Transcript chapter8_Part12008

Sustaining Biodiversity:
The Ecosystem Approach
Chapter 8
Sections 1-4
Key Concepts

Human impacts on biodiversity

Public lands and their use

Use and management of forest resources

Temperate and Tropical Deforestation

Problems associated with parks

Establishing and managing natural reserves

Protecting and sustaining aquatic biodiversity

Importance of ecological restoration

Sustaining the Earth’s biodiversity
Part 1
Part 2
Reintroducing Wolves to
Yellowstone (1995)
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Why wolves were killed-
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Wolf protection 1974 listed as endangered species
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Ecological importance- Keystone predator- culled
2 million killed 1850 - 1900
to “make the west safe for livestock and big-game animals”
herds of bison, elk, caribou and mule deer, keep coyote pop low, …

Yellowstone controversy- ranchers, hunters,
miners all opposed

Importance of biodiversity- ecological successwillow & aspen re-growth in riparian areas, more beavers, elk
carcasses feed grizzlies, coyote population reduced, squirrel
& fox pop increase = more food for eagles & hawks
Fig. 8-1, p. 154
Human Impacts on Biodiversity

Human “footprint”
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Disturbing the land- humans have disturbed
50 - 83% of Earth

Destruction of wetlands
half world’s wetlands lost in past 100 yrs
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Deforestation
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Aquatic biodiversity27% coral reefs severely damaged75% fish are fished at or above limit

Premature extinctionscurrent extinction rate likely 1,000 - 10,000 times
greater than before humans
Fig. 8-2, p. 155
The Species Approach
The Ecosystem Approach
Goal
Goal
Protect species from
premature extinction
Protect populations of species
in their natural habitats
Strategy
• Identify endangered
species
• Protect their critical
habitats
Tactics
• Legally protect
endangered species
• Manage habitat
• Propagate endangered
species in captivity
• Reintroduce species
into suitable habitats
Human
Impacts on
Biodiversity
Strategy
Preserve sufficient areas of
habitats in different biomes
and aquatic systems
Tactics
• Protect habitat areas through
private purchase or
government action
• Eliminate or reduce
populations of nonnative
species from protected areas
• Manage protected areas to
sustain native species
• Restore degraded ecosystems
Stepped Art
Fig. 8-3, p. 156
Natural Capital Degradation: Orangutans
< 20,000 Organutans left- disappear at a rate >2,000 per year
Natural Capital: Scarlet Macaw
Fig. 8-5, p. 157
Types of US Public Lands
(35% of US is public land)

Multiple-use lands: National Forest System; Natural
Resource Lands (BLM)
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Moderately restricted-use lands: Natural Wildlife Refuges

Restricted-use lands: Natural Park System; Natural
Wilderness Preservation System
What percent of U.S. land is
federally-owned public land?
35%
b. 7%
c. 55%
d. 3%
e. 0%
a.
US Federal Public Lands
National parks and preserves
National forests
(and Xs) National wildlife refuges
Fig. 8-6b, p. 158
Managing US Public Lands
principles of public land use
Conservationists
Developers
Protecting biodiversity is a primary goal Sell public lands / resources @ less
than market value
No subsidies or tax breaks for use of
resources
Slash funding for regulation
Public should get fair compensation for
use
Cut old growth forests in national
forests and replace with tree plantations
Users are responsible for environmental Open all public land to oil, mining, offdamage
roading and commercial development
Alternative views from developers and
industry
Eliminate Nat. Park Service, mine
without royalties, repeal Endangered
Species Act, …
Which of the following is a major
problem of U.S. national parks?
a.
b.
c.
d.
e.
wildfires
too much land area to manage
Popularity
lack of management plans
attack from vicious wildlife on
humans
It is permissible to trap
animals in most national
wildlife refuges.
a. True
b. False
The National Wilderness Preservation
System forbids the introduction of:
a. roads
b. fishing
c. camping
d. sailboats
e. APES students
Arctic National Wildlife Refuge
(CNN Video) 2 min
Types of Forests

Old-growth- not seriously disrupted for at least several hundred
years
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Second-growth - results from secondary succession

Tree plantation or tree farm - managed tract of uniformly
aged trees of one or two species. Clear cut when commercially valuable, then
replanted.
Major Services of Forests
Natural Capital
Ecological
services of
world’s
forests
valued at
$4.7
trillion per
year
Forests
Ecological
Services
Support energy
flow and
chemical cycling
>>>
Much greater than
Economic
Services
Fuelwood
Lumber
Reduce soil
erosion
Absorb and
release water
Pulp to make
paper
Value of
ecological
services much
greater than
value of
economic
services
Purify water
Purify air
Mining
Influence local
and regional
climate
Livestock grazing
Store
atmospheric
carbon
Recreation
Provide
numerous
wildlife habitats
Jobs
Fig. 8-7, p. 160
Types of Forest Management

Even-aged management (industry forestry) trees maintained @
about same age and size- simplified tree plantation- 1-2 fast-growing species
harvested on rotation cycle.
EX: Clear cutting
EX: Seed tree method: In the seed-tree method, 2-12 seed trees per acre (5-30/ha)
are left standing in order to regenerate the forest.
EX: Shelter wood method: The method's objective is to establish new forest
reproduction under the shelter of the retained trees.

