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William P. CunninghamUniversity of Minnesota

Mary Ann CunninghamVassar College

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Chapter 12Chapter 12Biodiversity: Preserving

Landscapes

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Outline• World Forests

Tropical and Boreal Forests Deforestation Forest Protection Threats to Temperate Forests Fire Management

• Grasslands and Overgrazing• Parks and Preserves

Terrestrial Marine

• Conservation and Economic Development

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World Forests

• Forests cover 30% of the world’s land surface. • Grasslands also cover about 30% of the land.• Most forests are in tropical (42%) and boreal

(33%) regions.• These two ecosystems provide many essential

resources such as lumber, paper pulp and livestock grazing.

• They also provide environmental services such as regulating climate, controlling water run-off, purifying water and air and providing wildlife habitat.

• They also have scenic, cultural and historic value

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Boreal and Tropical Forests are Abundant

• A Forest is defined as any area where trees cover more than 10% of the land.

• The largest remaining forests on the planet are found in cold high latitude areas and humid equatorial areas (Russia, Brasil, U.S., Canada, China)

• This definition covers areas ranging from Open Savannas where trees cover less than 20% of the land to Closed Canopy Forests where tree crowns overlap to cover most of the ground.

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Major Forest Types

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Tropical and Boreal Forests

• The largest tropical forests are in South America which has about 22% of the world’s forests and the largest undisturbed tropical rain forest.

• North America and Eurasia have vast areas of unaltered boreal forests.

• Old Growth or Primary Forests are those forests composed primarily of native species in which there is little indication of human activity and ecological processes are not significantly disturbed.

• These areas are home to much of the world’s biodiversity, ecological services and indigenous human cultures.

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Status of Primary Forests

• Only one third of all forests are Primary Forests• Tropical forests occupy now less than 10% of the

earth’s land surface.• Six million hectares of these forests are cleared or

heavily damaged each year.• 9 out of 10 of these countries where these forests

exist are experiencing unsustainable logging rates.

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50% of forest harvests are for firewood and are the main energy source for 1/3 of all humans

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Forest Destruction in Brazil

Logging roads

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Forests Provide Products1. Wood and paper

Developed countries provide less than half of industrial wood, but 80% of consumption (commercial logging responsible for 80% of forest destruction in Africa).

Paper pulp is 1/5 of all wood consumption, most of it happening in wealthy countries.

Fuelwood accounts for 1/2 of global wood use. monoculture forestry= one quarter of world’s forests are for

wood production in areas of reforestation, using fast growing single species with little biodiversity, providing poor ecological services such as soil erosion control and clean water production

Tree plantations= large areas typically planted with a single rapidly growing tree species; used for logging; all trees in it are same-aged, can be easily clear cut, and never develop into biologically diverse mature forests

successful reforestation plans in China, Korea, Japan

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• Tropical forests occupy less than 10% of land surface but contain half of all plant, animal and bacterial species on earth.

• 13 million hectares are deforested every year.• Clear-cutting= removal of all the trees within an area; results in

loss of biodiversity, soil erosion, sediment accumulation in nearby streams, muddslides, increased water temperature of nearby rivers affecting aquatic species

• Replanting accounts for re-vegetation of 5.7 million hectare per year ; however, only fast growing tree species can grow with a lot of direct sunlight resulting from clear cutting, resulting in reduced biodiversity; in addition, many times herbicides are used before replanting, and the herbicides run-off into streams and rivers

• At the current rate of deforestation, no primary forest will be left in Africa or Southeast Asia by the end of this century.

• The highest rate of deforestation is in Burundi.

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Causes for Deforestation

2. Conversion of forest to agriculture Accounts for 2/3 of destruction in Africa Conversion to cattle ranching is most common in Latin

America3. Large Scale Commercial Logging

Building roads to remove trees also allows entry to forest by farmers, miners, hunters.

