Habitat and Ecosystem Conservation
Habitat and Ecosystem Conservation
The Endangered Species Act (ESA) is designed to protect plant and animal species in danger of extinction. During the 1990s there was a growing concern that traditional methods of species protection, which take a species-by-species approach, were ineffective. Many alternatives were proposed. One of the most popular was a method variously termed the "habitat," "ecosystem," or "community" approach. The U.S. Fish and Wildlife Service (FWS) defines an ecosystem as a "geographic area including all the living organisms (people, plants, animals, and microorganisms), their physical surroundings (such as soil, water, and air), and the natural cycles that sustain them." Central to the new approaches is a focus on conservation of large intact areas of habitat. It is hoped that by focusing on entire habitats, rather than individual species recovery, numerous species will be protected before they reach critically low population sizes.
THE ECOSYSTEM APPROACH
Ecosystem conservation considers entire communities of species as well as their interactions with the physical environment and aims to develop integrated plans involving wildlife, physical resources, and sustainable use. Such an approach sometimes requires compromise between environmentalists and developers. This is the case for several Habitat Conservation Plans (HCPs) developed by the U.S. Fish and Wildlife Service in recent years. In Southern California developers and environmentalists had long battled over hundreds of thousands of biologically rich acres lying between Los Angeles and Mexico that were home to uncounted species of plants and animals. Developers wanted to build there, while federal regulators wanted to protect the habitat for wildlife. Haggling over small parcels of land had already cost significant time and money and caused frustration on both sides. A compromise resolution permitted developers to develop some large parcels of land while setting aside other large, intact regions as conservation areas. A similar agreement between developers and environmentalists was reached in the Texas Hill Country in 1996 and is effective for thirty years from that date. The Balcones Canyonlands Conservation Plan set aside 111,428 acres for ecosystem enhancement while allowing uncontested development of many thousands of acres of land in the central Texas corridor.
Endangered U.S. Ecosystems
In 1995 the first full review of the health of the American landscape was compiled by the National Biological Service and published by the U.S. Geological Survey (Reed F. Noss et al., Endangered Ecosystems of the United States: A Preliminary Assessment of Loss and Degradation, 1995). It is still considered the definitive study of U.S. ecosystem health. Although individual species had been studied previously, the health of the larger ecosystems had never before been considered. The study was based on surveys of state databases and the scientific literature. The report concluded that vast stretches of natural habitat, totaling nearly half the area of the forty-eight contiguous states, had declined to the point of endangerment. Ecosystems suffered in two ways. Quantitative losses were measured by a decline in the area of an ecosystem. Qualitative losses involved degradation in the structure, function, or composition of an ecosystem.
Of the ecosystems that had declined by over 70%, 58% were terrestrial, 32% were wetland areas, and 10% were aquatic. Forests, grasslands, barrens, and savannas dominated the list. (See Figure 3.1.) American ecosystems identified by the National Biological Service as suffering the greatest overall decline include grasslands, savannas, and barrens (55%), followed by shrublands (24%) and forests (17%).
The National Biological Service found that thirty-two American ecosystems had declined by more than 98% and were classified as "critically endangered." Fifty-eight had declined by 85% to 98% and were classified as "endangered." Thirty-eight others declined by 70% to 84% and were listed as "threatened."
Endangered ecosystems were found in all major regions of the United States except Alaska. The greatest losses occurred in the Northeast, the South, and the Midwest, as well as in California. Native grasslands, needlegrass steppes, and alkali sink scrubs are among the communities that have declined most precipitously in California.
Forests perform a wide variety of social and ecological functions. They provide homes and sustenance for forest dwellers, protect and enrich soils, affect local and regional climate through the evaporation and storage of water, and help stabilize the global climate by processing carbon dioxide.
Forests are broadly classified by latitude as either tropical, temperate, or boreal. Tropical forests, or rainforests, are predominantly evergreen and occur close to the equator, in areas with plentiful rain and little temperature variation year-round. There are tropical forests in Central and South America, Africa, South and Southeast Asia, and Australia. Tropical forests are characterized by the greatest diversity of biological species. For example, as many as 100 distinct tree species may inhabit a square kilometer (about 0.38 square miles). Vegetation is often so dense in tropical forests that very little light penetrates to the ground.
Temperate forests are found in areas with distinct warm and cold seasons, including North America, northern Asia, and western and central Europe. Many temperate forests are made up of deciduous trees—species that shed their leaves during winter. Plant diversity is not as great in temperate forests as in rainforests. There are perhaps three or four tree species per square kilometer.
Boreal forests, also known as taiga, are found at high latitudes in extremely cold climates where the growing season is short. Precipitation generally falls as snow rather than rain. Boreal forest flora include evergreen trees and lichen ground cover. Boreal forests are present in Siberia, Scandinavia, Alaska, and Canada.
North American Forests
Many U.S. forests are highly imperiled. One of the greatest threats to forests is deforestation via clear cutting, a method of logging in which all the trees in an area are cut. Serious damage to the old-growth forests of the Pacific Northwest, for example, is visible from National Aeronautics and Space Administration (NASA) satellite photos. Old-growth forests harbor many unique species, including numerous species that are threatened or endangered. An alternative to clear-cutting is selective management, in which only some trees are removed from an area. Even selective management practices, however, frequently deplete forests more quickly than they are able to recover. The lumber industry continues to battle with environmentalists and the U.S. Forest Service over the right to log national forest lands, including the unique redwood forests of the West Coast.
Huge forest fires raged through the western United States in 2000 and 2002. The Forest Service reported that these were two of the worst fire seasons in over fifty years. In 2002 forest fires scorched over seven million acres and caused over $1.7 billion in damages. The fires were partly the result of long decades of fire suppression. In response, President Bush announced the "Healthy Forest Initiative" in 2002. This initiative was immediately attacked by conservationists, who claimed that its only aim was to roll back federal regulations on logging, and that it was intended to benefit logging companies rather than to protect people or wildlife. Conservationists further argued that the Bush Administration was merely using the forest fires as an excuse for forwarding its pro-business/anti-environment agenda.
In addition to logging and fire risk, there are several other major threats to forests. These threats are highlighted by the U.S. Forest Service in America's Forests: 2003 Health Update (2003, http://www.fs.fed.us/publications/documents/foresthealthupdate2003.pdf). These threats include:
- Invasive insects and pathogens. Sudden Oak Death, caused by a new, unidentified pathogen, has killed thousands of oak and other species in coastal forests, mixed evergreen forests, and urban-wildland interfaces in California and southern Oregon. White pine blister rust is a nonnative fungus from Asia that has killed white pine trees in the western United States and Canada. The gypsy moth, first introduced from native habitats in Europe and Asia in the 1800s, continues to damage eastern U.S. forests. The hemlock woolly adelgid, native to Asia and introduced in the 1920s, continues to kill hemlock trees in the eastern United States.
