Sustaining Terrestrial Biodiversity: The Ecosystem Approach

Chapter 10

Standard 8: Students will know how water resources are used globally.

Standard 29: Students will understand the environmental impact of fishing.

Standard 26: Students will know the major types of public and federal lands.

Standard 40: Students will know the causes and consequences of the loss of biodiversity.

Core Case Study: Reintroducing Gray Wolves to Yellowstone

Around 1800

1850–1900: decline due to human activity

U.S. Endangered Species Act: 1973

1995–1996: relocation of gray wolves to Yellowstone Park

2008: Gray wolf no longer protected

What do you think would be the biggest threats to forest ecosystems?

What Are the Major Threats to Forest Ecosystems?

Unsustainable cutting Burning Diseases Insects Tropical deforestation

Forests Vary in Their Make-Up, Age, and Origins

Old-growth or primary forest • Uncut or regenerated primary forest not disturbed

by human activity or natural disaster for more than 200 years

• 36% of world’s forests

http://upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Biogradska_suma.jpg/300px-Biogradska_suma.jpg

Old-growth European Beech forest in Biogradska Gora National Park

, Montenegro

Coast Redwoods in old-growth forest inMuir Woods National Monument, Marin County, California.

Forests Vary in Their Make-Up, Age, and Origins

Second-growth forest: trees resulting from secondary ecological succession• 60% of world’s

forestshttp://www.seattle.gov/util/groups/public/@spu/documents/webproductionfile/02_013762.jpg

Fig. 10-3a, p. 216

Forests Vary in Their Make-Up, Age, and Origins

Tree plantation, tree farm or commercial forest: managed tract of uniformly aged trees• 4% of world’s

forests• May supply

most of the industrial wood in the future

A pine plantation in the United States. Tree plantations are usually easily distinguished from natural forests by the trees being planted in straight lines.

http://upload.wikimedia.org/wikipedia/commons/thumb/6/63/Pinus_taeda_plantation.jpg/220px-Pinus_taeda_plantation.jpg

Fig. 10-4, p. 217

Science Focus: Putting a Price Tag on Nature’s Ecological Services

Forests valued for ecological services• Nutrient cycling• Climate regulation• Erosion control• Waste treatment• Recreation• Raw materials

$4.7 Trillion per year

Unsustainable Logging is a Major Threat to Forest Ecosystems

Increased erosion

Sediment runoff into waterways

Habitat fragmentation

Loss of biodiversity

http://2.bp.blogspot.com/-63LjuJ2tybA/Tyqp8s2MyiI/AAAAAAAAITU/pK_-JHBUU-E/s1600/000.jpeg

Unsustainable Logging is a Major Threat to Forest Ecosystems

Major tree harvesting methods:• Selective cutting: intermediate aged or mature

trees in an uneven-aged forest are cut singly or in small groups

• Clear-cutting: all trees removed from an area• Strip cutting: clear cutting a strip of trees along

the contour of the land within a corridor narrow enough to allow natural regeneration within a few years

Fig. 10-8, p. 220

TRADE-OFFS

Clear-Cutting Forests

Advantages Disadvantages

Higher timber yields

Reduces biodiversity

Destroys and fragments wildlife habitats

Maximum profits in shortest time

Can reforest with fast-growing trees

Increases water pollution, flooding, and erosion on steep slopesGood for tree

species needing full or moderate sunlight

Eliminates most recreational value

Invasion

• Nonnative pests

• Disease• Wildlife

species

Insects and Climate Change Can Threaten Forest Ecosystems

Introduction of foreign diseases and insects• Accidental• Deliberate

Global warming• Rising temperatures• Trees more susceptible to diseases and pests• Drier forests: more fires• More greenhouse gases

Fire Can Threaten Forest Ecosystems

Surface fires• Usually burn leaf litter and undergrowth• May provide food in the form of vegetation that

sprouts after fire

http://www.nps.gov/ngpfire/Photos/jeca_ht_08.JPG

Fire Can Threaten Forest Ecosystems

Crown fires • Extremely hot: burns whole trees• Kill wildlife• Increase soil erosion

http://www.meto.umd.edu/~zli/Info/crown_fire-copy%20copy.jpg

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

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Fig. 10-12, p. 223

Case Study: Many Cleared Forests in the United States Have Grown Back

Forests of the eastern United States decimated between 1620 and 1920

Grown back naturally through secondary ecological succession

Biologically simplified tree plantations reduce biodiversity

Fig. 10-15, p. 225

NATURAL CAPITAL DEGRADATION

Major Causes of the Destruction and Degradation of Tropical ForestsBasic Causes Secondary Causes• Not valuing ecological services • Roads • Cattle ranching• Crop and timber exports • Fires • Logging• Government policies • Settler farming • Tree plantations

