Transcript Terrestrial Biodiversity

Terrestrial
Biodiversity
Chapters 11
& 12
Biodiversity
Increase Factors
Decrease Factors
•Middle stages of
succession
•Extreme environmental conditions
•Moderate environmental
disturbance
•Large environmental
disturbance
•Small changes in
environmental conditions
•Intense environmental stress
•Physically diverse habitat
•Severe shortages of
key resources
•Evolution
•Nonnative species
introduction
•Geographic isolation
Figure 11-2
Page 195
Value
 Intrinsic
(existence)- value regardless of
usefulness to us
 Instrumental- value based on usefulness to
us



Existence- value whether we see it or get
direct use from it (nonuse)
Aesthetic- appreciation of beauty (nonuse)
Bequest- willingness to pay to protect
natural capita for future use
Conservation Biology
 Uses
rapid response strategies to stem loss
& degradation of biodiversity
 Bioinformatics- applied science of
managing, analyzing, & communicating
biological information

Importance- to understand & sustain
biodiversity
Public Lands
 35%
of U.S. land
 73% (of the 35%) is in Alaska
National parks and preserves National forests
(and Xs) National wildlife refu
National parks and preserves National forests
(and Xs) National wildlife refu
Use of Public Land
1.
2.
3.
Protecting biodiversity, wildlife habitats,
& ecological functioning of public land
ecosystems
No government subsidies or tax breaks
for using or extracting resources on
public lands – user-pays approach
American people deserve fair
compensation for extraction of any
resources from their property
4.
All users or extractors of resources on
public lands should be responsible for
any environmental damage they cause
 Economist,
developers, & resource
extractors view public lands for their
usefulness in providing timber, mineral,
and other resources & ability to increase
economic growth
Figure 11-7
8
important ecological services provided
by forests
 7 important economic benefits of forests
Forest Growth
 Old-growth
forest- uncut forest or
regenerated forest that has not been
seriously disturbed by human activities or
natural disasters for at least several
hundred years
 Second-growth forest- a stand of trees
resulting from secondary ecological
succession
 Tree
plantation- tree farm- managed tract
with uniformly aged trees of 1 species that
are harvested by clear-cutting as soon as
they are commercially valuable;
replanted & recut
Weak trees
removed
Clear
cut
25
30
Years of growth
Seedlings
planted
15
10
5
Tree Harvesting
 Even-aged-
tree farm that consists of 1 or
2 fast-growing & economically desirable
species (6-10 yr harvest)
 Uneven-aged- variety of tree species at
many ages & sizes
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 fastgrowing trees
Destroys and
fragments some
wildlife habitats
Short time to
establish new
stand of trees
Needs less skill
and planning
Leaves moderate
to large openings
Increases soil
erosion
Best way to
harvest tree
plantations
Increases sediment
water pollution and
flooding when
done on steep
slopes
Good for tree
species needing
full or moderate
sunlight for growth
Eliminates most
recreational value
for several
decades
Figure 11-11
Page 203
Deforestation
 Temporary
or permanent removal of large
expanses of forest for agricultural use
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
Figure 11-12
Page 203
Forest Cover
 Difficult
to estimate due to lack of satellite
& radar data, unmonitored land-use
change, & different definitions of what
constitutes a forest
Bad News
1.
2.
Human activities have reduced original
forest cover by 20-50%
40% of remaining forests will be
converted to other uses within 10-20
years
Good News
 Total
temperate forests increase slightly
due to reforestation
 Cut areas of tropical forests have
increased tree cover from regrowth & tree
farms
Forest Value
 Estimated
economical value - $36
trillion/yr
 Economic savings provided by conserving
nature vs. immediate profits by exploiting
nature
 Government subsidies & tax incentives
support destruction & degradation
Solutions
Sustainable Forestry
•Grow more timber on long rotations
•Rely more on selective cutting and strip cutting
•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
Figure 11-13
Page 205
Good News
 Forest
cover more now than in 1920
 Many diverse second-growth forests from
cleared or partially cleared between
1620-1920
 Every year, more wood is grown than cut
Bad News
 Remaining
old-growth & diverse secondgrowth forests have been cut & replaced
with tree farms
 Disrupts ecosystem processes (energy
flows & chemical cycling)
 Reduces biodiversity
Sudden oak death
White pine blister rust
Pine shoot beetle
Beech bark disease Hemlock wooly adelgid
Figure 11-14
Page 207
Reduce Harmful Impacts
 Ban
imported timber
 Selectively remove or clear-cut infected
or infested trees
 Develop tree species that are genetically
resistant to common tree diseases
 Conventional pesticides & biological
controls
Forest Fires
 Surface
fire- burns undergrowth & leaf
litter
 Crown fire- extremely hot fire; burns whole
trees & leaps from treetop to treetop
 Ground fire- surface fire that goes
underground & burns partially decayed
leaves & peat
Protection From Fire
 Prevention
 Prescribed
burning (setting controlled
ground fires to prevent buildup of
flammable material)
Benefits of fires
 To


plants & animals:
Stimulate germination of certain tree seeds
Helps control pathogens & insects
Crown Fires
 Advantages-
clears out flammable small
trees & underbrush in high-risk areas
Disadvantages-???
Healthy Forest Initiative Law

Advantages
 Medium & large
trees are cut down
 Reduces groundlevel fuel &
vegetation in dry
forests
 Clears flammable
vegetation around
homes & buildings

Disadvantages
 Removal of tress
encourages dense
growths of highly
flammable young
trees & rapidly
growing underbrush
 Leaves behind
highly flammable
slash (debris)
Timber Harvesting
1.
2.
3.