- Invasive plants. About 1,400 species of nonnative plants are recognized as pest species that threaten forests and grasslands. Table 3.1 lists some of the most common ones. Invasive plant species currently affect over 100 million acres of U.S. forestland. The Forest Service spends about $16 million annually in preventing the spread of invasive plants such as the "mile-a-minute" weed, which infests northeastern forests, and leafy spurge, which affects ecosystems in southern Canada and the northern United States.
- Outbreaks of native insects. Certain native insects, including bark beetles, mountain pine beetles, and southern pine beetles, can also lay waste to native forests when they occur in large outbreaks.
TONGASS NATIONAL FOREST
During the first millennium ce, an expanse of ancient forest flourished along the entire western coast of the United States and Canada. Today, a portion of this habitat, a 500-mile expanse along the southeastern coast of Alaska, has been preserved as Tongass National Forest. Tongass National Forest represents an unblemished stretch of trees and other wildlife that has existed as a completely intact ecosystem for over a thousand years. It includes nearly eighteen million acres of virtually pristine woodland. The Tongass preserve comprises about one-fourth of the world's temperate rainforest and is the largest on earth.
In the mid-twentieth century, however, the federal government began to negotiate with logging companies to open small portions of the ancient forest for clear-cutting. This has generated ongoing debate in Congress. In the 1990s loggers appealed to the government to open more access roads to facilitate logging, whereas environmentalists fought to preserve the area from human tampering altogether. In May 2000 the National Forest Service drafted a proposal urging renewed protection of roadless areas. A successful lawsuit brought by the Natural Resources Defense Council in 2003 appeared to protect Tongass and other roadless national forests from logging. However, the Bush Administration exempted Tongass from these protections and has continued attempts to open more acreage of the forest to logging.
In June 2005 an amendment was voted down by the U.S. Senate that would have banned federal subsidies for new roads in Tongass. Proponents of the amendment argued that taxpayers should not have to pay for building roads that allow timber producers better access to old-growth trees in the forest. Critics charged that the roads serve many purposes, including the enhancement of tourism, recreational activities, and access by Forest Service rangers. At that time approximately 4% of the Tongass National Forest was open to logging.
Deforestation refers to the destruction of forests through the removal of trees, most often by clear-cutting or burning. It results in habitat loss for countless species of plants as well as animals. Deforestation is occurring globally, but is proceeding at a particularly alarming rate in the world's tropical rainforests, which comprise the most diverse ecosystems in the world. Deforestation is one of the most pressing environmental issues today.
In addition to destruction of habitat for numerous plant and animal species, the loss of forests has other effects as well. For example, forests play a crucial role in the global cycling of carbon—vegetation stores two trillion tons of carbon worldwide, roughly triple the amount stored in the atmosphere. When forest trees are cleared, the carbon they contain is oxidized and released to the air, adding to the carbon dioxide in the atmosphere. The burning of the Amazon rainforests and other forests thus has a twofold effect—the release of large amounts of carbon dioxide into the atmosphere and the loss of the trees that help absorb carbon dioxide.
|Species||Common name||Species||Common name|
|source: Adapted from "Invasive Plants List," in Fire Effects Information System: Invasive Plants, U.S. Department of Agriculture, U.S. Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Undated, http://www.fs.fed.us/database/feis/plants/weed/index.html (accessed March 8, 2006)|
|Acer platanoides||Norway maple||Imperata cylindrica||Cogon grass|
|Acroptilon repens||Russian knapweed||Kochia scoparia||Summer-cypress|
|Agropyron cristatum||Crested wheatgrass||Lepidium latifolium||Perennial pepperweed|
|Agropyron desertorum||Desert wheatgrass||Lespedeza bicolor||Bicolor lespedeza|
|Agrostis gigantea||Redtop||Lespedeza cuneata||Sericea lespedeza|
|Ailanthus altissima||Tree-of-heaven||Lespedeza striata||Common lespedeza|
|Alliaria petiolata||Garlic mustard||Ligustrum amurense||Amur privet|
|Amaranthus retroflexus||Rough pigweed||Ligustrum japonicum||Japanese privet|
|Artemisia abrotanum||Oldman wormwood||Ligustrum sinense||Chinese privet|
|Artemisia absinthium||Absinth wormwood||Ligustrum vulgare||European privet|
|Artemisia dracunculus||Tarragon||Linaria dalmatica||Dalmatian toadflax|
|Arundo donax||Giant reed||Linaria vulgaris||Yellow toadflax|
|Bromus hordeaceus||Soft chess||Lolium perenne||Perennial ryegrass|
|Bromus inermis||Smooth brome||Lolium multiflorum||Italian ryegrass|
|Bromus japonicus||Japanese brome||Lonicera × bella||Bell's honeysuckle|
|Bromus madritensis||Foxtail chess, red brome||Lonicera fragantissima||Winter honeysuckle|
|Bromus tectorum||Cheatgrass||Lonicera japonica||Japanese honeysuckle|
|Calluna vulgaris||Heather||Lonicera maackii||Amur honeysuckle|
|Cardaria chalapensis||Lens-podded hoary cress||Lonicera morrowii||Morrow's honeysuckle|
|Cardaria draba||Heart-podded hoary cress||Lonicera tatarica||Tatarian honeysuckle|
|Cardaria pubescens||Globe-podded hoary cress||Lonicera xylosteum||European fly honeysuckle|
|Carduus nutans||Musk thistle||Lygodium japonicum||Japanese climbing fern|
|Casuarina cunninghamiana||River sheoak||Lygodium microphyllum||Old World climbing fern|
|Casuarina equisetifolia||Australian-pine||Lythrum salicaria||Purple loosestrife|
|Casuarina glauca||Gray sheoak||Medicago sativa||Alfalfa|
|Celastrus orbiculatus||Oriental bittersweet||Melaleuca quinquenervia||Melaleuca|
|Centaurea diffusa||Diffuse knapweed||Melilotus alba||White sweetclover|
|Centaurea maculosa||Spotted knapweed||Melilotus officinalis||Yellow sweetclover|
|Centaurea solstitialis||Yellow starthistle||Microstegium vimineum||Nepalese browntop|
|Chondrilla juncea||Rush skeletonweed||Phalaris arundinacea||Reed canarygrass|
|Cirsium arvensis||Canada thistle||Phleum pratense||Timothy|
|Cirsium vulgare||Bull thistle||Poa pratensis||Kentucky bluegrass|
|Convolvulus arvensis||Field bindweed||Potentilla recta||Sulfur cinquefoil|
|Cynodon dactylon||Bermuda grass||Psathyrostachys juncea||Russian wildrye|
|Cynoglossum officinale||Houndstongue||Pueraria montana var. lobata||Kudzu|
|Cytisus scoparius||Scotch broom||Rosa multiflora||Multiflora rose|
|Cytisus striatus||Portuguese broom||Rubus discolor||Himalayan blackberry|
