Transcript Sustaining Biodiversity: The Ecosystem Approach

Sustaining Biodiversity:
The Ecosystem Approach
Chapter 8
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
– Wetlands, grasslands &
forests
• 83% land surface
disturbed
– Antarctica &
Greenland
Loss of Biodiversity
• Degradation of aquatic biodiversity
– 50% wetlands (globally)
– 15-35% coral reefs destroyed and damaged
• Ecological fishprint unsustainable
– 200 commercially valuable fish overfished or at
their sustainable yield
– 29% collapsed, w/90% in decline
– Need >2.5x current ocean area
– Japan, Indonesia and China
Lake Victoria
• Lake Victoria has lost their endemic fish species to large
introduced predatory fish.
Lake Victoria
• Reasons for loss of biodiversity:
– Introduction of Nile perch.
– Algal blooms from nutrient runoff.
– Invasion of water hyacinth has blocked
sunlight and deprived oxygen.
– Nile perch is in decline because it has
eaten its own food supply.
Why Protect Biodiversity
• Intrinsic value
– Value regardless of use to us
• Instrumental value
– Use Value: Usefulness in terms of economic
and ecological services. (farms, crops,
fisheries)
• Nonuse values
– Existence
– Aesthetic
– Bequest
Endangered Orangutans
8-2 Managing and Sustaining 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.
Forest Services
• Forests 30% of earth’s land surface –
– mostly in the mountains
Types of Forests
• Old-growth forests
– (primary, ancient,
primeval, frontier) diverse
– 150-500+ yrs old
– 22% of forests
• Second-growth forests
– Secondary succession
• Tree plantation
– Managed, uniform, clear
cut, economical, depletes
nutrients
Short Rotation Cycle Forestry
Loss of Original Forests
• DEFORESTATION – temporary & permanent
– 46% in 8,000 years, most since 1950
• Most in tropical areas, developing countries
– Crops and cattle
– Latin America, Indonesia, Africa
• Estimated loss of 40% intact forests within next 20 years
– Clearing is exponential (0.3-0.8%)
Video: U.S. Forests
Videos/US_Forests.mov
Roads and Forests
• Fragmentation, destruction, and degradation.
Natural Capital Degradation: Deforestation
Fig. 8-6, p. 155
Putting a Price Tag on Nature’s Ecological Services
The long-term health of an economy cannot be separated from
the health of the natural systems that support it.
• Estimated value of earth’s ecological services
– $33.2 trillion per year
– $4.7 trillion per year for forests
• What services do we need to start factoring
into land use?
Good News on Forests
• 2000–2005 net total forested area stabilized or
increased
– N. America, Europe, India, China, Turkey & Vietnam
• Most due to tree plantations
– Some secondary succession (cropland & cleared
forests)
• BENEFIT
– Wood needs, decreased erosion & nutrient loss, CO2
• LOSS
– Decreased biodiversity & nutrients
Return of Forests in the United States
• 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
• Second- and third-growth forests fairly diverse
• More wood grown than cut annually
• 40% of forests in National Forest System
– 155 National Forests
• LOSS: transformed into tree plantations
– Julia Hill – “Butterfly” – two years on a platform of California
redwood tree
Controversy over the National Forests
• Forest service mandate
– Principle of sustainable yield
• Harvest at replenishing rate
– Principle of multiple use
• Recreation, hunting & fishing in forests = 10x timber revenue
• Timber companies push for tree cutting to be primary goal
• Subsidized by taxpayers money
• Timber sales have lost money 97 out of last 100 yrs (cost of roads, timber prep,
admin, etc)
Harvest Methods
• Step one – build roads
– Erosion
– Invasive species
– Open up for human invasion
– DISQUALIFY LAND FOR PROTECTION AS WILDERNESS
• Step two – logging operations
– Selective cutting
– Strip cutting
– Clear cutting
Forest Harvesting Methods
Clear-cut Logging
Fig. 8-9, p. 157
Trade-offs: Clear-cutting Forests
Fig. 8-10, p. 157
Forests and Fires
• Surface fires
– Burn undergrowth only
– Cool fire
– Ecological benefits –
– remove flammables, release minerals & seeds (lodgepole), stimulate
germination (sequoia/jack pine), control pathogens, post-fire food (deer,
moose, elk, quail, etc)
• Crown fires
– Burn the entire tree, hot fire
– Occur in forests with lack of surface fires (buildup)
– Flames leap, are rapid, destructive, kill & erode
Management of Forest Fires
• Fire suppression in all types of forests
– Smokey Bear
• Some forests naturally fire adapted
– Not all fires are bad
– Prescribed fires
– Native Americans
Management of Forest Fires
Restoration of fire’s natural role:
• Allow fires to burn
• 60 m buffer zone around homes (thinning)
• Healthy Forests Restoration Act, 2003
– Allows timber companies to cut med-large trees in
return for clearing
– Exempts thinning projects from environmental review
– Paid for by taxpayers – may increase damage
Forest Fires
• Forest fires have increased – past 15 yrs
– Drying from climate change
– Increases climate change
Certifying Sustainably Grown Timber
• Forest Steward Council certification of forest
operations
– Scientific Certification Systems (SCS)
– Environmentally sound practices
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Sustainable yield harvest
Minimal erosion from operations
Retention of dead wood for wildlife habitat
Steward of land and water
– 2005 – only 6% certified
• Sweden, Poland, US, Canada
Solutions: Sustainable Forestry
Fig. 8-12, p. 159
Trees and Paper
• Many trees are cut for
paper production
• Alternatives
– Pulp from rice straw and
agricultural residues
(China)
– Kenaf (U.S.)
