Endangered Species Handbook

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Vanishing Species

The Unraveling Tapestry

     Now that prairies are plowed under and deserts are filled with subdivisions, the net effect of this recent massive habitat destruction and wildlife slaughter is being assessed.  An incomplete tally in the United States, including Hawaii, totals at least 99 species of animals and 240 plants presumed extinct during the past 400 years (Stein et al. 2000).   This high rate of extinctions reflects the losses of species and ecosystems described in Chapter 1, as well as those of Hawaii.  The Nature Conservancy, which established Natural Heritage Programs in every state to monitor native species, has compiled this and related data to alert the public of the urgent need to preserve the country's natural heritage (Stein and Flack 1997; Stein et al. 2000).  Its examination of the status of 20,439 US plants and animals found 7,817 species (38 percent) to be either vulnerable, imperiled or critically imperiled (Stein et al. 2000).  These conclusions were published in a book co-authored with the Association for Biodiversity Information, entitled Precious Heritage: The Status of Biodiversity in the United States (Stein et al. 2000).  This book also illustrates many of these beautiful plants and animals and threatened ecosystems.  It found more species in danger than the 2000 IUCN Red List due to slightly different categories, such as imperiled and critically imperiled, rather than critical and endangered, used in IUCN lists.  The latter organization also defines threatened species in terms of the rate of their decline, rather than their actual status.
 
     Precious Heritage found endemic species, defined as those restricted to the bounds of the United States, and breeding endemics, or those breeding only in the United States, were even more threatened than those with wide distributions.  Of the 875 endemic vertebrates in the lower 48 states, almost half (47 percent) are of conservation concern, compared to only 24 percent of all US vertebrate species (Stein et al. 2000). 90 percent of Hawaii’s endemics are imperiled in this study.  Freshwater species such as mussels, crayfish, beetles and dragonflies are also in steep decline (Stein et al. 2000).  More than 5,090 plants (33 percent of all native species) are threatened.
 
     Other studies are examining natural ecosystems in the country.  The National Biological Service of the US Department of the Interior reported in 1995 that during the 20th century alone, half the natural ecosystems of the lower 48 states became degraded to the point of endangerment (Stevens 1995).  More than 1,700 biologists participated in this study, part of a massive biological survey of America's plants and animals (Stevens 1995).  Along with the loss of the tall grass prairies and oak savannahs, more than 60 million acres of longleaf pine forests in the Southeast have been cut, and much of this land has been planted with tree farms, creating biologically sterile regions.  Northeastern old-growth hardwood forests, likewise, are critically endangered, and survive only in scattered remnants (Stevens 1995).  Grasslands in Long Island, the Northeast and California are threatened ecosystems, as are coastal prairies in Louisiana and sedge meadows in Wisconsin.  Streams in the Mississippi plain have been greatly damaged as well (Stevens 1995).  Fifty-eight natural communities have declined by 85 to 98 percent, and 38 others have declined by 70 to 84 percent (Stevens 1995). The National Biological Service has identified 126 endangered species through this study.  Each imperiled ecosystem is home to many threatened species, a reflection of their loss of habitat. This study underlined the importance of preserving large areas instead of small tracts of land, although the latter may be the only way to protect some highly endangered species, such as plants that have become greatly restricted in range.
 
     A 1997 study by the joint United States and Canadian branches of the World Wildlife Fund (WWF), "A Conservation Assessment of the Terrestrial Ecoregions of North America," appraised the ecoregions of the continent including Hawaii (Luoma 1997).  Ecoregions are areas defined by major habitat types and, unlike ecosystems, are confined to particular areas.  Eastern old-growth forests, for example, are ecosystems scattered over a great area amongst other ecosystems, while southeastern conifer forests constitute an ecoregion.  This study found 13 of the continent's 116 ecoregions to be imperiled "hot spots," harboring enormous biological diversity (Luoma 1997).   These include Florida's pine scrub, the conifer forests of the Southeast, Appalachia's mixed mesophytic forests, the tallgrass prairie and California coastal sage and chaparral (Luoma 1997). These findings were echoed in the world survey of threatened areas with great biological diversity, Hotspots, sponsored by Conservation International (Mittermeier et al. 1999).  The latter book is illustrated with spectacular color photographs of many disappearing landscapes and species of endangered hotspots, such as the California coastal region.  
 