|Dactylis glomerata||Orchard grass||Rubus laciniatus||Evergreen blackberry|
|Descurainia sophia||Flixweed tansymustard||Rumex acetosella||Sheep sorrel|
|Echinochloa crus-galli||Barnyard grass||Salsola kali||Russian-thistle|
|Elaeagnus angustifolia||Russian-olive||Schinus terebinthifolius||Brazilian peppertree|
|Elaeagnus umbellata||Autumn-olive||Sisymbrium altissimum||Tumblemustard|
|Elytrigia repens||Quackgrass||Sonchus arvensis||Perennial sowthistle|
|Eragrostis curvula||Weeping lovegrass||Sorghum halepense||Johnson grass|
|Eragrostis lehmanniana||Lehmann lovegrass||Spartium junceum||Spanish broom|
|Eremochloa ophiuroides||Centipede grass||Taeniatherum caput-medusae||Medusahead|
|Erodium cicutarium||Cutleaf filaree||Tamarix aphylla||Athel tamarisk|
|Eucalyptus globulus||Bluegum eucalyptus||Tamarix chinensis||Saltcedar|
|Euphorbia esula||Leafy spurge||Tamarix gallica||French tamarisk|
|Festuca arundinaceum||Tall fescue||Tamarix parviflora||Small-flowered tamarisk|
|Genista monspessulana||French broom||Tamarix ramosissima||Saltcedar|
|Halogeton glomeratus||Halogeton||Taraxacum officinale||Dandelion|
|Hypericum perforatum||St. Johnswort||Triadica sebifera||Tallowtree|
|Imperata brasiliensis||Brazilian satintail||Xanthium strumarium||Common cocklebur|
Furthermore, deforestation also results in forest fragmentation, which is itself detrimental for several reasons. First, forest fragmentation creates more "edge" habitats and destroys habitat for deep-forest creatures. Second, fragmentation isolates plant and animal populations, making them more vulnerable to local extinction. Third, some nonnative species thrive in edge habitats, and are able to invade and displace native species in a fragmented habitat. In North America, for example, songbirds like the wood thrush and the promontory warbler are declining due to increasing numbers of blue jays and parasitic brown-headed cowbirds, both of which flourish at forest edges. Finally, most trees are more susceptible to weather at forest edges.
Tropical forests are found in a band along the equator from Mexico into South America and across the Caribbean, central Africa, and parts of Asia. These forests include both lowland and upland (hill and mountainous) formations and vary in vegetative type. Most tropical forests are either dry or moist and are composed of deciduous vegetation that sheds its leaves at the end of the growing season. Lying closest to the equator are the tropical rainforests. They experience very warm temperatures year round and high amounts of precipitation. The vegetation is thick and lush and characterized by a large number of flowering and fruit-producing trees and vines. The largest concentration of tropical rainforests occurs in northern South America. However, they are also found in west central Africa and scattered across parts of Southeast Asia and northernmost Australia. Tropical rainforests are the world's most biologically rich habitats and are estimated to harbor 50% to 90% of the world's species. Biologists believe that many rainforest species have yet to be discovered and described by humans. In February 2006, the BBC reported that an international team of scientists had found a previously unknown jungle in Indonesia containing new species of butterflies, frogs, birds, and plants (http://newsvote.bbc.co.uk/mpapps/pagetools/print/news.bbc.co.uk/1/hi/sci/tech/4688000.stm).
Throughout the twentieth century tropical forests were depleted by logging and clearing for farms and ranches. The United Nations Food and Agriculture Organization (FAO) published an assessment of the world's tropical forests in Forest Resources Assessment 1990: Survey of Tropical Forest Cover and Study of Change Processes (1993). The FAO reported at that time that tropical forests covered 4.34 billion acres at the end of 1990, down from 4.72 billion acres at the end of 1980. The highest rates of deforestation were reported in Africa, Asia, Central America, and Mexico. During the 1980s an average of approximately thirty-eight million acres per year was deforested. The deforestation rate for tropical rainforests was eleven million acres per year. In an update, the FAO estimated that all tropical forests were deforested at an average of 22.7 million acres per year during the 1990s (Global Forest Resources Assessment 2000, 2005, http://www.fao.org/documents/show_cdr.asp?url_file1/4/DOCREP/004/Y1997E/ Y1997E00.HTM). The deforestation rate for tropical rainforests was 14.8 million acres per year.
The major underlying causes of tropical deforestation are economic—underdevelopment, unemployment, and poverty among the growing populations of tropical countries. Unrestricted by enforceable regulations, farmers clear forests to create meager cropland that is often useless three years after its conversion—this is because tropical forest soils are poor, because almost all available nutrients are locked up in the trees and other biomatter. Logging and the conversion of forestland to unsustainable, short-term agricultural use have resulted in the destruction of habitats, declining fisheries, erosion, and flooding. Forest loss also disrupts regional weather patterns and contributes to global climate change. Finally, it eliminates plant and animal species that may serve important medical, industrial, and agricultural purposes. However, arguments for protective measures that might not reap economic benefits for many decades are of little interest to farmers with families to feed. Developing countries frequently voice resentment over what they see as the hypocrisy of industrialized nations, which invariably engaged in similarly destructive practices to build their own economies.
Conservation of tropical forests presents a considerable challenge. The creation of protected areas alone has often proven ineffectual, mostly because the people who exploit forests are given no other options for meeting their economic needs. Many conservationists have started to focus on the promotion of sustainable development within rainforests. Agroforestry describes an agricultural strategy that involves the maintenance of diversity within developed tropical forest areas. This includes planting many different types of crops in patches that are mixed in among grazing lands and intact forest. Agroforestry often focuses on crops that produce goods for an indefinite period of time, including citrus fruits, bananas, cacao, coffee, and rubber.
Agroforestry can help to maintain soil quality as well as tropical biodiversity, allowing for a sustained productivity that makes it unnecessary to clear more and more areas of forest. In addition, rainforest conservationists have promoted the harvest of sustainable rainforest products, rather than unsustainable products such as timber. Sustainable harvests include those of medicines, food, and rubber.
