ENVIRONMENTAL SCIENCE

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ENVIRONMENTAL SCIENCE
13e
CHAPTER 9Sustaining Biodiversity The Ecosystem
Approach
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Wangari Maathai and the Green Belt Movement

• Began in Kenya in 1977
• Organizes poor women in rural Kenya
• 50,000 members protect forests
• Planted 20 million trees
• Fruits
• Building materials
• Firewood
• Similar programs in 30 African countries
• 2004 Nobel Peace Prize

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9-1 What Are Major Threats to Forest Ecosystems?

• Concept 9-1 Ecologically valuable forest
  ecosystems are being cut and burned at
  unsustainable rates in many parts of the world.

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Types of Forests

• Forests cover 30 of earths land surface
• Old-growth forests
• Second-growth forests
• Tree plantation

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Science Focus Putting a Price Tag on Natures
Ecological Services

• Estimated value of earths ecological services
• 33.2 trillion per year
• 4.7 trillion per year for forests
• Need to start factoring values into land use
• Ecological services can be a sustainable source
  of ecological income

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Harvest Methods

• Step one build roads
• Erosion
• Invasive species
• Open up for human invasion
• Step two logging operations
• Selective cutting
• Clear cutting
• Strip cutting

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Forests and Fires

• Surface fires
• Burn undergrowth only
• Cool fire
• Ecological benefits
• Crown fires
• Burn the entire tree
• Hot fire
• Occur in forests with lack of surface fires

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Loss of Original Forests

• Deforestation
• 46 in 8,000 years, most since 1950
• Most in tropical areas, developing countries
• Estimated loss of 40 intact forests within next
  20 years

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Good News on Forests

• 20002007 net total forested area stabilized or
  increased
• Most of the increase due to tree plantations
• Net loss of terrestrial biodiversity

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Return of Forests in the United States (1)

• U.S. forests
• Cover 30 of land
• Contain 80 of wildlife species
• Supply 67 of nations surface water
• Forest cover greater now than in 1920
• Secondary succession

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Return of Forests in the United States (2)

• Second- and third-growth forests fairly diverse
• More wood grown than cut
• 40 of forests in National Forest System
• Some forests transformed into tree plantations

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Tropical Forests

• Cover 6 of earths land area
• Habitat for 50 of terrestrial plants and animals
• Vulnerable to extinction specialized niches
• Rapid loss of 50,000170,000 km2 per year
• Some second-growth forests

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Causes of Tropical Forest Deforestation and
Degradation

• Population growth and poverty
• Economic reasons
• Logging
• Ranching
• Farming
• Government subsidies
• Fires raise temperatures and reduce rainfall

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9-2 How Should We Manage and Sustain Forests?

• Concept 9-2 We can sustain forests by
  emphasizing the economic value of their
  ecological services, removing government
  subsidies that hasten their destruction,
  protecting old-growth forests, harvesting trees
  no faster than they are replenished, and planting
  trees.

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Management of Forest Fires (1)

• Fire suppression in all types of forests
• Increased amounts of underbrush
• Increased probability of crown fires

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Management of Forest Fires (2)

• Prescribed fires
• Allow some fires to burn
• Thin vegetation from forests
• Thin around vulnerable homes
• Decrease flammability of homes

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Science Focus Certifying Sustainably Grown Timber

• Forest Steward Council certification of forest
  operations
• Environmentally sound practices
• Sustainable yield harvest
• Minimal erosion from operations
• Retention of dead wood for wildlife habitat

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Trees and Paper

• Many trees are cut for paper production
• Alternatives
• Pulp from rice straw and agricultural residues
  (China)
• Kenaf (U.S.)
• Hemp

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9-3 How Should We Manage and Sustain Grasslands?

• Concept 9-3 We can sustain the productivity of
  rangeland by controlling the number and
  distribution of grazing livestock and by
  restoring degraded grasslands.

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Grasslands

• Provide important ecological services
• Second most used and altered ecosystem by humans
• 42 grazed by cattle, sheep, and goats
  rangeland (open) and pasture (fenced)
• Overgrazing

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9-4 How Should We Manage and Sustain Parks and
Nature Reserves?

• Concept 9-4 We need to put more resources into
  sustaining existing parks and nature reserves and
  into protecting much more of the earths
  remaining undisturbed land area.

