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13e. ENVIRONMENTAL SCIENCE. CHAPTER 9: Sustaining Biodiversity: The Ecosystem Approach. 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 - PowerPoint PPT PresentationTRANSCRIPT
ENVIRONMENTAL SCIENCE 13e
CHAPTER 9:Sustaining Biodiversity: The Ecosystem Approach
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
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.
Types of Forests
• Forests cover 30% of earth’s land surface
• Old-growth forests
• Second-growth forests
• Tree plantation
Fig. 9-2, p. 180
Fig. 9-3, p. 180
Years of growth
Weak treesremoved
Seedlingsplanted
Clear cut
30 yrs
25 yrs
5 yrs 10 yrs
15 yrs
Fig. 9-3, p. 180
Fig. 9-3, p. 180
Fig. 9-4, p. 181
Fig. 9-4, p. 181
Natural Capital
Fuelwood
Lumber
Pulp to makepaper
Mining
Livestockgrazing
Recreation
Jobs
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
Provide numerous wildlife habitats
EcologicalServices
EconomicServices
Forests
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
• Ecological services can be a sustainable source of ecological income
Fig. 9-A, p. 181
Harvest Methods
• Step one: build roads– Erosion– Invasive species– Open up for human invasion
• Step two: logging operations– Selective cutting– Clear cutting– Strip cutting
Fig. 9-5, p. 182
Cleared plotsfor agriculture
New highway
Old growth
HighwayCleared plotsfor grazing
Fig. 9-5, p. 182
New highway
Old growth
Cleared plotsfor agriculture
HighwayCleared plotsfor grazing
Stepped Art
Fig. 9-5, p. 182
Fig. 9-6, p. 182
Clearstream
(a) Selective cutting
Fig. 9-6, p. 182
Fig. 9-6, p. 182
Muddystream
(b) Clear-cutting
Fig. 9-6, p. 182
Fig. 9-6, p. 182
Cut 1year ago
(c) Strip cuttingUncut
Clearstream
Uncut
Cut 3–10years ago
Dirt road
Fig. 9-6, p. 182
Stepped Art
(b) Clear-cutting
Muddy stream
UncutCut 1 year ago
Dirt road
Cut 3–10 years ago
Uncut
Clear stream
(a) Selective cutting
(c) Strip cutting
Clear stream
Fig. 9-6, p. 182
Fig. 9-7, p. 182
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
Fig. 9-8, p. 183
Fig. 9-8, p. 183
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
Fig. 9-9, p. 184
Fig. 9-10, p. 184
Good News on Forests
• 2000–2007 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
• Some forests transformed into tree plantations
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
• Some second-growth forests
Causes of Tropical Forest Deforestation and Degradation
• Population growth and poverty
• Economic reasons– Logging
– Ranching
– Farming
• Government subsidies
• Fires raise temperatures and reduce rainfall
Fig. 9-11, p. 186
Fig. 9-11, p. 186
Natural Capital Degradation
• Not valuing ecological services
• Crop and timber exports
• Government policies
• Poverty
• Population growth
• Roads
• Fires
• Settler farming
• Cash crops
• Cattle ranching
• Logging
• Tree plantations
Basic Causes Secondary Causes
Settler farming
Cattle ranching
Tree plantations
Cash crops
Logging
RoadsFires
Major Causes of the Destruction and Degradation of Tropical Forests
Fig. 9-12, p. 187
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.
Fig. 9-13, p. 188
Management of Forest Fires (1)
• Fire suppression in all types of forests
• Increased amounts of underbrush
• Increased probability of crown fires
Management of Forest Fires (2)
• Prescribed fires
• Allow some fires to burn
• Thin vegetation from forests
• Thin around vulnerable homes
• Decrease flammability of homes
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.)
– Hemp
Fig. 9-14, p. 189
Ways to Reduce Tropical Deforestation
• Debt-for-nature swaps
• Conservation concessions
• Gentler logging methods
• Encourage use of wood substitutes
Fig. 9-15, p. 190
Fig. 9-15, p. 190
Sustaining Tropical Forests
Protect the most diverse andendangered areas
Educate settlers aboutsustainable agriculture andforestry
Subsidize only sustainableforest use
Protect forests withdebt-for-nature swaps andconservation concessions
Certify sustainably growntimber
Reduce poverty
Slow population growth
Encourage regrowththrough secondarysuccession
Rehabilitate degradedareas
Concentrate farmingand ranching inalready-cleared areas
Prevention
Solutions
Restoration
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.