• More paper pulp/land area
• Require fewer pesticides
and herbicides
http://www.environmentalpaper.org/PAPER-statistics.html
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 (size of US)
– Lost 50% since 1950
• Habitat for 50% of terrestrial plants and animals
– Diversity increases pole to equator
• Vulnerable to extinction – specialized niches
• Rapid loss of 50,000–170,000 km2 per year
• Imazon (2004) - land occupation/deforestation = 47%
Burning of a Tropical Forest
• Accounts for ¾ greenhouse gas emissions.
Fig. 8-14, p. 160
Destruction of Tropical Forests
Causes of Tropical Forest Deforestation and Degradation
• Population growth and poverty
– Subsistence farming & poor search for land
• Government subsidies
– Reducing cost of harvest and grazing
– Gov. gives title to land-clearers to reduce poverty but don’t
teach sustainability (Ind, Mex, Brazil)
• International lending agencies encourage development
– Roads, soybeans, coffee, mines, logging, oil, dams
– Africa, Latin America
Effects of Tropical Deforestation
• Fragmentation of remaining patches
– Roads, erosion, toppling
• Remaining forests get drier and may burn
– Degrades biodiversity
– CO2 to the atmosphere
– Accelerates climate change
– Converts forest to savannah
Animation: Effects of Deforestation
Animations/effects_deforestation.html
How to Protect Tropical Forests
• Teach settlers to practice small-scale sustainable
agriculture
• Harvest renewable resources from the forests
• Debt-for-nature swaps
– Foreign aid & debt relief to be stewards
• Conservation concessions
– Gov & NPOs give $
• Gentler logging methods
Solutions: Sustaining Tropical Forests
Fig. 8-16, p. 162
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
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
• Ecological services
– Soil formation, erosion control, nutrient cycling, carbon
storage, maintaining biodiversity
• Second most used and altered ecosystem by
humans
– Rangeland - unfenced (temperate/tropical) forage
land
• 42% grazed by cattle, sheep, and goats
• Pasture – fenced, managed, sometimes planted
• Grow from the bottom – tops dispensable
Grasslands
Grasslands
• Overgrazing – over carrying capacity
– Erosion/compaction,
– Invasives (sagebrush, mesquite, cactus, cheatgrass and salt
cedar)
– loss of productivity
Video: Desertification in China
Videos/Desertification_in_China.mov
Manage Rangelands Sustainably
• Practice rotational grazing
– Move fences and confine animals
• Fence out riparian zone areas
Manage Rangelands Sustainably
• Suppress invader plants
– Expensive – herbicides, uproot, trample
• Replant barren soil with seeds
– Expensive – seeds and fertilizer
• Employ controlled burns to control exotic vegetation
San Pedro River Rangelands
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
Problems Protecting National Parks
• Local people invade parks to survive
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Illegal logging & mining
Wildlife poaching
Most parks too small to protect large animals
Result in invasion of nonnative species
Stresses on U.S. National Parks
• System Est. 1912 by Congress
– 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 (places we don’t want to
live) – 95% reserved for human use
• Need for conservation
– Minimum 20% of land in biodiversity reserves –
multiple examples of all biomes
Solutions for Protection
• Requires action – bottom-up political pressure
– We, the people
• Nature Conservancy – world’s largest private system
of reserves
– Maintained by private, local citizens
– Opposed by those who say areas contain valuable resources
• Buffer zone Concept
– U.N. Biosphere Reserves (425) – underfunded/staffed
– Locals to manage reserves and buffer zones
Model Biosphere Reserve
Fig. 8-20, p. 167
Solutions: National Parks
Fig. 8-19, p. 166
Case Study: Costa Rica
• Superpower of biodiversity
– More bird species than all North America
• Government eliminated deforestation subsidies
– Paid landowners to maintain/restore tree coverage
• Goal to make sustainable forestry profitable
– Has gone from highest to lowest deforestation
Costa Rica’s Megareserve Network
• Conserved 25% of its land, 8 megareserves
Fig. 8-21, p. 167
Protecting Wilderness Protects Biodiversity
• Wilderness – land legally set aside/undeveloped
– US Wilderness Society - Minimum size >4,000 km2
– Otherwise impacted by air, noise, water pollution
• Preserves natural capital
• Centers for evolution
• CRITICS: we cannot use it for its economic value
STEPS: FWS - NPS
STEPS: USFS
Controversy over Wilderness Protection in the U.S.