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National Parks

• gt1,100 national parks in 120 countries
• Only 1 of parks in developing countries are
  protected
• Local people invade parks to survive
• Logging
• Mining
• Poaching

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Problems Protecting National Parks

• Illegal logging
• Illegal mining
• Wildlife poaching
• Most parks too small to protect large animals
• Invasion of nonnative species

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Stresses on U.S. National Parks

• 58 major national parks
• Biggest problem is popularity
• Damage from nonnative species
• Threatened islands of biodiversity
• Need 6 billion for overdue repairs

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Nature Reserves Occupy a Fraction of Earth

• 12 of earths land protected
• Only 5 fully protected 95 reserved for human
  use
• Need for conservation
• Minimum 20 of land in biodiversity reserves
• Protection for all biomes

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Solutions for Protection

• Ecological insurance policy
• Buffer zones around protected areas
• Locals to manage reserves and buffer zones
• United Nations 531 biosphere reserves in 105
  countries

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Science Focus Reintroducing the Gray Wolf to
Yellowstone National Park

• Reduced to a few hundred in lower 48 by 1973
• Keystone species
• Restoration proposal angered ranchers, hunters,
  loggers
• 1995 - reintroduced in Yellowstone, 124 by 2008
• Positive ripple effect after reintroduction

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Case Study Costa Rica

• Superpower of biodiversity
• Conserved 25 of its land, 8 megareserves
• Government eliminated deforestation subsidies
• Paid landowners to maintain and restore tree
  coverage
• Boosts ecotourism

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Protecting Wilderness Protects Biodiversity

• Wilderness
• Preserves biodiversity
• Centers for evolution

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Case Study Controversy over Wilderness
Protection in the U.S.

• 1964 Wilderness Act
• Ten-fold increase from 1970 to 2008
• 4.6 of U.S. land protected, 75 of that in Alaska

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9-5 How Can We Help to Sustain Terrestrial
Biodiversity?

• Concept 9-5 We can help to sustain terrestrial
  biodiversity by identifying and protecting
  severely threatened areas (biodiversity
  hotspots), rehabilitating damaged ecosystems
  (using restoration ecology), and sharing with
  other species much of the land we dominate (using
  reconciliation ecology).

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Three Principles to Protect Ecosystems

1. Map and inventory the worlds terrestrial and
   aquatic ecosystems
2. Locate and protect the most endangered
   ecosystems, with a focus on biodiversity
3. Seek to restore as many degraded ecosystems as
   possible

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Protecting Global Biodiversity Hotspots

• 17 megadiversity countries, mostly in tropics and
  subtropics
• Two-thirds of biodiversity
• Developing countries economically poor and
  biodiversity rich
• Protect biodiversity hotspots

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Ecological Restoration

• Restoration
• Rehabilitation
• Replacement
• Creating artificial ecosystems

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Science-based Principles for Restoration

• Identify cause of degradation
• Stop abuse by reducing factors
• Reintroduce species if necessary
• Protect area from further degradation

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Case Study Ecological Restoration of Tropical
Dry Forest in Costa Rica

• One of worlds largest ecological restoration
  projects
• Restore a degraded tropical dry forest and
  reconnect it to adjacent forests
• Involve 40,000 people in the surrounding area
  biocultural restoration
• Ecotourism

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Restoration Ecology

• Creating new habitats to conserve species
  diversity in areas where people live, work, play
• People learn to protect local species and
  ecosystems
• Sustainable ecotourism
• Golden Gate Park in San Francisco

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9-6 How Can We Help to Sustain Aquatic
Biodiversity?

• Concept 9-6 We can help to sustain aquatic
  biodiversity by establishing protected
  sanctuaries, managing coastal development,
  reducing water pollution, and preventing
  overfishing.

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Impacts on Aquatic Ecosystems (1)

• Destroyed or degraded by human activities
• Coastal habitats disappearing 2-10 times faster
  than tropical forest
• Rising sea levels will destroy coral reefs and
  some low islands
• Ocean floor degradation 150 times larger than
  area clear-cut annually

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Impacts on Aquatic Ecosystems (2)

• Freshwater habitat disruption
• Dams
• Water withdrawals from rivers
• Likely extinction
• 34 marine fish species
• 71 freshwater species
• Greater than any other group of species

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Overfishing

• Fishery
• Fishprint
• 157 overfishing
• 90 of large open-ocean fishes have disappeared
  since 1950

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Case Study Industrial Fish Harvesting Methods

• Trawler fishing
• Purse-seine fishing
• Longlining
• Drift-net fishing

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Why Is Protection of Marine Biodiversity So
Difficult?

• Human aquatic ecological footprint expanding
• Not visible to most people
• Viewed as an inexhaustible resource
• Most ocean areas outside jurisdiction of a country

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Solutions for Marine Ecosystems

• Protect endangered and threatened species
• Establish protected marine sanctuaries
• Marine reserves work well and quickly
• Integrated coastal management
• Protect existing coastal wetlands

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Three Big Ideas from This Chapter - 1

• The economic values of the important ecological
  services provided by the worlds ecosystems need
  to be included in the prices of goods and
  services.

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Three Big Ideas from This Chapter - 2

• We can sustain terrestrial biodiversity by
  protecting severely threatened areas, restoring
  damaged ecosystems, and sharing with other
  species much of the land we dominate.