Core Case Study: North American Gray Wolf
Reduced to a few hundred
Keystone species
Restoration proposal angered ranchers, hungers, loggers
1995, reintroduced in Yellowstone, 136 by 2007
Positive ripple effect after reintroduction
8-1 How Are We Affecting the Earth’s Biodiversity and Why Should We Protect It?
Concept 8-1A We are degrading and destroying biodiversity in many parts of the world and these threats are increasing.
Concept 8-1B We should protect biodiversity because it exists and because of its usefulness to us and other species.
Loss of Biodiversity
Earth’s biodiversity depleted and degraded
83% land surface disturbed
Degradation of aquatic biodiversity
Ecological fishprint unsustainable
Why Protect Biodiversity
Intrinsic value
Instrumental value
Nonuse values• Existence
• Aesthetic
• Bequest
8-2 How Should We Manage and Sustain Forests?
Concept 8-2 We can sustain forests by recognizing the economic value of their ecological services, protecting old-growth forests, harvesting trees no faster than they are replenished, and making most paper from fast-growing plants and agricultural residues instead of trees.
Fig. 8-5, p. 154
Years of growth
Weak treesremoved
Seedlingsplanted
Clear cut
30 yrs
25 yrs
5 yrs 10 yrs
15 yrs
Loss of Original Forests
46% in 8,000 years, most since 1950
Most in tropical areas, developing countries
Estimated loss of 40% intact forests within next 20 years
Science Focus: Putting a Price Tag on Nature’s Ecological Services
Estimated value of earth’s ecological services• $33.2 trillion per year
• $4.7 trillion per year for forests
Need to start factoring values into land use
Fig. 8-7, p. 156
Cleared plotsfor agriculture
New highway
Old growth
HighwayCleared plotsfor grazing
Fig. 8-7, p. 156
New highway
Old growth
Cleared plotsfor agriculture
HighwayCleared plotsfor grazing
Stepped Art
Good News on Forests
2000–2005 net total forested area stabilized or increased
Most of the increase due to tree plantations
Net loss of terrestrial biodiversity
Return of Forests in the United States (1)
U.S. forests • Cover ~30% of land
• Contain ~80% of wildlife species
• Supply ~67% of nation’s surface water
Forest cover greater now than in 1920
Secondary succession
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
Forests transformed into tree plantations
Individuals Matter: Butterfly in a Redwood Tree
Julia Hill – “Butterfly” – two years on a platform of California redwood tree
Protest clear-cutting of the ancient trees
Nonviolent civil disobedience
Lost battle, but her tree was saved
Controversy over the National Forests
Forest service mandate• Principle of sustainable yield
• Principle of multiple use
Timber companies push for tree cutting to be primary goal
Harvest Methods (1)
Step one – build roads• Erosion
• Invasive species
• Open up for human invasion
Step two – logging operations• Selective cutting
• Strip cutting
• Clear cutting
Fig. 8-8c, p. 156
Cut 1year ago
(c) Strip cuttingUncut
Clearstream
Uncut
Cut 3–10years ago
Dirt road
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
Management of Forest Fires
Fire suppression in all types of forests
Some forests naturally fire adapted
Restoration of fire’s natural role
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
Trees and Paper
Many trees are cut for paper production
Alternatives• Pulp from rice straw and agricultural residues
(China)
• Kenaf (U.S.)
8-3 How Serious Is Tropical Deforestation and How Can It Be Reduced?
Concept 8-3 We can reduce tropical deforestation by protecting large forest areas, teaching settlers about sustainable agriculture and forestry, using government subsidies that encourage sustainable forest use, reducing poverty, and slowing population growth.
Tropical Forests
Cover 6% of earth’s land area
Habitat for 50% of terrestrial plants and animals
Vulnerable to extinction – specialized niches
Rapid loss of 50,000–170,000 km2 per year
Causes of Tropical Forest Deforestation and Degradation
Population growth and poverty
Government subsidies
International lending agencies encourage development
Effects of Tropical Deforestation
Fragmentation of remaining patches
Remaining forests get drier and may burn• Degrades biodiversity
• CO2 to the atmosphere
• Accelerates climate change
How to Protect Tropical Forests
Teach settlers to practice small-scale sustainable agriculture
Harvest renewable resources from the forests
Debt-for-nature swaps
Conservation concessions
Gentler logging methods
Individuals Matter: Wangari Maathai and Kenya’s Green Belt Movement
Backyard small tree nursery
Organized poor women
Women paid for each surviving seedling planted• Breaks cycle of poverty
• Reduces environmental degradation
• People walk less distance to get fuelwood
Sparked projects in +30 African countries
8-4 How Should We Manage and Sustain Grasslands?
