOGICAL RESTORATIONECOLOGICAL RESTORATION

RestorationRestoration: trying to return to a condition as : trying to return to a condition as similar as possible to original state.similar as possible to original state.

RehabilitationRehabilitation: attempting to turn a : attempting to turn a degraded ecosystem back to being degraded ecosystem back to being functional.functional.

ReplacementReplacement: replacing a degraded : replacing a degraded ecosystem with another type of ecosystem.ecosystem with another type of ecosystem.

Creating artificial ecosystemsCreating artificial ecosystems: such as : such as artificial wetlands for flood reduction and artificial wetlands for flood reduction and sewage treatment.sewage treatment.

ECOLOGICAL RESTORATIONECOLOGICAL RESTORATION

Five basic science-based principles for Five basic science-based principles for ecological restoration:ecological restoration: Identify cause.Identify cause. Stop abuse by eliminating or sharply reducing Stop abuse by eliminating or sharply reducing

factors.factors. Reintroduce species if necessary.Reintroduce species if necessary. Protect area form further degradation.Protect area form further degradation. Use adaptive management to monitor efforts, Use adaptive management to monitor efforts,

assess successes, and modify strategies.assess successes, and modify strategies.

Will Restoration Encourage Further Will Restoration Encourage Further Destruction?Destruction?

There is some concern that ecological There is some concern that ecological restoration could promote further restoration could promote further environmental destruction and degradation.environmental destruction and degradation. Suggesting that any ecological harm can be Suggesting that any ecological harm can be

undone.undone. Preventing ecosystem damage is far cheaper Preventing ecosystem damage is far cheaper

than ecological restoration.than ecological restoration.

WHAT CAN WE DO?WHAT CAN WE DO?

Eight priorities for protecting biodiversity:Eight priorities for protecting biodiversity: Take immediate action to preserve world’s Take immediate action to preserve world’s

biological hot spots.biological hot spots. Keep intact remaining old growth.Keep intact remaining old growth. Complete mapping of world’s biodiversity for Complete mapping of world’s biodiversity for

inventory and decision making.inventory and decision making. Determine world’s marine hot spots.Determine world’s marine hot spots. Concentrate on protecting and restoring lake and Concentrate on protecting and restoring lake and

river systems (most threatened ecosystems).river systems (most threatened ecosystems).

WHAT CAN WE DO?WHAT CAN WE DO?

Ensure that the full range of the earths Ensure that the full range of the earths ecosystems are included in global conservation ecosystems are included in global conservation strategy.strategy.

Make conservation profitable.Make conservation profitable. Initiate ecological restoration products to heal Initiate ecological restoration products to heal

some of the damage done and increase share of some of the damage done and increase share of earth’s land and water allotted to the rest of earth’s land and water allotted to the rest of nature.nature.

Fig. 10-27, p. 219

• Adopt a forest.

• Plant trees and take care of them.

• Recycle paper and buy recycled paper products.

• Buy sustainable wood and wood products.

• Choose wood substitutes such as bamboo furniture and recycled plastic outdoor furniture, decking, and fencing.

• Restore a nearby degraded forest or grassland.

• Landscape your yard with a diversity of plants natural to the area.

• Live in town because suburban sprawl reduces biodiversity.

Sustaining Terrestrial Biodiversity

What Can You Do?

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Chapter 10 Sustaining Terrestrial Biodiversity: The Ecosystem Approach