     An inventory of rare, endangered and extinct North American plants and animals, being compiled by the National Biological Service, has verified that the impoverishment of America's natural ecosystems has affected not just isolated species, but entire communities of species.  It predicts a steady increase in the number of threatened species because of continued destruction of natural habitats.  Habitat loss is the greatest threat to US wildlife and plants, but trade, persecution and pollution play roles as well.  Agriculture was ranked as the primary threat to native US species by The Nature Conservancy study, threatening about 45 percent of plants and animals, while development of land followed, threatening about 34 percent; water projects were the next major threat, and livestock grazing, pollutants, road building, logging and mining had important, but lesser, effects on species and ecosystems (Stein et al. 2000).
 
     Threatened species tend to be located in certain "hot spots" in the United States.  The one with the largest number of species is Hawaii, with 5,000 populations of species considered imperiled by The Nature Conservancy (Stein et al. 2000).  In the continental United States, a preponderance of threatened species occurs in the Florida Panhandle, central Florida and the Florida Keys, the Appalachian Mountains, the Cumberlands and Southern Ridge, Cape Cod and Martha's Vineyard, southern California, the Pacific Northwest and southeastern Alaska, as mapped in Precious Heritage.  The Status of Biodiversity in the United States (Stein et al. 2000; page 166).  The Cumberlands and Southern Ridge and Valley of northern Alabama and southeastern Tennessee have the country's largest number of imperiled species--186--mainly as a result of the mussels, crayfish and freshwater snails of this region.  The Central Appalachian Forest to the northeast has 154 threatened species, with a high percentage of aquatic species as well, including many rare salamanders and woodland plants.  The Great Basin Desert of Utah and neighboring states is another species-rich area, with 113 threatened species, while the California South Coast sagebrush ecosystem has 138 threatened species found nowhere else on Earth (Stein et al. 2000).  (See Grasslands, Shrublands and Deserts chapter).
 
     The list of US species in danger of extinction grows longer each year, with a dramatic rise in the number of imperiled invertebrates in the 20th century.  Fully 68 percent of freshwater mussels, more than 100 species, are threatened, making them the most endangered group of native animals.  Fifty percent of native crayfish are threatened, according to the Nature Conservancy (Clancy 1997).  The majority of surviving species are highly endangered from alteration of their clear, fast-flowing rivers and streams by federally sponsored dams, channeling and diking that have turned most waterways in the Southeast into muddy ditches and artificial lakes.  Pollution and introduction of non-indigenous species of mollusks and crustaceans competing for food have also played roles in the decline of some of these mussels and crayfish.  The Hawaiian Islands are home to a variety of colorful and endemic tree snails.  Introduction of exotic snail species and habitat destruction have already extinguished many of these, and endangered others. 
 
     Many species of butterflies, which are important pollinators, are in decline.  The Xerces Blue (Glaucopsyche xerces), a beautiful butterfly native to California, became extinct in the 1940s (Stein et al. 2000).  Eight moth species and two other mainland butterflies are possibly extinct, as are 50 bee species native to Hawaii (Stein et al. 2000).  Eight mainland butterfly species are critically endangered, and 109 are threatened, according to The Nature Conservancy (Stein et al. 2000).  Dragonflies and damselflies, which predate the dinosaurs, have also lost ground.  Two Hawaiian species are possibly extinct, and 79 more are considered imperiled (Stein et al. 2000).
 
