Download Chapter 6

Sustaining Biodiversity:
The Ecosystem Approach
Chapter 6
Biodiversity - Defined
• Speciation – Extinction = Biodiversity
– Raw genetic material for further evolution
Succession
• Highest diversity occurs when there is
enough disturbance to prevent the
dominant competitors from taking over,
but not so much that the community is
unable to develop.
Human Activities and Biodiversity
Habitat Loss and Degradation
Greatest threat to species diversity
“HIPPO”
Habitat destruction
Invasive species
Population (humans) growth
Pollution
Over-harvesting
Rate = 80 million new people/year
+ New York City every month
+ Germany every year
+ United States every 3.7 years
Biodiversity is
affected by human
population size
and resource
use
Agriculture
Economic production
and consumption
Industry
Recreation
Global Biodiversity Status
Forests
Rainforests
Grassland
Desert
Everything
5% of our virgin forests remain uncut
2% of our native grasslands are left in
their native state
15% of our redwood forests are old growth
Less than 50% of our wetlands remain
Their existence being deemed less important than
others…
Open Season On Wetlands Destruction Begins
Menards filling wetlands for new store
In Puget Sound, we have lost 70% of our
estuaries to farms and development
Over 800 miles of
Puget Sound shoreline
has been armed with
bulkheads.
Importance of Biodiversity
• Intrinsic value – right to exist, to have evolved
means they have important roles
• Instrumental value – because of their use to us
• Existence value – knowing it exists
• Aesthetic value – wildlife viewing
• Bequest value – willing to pay for its existence
Solutions for Protecting Biodiversity
Types of US Public Lands
• Multiple-use lands: National Forests;
National Resource Lands (BLM)
• Moderately-restricted use lands: National
Wildlife Refuges
• Restricted-use lands: National Park
System; National Wilderness Preservation
System
US Public Lands
Fig. 11-6 p. 198
Managing US Public Land
Conservation biologists
support:
• Biodiversity and
ecological function
• No subsidies or tax
breaks for use
• Public should get fair
compensation
• Users held responsible
for actions
•
•
•
•
Developers and
Resource Extractors
Support:
Sell public land
Cut funding to
administer lands
Cut old growth forests
Drill in the Artic Refuge
Ecological and
economic
services of
forests
Trade-Offs
Logging in U.S. National Forests
and other publicly owned lands
Advantages
Helps meet
country’s timber
needs
Cut areas grow
back
Keeps lumber
and paper prices
down
Provides jobs in
nearby
communities
Promotes
economic
growth in nearby
communities
Disadvantages
Provides only 4% of
timber needs
Ample private forest
land to meet timber
needs
Has little effect on
timber and paper
prices
Damages nearby
rivers and fisheries
Recreation in
national forests
provides more local
jobs and income for
local communities
than logging
Decreases
recreational
opportunities
*
Clear cutting our forests: Advantages and Disadvantages
Advantages
Higher timber yields
Maximum economic return in
shortest time
Can reforest with genetically
improved fast-growing trees
Short time to establish new
stand of trees
Needs less skill and planning
Best way to harvest tree
plantations
Good for tree species needing
full or moderate sunlight for
growth
Trade-Offs
Clear-Cutting Forests
Disadvantages
Reduces biodiversity
Disrupts ecosystem processes
Destroys and fragments some
wildlife habitats
Leaves moderate to large
openings
Increases soil erosion
Increases sediment water
pollution and flooding when
done on steep slopes
Eliminates most recreational
value for several decades
Sustainable Forestry
• Several methods can be used to sustain
harvests and maintain biodiversity
Longer rotations will provide a more
stable ecosystem and greater biodiversity
Selective logging leaves habitat,
minimizing disturbance and
Habitat fragmentation and island biogeography
Leave snags and
downed logs for
cavity nesting animals
Logging roads like this one have dozens of ditches, culverts and other conduits that
dump pollution from clear cut and herbicide-sprayed hillsides directly into
streams and rivers.
Recent efforts by the forest industry, the tribes and
government agency scientists have worked to lessen the
impacts of logging roads.
Include ecological
services in estimating
economic value
Rainforests harbor the greatest gene pool in the world. The
rainforest has nurtured this "pool" to become home for
170,000 of the world's 250,000 known plant species.
Tropical Deforestation: Consequences
• Rapid and increasing
• Loss of biodiversity
• Loss of resources
(e.g., medicines)
• Contributes to global
warming
Tropical Deforestation: Causes
• Population growth
• Poverty
• Environmentally harmful government
subsidies (encourage poor to colonize
tropical forests)
• Debts owed to developed countries
• Low value of ecological services
Managing and Sustaining National
Parks
•
•
•
•
•
•
Inadequate protection
Often too small to sustain biodiversity
Invasions by nonnative species
Too many human visitors
Traffic jams and air pollution
Better pay for park staff
Establishing, Designing, and
Managing Nature Reserves
• Include moderate to large tracts of land
• Involve government, private sector and
citizens
• Biosphere reserves
• Adaptive ecosystem management
• Protect most important areas (“hot spots”)
• Wilderness areas
Ecological Restoration: Basic Principles
•
•
•
•
•
Mimic nature
Recreate lost niches
Rely on pioneer species
Control nonnative species
Reconnect small patches
Protecting Biodiversity in
Washington State
• Governor Locke’s Executive Order
• Establishment of the Washington Biodiversity
Council
– Develop 30-year comprehensive prioritized
strategy to protect biodiversity
– Assess existing and potential landowner incentive
program
– Develop public education and a web site
– By December 31, 2007
Ecosystem Planning in
Washington State
• Mitigation “banks”
• Growth Management Act Critical Area
Ordinances
• CREP and CRP
• Marine Protected Areas
• Eco-regional Assessments for
Biodiversity