Terrestrial BiodiversityChapters 11& 12

Biodiversity

Increase Factors

•Middle stages of succession

•Moderate environmental disturbance

•Small changes in environmental conditions

•Physically diverse habitat

•Evolution

Decrease Factors

•Extreme environ- mental conditions

•Large environmental disturbance

•Intense environ- mental stress

•Severe shortages of key resources

•Nonnative species introduction

•Geographic isolation

Figure 11-2Page 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 refuges

National parks and preserves National forests(and Xs) National wildlife refuges

Use of Public Land1. Protecting biodiversity, wildlife

habitats, & ecological functioning of public land ecosystems

2. No government subsidies or tax breaks for using or extracting resources on public lands – user-pays approach

3. 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

Years of growth30

2515

10

5

Clear cut

Weak treesremoved

Seedlingsplanted

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

Figure 11-11Page 203

Trade-Offs

Clear-Cutting Forests

Advantages Disadvantages

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

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

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 11-12Page 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 News1. Human activities have reduced original

forest cover by 20-50%2. 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

Figure 11-13Page 205

Solutions

Sustainable Forestry

•Grow more timber on long rotations

•Rely more on selective cutting and strip cutting

•No clear-cutting, seed-tree, or shelterwood cuttingon 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 inestimating economic value

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 second-

growth forests have been cut & replaced with tree farms

Disrupts ecosystem processes (energy flows & chemical cycling)

Reduces biodiversity

Figure 11-14Page 207

Sudden oak death White pine blister rust Pine shoot beetle Beech bark disease Hemlock wooly adelgid

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 ground-level 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 Harvesting1. Pressure on Congress by timber

companies2. Forestry Service keeps money from

timber harvest3. Government subsidies

Revenue from timber sales does not cover the cost of road building, timber sale preparation, administration & other overhead costs

Trade-Offs

Advantages Disadvantages

Logging in U.S. National Forests

Helps meet country’s timber needs

Cut areas grow back

Keeps lumber and paper pricesdown

Provides jobs in nearby communities

Promotes economic growth in nearby communities

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 forestsprovides more localjobs and incomefor local communities thanlogging

Decreasesrecreationalopportunities Figu

re 11-16Page 210

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

•Not valuing ecological services•Exports•Government policies•Poverty•Population growth•Roads

Secondary Causes

Basic Causes

Figure 11-19Page 213

Protect most diverse andendangered areas

Educate settlers about sustainableagriculture and forestry

Phase out subsidies that encourageunsustainable forest use

Add subsidies that encouragesustainable forest use

Protect forests with debt-for-natureswaps, conservation easements,and conservation concessions

Certify sustainably grown timber

Reduce illegal cutting

Reduce poverty

Slow population growth

Reforestation

Rehabilitation of degradedareas

Concentrate farming andranching on already-clearedareas

RestorationPrevention

Solutions

Sustaining Tropical Forests

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

Figure 11-20Page 215

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

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 areaCore area

Buffer zone 1Buffer zone 1

Buffer zone 2Buffer zone 2

Human settlements

Tourism andeducation center

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 Management1. Maintain & restore sustainability &

biological diversity2. Seek government consensus on how to

achieve common conservation objectives

3. Use failures as opportunities for learning & improvement

4. Continual information gathering

Wilderness Undeveloped lands protected from

human exploitation (1.8% of land in lower U.S.)

Importance- to protect areas as centers for evolution

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 Restoration1. Mimic nature & natural processes &

ideally let nature do most of the work, usually through secondary ecological succession

2. Recreate important ecological niches that have been lost

3. Rely on pioneer species, keystone species, foundation species, & natural ecological succession to facilitate restoration

4. Control or remove harmful nonnative species

5. 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 & Species1. Take immediate action to preserve hot

spots2. Keep old-growth forests intact3. Complete mapping of terrestrial &

aquatic biodiversity4. Find marine hot spots5. Protect & restore lakes & rivers6. Ensure all terrestrial & aquatic

ecosystems are being conserved

7. Make conservation profitable8. Initiate ecological restoration products

worldwide