     Seventeen species of freshwater fish are extinct or possibly extinct, and the United States leads the world in the number of threatened freshwater fish: The Nature Conservancy lists 283 species (Stein et al. 2000).  Habitat loss in the form of dams, river diversion and channeling, as well as pollution, has played major roles endangering these fish.  Logging has destroyed many clear rivers and streams where salmon and trout breed.  The majority of rivers and bodies of water are still polluted despite the Clean Water Act, and contaminants have caused malformations and high mortalities in fish populations.  Introductions of non-indigenous fish for sport fishing have imperiled a large number of species.  Brown Trout from Europe and Rainbow Trout placed in areas where they are not native have severely threatened native trout, such as the Cutthroat Trout of western lakes and rivers.  In many cases, multiple factors combine to push native fish toward extinction.
 
     The United States is second only to Australia in the number of threatened reptiles and amphibians.  The Nature Conservancy lists 51 imperiled reptiles and 82 imperiled amphibian species (Stein. 2000).  This amounts to an estimated 40 percent of US amphibians, and 18 percent of native reptiles--extremely high rates.   Amphibians are declining worldwide from various causes including habitat loss, pollution, disease, pesticides and ultraviolet radiation from thinning of the Earth's ozone layer.
 
     The total of 71 US bird species that BirdLife International's research placed in various categories of threat includes 33 species from the Hawaiian Islands (BI 2000).  The Nature Conservancy found an even greater number through their intensive Natural Heritage Program research:  83 species of birds at risk in the United States, or about 11 percent of all native species (Stein et al. 2000).  This is a smaller percentage than for reptiles and amphibians but, when analyzed by region, a large percentage of Hawaii's birds are threatened.  A steady increase in the number of threatened birds has occurred in this century.  The major causes threatening US mainland and seabirds are destruction of habitat, pesticides and pollution.  In the Hawaiian Islands, introduced animals, disease and destruction of forests and wetlands are the major threats to endemic birds, as well as to plant life and invertebrate fauna. 
 
     The Nature Conservancy considers 65 species of US mammals, or about 16 percent of all native mammals, to be threatened (Stein et al. 2000).  The loss of habitat from development, logging, livestock grazing, mining and other forms of destruction is the foremost threat to mammals.  Added to this, pollution affects many aquatic mammals, and predator and rodent control programs to benefit livestock and agricultural interests affect foxes, wolves, and prairie dogs.  A growing number of bats have been added to the list of threatened US mammals, an indication of a loss of habitat, as a result of caves being disturbed or vandalized, loss of large roosting trees to logging, pesticide use, and persecution by those not aware of bats’ ecological importance and who have exaggerated ideas of their supposed threats to humans.
  
     Although lists of native North American threatened plants are far from complete, they reflect the rate at which ecosystems have become imperiled.  The Nature Conservancy found 6,460 United States vascular plants to be imperiled (Stein et al. 2000).  Of these, a very large number--1,385--are Critically Imperiled, 1,341 Imperiled and 3,338 species Vulnerable.  Hawaii is a center for threatened plants.  The 1997 IUCN Red List of Threatened Plants found a somewhat smaller number of threatened US plants; 4,488 species, or 29 percent of native plants.  Still, the United States had the highest number of endangered plants of any country in the world (Walter and Gillett 1998).  In terms of the percent of native plants that are threatened, only St. Helena, Mauritius, and the Seychelles had higher rates (Walter and Gillett 1998) Few countries of the world have legislation similar to the US Endangered Species Act, which has helped hundreds of endangered plants.
 
     Many US plants are adapted to specific types of soil or microclimates, and human disturbances can threaten them.  Prairie plants are among the most threatened.  California's grasslands have been reduced by more than 90 percent, leaving many endangered plants; it has many endemic species in its southern chaparral and shrubland, which are being bulldozed to make way for new housing developments.  The state's mild climate and varied landscape have given rise to great diversity, which is extremely threatened.  Of 25 presumed and 21 possibly extinct species in the state, about half, or 24, are plants (Stein and Flack 1997).  Although endemic plants are not as numerous on the mainland as in some island habitats, North America is home to a great many unique and beautiful plants, which are finally beginning to receive the conservation attention they deserve. 
 