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
Fig. 9-16, p. 191
Manage Rangelands Sustainably
• Practice rotational grazing
• Fence out riparian zone areas
• Suppress invader plants– Herbicides
– Mechanical removal
– Controlled burning
– Short-term trampling
Fig. 9-17, p. 191
Fig. 9-17, p. 191
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 earth’s remaining undisturbed land area.
National Parks
• >1,100 national parks in 120 countries• Only 1% of parks in developing
countries are protected– Local people invade parks to survive– Logging– Mining– Poaching
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
• 58 major national parks
• Biggest problem is popularity
• Damage from nonnative species
• Threatened islands of biodiversity
• Need $6 billion for overdue repairs
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
• “Ecological insurance policy”
• Buffer zones around protected areas
• Locals to manage reserves and buffer zones
• United Nations: 531 biosphere reserves in 105 countries
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
Fig. 9-B, p. 193
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
Fig. 9-18, p. 194
Fig. 9-18, p. 194
Caribbean SeaNicaragua
Panama
CostaRica
Buffer zone
National parkland
Pacific Ocean
Protecting Wilderness Protects Biodiversity
• Wilderness
• Preserves biodiversity
• Centers for evolution
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
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).
Three Principles to Protect Ecosystems
1. Map and inventory the world’s 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
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
Fig. 9-19, p. 196
Supplement 4, Fig. 2, p. S16
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
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
Fig. 9-20, p. 198
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.
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
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
Fig. 9-21, p. 199
Fig. 9-21, p. 199
Overfishing
• Fishery
• Fishprint
• 157% overfishing
• 90% of large open-ocean fishes have disappeared since 1950
Fig. 9-22, p. 200
Case Study: Industrial Fish Harvesting Methods
• Trawler fishing
• Purse-seine fishing
• Longlining
• Drift-net fishing
Fig. 9-23, p. 201
Fig. 9-23, p. 201
Float
Trawlerfishing
Drift-net fishing
Purse-seine fishingSonar
Long line fishing
lines withhooks
Fish farmingin cage Spotter airplane
Deep seaaquaculture cage Fish caught
by gills
Buoy
Fish farming in cage Spotter airplane
Trawler fishing
Sonar Purse-seine fishing
Long line fishing
lines with hooks
Deep sea aquaculture cage
Drift-net fishing
Float Buoy
Fish caught by gills Stepped Art
Fig. 9-23, p. 201
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
Fig. 9-24, p. 202
Fig. 9-24, p. 202
Managing FisheriesFishery Regulations
Set catch limits well below themaximum sustainable yield
Improve monitoring andenforcement of regulations
Economic Approaches
Sharply reduce or eliminatefishing subsidies
Charge fees for harvesting fishand shellfish from publiclyowned offshore waters
Certify sustainable fisheries
Protect Areas
Establish no-fishing areas
Establish more marineprotected areas
Rely more on integratedcoastal management
Consumer Information
Label sustainably harvested fish
Publicize overfished andthreatened species
Bycatch
Dump ballast water far atsea and replace withdeep-sea water
Filter organisms from shipballast water
Kill organisms in ship ballast water
Nonnative Invasions
Depend more onherbivorous fish species
Control pollution morestrictly
Restrict coastal locations for fish farms
Aquaculture
Ban throwing edible andmarketable fish back intothe sea
Use net escape devices forseabirds and sea turtles
Use wide-meshed nets toallow escape of smaller fish
Solutions
Three Big Ideas from This Chapter - #1
The economic values of the important ecological services provided by the world’s ecosystems need to be included in the prices of goods and services.
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.
Three Big Ideas from This Chapter - #3
We can sustain aquatic biodiversity by establishing protected sanctuaries, managing coastal development, reducing water pollution, and preventing overfishing.
Animation: Ocean Provinces
PLAYANIMATION
Animation: Humans Affect Biodiversity
PLAYANIMATION
Animation: Habitat Loss and Fragmentation
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Animation: Area and Distance Effects
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Animation: Succession
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Animation: Hubbard Brook Experiment
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Animation: Effects of Air Pollution in Forests
PLAYANIMATION
Animation: Effects of Deforestation
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Animation: Biodiversity Hot Spots
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Animation: Resources Depletion and Degradation
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Animation: Species Diversity By Latitude
PLAYANIMATION
Video: Easter Island
PLAYVIDEO
Video: New Species Found
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Video: Bachelor Pad at the Zoo
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Video: Desertification in China
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Video: U.S. Forests
PLAYVIDEO
Video: Marine Sanctuary
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Video: Sea Turtle Release
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