Rotation cycles: 25-30 years (temperate), 6-10 years (tropical)
EX: Strip cutting

Uneven-aged management- variety of species w/ range of ages
& sizes. Goals: biodiversity, sustainable high quality timber
EX: Selective cutting
Sustainable management intensive management of as little as 20%
of world’s forests could meet current and future demand for commercial
wood / fiber
EX: Combine aspects of a number of these management techniques.
Tree Plantation
Fig. 8-8, p. 160
Degradation of Forests from
Logging Roads
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Increased erosion and sediment runoff
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Habitat fragmentation
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Biodiversity loss
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Pathways for pests, diseases, and invasive species

More accessible for humans
Degradation of Forests
Cleared plots
for grazing
Highway
Cleared plots
for agriculture
Fig. 8-10b, p. 161
Degradation
from Clear-cut
Logging
Fig. 8-12, p. 163
Tradeoffs of Clear-cutting Forests
Trade-Offs
Clear-Cutting Forests
Advantages
Disadvantages
Higher timber yields
Reduces biodiversity
Maximum economic return
in shortest time
Disrupts ecosystem processes
Can reforest with genetically
improved fast-growing trees
Destroys and fragments some
wildlife habitats
Leaves moderate to large openings
Short time to establish new
stand of trees
Needs less skill and planning
Increases soil erosion
Increases sediment water pollution and
flooding when done on steep slopes
Best way to harvest tree plantations
Good for tree species needing
full or moderate sunlight for growth
Eliminates most recreational value for
several decades
Fig. 8-13, p. 163
Harmful Effects of Deforestation
Natural Capital Degradation
Deforestation
• Decreased soil fertility from erosion
• Runoff of eroded soil into aquatic systems
• Premature extinction of species with
specialized niches
• Loss of habitat for migratory species such as
birds and butterflies
• Regional climate change from extensive clearing
• Releases CO2 into atmosphere from burning
and tree decay
• Accelerates flooding
© 2006 Brooks/Cole - Thomson
Fig. 8-14, p. 164
Deforestation has all of the following
effects except:
a. increase in soil fertility.
b. regional climate change.
c. flooding.
d. extinction of species with specialized
niches.
e. increase in soil erosion.
Sustainable Forestry
Solutions
Sustainable Forestry
• Grow more timber on long rotations
• Rely more on selective cutting and strip cutting
Conserves
biodiversity,
water & soil
resources
• No clear-cutting, seed-tree, or shelterwood cutting
on steeply sloped land
• No fragmentation of remaining large blocks of forest
• Sharply reduce road building into uncut forest areas
• Leave most standing dead trees and fallen timber for
wildlife habitat and nutrient recycling
• Certify timber grown by sustainable methods
• Include ecological services of trees and forests in
estimating economic value
© 2006 Brooks/Cole - Thomson
Fig. 8-15, p. 164
Surface and Crown Forest Fires
Ground fire = underground surface fire, common in northern peat bogs
Fig. 8-16, p. 166
Minimizing Forest Damage from Fire
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Prescribed burning- reduce underbrush
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Allow small fires in National Parks, forests &
wilderness to burn (if people & property not threatened)
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Defensible space- clear 200 feet around buildings
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Effects of the Healthy Forests Initiative
Timber Co. allowed to take large/medium trees in Nat. Forests if
they clear away smaller, fire-prone trees- criticized by fire
scientists (large tree most fire resistant, logging creates slash)
Healthy Forests Initiative
(CNN Video)
Read
more
about
this!
Managing US National Forests
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Status of US forests- 30% of USA forested, more wood grown than cut
more forests now than in 1920 (old growth forests decreasing)
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Importance of national forests

Management of forests

Lost revenue from timber sales- timber sales from US federal land lost
taxpayer money in 97 of past 100 years
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Controversies of logging national forests- 10x more $ and 7x more jobs
added to economy by using national forests for recreation, hunting & fishing

Tree-free fibers and paper- agricultural residues, kenaf & industrial hemp
Logging in U.S. National Forests
Trade-Offs
Logging in U.S. National Forests
Advantages
Disadvantages
Helps meet country’s timber needs
Provides only 4% of timber needs
Cut areas grow back
Ample private forest land to meet
timber needs
Keeps lumber and paper prices down
Has little effect on timber and paper
prices
Damages nearby rivers and fisheries
Provides jobs in nearby communities
Promotes economic growth
in nearby communities
*Recreation in national forests provides
more local jobs and income for local
communities than logging
Decreases recreational opportunities
Fig. 8-17, p. 168
Kenaf
Holds potential to
greatly reduce
pressure to cut trees
for paper
End Part 1
Fig. 8-18, p. 169