Concept 8-4 We can sustain the productivity of rangeland by controlling the number and distribution of livestock and by restoring degraded rangeland.
Grasslands
Provide important ecological services
Second most used and altered ecosystem by humans
42% grazed by cattle, sheep, and goats – rangeland and pasture
Overgrazing
Manage Rangelands Sustainably
Practice rotational grazing
Fence out riparian zone areas
Suppress invader plants
Replant barren soil with seeds
Employ controlled burns to control exotic vegetation
8-5 How Should We Manage and Sustain Parks and Nature Reserves?
Concept 8-5 Sustaining biodiversity will require protecting much more of the earth’s remaining undisturbed land area, starting with the most endangered biodiversity hot spots.
National Parks
>1,100 national parks in 120 countries
Only 1% of parks in developing countries are protected
Local people invade parks to survive
Problems Protecting National Parks
Illegal logging
Illegal mining
Wildlife poaching
Most parks too small to protect large animals
Invasion of nonnative species
Stresses on U.S. National Parks
Biggest problem popularity
Damage from nonnative species
Threatened islands of biodiversity
Nature Reserves Occupy a Fraction of Earth
12% of earth’s 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
Solutions for Protection
Requires action – bottom-up political pressure
Nature Conservancy – world’s largest private system of reserves
Buffer zones around protected areas
Locals to manage reserves and buffer zones
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
Goal to make sustainable forestry profitable
Fig. 8-20, p. 167
Biosphere Reserve
Buffer zone 2
Humansettlements
Researchstation
Visitoreducationcenter
Core area
Buffer zone 1
Protecting Wilderness Protects Biodiversity
Wilderness
Minimum size >4,000 km2
Preserves natural capital
Centers for evolution
Case Study: Controversy over Wilderness Protection in the U.S.
1964 Wilderness Act
Roadless Rule protects 400,000 sq. miles
Pressure from oil, gas, mining, and logging
Protecting Global Biodiversity Hotspots
17 megadiversity countries in tropics and subtropics
Two-thirds of biodiversity
Developing countries economically poor and biodiversity rich
Protect biodiversity hotspots
8-6 What Is the Importance of Restoration Ecology?
Concept 8-6 Sustaining biodiversity will require a global effort to rehabilitate and restore damaged ecosystems.
Ecological Restoration
Ecological Restoration
Restoration
Rehabilitation
Replacement
Creating artificial ecosystems
Science-based Principles for Restoration
Identify cause of degradation
Stop abuse by reducing factors
Reintroduce species if necessary
Protect area from further degradation
Case Study: Ecological Restoration of Tropical Dry Forest in Costa Rica
One of world’s 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
Will Restoration Encourage Further Degradation
Some worry environmental restoration suggests any harm can be undone
Scientists disagree• Restoration badly needed
• Altered restored site better than no restoration
8-7 How Can We Help Sustain Aquatic Biodiversity?
Concept 8-7 We can sustain aquatic biodiversity by establishing protected sanctuaries, managing coastal development, reducing water pollution, and preventing overfishing.
Three Patterns of Aquatic Biodiversity
Greatest biodiversity in coral reefs, estuaries, and deep-ocean floor
Higher near the coast than in open sea
Higher in the bottom region of ocean than in surface layer
Human Impacts on Aquatic Ecosystems
Destroyed or degraded by human activities
Ocean floor degradation 150 times larger than area clear-cut annually
75% of most valuable fish species overfished
Likely extinction• 34% marine fish species
• 71% freshwater species
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
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
8-8 What Should Be Our Priorities for Protecting Biodiversity?
Concept 8-8 Sustaining the world’s biodiversity requires mapping terrestrial and aquatic biodiversity, protecting terrestrial and aquatic hotspots and old-growth forests, initiating ecological restoration projects worldwide, and making conservation profitable.
Priorities for Protecting Biodiversity
Map terrestrial and aquatic biodiversity
Immediately preserve biodiversity hotspots
Keep old-growth forests intact
Protect and restore lakes and rivers
Initiate ecological restoration
Make conservation profitable