Transcript Chapter 10 - School District of La Crosse

Chapter 10
Sustaining Terrestrial
Biodiversity: The
Ecosystem Approach
Core Case Study:
Reintroducing Wolves to Yellowstone
 Endangered

1850-1900 two million
wolves were destroyed.
 Keystone



Species
Species
Keeps prey away from open
areas near stream banks.
Vegetation reestablishes.
Species diversity expands.
Figure 10-1
HUMAN IMPACTS ON
TERRESTRIAL BIODIVERSITY
 We
have depleted
and degraded some
of the earth’s
biodiversity and these
threats are expected
to increase.
Figure 10-2
Why Should We Care About
Biodiversity?
 Intrinsic
Value
Ethical—organisms
exist so they should
be allowed to do so.
Figure 10-3
Why Should We Care About
Biodiversity?
 Instrumental
1.
Value
Use Value: For the
usefulness in terms
of economic,
medical, recreational
and ecological
services.
6% of GDP, 5% Growth
Figure 10-3
Why Should We Care About
Biodiversity?
 Instrumental
Value
2. Nonuse Value:
existence, aesthetics,
bequest for future
generations.
Figure 10-3
Ecosystem Approach
 What
species and ecosystems?
 Locate and protect most endangered
ecosystems.
 Biodiversity friendly development
 Refuges, sanctuaries, etc. (USFWS-Natl.
Refuge System Improvement Act)
Wisconsin Forest Land
 Approx.
16 million acres of forest land in
Wisconsin.
 60% is privately owned
 The rest is incorporated into state, county,
federal and tribal land holdings.
 1.5 million acres in the Chequamegon-Nicolet
National Forest
 5.7 million acres of public land—not all
forested
TIMBER!!!
 Is
it bad to cut down a tree?
 “Fern
Gully”
or Paul Bunyan?
MANAGING AND SUSTAINING
FORESTS
 Forests
provide a
number of ecological
and economic services
that researchers have
attempted to estimate
their total monetary
value.
Figure 10-4
Types of Forests
 Old-growth
forest: uncut
or regenerated forest that
has not been seriously
disturbed for several
hundred years.


22% of world’s forest.
Hosts many species with
specialized niches.
Figure 10-5
Types of Forests

Second-growth forest: (63%)a stand of trees
resulting from natural secondary succession.
 Tree plantation: (5%) planted stands of a particular
tree species.
Figure 10-6
Global Outlook:
Extent of Deforestation

Human activities have
reduced the earth’s
forest cover by as
much as half.
 Losses are
concentrated in
developing countries.
 0.3-0.8% degrade/yr
 40% OG in 2 decades
Figure 10-7
Current Forestry Trends
Global Forest Resources Assessment 2010
Harvesting Trees
 Trees
can be harvested
individually from diverse
forests (selective cutting),
an entire forest can be cut
down (clear cutting), or
portions of the forest is
harvested (e.g. strip
cutting).
Figure 10-9
Harvesting Trees
Effects of clear-cutting in the
state of Washington, U.S.
Figures 10-10 and 10-11
Harvesting Trees
 Building
roads into previously inaccessible
forests paves the way for fragmentation,
destruction, and degradation.
Figure 10-8
Solutions
 We
can use forests
more sustainably by
emphasizing:



Economic value of
ecological services.
Harvesting trees no
faster than they are
replenished.
Protecting old-growth
and vulnerable areas.
Figure 10-12
CASE STUDY:
FOREST RESOURCES AND
MANAGEMENT IN THE U.S.
 U.S.
forests cover more area than in 1920.
(40% is in protected forests)
 Since the 1960’s, an increasing area of old
growth and diverse second-growth forests
have been clear-cut. (MONOCULTURE)



Often replace with tree farms.
Decreases biodiversity.
Disrupts ecosystem processes.
FIRE
 Are
forest fires natural?
 Are
forest fires good?
 Bad??
 Explain!!!
Types and Effects of Forest Fires

Depending on their intensity, fires can benefit or
harm forests.


Burn away flammable ground material.
Release valuable mineral nutrients.
Figure 10-13
Solutions:
Controversy Over Fire Management
 To



reduce fire damage:
Set controlled surface fires.
Allow fires to burn on public lands if they don’t
threaten life and property.
Clear small areas around property subject to fire.
Controversy over Logging in U.S. National
Forests
 There
has been an
ongoing debate over
whether U.S.
national forests
should be primarily
for:




Timber.
Ecological services.
Recreation.
Mix of these uses.
Figure 10-14
Solutions:
Controversy Over Fire Management
 In
2003, U.S. Congress passed the Healthy
Forest Restoration Act:



Allows timber companies to cut medium and
large trees in 71% of the national forests.
In return, must clear away smaller, more fireprone trees and underbrush.
Some forest scientists believe this could increase
severe fires by removing fire resistant trees and
leaving highly flammable slash.
Solutions:
Reducing Demand for Harvest Trees
 Tree
harvesting can
be reduced by
wasting less wood
and making paper
and charcoal fuel
from fibers that do
not come from trees.