4. Fires destroy 350 million hectares of forest/year Many of these are set intentionally to clear land for

other uses. Forest fires may get worse with global climate change

and drought

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Rain Forests Burning in Brazil

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Causes for Deforestation

5. Biofuel Production Biofuel production is responsible for forest

destruction in Southeast Asia.- ie. Oil Palm Plantations produce oil for

cooking, industrial use and biodiesel production.

Use of cornfields to produce ethanol biofuels in the US has resulted in increased grain prices on the world market and conversion of forest in Brazil to agriculture to produce corn for food.

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Forest Protection• Some places are being reforested• About 12% of world’s forests are now protected.

Africa has the largest protected area (by %) Guanacaste National Park in Costa Rica is a model area for

forest guardianship; grazing is encouraged in this park for horses and cows to help seed dispersal.

Brazil is a leader in establishing forest reserves and allows native people to engage in non-destructive extraction of resources in the forest (rubber tapping, nut collecting), recognizing their right to live in the forest

• The REDD Program (Reducing Emissions from Deforestation and Forest Degradation in Developing Countries; program launched by UN in 2008)- allows less developed countries to get money in compensation for protecting their forests by selling carbon offset credits to more developed countries who need carbon emissions credits.

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What are Carbon Offsetting?

• Scientific consensus states that carbon emissions must be reduced by 80% by 2050 to avoid temperature rise of more than 2oC. 

• Carbon offsetting is the use of carbon credits to enable businesses to compensate for their emissions, meet their carbon reduction goals and support the move to a low carbon economy.  Businesses compensate for their environmental impact by supporting  renewable energy projects (solar, wind, geothermal, hydro, biomass power), sustainable forestry (reforestation and rainforest rehabilitation) and resource conservation projects (protecting biodiversity) which generate reductions in greenhouse gas emissions. 

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Forest Conservation by RegionEven though Africa has the largest forest conservation reserves, there’s little practical protection as the park rangers are outnumbered by gunned poachers, militia, and drug-runners who threatenthe forests and inhabitants.

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Forest Protection• People are protecting local forests.

The Chipko Andolan movement in India (1970s): nonviolent, passive resistance movements to protest unfair government policies. Women hugged trees in a non-violent protest to prevent logging and preserve firewood for their families; today there are 4000 groups as part of this movement, working to save India’s forests.

Debt for Nature Swaps - conservation organizations buy a country’s debt obligations at a huge discount, then offer to cancel the debt if the debtor country protects biologically important areas

- Ex: Conservation International bought $650 K for $100K and Bolivia accepted to protect 1 mil ha around the Beni Biosphere Reserve

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Temperate Rainforests are also Threatened

• Although the total forest area in North America has remained constant for the last several years, forest management policies in the US and Canada continue to be controversial.

• Large areas of the Temperate Rainforest in the Pacific Northwest have been set aside to protect endangered species such as the Great Bear Rainforest in British Columbia, Canada; this area contains ¼ of the left over temperate rainforests, the white-cream Kermode “Spirit” Bear, 20% of the left over wild salmon, whales, dolphins, and sea otters.

• Logging is still allowed in surrounding lands though, resulting in fragmented old growth forest habitat and loss of structural complexity and biodiversity.

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Other Threats to Temperate Forests• Road building in wilderness areas is

especially controversial as it causes erosion, forest fragmentation, and allows potential access for hunting, invasive species, and extractive activities like mining which destroy wilderness.

• Climate change causes rising global temperatures, droughts, insect infestation threats and wildfires, all being grave threats to temperate forests.

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Fire Management• U.S. has had a policy of aggressive fire control for the last 70

years.• However, recent studies indicate many biological communities

are fire-adapted and require periodic burning for regeneration.• Prescribed burn= a fire deliberately set under controlled

conditions in order to reduce the accumulation of dead biomass on a forest floor

• Eliminating fires has caused woody debris to accumulate over the years. As a result, many fires are now larger and more severe.

• 40% of all federal lands are at risk of severe fires.• Many Americans are moving to remote areas and 40 million

now live in areas of high wildfire risk.