Wetlands are transitional areas between land and water bodies where water periodically floods the land or saturates the soil. The term wetland includes environments such as marshes, swamps, bogs, and estuaries. Wetlands may be covered in shallow water most of the year or be wet only seasonally. Plants and animals found in wetlands are uniquely adapted to these conditions.
Wetlands in the United States are highly diverse because of regional differences in climate, geology, soils, and vegetation. According to the National Audubon Society there are approximately 100 million acres of wetlands in the country. The majority of this is freshwater wetland. The rest is tidal, or saltwater, wetland and is found along the coasts. Wetlands are found in nearly all states—there are Arctic tundra wetlands in Alaska, peat bogs in the Appalachians, and riparian (riverbank) wetlands in the arid West.
The Audubon Society reported that in 2006 well over half the original North American wetlands had vanished. A few states had lost nearly all their original wetlands. With the recognition of the importance of wetlands and the institution of protective measures, the pace of wetland loss has slowed in recent decades. The U.S. Environmental Protection Agency (EPA) reported that about 58,500 wetland acres were lost each year between 1986 and 1997, with forested wetlands suffering the most damage. Although this represents an 80% drop from the previous decade, wetland loss is still significant. Wetlands provide critical habitats for fish and wildlife. They also purify polluted water and check the destructive power of floods and storms. Finally, wetlands provide recreational opportunities such as fishing, hunting, photography, and wildlife observation. As of December 2004 the EPA estimated that approximately 60,000 acres of wetland habitat continued to be lost each year in the United States (http://www.epa.gov/owow/wetlands/pdf/overview.pdf).
Bogs are nontidal wetland ecosystems that form where poor drainage and low oxygen levels combine with a low mineral content to retard the decay of organic material. Over time, peat (partially decayed organic substances) begins to solidify, forming layers over the surface of ponds. Migrating birds and amphibians, including some salamanders, are among the animals most commonly found in bog habitats. Bog flora include coarse, grass-like plants called sedges and unusual carnivorous plants such as sundew and pitcher plants. Carnivorous plants capture and digest small insects in order to obtain nutrients unavailable in their unique environments, most often minerals such as nitrogen and phosphorus. The leaves of the sundew are covered with hundreds of tiny "tentacles" that are used to trap insects. The sundew traps an average of five insects per month. Pitcher plants maintain a pool of acidic fluid at the bottom of their "pitchers." Hairs on the inside of the pitchers point downward, preventing insects from exiting once they enter. Insects are attracted to the pitchers by the enticing red color inside.
Bog plants are threatened primarily by encroaching urbanization. Boggy wetlands are either drained or filled for use as dumping grounds. In addition, the suppression of naturally occurring fires discourages the formation of bog ecosystems. One bog species, the funnel-shaped green pitcher plant, first appeared on the Endangered Species List in 1979. Found in Alabama, North Carolina, and Georgia, it has declined largely due to collection by humans, who find these insect-eating plants both interesting and exotic. The collection of carnivorous plant species has also disrupted bog ecosystems by allowing mosquitoes and flies to proliferate.
The Florida Everglades
The Everglades covers approximately 5,000 square miles of southern Florida. (See Figure 3.2.) It includes a wide diversity of both temperate and tropical habitat types, including sawgrass prairies, mangrove swamps, pine forests, cypress forests, marshes, and estuaries, and represents one of the wildest and most inaccessible areas in the United States. The area was formed by centuries of water flow from Lake Okeechobee in south-central Florida to Florida Bay, and is often described as a shallow "river of grass." The highest land in the Everglades is a mere seven feet above sea level. Everglades National Park is the largest remaining subtropical wilderness in the United States, and is home to such endangered species as the American crocodile, Florida panther, wood stork, and West Indian manatee. The Everglades became a National Park in 1947, and the region has also been designated an International Biosphere Reserve, a World Heritage Site, and a Wetland of International Importance.
Everglades habitats are now threatened by many factors. First, water control through an extensive system of canals and levees has brought both droughts and floods to Everglades lands. Much of the Everglades' water has traditionally been diverted for irrigation or to supply metropolitan areas. In fact, the portion of the Everglades inundated by water was reduced drastically over the twentieth century, destroying numerous habitat areas. Occasional releases of large amounts of water, on the other hand, flood habitats, harming species such as alligators, whose nests may be washed away. Pollution is a second factor in Everglades deterioration. Harmful pollutants now found in the Everglades include fertilizers and pesticides from agricultural runoff, as well as mercury. Fertilizers encourage the rampant growth of vegetation that chokes wetlands, while pesticides and mercury poison species. One plant species that is affected is Garber's spurge, a beach herb that thrives in sandy peripheral soil. With its decline, parts of the Everglades have been more prone to soil erosion.
Invasive species have also altered Everglades habitats. Alien species such as Brazilian pepper and Australian pine have reduced native plant populations. Finally, fire suppression related to human encroachment has caused habitat alteration. Park officials now adhere to a prescribed burn schedule, setting fires in three to tenyear intervals as necessary.
Multiple efforts were made in the 1990s and early 2000s to help restore the Everglades. Florida's Everglades Forever Act, passed in 1994, attempted to limit agricultural runoff as well as set water quality standards. The Comprehensive Everglades Restoration Plan, passed by Congress in 2000, is a thirty-eight year project drawn up by the U.S. Army Corps of Engineers. It aims to restore natural water flow patterns in the Everglades and to redirect water to the marshes.
Tidal Wetlands—The Mangroves
Mangrove forests are among the most biodiverse wetland ecosystems on earth. They are found in tropical coastal waters, often near river mouths. The tree species found in mangrove forests possess special roots that allow them to survive in brackish water. Mangrove forests harbor numerous unique species worldwide, such as crabeating monkeys, fishing cats, and diverse species of birds and fish. They also provide food and wood for local communities, stabilize coastlines, and provide barriers from the sea during storms. Mangrove forests once lined three-quarters of the world's tropical coasts. Now, according to the World Resources Institute, an environmental advocacy group, less than half these forests remain ("Scorecard of Ecosystem Conditions and Changing Capacities," http://pubs.wri.org/pubs_content_print.cfm? ContentID=184). Indonesia, a country of more than 13,000 islands, possesses the most mangrove forestland of any country. Brazil and Australia also have extensive mangrove habitats.