Kenaf is a promising
plant for paper
production.
Figure 10-15
CASE STUDY: TROPICAL
DEFORESTATION
 At
least half of the
world’s terrestrial plant
and animal species live
in tropical rain forests.
 Large areas of tropical
forest are burned to
make way for cattle
ranches and crops.
Figure 10-17
Why Should We Care about the Loss
of Tropical Forests?
 About
2,100 of the 3,000 plants identified by
the National Cancer Institute as sources of
cancer-fighting chemicals come from tropical
forests.
Figure 10-18
Solutions
Sustaining Tropical Forests
Prevention
Protect most diverse and endangered
areas
Restoration
Reforestation
Educate settlers about sustainable
agriculture and forestry
Phase out subsidies that encourage
unsustainable forest use
Add subsidies that encourage
sustainable forest use
Rehabilitation of degraded
areas
Protect forests with debt-for-nature
swaps and conservation easements
Certify sustainably grown timber
Reduce illegal cutting
Reduce poverty
Slow population growth
Concentrate farming and
ranching on already-cleared
areas
Fig. 10-20, p. 207
NATIONAL PARKS
 Countries
have established more than 1,100
national parks, but most are threatened by
human activities.




Local people invade park for wood, cropland,
and other natural resources.
Loggers, miners, and wildlife poachers also
deplete natural resources.
Many are too small to sustain large-animal
species.
Many suffer from invasive species.
Case Study: Stresses on U.S.
National Parks
 Overused
due to
popularity.
 Inholdings (private
ownership) within
parks threaten
natural resources.
 Air pollution.
Figure 10-23
 Suggestions
for
sustaining and
expanding the
national park
system in the
U.S.
Figure 10-24

34 hotspots identified by ecologists as important and
endangered centers of biodiversity.
Figure 10-26
NATURE RESERVES
 Ecologists
call for protecting more land to
help sustain biodiversity, but powerful
economic and political interests oppose doing
this.



Currently 12% of earth’s land area is protected.
Only 5% is strictly protected from harmful human
activities.
Conservation biologists call for full protection of
at least 20% of earth’s land area representing
multiple examples of all biomes.
How Would You Vote?
 Should
at least 20% of the Earth's land area
be strictly protected from economic
development?


a. No. Such protections would encourage people
to poach and illegally extract resources from the
expanded reserves.
b. Yes. The project is desperately needed to
protect the Earth's biodiversity.
NATURE RESERVES
 Large
and medium-sized reserves with buffer
zones help protect biodiversity and can be
connected by corridors.
 Costa
Rica has
consolidated its parks
and reserves into 8
megareserves
designed to sustain
80% of its biodiversity.
Figure 10-10B
NATURE RESERVES
 Geographic
Information System (GIS)
mapping can be used to understand and
manage ecosystems.


Identify areas to establish and connect nature
reserves in large ecoregions to prevent
fragmentation.
Developers can use GIS to design housing
developments with the least environmental
impact.
NATURE RESERVES
 We
can prevent or slow down losses of
biodiversity by concentrating efforts on
protecting global hot spots where significant
biodiversity is under immediate threat.
 Conservation biologists are helping people in
communities find ways to sustain local
biodiversity while providing local economic
income.
Wilderness Areas in US





*area of 1500 sq. miles that is protected from air,
water, noise pollution (us!!)
4.6% of US land, only 413 areas in lower 48, only 4
fit the square mileage for wilderness, 150000squ
miles in Natl. Forest was protected by Roadless
Rule until 2005 when the Bush Admin. Dropped the
rule and allowed mining, etc.
Biologists say preserve wilderness as:
*as natural capital (natural capital)
*centers for evolution
ECOLOGICAL RESTORATION
 Restoration:
trying to return to a condition as
similar as possible to original state.
 Rehabilitation: attempting to turn a
degraded ecosystem back to being
functional.
 Replacement: replacing a degraded
ecosystem with another type of ecosystem.
 Creating artificial ecosystems: such as
artificial wetlands for flood reduction and
sewage treatment.
How Would You Vote?

Should we mount a massive effort to restore
ecosystems we have degraded even though this
will be quite costly?