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Ecosystem Management

• In 1990s, the U.S. Forest Service began to shift its focus from timber production towards ecosystem management, attempting to integrate sustainable ecological, economic, and social goals in this approach. This approach includes: Managing across whole landscapes over ecological time

scales Considering human needs and promoting sustainable

economic development Maintaining biological diversity and ecosystem processes Generating meaningful public involvement and collective

decision making Adapting management over time based on conscious

experimentation and routine monitoring

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• Selective cutting= a method of harvesting trees that involves the removal of single trees or a relatively small number of trees from among many in a forest; has less extensive environmental impact than clear-cutting; creates small opening which allow trees to reseed

• Ecologically sustainable forestry= an approach to removing trees from forests in ways that don’t affect the viability of other trees in the forest; example: use horses to pull logs in order to reduce soil compaction; problem: much more costly than mechanical logging practices

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Grasslands• Occupy about 1/4 of world’s land surface• Frequently converted to cropland, urban areas, or other

human use• Each year, grasslands are disturbed 3 X more than tropical

rainforests• There are more threatened plant species in species- rich

rangelands than in any other American biome• Can be used sustainably to increase domestic animals

productivity and also maintain biodiversity in the grassland ecosystem Pastoralists= people who live by herding animals; they

herd their animals by adjusting to variations in rainfall and seasonal conditions.

• When grazing is consciously managed, it can improve the quality of the range

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Overgrazing

• Overgrazing leads to desertification= process of converting fertile land to barren, desecated ground

• 75% of rangelands in the world are degraded; one-third of that is due to overgrazing.

• 55% of U.S. public grasslands are in poor or very poor condition.

• Grazing fees= fees charged to ranchers for use of federal grasslands; these fees are below market value (1/4th the price of maintaining the federal land) and represent a hidden subsidy (financial aid, support) to ranchers.

• Ranchers defend themselves by claiming that without a viable ranch economy, western lands would be further subdivided into small ranchetes, and the environmental quality would be degraded.

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New Grazing Methods• When cattle graze freely, they eat the tender and tasty grasses,

leaving the tough species to gradually dominate the landscape.• Overgrazing allows populations of unpalatable or inedible

species (ex: sage,cacti, mesquite) to build up on rangelands • Rotational grazing confines animals to a small area for a day or

two before shifting them to a new location, simulating the effects of wild herds; it allows the livestock to eat everything in that area, keep weeds in check, trample the ground well, and fertilize it with manure before they move to another area; however, it doesn’t always work as some plant communities cannot tolerate grazing.

• Ranchers also raise wild species such as red deer, impala, oryx, which forage more efficiently, resist climate better, and fend off predators, diseases and pests better than cattle

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Rangeland Soil Degradation

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Rotational Grazing

• Intensive rotational grazing encloses livestock in a small area for a short time within a movable electric fence to force them to eat vegetation evenly and fertilize the area evenly.

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Parks and Preserves• 12% of Earth’s land area is protected.• The World Conservation Union divides protected areas into 5 categories,

depending on the level of allowed human use• Categories of protection are shown in Table 12.19. They range from

ecological reserves/wilderness in which little or no human impact is permitted, to areas of multiple use such as recreation areas.

• Some particularly sensitive wildlife sanctuaries allow only research groups and a limited number of people to enter per year, to prevent destruction of sensitive wildlife or introduction of invasive species

30Growth of number of protected areas worldwide

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Parks and Preserves

• In the developing world, some parks exist only on paper because they do not have money for staff and management.

• Brazil has the largest protected area. With more than 25% of the world’s tropical forests, Brazil is especially important to biodiversity.

• Some biomes are well represented in nature preserves, while others are underprotected.

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Preserves Are Still Not Safe from Exploitation

The following are still happening in parks and preserves, as many times countries with important biomes are lacking funds and personnel to enforce the rules and manage the areas:•Excessive stock grazing•Dam building•Oil drilling•Mining•Logging/clear cutting up to park boundaries•Coral reefs damaged by dynamite fishing•Hunting: eggs from endangered sea turtles are taken by hunters•Overuse by the public, traffic congestion•pollution, smog from power plants just outside the park

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Thousands of people waiting for a Yellowstone Geiser eruption

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World Conservation Strategy

• Developed by the IUCN (International Union for Conservation of Nature) to protect natural resources, emphasizing nature protection and public education over entertainment

• Has 3 objectives: Maintain essential ecological processes and life

support systems (soil regeneration, water recycling and purification)

Preserve genetic diversity essential to improving cultivated plants and domestic animals

Ensure that utilization of wild species and ecosystems is sustainable.

