Chapter 6 Sustaining Biodiversity: The Ecosystem Approach

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Chapter 6Sustaining Biodiversity The
Ecosystem Approach
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6-1 What Are the Major Threats to Forest
Ecosystems?

• Concept 6-1 Unsustainable cutting and burning of
  forests, especially in tropical areas, is a
  potentially catastrophic problem because of the
  vital ecological services at risk and the growing
  contribution to global warming.

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

• Old-growth or primary forest
• 36 of worlds forests
• Second-growth forest
• 60 of worlds forests
• Tree plantation, tree farm or commercial forest
• 4 of worlds forests
• May supply most of the industrial wood in the
  future

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Rotation Cycle of Cutting and Regrowth of a
Monoculture Tree Plantation
Fig. 6-1, p. 111
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Weak trees removed
25 yrs
Clear cut
30 yrs
15 yrs
Years of growth
Seedlings planted
5 yrs
10 yrs
Fig. 6-1, p. 114
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Forests Provide Important Economic and
Ecological Services (1)

• Support energy flow and chemical cycling
• Reduce soil erosion
• Absorb and release water
• Purify water and air
• Influence local and regional climate
• Store atmospheric carbon
• Habitats

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Forests Provide Important Economic and
Ecological Services (2)

• Wood for fuel
• Lumber
• Pulp to make paper
• Mining
• Livestock grazing
• Recreation
• Employment

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Natural Capital Major Ecological and Economic
Services Provided by Forests
Fig. 6-2, p. 111
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Unsustainable Logging is a Major Threat to Forest
Ecosystems (1)

• Increased erosion
• Sediment runoff into waterways
• Habitat fragmentation
• Loss of biodiversity

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Unsustainable Logging is a Major Threat to Forest
Ecosystems (2)

• Invasion by
• Nonnative pests
• Disease
• Wildlife species
• Major tree harvesting methods
• Selective cutting
• Clear-cutting
• Strip cutting

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Natural Capital Degradation Building Roads into
Previously Inaccessible Forests
Fig. 6-3, p. 112
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Cleared plots for grazing
Highway
New highway
Cleared plots for agriculture
Old growth
Fig. 6-3, p. 112
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Fig. 6-3a, p. 112
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Fig. 6-3b, p. 112
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Major Tree Harvesting Methods
Fig. 6-4, p. 113
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Fig. 6-4a, p. 113
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(a) Selective cutting
Clear stream
Fig. 6-4a, p. 113
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Fig. 6-4b, p. 113
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(b) Clear-cutting
Muddy stream
Fig. 6-4b, p. 113
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Fig. 6-4c, p. 113
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(c) Strip cutting
Uncut
Cut 1 year ago
Dirt road
Cut 310 years ago
Uncut
Clear stream
Fig. 6-4c, p. 113
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Stepped Art
Fig. 6-4, p. 113
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We Have Cut Down Almost Half of the Worlds
Forests

• Deforestation
• Tropical forests
• Especially in Latin America, Indonesia, and
  Africa
• Boreal forests
• Especially in Alaska, Canada, Scandinavia, and
  Russia

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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 in the eastern states
• Biologically simplified tree plantations reduce
  biodiversity

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Tropical Forests are Disappearing Rapidly

• Majority of loss since 1950
• Africa, Southeast Asia, South America
• 98 will be gone by 2022
• Role of deforestation in species extinction
• Secondary forest can grow back in 15-20 years

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Causes of Tropical Deforestation Are Varied and
Complex

• Population growth
• Poverty of subsistence farmers
• Ranching
• Lumber
• Plantation farms palm oil
• Begins with building of roads
• Many forests burned
• Can tilt tropical forest to tropical savanna

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Natural Capital Degradation Deforestation
Fig. 6-5, p. 113
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Major Causes of the Destruction and Degradation
of Tropical Forests
Fig. 6-6, p. 115
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NATURAL CAPITAL DEGRADATION
Major Causes of the Destruction and Degradation
of Tropical Forests
Basic Causes
Direct Causes
Not valuing ecological services
Roads
Cattle ranching
Fires
Logging
Crop and timber exports
Settler farming
Tree plantations
Government policies
Cash crops
Poverty
Population growth
Cattle ranching
Tree plantations
Logging
Cash crops
Settler farming
Fires
Roads
Fig. 6-6, p. 115
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6-2 How Should We Manage and Sustain Forests?