Mangroves are disappearing in part because they have traditionally been regarded as sinister, malarial wastelands. In Florida, for example, mangroves were flooded every year to control mosquito populations. Mangrove forests have also been sold to logging companies for paper pulp, pest-proof timber, and chipboard for coastal development. Many mangrove forests have also been replaced with saltwater ponds for commercial shrimp farming. The shrimp industry is perhaps the most immediate threat to mangrove forests today.
During the Vietnam War, herbicides were dumped on an estimated 124,000 hectares (approximately 306,410 acres) of mangrove forests in South Vietnam. These areas remain, for the most part, entirely barren—a true wasteland.
The continued survival of endangered and threatened species is dependent on the presence of suitable habitat for them. Due to agricultural and urban development, much of the land in the United States has been rendered unsuitable for this purpose. However, federal, state, and private efforts to preserve land from harmful development have been successful to some degree. As a result there are conservation areas throughout the country that provide varying levels of refuge for endangered and threatened species.
U.S. LAND CONSERVATION EFFORTS
The early American colonists were impressed by the abundance of natural resources they found in North America and by the vast expanses of land available for settlement. Settlers migrated to the West and South, building towns and developing land for agriculture and industry. New modes of transportation allowed access to areas previously undisturbed by humans. Widespread development and demand for food, water, lumber, and other goods began to stress some natural resources. Massive areas of forest were cleared of trees. Passenger pigeons and heath hens were driven to extinction. Buffalo, elk, and beaver stocks were nearly destroyed.
In the United States's first century as a nation, the federal government owned about 80% of the nation's land. The government started surveying and selling its land holdings to states, settlers, and railroad companies in about 1785. During the nineteenth century awareness began growing in the United States about the scarcity and value of natural resources. In 1892 John Muir (1838–1914) established the Sierra Club, an organization devoted to recreation, education, and conservation. President Theodore Roosevelt (1858–1919) set aside millions of acres of land under federal government control for national refuges, forests, and parks.
By the end of the nineteenth century, the government had transferred most of its lands to private ownership. It also allowed private use of remaining federal lands. After several decades of rapid development and unrestricted use, much of the nation's land and natural resources were significantly degraded. Responding to mounting concerns, Congress slowly redefined the federal government's role in land management from temporary to permanent retention as well as active stewardship.
During the 1960s, increasing scientific and public concern about the declining condition of the country's natural resources led Congress to enact a number of laws to conserve both federal and nonfederal lands. These laws regulate activities that affect air, water, soil, plants, and animals. With increasing environmental legislation, the land management framework evolved into a complex collection of agencies, land units, and laws. Different agencies have different priorities, which are reflected in how they manage the resources under their care. The effects of these different missions are particularly evident in places where two agencies hold adjacent lands. For example, the National Park Service (Department of the Interior) oversees Yellowstone National Park, where timber harvesting is prohibited, whereas the U.S. Forest Service (Department of Agriculture) allows large areas to be clear-cut in the adjacent Targhee National Forest in Idaho.
The National Park System
In 1849 the U.S. Congress passed a bill creating the U.S. Department of the Interior (DOI). The DOI was responsible for a wide variety of matters, including constructing water systems, exploring wilderness areas in the West, and managing public lands and public parks. In 1872 Yellowstone National Park was created by an act of Congress and was the first national park established in the world. Over the next four decades more than a dozen national parks were established in the United States, along with twenty-one national monuments. In 1916 a new agency, the National Park Service (NPS), was created under the DOI to manage these federal lands.
As of 2006 there were 388 units in the National Park System covering nearly eighty million acres. The units include national parks, monuments, preserves, lake-shores, seashores, wild and scenic rivers, trails, historic sites, military parks, battlefields, historical parks, recreation areas, memorials, and parkways. The map in Figure 3.3 shows the location and ranges of National Parks in the United States. In addition to preserving habitats that range from Arctic tundra to tropical rain forest, the system protects many imperiled plant and animal species.
In late 2005 the NPS published a proposed revision of the National Park Service Management Policies (2005, http://parkplanning.nps.gov/document.cfm?projectId=13746&documentID=12825). Section 220.127.116.11 of the document discusses the management of endangered and threatened species on NPS lands. The agency notes that it engages in the following activities:
- Cooperates with the U.S. Fish and Wildlife Service and National Marine Fisheries Service to ensure that National Park Service actions comply with the Endangered Species Act
- Operates programs to inventory, monitor, restore, and maintain the habitats of listed species
- Works to control invasive nonnative species
- Prevents visitors from damaging vital habitats
- Reestablishes depleted populations to maintain the species
- Manages critical habitat and recovery areas designated under the ESA
|Areas located within National Forest Service boundaries, September 30, 2005|
|Area kind||Number of units||Gross acreage||Non forest service acreage||Other acreage|
|Note: Other acreage refers to areas located within National Forest System boundaries that are not federally owned or administered by the U.S. Forest Service.|
|source: "Table 1. National and Regional Areas Summary," in Land Areas Report as of September 30, 2005, U.S. Department of the Interior, 2005, http://www.fs.fed.us/land/staff/lar/LAR05/table1.htm (accessed March 8, 2006)|
|Land utilization projects||6||1,876||1,876||0|
|Research and experimental areas||20||73,154||64,871||8,283|
|Western regional totals (regions 1 through 6)|
|Land utilization projects||4||1,834||1,834||0|
|Research and experimental areas||6||60,598||60,598||0|
|Eastern regional totals (regions 8 and 9)|
|Land utilization projects||2||42||42||0|
|Research and experimental areas||14||12,556||4,273||8,283|
|Alaska region totals (region 10)|
- Cooperates with other agencies involved in setting critical habitat and recovery areas and participates in the recovery planning process
- Works with federal and state agencies and nongovernmental organizations to promote conservation agreements for candidate species
- Conducts activities and allocates funds to address endangered, threatened, proposed, and candidate species.
The National Parks have played a significant role in the return of several species, including red wolves and peregrine falcons. National Parks also contain designated critical habitat for numerous listed species. However, not all of these are publicly disclosed, in order to protect rare species from collectors, vandals, or curiosity seekers.
The National Forests
In 1905 the U.S. Forest Service was established as an agency of the U.S. Department of Agriculture. As of February 2006 the Forest Service managed nearly 193 million acres of public lands in 155 national forests and twenty national grasslands. (See Table 3.2.) A map of the locations of U.S. national forests and grasslands is shown in Figure 3.4. National forest lands also include numerous lakes and ponds. National forest land is, in general, not conserved to the same degree as National Park lands. For example, much logging occurs within these forests.