• Poverty • Cash crops

• Population growthCattle ranching

Tree plantations

Logging

Cash crops

Settler farming

FiresRoads

http://photos.mongabay.com/07/regional_defor-336.jpg

Tropical Forests are Disappearing Rapidly

Majority of loss since 1950

Brazil and Indonesia tropical forest loss

Role of deforestation in species’ extinction

http://www.foodbeautylove.com/wp-content/uploads/2012/10/Rainforest-Deforestation.jpg

http://mongabay-images.s3.amazonaws.com/13/AMAZON-DEFORESTATION-full.jpg

http://photos.mongabay.com/07/regional_defor-336.jpg

How Should We Manage and Sustain Forests

Emphasize the economic value of their ecological services

Protect old-growth forests Harvest trees no faster than they are

replenished Use sustainable substitute resources.

Fig. 10-17, p. 227

We Can Improve the 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

Smokey the Bear Campaign

We Can Improve the Management of Forest Fires

2003 Healthy Forests Restoration Act• Allows timber companies to cut down

economically valuable medium size and large trees in 71% of the country’s national forests in return for clearing away smaller, more fire prone trees and underbrush• Companies NOT required to do prescribed burns• Thinning projects exempt from environmental

review• Criticized for NOT following known management

techniques

Science Focus: Certifying Sustainably Grown Timber

Collins Pine • Owns and manages protective timberland

Forest Stewardship Council• Nonprofit • Developed list of environmentally sound practices• Certifies timber and products

We Can Reduce the Demand for Harvested Trees

Up to 60% of the wood used in the U.S. is wasted unnecessarily

Improve the efficiency of wood use

Make tree-free paper• Rice straw used in China• Kenaf• Hemp

Case Study: Deforestation and the Fuelwood Crisis

Possible solutions• Establish small plantations of fast-growing

fuelwood trees and shrubs• Burn wood more efficiently• Solar or wind-generated electricity

Haiti: ecological disaster: only 2% of it’s land is left forested, soils have eroded

South Korea: model for successful reforestation

Governments and Individuals Can Act to Reduce Tropical Deforestation

Reduce fuelwood demand

Practice small-scale sustainable agriculture and

forestry in tropical forest

Debt-for-nature swaps

Conservation concessions

Use gentler logging methods

Buy certified lumber and wood products

Individuals Matter: Wangari Maathari and Kenya’s Green Belt Movement

Green Belt Movement: 1977• Self-help group of

women in Kenya• Women paid for each

seedling planted that survives

Nobel Peace Prize: 2004

Pygmy tribes in Africa have been given GPS units to help them fight logging and poaching in their area

http://www.newscientist.com/blogs/onepercent/2012/02/21/1.jpg

http://comingworldwar3.files.wordpress.com/2010/06/bree-keyton-and-the-pygmies-600x450.jpg

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.

Some Rangelands Are Overgrazed

Important ecological services of grasslands• Soil formation• Erosion control• Nutrient cycling• Storage of atmospheric carbon dioxide in

biomass• Maintenance of diversity

Some Rangelands are Overgrazed

Overgrazing of rangelands• Reduces grass cover• Leads to erosion of soil by water and wind• Soil becomes compacted • Enhances invasion of plant species that cattle

won’t eat

Fig. 10-20, p. 232

Fig. 10-21a, p. 233

We Can Manage Rangelands More Sustainably

Rotational grazing

Suppress growth of invasive species• Herbicides• Mechanical removal• Controlled burning• Controlled short-term trampling

We Can Manage Rangelands More Sustainably

Replant barren areas

Apply fertilizer

Reduce soil erosion

Fig. 10-21b, p. 233

Rangeland Management Purposes

Produces forage for livestock Habitat for many wildlife species Protects soil from erosion Germplasm bank

• Germplasm: The genetic material, especially its specific molecular and chemical constitution, that carries the inherited characteristics of an organism from one generation to the next by means of the germ cells

Purifies and enhances the environment Recreation

Brainstorm with a partner, groups who support each purpose and why – Fill in worksheet

Case Study: Grazing and Urban Development the American West

American southwest: population surge since 1980

Land trust groups: limit land development

Reduce the harmful environmental impact of herds• Rotate cattle away from riparian areas• Use less fertilizers and pesticides• Operate ranch more economically

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.