Pressure on Congress by timber
companies
Forestry Service keeps money from
timber harvest
Government subsidies
Revenue from timber sales does not
cover the cost of road building, timber
sale preparation, administration & other
overhead costs
Trade-Offs
Logging in U.S. National Forests
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
Figur
Tree-free paper
 Advantages-
faster growth; less
pesticides; nitrogen-fixing
 Disadvantages-
???
Tropical Forests
 Being
cleared – FAST!
 50,000
to 170,000 km2 / year
 Problem-
important ecological &
economic services provided by forests
•Oil drilling
•Mining
•Flooding from dams
•Tree plantations
•Cattle ranching
•Cash crops
•Settler farming
•Fires
•Logging
•Roads
Secondary Causes
•Not valuing
ecological services
•Exports
•Government policies
•Poverty
•Population growth
•Roads
Basic Causes
Solutions
Sustaining Tropical Forests
Figure 11-19
Page 213
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, conservation easements,
and conservation concessions
Certify sustainably grown timber
Reduce illegal cutting
Reduce poverty
Slow population growth
Concentrate farming and
ranching on already-cleared
areas
Debt-for-nature Swap
 Goal
is to make it profitable for countries
to protect tropical forests countries act
as custodians of protected forest reserves
in return for foreign aid or debt relief
Sustainable farming & logging
 Tropical
forests- help new settlers learn
how to practice small-scale sustainable
agriculture & forestry; multi-layered system
of agroforestry – cultivate as many as 75
species on 2.5 acres
 Kenya’s Green Belt Movement- women’s
self-help group establish tree nurseries
raise seedlings & plant/protect a trees for
each of Kenya’s people
Threats to National Parks
 Loggers
 Miners
 Poachers
 Too
little money
 Too few employees
 Too small to sustain many large animal
species
 Invasion by nonnative species
Solutions
National Parks
•Integrate plans for managing parks and nearby federal
lands
•Add new parkland near threatened parks
•Buy private land inside parks
•Locate visitor paring outside parks and use shuttle buses
for entering and touring heavily used parks
•Increase funds for park maintenance and repairs
•Survey wildlife in parks
•Raise entry fees for visitors and use funds for park
management and maintenance
•Limit number of visitors to crowded park rangers
•Increase number and pay of park rangers
•Encourage volunteers to give visitor lectures and tours
•Seek private donations for park maitenance and repairs
Figur
Protected Land
 SHOULD
protect at least 20%
 Only 7%is strictly protected
Costa Rica
 By
mid-1970s had established parks &
reserves for ¼ of land (6% for indigenous
people)
 Parks & reserves are consolidated into 8
mega-reserves designed to sustain 80% of
biodiversity
 Eco-tourism is now the country’s largest
source of income
Large Reserves
 Advantages-
sustain more species &
provide greater habitat diversity; minimize
area of outside edges exposed to natural
disturbances, invading species, & human
disturbances
 Disadvantages- ??
Corridors between Reserves
 Advantages-
help support more species &
allow migration of vertebrates; seasonal
migrations; allow for shifts in rage to
accommodate global climate change
 Disadvantages- ???
Biosphere Reserve
Core area
Buffer zone 1
Buffer zone 2
Tourism and
education center
Human
settlements
Research
station
Biosphere Reserve
 Core
area- important ecosystem hat the
government legally protects from all
human activities except non-destructive
research & monitoring
 Buffer zone- surrounds & protects core
area; emphasis on non-destructive
research, education, & recreation
 Transition
zone (2nd buffer)- surrounds inner
buffer zone; local people can engage in
more intensive sustainable forestry,
grazing, hunting, fishing, agriculture &
recreation
Adaptive Ecosystem
Management
1.
2.
3.
4.
Maintain & restore sustainability &
biological diversity
Seek government consensus on how to
achieve common conservation
objectives
Use failures as opportunities for learning
& improvement
Continual information gathering
Wilderness
 Undeveloped
lands protected from
human exploitation (1.8% of land in lower
U.S.)
 Importance-
for evolution
to protect areas as centers
 Advantages-
??
 Disadvantages-
keeps areas of the planet
from being economically useful to
humans
Fixes
 Restoration-
return habitat to natural state
 Rehabilitation- return habitat to functional
or useful state without restoring original
condition
 Remediation- cleaning up chemical
contaminants to project human health
 Replacement- replace degraded
ecosystem with another type of
ecosystem
5 Principles for Restoration
1.
2.
3.
Mimic nature & natural processes &
ideally let nature do most of the work,
usually through secondary ecological
succession
Recreate important ecological niches
that have been lost
Rely on pioneer species, keystone
species, foundation species, & natural
ecological succession to facilitate
restoration
4.
5.
Control or remove harmful nonnative
species
Reconnect small patches to create
larger ones & create corridors
 Concerns-
encourage environmental
destruction & degradation by suggesting
all harm can be undone
Tropical Dry Forest
 In
Costa Rica
 Biocultural
restoration- making nearby
residents an essential part of restoration of
degraded forest
Protecting Remaining
Ecosystems & Species
1.
2.
3.
4.
5.
6.
Take immediate action to preserve hot
spots
Keep old-growth forests intact
Complete mapping of terrestrial &
aquatic biodiversity
Find marine hot spots
Protect & restore lakes & rivers
Ensure all terrestrial & aquatic
ecosystems are being conserved
7.
8.
Make conservation profitable
Initiate ecological restoration products
worldwide