Within the Forest Service, the Threatened, Endangered, and Sensitive Species Program focuses on wildlife conservation. The Secretary of Agriculture's Policy on Fish and Wildlife directs the Forest Service to "manage habitats for all native and desired nonnative plants, fish and wildlife species to maintain viable populations of each species; identify and recover threatened and endangered plant and animal species" and to avoid actions "which may cause species to become threatened or endangered." In addition, the Forest Service has another designation called "sensitive species" for species considered unique, rare, endemic or meeting other criteria.
Endangered, threatened and sensitive species on national forest lands are subjected to biological evaluations to determine the effects on them of management activities. Conservation measures are also incorporated to preserve these species.
The National Wildlife Refuge System
In 1903 President Theodore Roosevelt established the National Wildlife Refuge System (NWRS) and designated the first refuge at Pelican Island, Florida. The refuge was home to a population of brown pelicans, which were being slaughtered for their popular feathers. Over the next century hundreds of additional refuges were designated throughout the country.
The NWRS is the only network of federal lands and waters managed principally for the protection of fish and wildlife. As of March 2006 it covered ninety-six million acres and included 545 refuges and thousands of small wetlands around the country. Yukon Delta, the largest of the Alaskan refuges, comprises twenty million acres. Approximately one-third of the total refuge acreage is wetland habitat, reflecting the importance of wetlands for wildlife survival.
Fifty-nine of the refuges were established specifically for endangered species, as shown in Table 3.3. These refuges cover more than 360,000 acres and are located in twenty states and the U.S. Virgin Islands. California is home to fourteen of the refuges, followed by Florida with
|National Wildlife Refuges established for endangered species|
|State||Unit name||Species of concern||Unite acreage|
|Alabama||Sauta Cave NWR||Indiana bat, gray bat||264|
|Fern Cave NER||Indiana bat, gray bat||199|
|Key Cave NWR||Alabama cavefish, gray bat||1,060|
|Watercress Darter NWR||Watercress darter||7|
|Arkansas||Logan Cave NWR||Cave crayfish, gray bat, Indiana bat, Ozark cavefish||124|
|Arizona||Buenos Aires NWR||Masked bobwhite quail||116,585|
|Leslie Canyon||Gila topminnow, yaqui chub, peregrine falcon||2,765|
|San Bernardino NWR||Gila topminnow, yaqui chub, yaqui catfish, beautiful shiner, Huachuca water umbel||2,369|
|California||Antioch Dunes NWR||Lange's metalmark butterfly, Antioch Dunes evening-primrose, Contra costa wallflower||55|
|Bitter Creek NWR||California condor||14,054|
|Blue Ridge NWR||California condor||897|
|Castle Rock NWR||Aleution Canada goose||14|
|Coachella Valley NWR||Coachello Valley fringe-toed lizard||3,592|
|Don Edwards San Francisco Bay NWR||California clapper rail, California least tern, salt marsh harvest mouse||21,524|
|Ellicott Slough NWR||Santa Cruz long-toed salamander||139|
|Hopper Mountain NWR||California condor||2,471|
|Sacramento River NWR||Valley elderberry longhorn beetle, bald eagle, Least Bell's vireo||7,884|
|San Diego NWR||San Diego fairy shrimp, San Diego mesa mint, Otay Mesa mint, California orcutt grass, San Diego button-celery||1,840|
|San Joaquin River NWR||Aleutian Canada goose||1,638|
|Seal Beach NWR||Light-footed clapper rail, California least tern||911|
|Sweetwater Marsh NWR||Light-footed clapper rail||316|
|Tijuana Slough NWR||Light-footed clapper rail||1,023|
|Florida||Archie Carr NWR||Loggerhead sea turtle, green sea turtle||29|
|Crocodile Lake NWR||American crocodile||6,686|
|Crystal River NWR||West Indian manatee||80|
|Florida Panther NWR||Florida panther||23,379|
|Hobe Sound NWR||Loggerhead sea turtle, green sea turtle||980|
|Lake Wales Ridge NWR||Florida scrub jay, snakeroot, scrub blazing star, Carter's mustard, papery whitlow-wort, Florida bonamia, scrub lupine highlands scrub hypericum, Garett's mint, scrub mint, pygmy gringe-tree, wireweed, florida ziziphus, scrub plum, eastern indigo snake, bluetail mole skink, sand skink||659|
|National Key Deer Refuge||Key deer||8,542|
|St. Johns NWR||Dusky seaside sparrow||6,255|
|Hawaii||Hakalau Forest NWR||Akepa, akiapolaau, ˋoˋu, Hawaiian hawk, Hawaiian creeper||32,730|
|Hanalei NWR||Hawaiian stilt, Hawaiian coot, Hawaiian moorhen. Hawaiian duck||917|
|Haleia NWR||Hawaiian stilt, Hawaiian coot, Hawaiian moorhen, Hawaiian duck||241|
|James C. Campbell NWR||Hawaiian stilt, Hawaiian coot, hawaiian moorhen, Hawaiian, duck||164|
|Kakahaia NWR||Hawaiian stilt, Hawaiian coot||45|
|Kealia Pond NWR||Hawaiian stilt, Hawaiian coot||691|
|Pearl Harbor NWR||Hawaiian stilt||61|
|Iowa||Driftless Area NWR||Iowa pleistocene turtle||521|
|Massachusetts||Massasoit NWR||Plymouth red-bellied turtle||184|
|Michigan||Kirtland's Warbler WMA||Kirtland's warbler||6,535|
|Mississippi||Sandhill Crane NWR||Mississippi sandhill crane||19,713|
|Missouri||Ozark Cavefish NWR||Ozark cavefish||42|
|Pilot Knob NWR||Indiana bat||90|
|Nebraska||Karl E. Mundt NWR||Bald eagle||19|
|Nevada||Ash Meadows NWR||Devil's Hole pupfish, Warm Springs pupfish, Ash Meadows Amargosa pupfish, Ash Meadows speckled dace, Ash Meadows naucorid, Ash Madows blazing star, Amargosa niterwort, Ash Meadows milk-vetch, Ash Meadows sunray, Spring-loving centaury, Ash Meadows gumplant, Ash Meadows invesia||13,268|
|Moapa Valley NWR||Moapa dace||32|
|Oklahoma||Ozark Plateau NWR||Ozark big-eared bat, gray bat||2,208|
|National Wildlife Refuges established for endangered species [continued]|
|State||Unit name||Species of concern||Unite acreage|
|Note: NWR=National Wildlife Refuge, WMA=Wildlife Management Area.|
|source: "National Wildlife Refuges Established for Endangered Species," in America's National Wildlife Refuge System, U.S. Department of the Interior, U.S. Fish and Wildlife Service, 2006, http://www.fws.gov/refuges/habitats/endSpRefuges.html (accessed February 28, 2006)|
|Oregon||Bear Valley NWR||Bald eagle||4,200|
|Julia Butler Hansen Refuge for Columbian White-tail Deer||Columbian white-tailed deer||2,750|
|Nestucca Bay NWR||Aleutian Canada goose||457|
|South Dakota||Karl E. Mundt NWR||Bald eagle||1,044|
|Texas||Attwater Prairie Chicken NWR||Attwater's greater prairie chicken||8,007|
|Balcones Canyonlands NWR||Black-capped vreo, golden-cheeked warber||14,144|
|Virgin Islands||Green Cay NWR||St. Croix ground lizard||14|
|Sandy Point NWR||Leatherback sea turtle||327|
|Virginia||James River NWR||Bald eagle||4,147|
|Mason Neck NWR||Bald eagle||2,276|
|Washington||Julia Butler Hansen Refuge for Columbian White-tail Deer||Columbian white-tailed deer||2,777|
|Wyoming||Mortenson Lake NWR||Wyoming toad||1,776|
eight refuges and Hawaii with seven refuges. The refuges range in size from the seven-acre Watercress Darter refuge in Alabama to the 116,585—acre Buenos Aires refuge in Arizona. Protected species include a variety of plants and animals.
