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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