• Concept 6-2 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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Solutions Sustainable Forestry
Fig. 6-7, p. 116
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Individuals Matter Wangari Maathari and Kenyas
Green Belt Movement

• Green Belt Movement 1977
• Self-help group of women in Kenya
• Success of tree planting
• 50,000 members planted 40 million trees
• Women are paid for each tree that survives
• Slows soil erosion
• Shade and beauty
• Combats global warming
• Nobel Peace Prize 2004

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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

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Solutions Sustaining Tropical Forests
Fig. 6-8, p. 117
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6-3 How Should We Manage and Sustain Parks and
Natural Reserves?

• Concept 6-3 Sustaining biodiversity will require
  more effective protection of existing parks and
  nature reserves, as well as the protection of
  much more of the earths remaining undisturbed
  land area.

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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

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Case Study Stresses on U.S. Public Parks (1)

• 58 Major national parks in the U.S.
• Biggest problem may be popularity
• Noise
• Congestion
• Pollution
• Damage or destruction to vegetation and wildlife

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Case Study Stresses on U.S. Public Parks (2)

• Damage from nonnative species
• Boars and mountain goats
• Introduced plants, insects, worms
• Native species sometimes killed or removed
• Threatened islands of biodiversity
• Air pollution
• Need billions in trail and infrastructure repairs

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Solutions National Parks
Fig. 6-9, p. 119
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Science Focus Reintroducing the Gray Wolf to
Yellowstone National Park

• Keystone species
• 1995 reintroduced 2009 116 wolves in park
• Prey on elk and push them to a higher elevation
• Regrowth of aspen, cottonwoods, and willows
• More beaver dams, more wetlands, more aspens
• Reduced the number of coyotes
• Fewer attacks on cattle
• More smaller mammals

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Nature Reserves Occupy Only a Small Part of the
Earths Land

• Currently less than 13 is protected
• Conservationists goal protect 20
• Cooperation between government and private groups
  and concerned individuals
• Nature Conservancy
• Land trust groups

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Solutions A Model Biosphere Reserve
Fig. 6-10, p. 120
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Biosphere Reserve
Core area
Research station
Visitor education center
Buffer zone 1
Human settlements
Buffer zone 2
Fig. 6-10, p. 120
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Case Study Costa RicaA Global Conservation
Leader

• 19631983 cleared much of the forest
• 19862006 forests grew from 26 to 51
• Goal net carbon dioxide emissions to zero by
  2021
• ¼ of land in nature reserves and natural parks
  global leader
• Earns 1 billion per year in tourism

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Solutions Costa Rica Parks and Reserves8
Megareserves
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Protecting Wilderness Is an Important Way to
Preserve Biodiversity

• Wilderness
• Land officially designated as having no serious
  disturbance from human activities
• Wilderness Act of 1964
• Controversial

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Case Study Controversy over Wilderness
Protection in the United States

• Wilderness Act of 1964
• Protect undeveloped lands
• 2 of lower 48 protected, mostly in West
• 10-fold increase from 1970 to 2010
• 2009
• 2 million more acres get wilderness protection
• 50 increase in length of wild and scenic rivers

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6-4 What is the Ecosystem Approach to Sustaining
Biodiversity?

• Concept 6-4 We can help sustain biodiversity by
  identifying and protecting severely threatened
  areas (biodiversity hotspots), restoring damaged
  ecosystems, and sharing as much of the earths
  land as possible with other species.

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We Can Use a Four-Point Strategy to Protect
Ecosystems

• Map global ecosystems identify species
• Locate and protect most endangered ecosystems and
  species
• Restore degraded ecosystems
• Development must be biodiversity-friendly
• Are new laws needed?

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Protecting Global Biodiversity Hot Spots Is an
Urgent Priority

• 34 biodiversity hot spots rich in plant species
• 2 of earths surface, but 50 of flowering plant
  species and 42 of terrestrial vertebrates
• 1.2 billion people

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Endangered Natural Capital 34 Biodiversity
Hotspots
Fig. 6-12, p. 123
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We Can Rehabilitate and Restore Ecosystems That
We Have Damaged (1)

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

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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

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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

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We Can Share Areas We Dominate With Other Species

• Reconciliation ecology
• Invent and maintain habitats for species
  diversity where people live, work, and play
• Community-based conservation
• Belize and the black howler monkeys
• Protect vital insect pollinators

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Case Study The Blackfoot ChallengeReconciliation
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

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What Can You Do? Sustaining Terrestrial
Biodiversity
Fig. 6-13, p. 125
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Concept 6-5 How Can We Protect and Sustain Marine
Biodiversity?