Table 3.4 shows all federally listed threatened and endangered animal species known to occur on units of the NWRS. The list comprises 185 species in total, including fifty-five species of birds, forty-five species of mammals, and thirty-three species of fish. In addition, ninety-eight threatened and endangered plant species are found in the NWRS system, as shown in Table 3.5.
Many other listed animal species use refuge lands on a temporary basis for breeding or migratory rest stops. Virtually every species of bird in North America has been recorded in the refuge system.
Wilderness Preservation System Areas
In 1964 the U.S. Congress passed the Wilderness Act. Its purpose was to designate certain areas of undeveloped federal land as the National Wilderness Preservation System. The act noted that these areas were to be "where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain."
As of 2006 nearly 700 of these so-called wilderness areas have been designated across the country covering more than 105 million acres. (See Figure 3.5.) The lands are owned or administered by the USFWS, the USDA Forest Service, the National Park Service, or the Bureau of Land Management. All of the wilderness areas occur within national wildlife refuges, expect for one—the Mount Massive Wilderness Area located at the Leadville National Fish Hatchery in Colorado. Alaska, California, and other western states are home to most of the wilderness areas.
Unlike National Parks, which are intended for use by large numbers of visitors, wilderness areas are intended to be pristine, with limited access and no amenities. True wilderness remains, for most humans, a place to visit only rarely. Nonetheless, the number of people using wilderness areas has increased steadily. Many visitors, as well as park managers, have complained about the intrusions of civilization—cell phones, snowmobiles, and aircraft—into wilderness areas.
The Debate over Use of Federally Protected Lands
Since federal conservation lands were first set aside, a national debate has raged over how they should be used. Many of these lands contain natural resources of great value in commercial markets, including timber, oil, gas, and minerals. Political and business interests that wish to harvest these resources are pitted against environmentalists who want to preserve the lands in as pristine condition as possible. During the 1990s such a battle raged over the issue of logging in old-growth forests of the Pacific Northwest—the same forests that provided habitat for endangered northern spotted owls. A similar controversy has been brewing for decades over the drilling of oil and gas in the Arctic National Wildlife Refuge (ANWR).
OIL DRILLING IN THE ARCTIC NATIONAL WILDLIFE REFUGE?
The Arctic National Wildlife Refuge is located in northern Alaska as shown in Figure 3.6. Covering nineteen million acres, it is the largest national wildlife refuge in the United States. ANWR was established in 1980 by passage of the Alaska National Interest Lands Conservation Act (http://alaska.fws.gov/asm/anilca/toc.html). In Section 1002 of the act, the U.S. Congress deferred a decision on the future management of 1.5 million acres of ANWR, because of conflicting interests between potential oil and gas resources thought to be located there and the area's importance as a wildlife habitat. This disputed area of coastal plain came to be known as the 1002 area. It is shown in detail in Figure 3.7.
|Threatened and endangered animal species known to occur on units of the National Wildlife Refuge system|
|source: "Threatened and Endangered Animal Species Found on the National Wildlife Refuge System," in America's National Wildlife Refuge System, U.S. Department of the Interior, U.S. Fish and Wildlife Service, 2006, http://www.fws.gov/refuges/habitats/endSpAnimals.html (accessed March 8, 2006)|
|Threatened and endangered animal species known to occur on units of the National Wildlife Refuge system|
|source: "Threatened and Endangered Plant Species Found on the National Wildlife Refuge System," in America's National Wildlife Refuge System, U.S. Department of the Interior, U.S. Fish and Wildlife Service, 2006, http://www.fws.gov/refuges/habitats/endSpPlant.html (accessed March 8, 2006)|
There has been interest in tapping the oil deposits in northern Alaska since the early 1900s. The area was first explored for oil and gas resources in the 1940s and 1950s. It was also in the 1950s, however, that people became aware of the ecological value of these lands, and a compromise was reached in which the northeastern part of the state was set aside as a wildlife range (later refuge), while drilling began—and continues—in the northwestern part of the state. Production of oil and gas in the refuge area—the 5% of Alaska's North Slope not already open to drilling—was also prohibited at that time unless specifically authorized by Congress.
In 1987 the Department of the Interior (DOI) submitted a report to Congress on the resources of the 1002 area. At that time only a few oil accumulations had been found near ANWR. Over the next decade, much larger oil fields were discovered as shown by the shaded areas in Figure 3.7. In 1998 the U.S. Geological Survey (USGS) performed a petroleum assessment of the 1002 area and the adjacent state waters. An updated assessment performed in 2001 found that there was a 95% probability of 5.7 billion barrels of oil being recoverable from the assessed area, with most of the oil coming from the undeformed part of the 1002 area. The undeformed area has a geologic structure composed of rock layers that are mostly horizontal. This makes for more successful drilling than in the deformed area where rock layers are folded and faulted.
The protected status of ANWR has been challenged by large oil companies and their political supporters. When Republicans took control of Congress in 1995, they passed legislation to allow for drilling in ANWR, but President Clinton vetoed the bill. The succeeding administration under President George W. Bush has been much more supportive of drilling in the refuge.