National Parks Face Many Environmental Threats

Worldwide: 1100 major national parks

Parks in developing countries • Greatest biodiversity• 1% protected against• Illegal animal poaching• Illegal logging and mining

Fig. 10-23, p. 236

Case Study: Stresses on U.S. Public Parks

58 Major national parks in the U.S.

Biggest problem may be popularity• Noise • Congestion• Pollution• Damage or destruction to vegetation and wildlife

Repairs needed to trails and buildings

Science Focus: Effects of Reintroducing the Gray Wolf to Yellowstone National Park

Gray wolves prey on elk and push them to a higher elevation• Regrowth of aspen, cottonwoods, and willows• Increased population of riparian songbirds

Reduced the number of coyotes• Fewer attacks on cattle

Wolf pups susceptible to parvovirus carried by dogs

Nature Reserves Occupy Only a Small Part of the Earth’s Land

Conservationists’ goal: protect 20% of the earth’s land

Cooperation between government and private groups

Nature Conservancy

Eco-philanthropists

Developers and resource extractors opposition

Designing and Connecting Nature Reserves

Large versus small reserves

The buffer zone concept• United Nations: 529 biosphere reserves in 105

countries

Habitat corridors between isolated reserves• Advantages• Disadvantages

Case Study: Costa Rica—A Global Conservation Leader

1963–1983: cleared much of the forest

1986–2006: forests grew from 26% to 51%• Goal: to reduce net carbon dioxide emissions to

zero by 2021

Eight zoned megareserves• Designed to sustain around 80% of Costa Rica’s

biodiversity

Protecting Wilderness Is an Important Way to Preserve Biodiversity

Pros

Cons

Case Study: Controversy over Wilderness Protection in the United States

Wilderness Act of 1964

How much of the United States is protected land?

Roadless Rule

2005: end of roadless areas within the national forest system

10-5 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.

10-5 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.

We Can Use a Four-Point Strategy to Protect Ecosystems

Map global ecosystems; identify species

Locate and protect most endangered species

Restore degraded ecosystems

Development must be biodiversity-friendly

Are new laws needed?

Protecting Global Biodiversity Hot Spots Is an Urgent Priority

1988: Norman Myers• Identify biodiversity hot spots rich in plant species

Not sufficient public support and funding

Drawbacks of this approach• May not be rich in animal diversity• People may be displaced and/or lose access to

important resources

Fig. 10-26, p. 241

Fig. 10-27, p. 241

Case Study: A Biodiversity Hot Spot in East Africa

Eastern Arc Mountains of Tanzania, Africa• Highest concentration of endangered species on

earth

Threatened due to• Killing of forests by farmers and loggers• Hunting• Fires

Protecting Ecosystem Services Is Also an Urgent Priority

U.N. Millennium Ecosystem Assessment: 2005• Identify key ecosystem services• Human activities degrade or overuse 62% of the

earth’s natural services

Identify highly stressed life raft ecosystems

We Can Rehabilitate and Restore Ecosystems That We Have Damaged (1)

Study how natural ecosystems recover• Restoration• Rehabilitation• Replacement• Creating artificial ecosystems

We Can Rehabilitate and Restore Ecosystems That We Have Damaged (2)

How to carry out most forms of ecological restoration and rehabilitation• Identify what caused the degradation• Stop the abuse• Reintroduce species, if possible• Protect from further degradation

Fig. 10-29, p. 245

Science Focus: Ecological Restoration of a Tropical Dry Forest in Costa Rica

Guanacaste National Park restoration project• Relinked to adjacent rain forest• Bring in cattle and horses – aid in seed dispersal• Local residents – actively involved

Will Restoration Encourage Further Destruction?

Preventing ecosystem damage is cheaper than restoration

About 5% of the earth’s land is preserved from the effects of human activities

We Can Share Areas We Dominate With Other Species

Win-Win Ecology: How Earth’s Species Can Survive in the Midst of Human Enterprise, by Michael L. Rozenweig, 2003• Reconciliation or applied ecology• Community-based conservation• Belize and the black howler monkeys• Protect vital insect pollinators• Bluebird protection with special housing boxes• Berlin, Germany: rooftop gardens• San Francisco: Golden Gate Park

Case Study: The Blackfoot Challenge—Reconciliation Ecology in Action

1970s: Blackfoot River Valley in Montana threatened by• Poor mining, logging, and grazing practices• Water and air pollution• Unsustainable commercial and residential

development

Community meetings led to• Weed-pulling parties• Nesting structures for waterfowl• Developed sustainable grazing systems