Chapter 12 - Biodiversity: Preserving Landscapes

Status of Old Growth Forests

-One third of all the world's forests are Old Growth Forests -Six million hectares of these forests are cleared or heavily damaged each year. -9 out of 10 of the countries where 80% of these forests exist are experiencing unsustainable logging rates.

Size and Design of Nature Preserves

-SLOSS Debate - is it better to have single large or several small reserves? -Core Habitat - areas deep in interior -Edge Effects - habitat edges -Corridors of natural habitat essential to connect smaller habitat areas to one another

World Forests

-forests cover 30% of the world's land surface -grasslands also cover about 30% of the land -most remaining forests are in tropical and boreal 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

Grasslands

-occupy about 1/4 of world's land surface -frequently converted to cropland, urban areas, or other human use -rate of disturbance is 3 times that of tropical rain forest -more threatened plants in rangelands than in any other american biome

Size and Design of Nature Preserves

As human disturbance fragments the ecosystem, habitat is broken into increasingly isolated islands with less core and more edge, supporting fewer rare species

Causes of Deforestation

Conversion of forest to agriculture -Accounts for 2/3 of destruction in Africa -Conversion to cattle ranching and soy farming is most common in Latin America Large Scale Commercial Logging -Building roads to remove trees also allows entry to forest by farmers, miners, hunters. Fires destroy 350 million hectares of forest/year -Many of these are set intentionally to clear land for other uses.

World Conservation Strategy

Developed by the IUCN - International Union for Conservation of Nature Has 3 objectives for protecting natural resources: -Maintain essential ecological processes and life support systems (soil regeneration and protection, nutrient cycling, and water purification) -Preserve genetic diversity essential to improving cultivated plants and domestic animals -Ensure that utilization of wild species and ecosystems is sustainable.

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. -Refuge can replenish nearby areas. 90% of coral reefs are threatened by rising temperatures, destructive fishing, coral mining and sediment runoff. -If conditions persist, all will be gone in 50 years

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.

Landscape Ecology

Science that examines the relationship between spatial patterns and ecological processes such as species movement or survival Landscape ecologists measure variable such as: -Habitat size -Shape -Relative amount of core and edge -Kinds of land cover surrounding habitat

Forest Protection

Some places are being reforested About 12% of world's forests are now protected. -Africa has the largest % of area protected - largely ineffective - poachers, drug runners, invading militias -Guanacaste National Park in Costa Rica is a model area for forest guardianship - restoring ranchland to forests -Brazil is a leader in establishing forest reserves and allows traditional peoples to engage in nondestructive extraction of resources in the forest (rubber tapping, nut collecting).

Conservation and Economic Development

Struggle to save ecosystems cannot be divorced from struggle to meet human needs. -Ecotourism - tourism that is ecologically and socially sustainable; more beneficial in many places than extractive industries such as mining or logging -Native people have valuable ecological knowledge that can be used in ecosystem management - integrating needs of humans with the needs of nature -UNESCO (1986) initiated "Man and Biosphere" program (MAB) calling for the establishment of biosphere reserves, protected areas divided into zones with different purposes

Grazing

can be used sustainably, as pastorlalists herd their animals to adjust to variations in rainfall and seasonal conditions. often overgrazed which can lead to desertification

Debt for Nature Swaps

conservation organizations buy debt obligations, then offer to cancel the debt if the debtor country protects biologically important areas

Ecosystem Management

ecosystem management attempts to integrate sustainable ecological, economic, and social goals in unified systems approach -managing across whole landscapes, watersheds, or regions over ecological time scales -considering human needs and promoting sustainable economic development and communities -maintaining biological diversity and ecosystem processes -utilizing cooperative institutional arrangements -generating meaningful stakeholder and public involvement and facilitating collective decision making -adapting management over time, based on conscious experimentation routine monitoring

Parks and Preserves

-12% of Earth's land area is protected in a park, preserve, or wildlife management area -Categories of protection are shown below-with Allowed Human Impact or Intervention indicated 1. Ecological reserves and wilderness areas-Little or none 2. National parks-Low 3. Natural monuments and archaeological sites-Low to medium 4. Habitat and wildlife management areas-Medium 5. Cultural or scenic landscapes, recreation areas-Medium to high