Environmentalists argue that studies by the Fish and Wildlife Service suggest that oil drilling in the refuge will harm many Arctic species, by taking over habitat, damaging habitats through pollution, interfering with species activities directly, or increasing opportunities for invasive species. ANWR harbors the greatest number of plant and animal species of any park or refuge in the Arctic, including a multitude of unique species such as caribou, musk oxen, polar bears, arctic foxes, and snow geese. Because of the harsh climate, Arctic habitats are generally characterized by short food chains and extreme vulnerability to habitat disturbance. The majority of Arctic species already live "on the edge." Consequently, the decline of even a single species is likely to have dramatic effects on the entire community.
Some environmentalists consider the 1002 area to be one of the most ecologically diverse and valuable parts of the refuge. Among the species that would be affected if drilling is permitted are polar bears, whose preferred sites for building dens are in the 1002 area (see Figure 3.8) and caribou, which use this area for calving—giving birth to young (see Figure 3.9.)
In 2001 the House of Representatives again passed a bill allowing for drilling within the refuge. However, the Senate rejected this proposal in 2002. The terrorist attacks of September 11, 2001, and heightened tensions in the Middle East have encouraged some politicians to emphasize the national security aspects of oil development in ANWR. They argue that the United States cannot be truly secure until it reduces its dependence on foreign oil. The Bush administration has continued to press for oil drilling in ANWR. During 2005 ANWR drilling measures were added to bills related to energy, the fiscal year 2006 budget, and defense appropriations. Various versions of these bills were approved by either the Congress or the Senate at one time or another; however, the drilling measures were ultimately dropped from the final bills.
Private Lands Conservation
Federal and state governments are not the only entities involved in land conservation. Increasingly environment-minded private organizations and citizens are purchasing land with the intent of preserving it for wild life. Such national environmental groups as the Nature Conservancy participate in these endeavors. The Nature Conservancy Web site states that the organization helps to protect approximately fifteen million acres in the United States. Other major groups engaged in private land conservation include the Conservation Fund, the Trust for Public Land, the Land Trust Alliance, Society for the Protection of New Hampshire Forests, and the Rocky Mountain Elk Foundation.
Every three years the Land Trust Alliance conducts a census on lands held for private conservation. The latest census was completed in 2003 and found that more than 9.3 million acres of land were held in local and regional land trusts, up from 4.7 million acres in 1998. Land trusts either purchase land outright or develop private, voluntary agreements called conservation easements or restrictions that limit future development of the land. The census estimated that an additional twenty-five million acres in land were protected by national land trusts.
INTERNATIONAL EFFORTS AT CONSERVATION
The United Nations Environment Programme (UNEP) was established to address diverse environmental issues on an international level. Many of its conventions have been extremely valuable in protecting global biodiversity and natural resources. UNEP has also helped to regulate pollution and the use of toxic chemicals.
THE CONVENTION ON INTERNATIONAL TRADE IN ENDANGERED SPECIES (CITES)
The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is an international agreement administered under UNEP that regulates international trade in wildlife. CITES is perhaps the single most important international agreement relating to endangered species and has contrib critically to the protection of many threatened species. The international wildlife trade is estimated to involve hundreds of millions of specimens annually.
CITES was first drafted in 1963 at a meeting of the International Union for Conservation of Nature and Natural Resources (IUCN; now the World Conservation Union), and went into effect in 1975. Protected plant and animals are listed in three separate CITES appendices depending on degree of endangerment. Appendix I includes species that are in immediate danger of extinction. CITES generally prohibits international trade of these species. Appendix II lists species that are likely to become in danger of extinction without strict protection from international trade. Permits may be obtained for the trade of Appendix II species only if trade will not harm the survival prospects of the species in the wild. Appendix III lists species whose trade is regulated in one or more nations. Any member nation can list a species in Appendix III to request international cooperation in order to prevent unsustainable levels of international trade. Nations agree to abide by CITES rules voluntarily. In 2006 there were more than 150 nations participating in the agreement.
Convention on Biological Diversity
The United Nations Convention on Biological Diversity was set up to conserve biodiversity and to promote the sustainable use of biodiversity. The Convention supports national efforts in the documentation and monitoring of biodiversity, the establishment of refuges and other protected areas, and the restoration of degraded ecosystems. It also supports goals related to the maintenance of traditional knowledge of sustainable resource use, the prevention of invasive species introductions, and the control of invasive species that are already present. Finally, it funds education programs promoting public awareness of the value of natural resources.
Convention on Migratory Species of Wild Animals
The Convention on the Conservation of Migratory Species of Wild Animals (also known as the CMS or Bonn Convention) recognizes that certain migratory species cross national boundaries and require protection throughout their range. This convention aims to "conserve terrestrial, marine, and avian migratory species throughout their range." CMS was originally signed in Bonn, Germany, in 1979 and went into force in November 1983. As of February 2006 more than ninety nations in Africa, Central and South America, Asia, Europe, and Oceania were involved in the agreement. The United States and several other nations are not official parties to the agreement but nonetheless abide by its rules.
CMS provides two levels of protection to migratory species. Appendix I species are endangered and strictly protected. Appendix II lists species that are less severely threatened but would nonetheless benefit from international cooperative agreements. Appendix II agreements have been drawn up for groups such as European bats, Mediterranean and Black Sea cetaceans (whales and related species), Baltic and North Sea cetaceans, Wadden Sea seals, African-Eurasian migratory water birds, and marine turtles. In 2004 the Agreement on the Conservation of Albatrosses and Petrels came into effect. Because these sea birds are highly migratory, their conservation requires broad international agreements in addition to efforts by individual nations.
World Commission on Protected Areas
The IUCN's World Commission on Protected Areas (WCPA) is the leading international body dedicated to the selection, establishment, and management of national parks and protected areas. It has helped set up many natural areas around the world for the protection of plant and animal species, and also maintains a database of protected areas. Protected areas often consist of a core zone where wildlife cannot legally be disturbed by human beings, surrounded by "buffer zones," transitional spaces that act as shields for the core zone. On the periphery are areas for managed human living. A protected area is defined as "an area of land and/or sea especially dedicated to the protection and maintenance of biological diversity, and of natural and associated cultural resources, and managed through legal or other effective means."
Conservation biology theory advocates that protected areas should be as large as possible in order to increase biological diversity and to buffer refuges from outside pressures. The world's largest protected areas are Greenland National Park (Greenland), Ar-Rub'al-khali Wildlife Management Area (Saudi Arabia), Great Barrier Reef Marine Park (Australia), Qiang Tang Nature Reserve (China), Cape Churchill Wildlife Management Area (Canada), and the Northern Wildlife Management Zone (Saudi Arabia).