• 1964 Wilderness Act
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National Wilderness Preservation System
Increased wilderness 10-fold (1970-2000),
¾ in Alaska, 98% of lower 48 unprotected
Only 4 of 413 wilderness areas >4,000 sq km, 81 of 233 distinct ecosystems
• Roadless Rule protects 400,000 sq. miles
• Pressure from oil, gas, mining, and logging
– 2005 Secretary of Interior removed protection & disqualified
cow paths and off-road vehicle trails
Global Biodiversity Hotspots
• 17 megadiversity countries in tropics and subtropics
– Indonesia, Colombia, Mexico, Brazil, Ecuador
• Two-thirds of biodiversity
Animations/hotspots.html
– Biodiversity hotspots – economically poor/diversity rich
Biodiversity Hotspots in the U.S.
Fig. 8-23, p. 169
8-6 Restoration Ecology
• Concept 8-6 Sustaining biodiversity will
require a global effort to rehabilitate and
restore damaged ecosystems.
Ecological Restoration
• Ecological Restoration – repairing the damage
– Replanting, reclaiming urban (brownfields), restoring wetlands, reintroducing
natives/removing invasives & dams
– effective if GLOBAL & mostly natural (secondary succession)
• Restoration – return to similar state
• Rehabilitation – return to functional/useful, not necessarily
natural
• Replacement – for another ecosystem
• Creating artificial ecosystems – e.g. wetlands
Science-based Principles for Restoration
1. Identify cause of degradation
– Pollution, overgrazing, invasives
2. Stop abuse by reducing factors
– Remove soil, invasives, cut down on grazing
3. Reintroduce species if necessary
– Pioneer, keystone, foundation
4. 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?
• It’s cheaper to protect than to restore
• Does environmental restoration suggest any
harm can be undone?
• Scientists disagree
– Restoration badly needed
– Altered restored site better than no restoration
What Can You Do?
Fig. 8-24, p. 171
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
• Relatively little known about the ocean and
freshwater systems
• 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
– More diverse habitats & food sources
Human Impacts on Aquatic Ecosystems
• Ecological Services
– $1.7 trillion/yr
– $3.2 million/minute
• Human activities
– Ocean floor degradation 150x larger than area clear-cut
annually
– 75% of most valuable fish species overfished
• IUCN - Likely extinction within our lifetime (more
than any other group of species)
– 34% marine fish species
– 71% freshwater species
Effects of Bottom Trawling
• 2004- Scientists attempted high-seas bottom trawling
moratorium
– Iceland, Russia, China & S. Korea blocked it
Fig. 8-25, p. 172
Why Is Protection of Marine Biodiversity So Difficult?
• Human aquatic ecological footprint expanding
• Not visible to most people
• Viewed as an inexhaustible resource
Why Is Protection of Marine Biodiversity So Difficult?
• Most ocean areas outside jurisdiction of a country
Solutions for Marine Ecosystems
• Protect endangered and threatened species
– ESA, MMPA, MBTA, The Bald and Golden Eagle Protection Act, the Wild Bird Conservation Act
– CITES, International Convention on the Regulation of Whales, and the Convention for the
Protection and Development of the Marine Environment of the Wider Caribbean Region
• Establish protected marine sanctuaries
– Since 1986, IUCN has established 1,300 global MPAs
• Marine reserves – work well and quickly
– Pops double, reproduction triples, adult size grows, diversity
increases by 25%
• Integrated coastal management
• Protect existing coastal wetlands
Solutions: Managing Fisheries
Fig. 8-26, p. 173
8-8 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