Overgrazing

-75% of rangeland in the world are degraded; onethird of that is due to overgrazing -55% of US public range lands are in poor or very poor condition -grazing fees charged to use of public lands are below market value and represent a hidden subsidy to ranchers -ranchers claim that without a variable ranch economy, western lands would be further subdivided

Temperate Forests 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. -Logging is still allowed in surrounding lands, resulting in fragmented old growth forest habitat. -Road building in wilderness areas is especially controversial as it causes erosion and allows potential access for extractive activities like mining.

Causes for Deforestation

-Biofuel production is responsible for forest destruction in Southeast Asia -Palm oil plantations produce oil for cooking, industrial use and now biodiesel production

How Small Can a Habitat Be?

-Brazilian scientists are tracking wildlife in plots of various sizes, either connected to existing forests or surrounded by clear-cuts -Some species disappear quickly, especially from small areas -Sun-loving species flourish in forest edges -Study revealed importance of maintaining core habitat

Overuse of National Parks in U.S.

-Entertainment trumped nature protection -Fire suppression resulted in large fires -Traffic congestion -Surrounding areas clear cut or mined -Air pollution and smog -Parks are profitable, but do not get to keep the money they generate.

Preserves Not Safe from Exploitation

-Excessive stock grazing -Dam building -Oil drilling -Mining -Logging -Coral reefs damaged by dynamite fishing -Hunting; eggs from endangered sea turtles are taken by hunters -Overuse by the public

Forests Provide Products

-Paper and pulp is ⅕ of all wood consumption (Most used in wealthier countries -- North America, Europe, and Asia) -U.S., Russia, and Canada are largest producers of paper pulp and industrial wood products -One quarter of world's forests are managed for wood production, much of replanted in single species monoculture forestry (Scientific planning for sustainable harvests, Monoculture forestry produces rapid growth and easier harvesting, Supports little diversity and few ecological services (soil erosion control, clean water production, etc.)

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.

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. -Primary Forests or Old Growth 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.

Tropical Forests and Being Cleared

-Tropical forests occupy less than 10% of land surface but contain half of all plant, animal and microbial species on earth. -30,000 hectares are deforested every day. -Replanting or succession accounts for revegetation of 5.7 million hectare per year; this results in a net loss of 7.3 million hectares per year. -At the current rate of deforestation, no primary forest will be left in most countries outside of parks or preserves by the end of this century.

Fire Management

-US has had a policy of aggressive fire control for the 70 years -recent studies indicate many biological communities are fire-adapted and require periodic burning for regeneration -eliminating fires has caused woody debris to accumulate over the years. as a results, many fires are now larger and more severe -today 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

New Grazing Methods

-When cattle graze freely, they eat the tender grasses leaving the tough species to gradually dominate the landscape. -Rotational grazing confines animals to a small area for a day or two before shifting them to a new location. -Doesn't work everywhere; some plant communities (e.g. desert Southwest) cannot tolerate grazing. -Can raise wild species such as bison, which forage more efficiently and fend off predators, diseases and pests better than cattle; different feeding preferences

Forests Provide Valuable Products

-Wood plays a bigger role in modern economy than any other commodity -There is hardly and industry that doesn't use wood or wood products somewhere in manufacturing or marketing processes -Total annual wood consumption is ~ 4 billion m3 - more than steel and plastic combined -International trade > $100 billion per year -Developed countries produce < ½ of all industrial wood but consume 80% -Tropics produce ½ of all industrial wood yet consume 20%

Boreal and Tropical Forests are Abundant

-a forest is defined as any area where trees cover more than 10% of the land -the largest bremaining forests on the planet are found in cold high latitude areas and humid equatorial areas -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

Other Threats to Temperate Forests

-climate change, insect threats, and wildfires are also major threats to temperate forests which are interconnected -rising global temperature can trigger droughts which make trees more vulnerable to insect infestations and fires