• Concept 6-5 We can help to sustain marine
  biodiversity by using laws and economic
  incentives to protect species, setting aside
  marine reserves to protect ecosystems, and using
  community-based integrated coastal management.

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We Have Much to Learn about Aquatic Biodiversity
(1)

• Greatest marine biodiversity
• Coral reefs
• Estuaries
• Deep-ocean floor
• Biodiversity is higher
• Near the coast than in the open sea
• In the bottom region of the ocean than the
  surface region

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We Have Much to Learn about Aquatic Biodiversity
(2)

• Threats
• Pressure on all aquatic ecosystems
• Dredging by trawler boats
• Coral reefs threatened by pollution, growing
  acidity, warmer waters
• Introduction of invasive species
• Human population growth
• Climate change
• Overfishing

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There Are Ways to Protect and Sustain Marine
Biodiversity (1)

• Why is it hard to protect marine biodiversity?
• Human ecological footprint and fishprint are
  expanding
• Much of the damage in the ocean is not visible
• The oceans are incorrectly viewed as an
  inexhaustible resource
• Most of the ocean lies outside the legal
  jurisdiction of any country

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There Are Ways to Protect and Sustain Marine
Biodiversity (2)

• 1975 Convention on International Trade in
  Endangered Species
• 1979 Global Treaty on Migratory Species
• U.S. Marine Mammal Protection Act of 1972
• U.S. Endangered Species Act of 1973
• U.S. Whale Conservation and Protection Act of
  1976
• 1995 International Convention on Biological
  Diversity

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There Are Ways to Protect and Sustain Marine
Biodiversity (3)

• Marine reserves
• Off-limits to destructive human activities
• Fish populations double
• Fish size grows
• Reproduction triples
• Species diversity increase by almost one-fourth

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There Are Ways to Protect and Sustain Marine
Biodiversity ( 4 )

• Economic incentives for protection
• Ecotourism protects turtles and whales
• Integrated coastal management
• Community-based group to prevent further
  degradation of the ocean

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Solutions Managing Fisheries
Fig. 6-14, p. 127
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Freshwater Ecosystems Are under Major Threats

• 40 of worlds rivers are dammed
• Many freshwater wetlands destroyed
• Invasive species
• Threatened species
• Overfishing
• Human population pressures

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Case Study Can the Great Lakes Survive Repeated
Invasions by Alien Species?

• Collectively, worlds largest body of freshwater
• Invaded by at least 162 nonnative species
• Sea lamprey
• Zebra mussel
• Asian carp

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We Can Protect Freshwater Ecosystems by
Protecting Watersheds

• Freshwater ecosystems protected through
• Laws
• Economic incentives
• Restoration efforts
• Wild rivers and scenic rivers
• 1968 National Wild and Scenic Rivers Act

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What Should Be Our Priorities?

• Concept 6-7 We can help to sustain the worlds
  biodiversity by mapping it, protecting
  biodiversity hotspots, creating large terrestrial
  and aquatic reserves, and carrying out ecological
  restoration of degraded terrestrial and aquatic
  systems.

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We Need to Establish Priorities for Protecting
Biodiversity

• Edward O. Wilson
• Complete the mapping of the worlds terrestrial
  and aquatic biodiversity
• Identify and preserve hotspots and deteriorating
  ecosystem services that threaten life
• Keep old-growth forests intact cease their
  logging
• Create large, fully protected marine reserves
• Protect and restore lakes and rivers
• Ecological restoration projects
• Make conservation financially rewarding

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Three Big Ideas

1. The economic values of the important ecological
   services provided by the worlds ecosystems are
   far greater than the value of raw materials
   obtained from those systems.
2. Terrestrial and aquatic ecosystems are being
   severely degraded by human activities that lead
   to habitat disruption and loss of biodiversity.

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Three Big Ideas

1. We can help to sustain the worlds biodiversity
   by mapping it, protecting biodiversity hotspots,
   creating large terrestrial and aquatic reserves,
   and carrying out ecological restoration of
   degraded terrestrial and aquatic ecosystems.