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Marine Ecosystems Need Protection

• Global fish stocks are becoming depleted and biologists are calling for protected areas where species can be sheltered. 20% of nearshore territory should be marine refuge area. Marine refuges can quickly replenish fish stocks in

nearby areas; so even closing reserves to fishing only for a few months can be beneficial in restoring marine population.

• 90% of existing coral reefs are threatened by rising temperatures, destructive fishing, coral mining and sediment runoff. If conditions persist, all will be gone in 50 years. Coral reefs are similar to old growth rainforests as they

are biologically rich, are sensitive to disturbance, and need a century or more to recover from damage

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Marine Reserves Protect Ecosystems

• Some countries are establishing large marine reserves especially to protect coral reefs.

• Australia has the largest marine reserve: The Great Barrier Reef Marine Park.

• In 2007 the U.S. declared 3 new National Marine Monuments in US territorial waters in the Pacific.

• Altogether though, marine reserves only make up 10% of the world’s protected areas even though oceans cover 70% of the earth’s surface.

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Great Barrier Reef Marine Park

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Conservation and Economic DevelopmentCAN Work Together

• Struggle to save ecosystems cannot be divorced from struggle to meet human needs.

• Many biologically rich communities are in developing countries

• immediate survival supersedes long-term environmental concerns Ecotourism - tourism that is ecologically and socially

sustainable over long term, as compared to unsustainable logging and mining

Native people have valuable ecological knowledge that can be used in ecosystem management.

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A Model Biosphere Reserve

1945- UNESCO was created, trying to create holistic policies that are capable of addressing the social, environmental and economic dimensions of sustainable practices1986- UNESCO initiated the designation of biosphere reserves= protected areas divided into zones with different purposes, recognizing the need for people to access resources; critical ecosystem if preserved in the core; research and tourism are in the buffer zone.

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Size and Shape of Nature Preserves Can Dictate Species Survival

• SLOSS debate - Is it better to have single large or several small reserves?

• Edge effects=habitat edges having different amount of sunlight, wind, and predators than the interior of the habitat

• Corridors of natural habitat= they connect smaller habitat areas a and satisfy human needs and pressures which result in habitat fragmentation; allow populations to maintain genetic diversity

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Size and Shape of Nature Preserves

• One of the reasons that large preserves are considered better than small reserves is that they have more core habitat, area deep within the interior of the habitat that has better conditions for specialized species. As human disturbance fragments the ecosystem,

habitat is broken into increasingly isolated islands with less core and more edge effects, supporting fewer species.

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Landscape Ecology

• Landscape ecology - science that examines the relationship between spatial patterns and ecological processes such as species movement or survival

• Variables: Habitat size Shape Relative amount of core and edge Kinds of land cover surrounding habitat

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How Small Can a Habitat Be?

Brazil: wildlife in plots of various sizes is being trackedin plots of various sizes; the largest andmost specialized species die first

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VOCABULARY• Forest• Open savannas• Closed canopy forests• Old growth/primary

forests• Monoculture forestry• Tree plantations• Clear cutting• Biofuel production• The REDD program• Carbon offsetting• The Chipko Andolan

movement • Debt for Nature swaps• Great Bear Rainforest

• Prescribed burn• Selective cutting• Ecologically sustainable forestry• Pastoralists• Overgrazing• Grazing fees• Rotational grazing• Sensitive wildlife sanctuaries• Parks • IUCN• Great Barrier Reef Marine Park• Biosphere Reserve • UNESCO• SLOSS debate• Edge effects• Corridors of natural habitat• Core habitat• Landscape ecology