     Research is uncovering potential economic value in some native plants. One threatened US plant, the Scrub Mint (Dicerandra frutescens), yields a natural insecticide in its oil that repels a wide variety of insects, from ants to cockroaches (Aylsworth 1998).  This white-flowered plant is presently restricted to a few hundred acres in central Florida, and it only came under scrutiny in the 1990s, when a Cornell biologist, Dr. Thomas Eisner, discovered its potential as a natural insecticide (Aylsworth 1990).  This mint may be protected from extinction in time, thanks in large part to Eisner's research. 
 
     In spite of some sizeable natural areas in the United States preserved by the Wilderness Act and as federal or state land holdings, the country has become increasingly urbanized and cultivated for agriculture.  Americans have gradually altered the landscape so that much of it, especially in the East, now resembles Western Europe's heavily populated countries where wilderness has been all but eliminated.
 
     Recent ecological research on the effects of suburban sprawl on the environment have shown it to crowd out as many species as more densely populated areas (Revkin 1997).  Diversity of species declines in these areas as green lawns, manicured gardens and asphalt cover the land and pollute the ground water with pesticides, fertilizers and herbicides and kill off beneficial insects and other animals.  Developers drain beaver ponds and wetlands and turn streams and rivers into concrete-lined ditches.  With each acre lost, species decline.  The brilliantly colored warblers and songbirds of eastern forests, for example, have been severely affected by fragmentation of both their breeding and wintering habitats.  For the majority of such declining species, endangered listing comes only when they have been reduced to a small fraction of their original populations.  The species that are listed by the IUCN or The Nature Conservancy in various categories of threat have reached a point where their very survival is at risk.  In some cases, species, which were once described as naturally rare, are very restricted in distribution, especially plants and fish inhabiting desert springs or mollusks found only in a particular river system.  For the majority of threatened US wildlife, however, their status a few hundred years ago would have been described as secure.  It is all the more indicative of a crisis situation regarding American biodiversity that so many species, and such large percentages of their classes or types, are now headed toward extinction.
 
     Should all US species currently threatened become extinct, a biological tragedy will take place.  Preventing such a catastrophe has not yet captured the public’s attention or involved a zealous effort on the part of the US government.  Important work on biodiversity studies is being done by various federal agencies, but the major burden of activism regarding preservation of endangered species and the environment has fallen to private conservation organizations. 
 
     The WWF report entitled "A Conservation Assessment of the Terrestrial Ecoregions of North America," accuses the US government of "doing a worse job of protecting its biological resources than many poorer countries with few resources for biodiversity conservation" (Luoma 1997).  It concludes that the wealthiest country in the world places the preservation of its natural resources among its lowest priorities.
 
     Without detailed information on the biodiversity of this country, it will be impossible to protect it, yet funds are inadequate to carry out a comprehensive assessment.  Many opponents of the biodiversity studies in Congress have expressed fear that they would be used to expand the list of species on the Endangered Species Act and obstruct development programs.  They succeeded in blocking formation of the National Biological Service, which Clinton Administration Secretary of the Interior Bruce Babbitt had to create administratively.  The constant deterioration of the land through development, pollution and introduction of exotic species makes these studies all the more timely.  This is a critical time of rapid environmental destruction and a turning point for many species which, without urgent protective action, will follow the deadly trails of the Passenger Pigeon, Carolina Parakeet, Sea Mink and hundreds of other lost plants and animals.
 
     The US Endangered Species Act is one of the strongest and most effective laws in the world and has been a model for similar legislation globally.  Many countries, including Canada, still lack national endangered species laws.  Although private organizations acquire habitat and carry out many important programs, the legal protection the Endangered Species Act provides is key to the protection of many endangered species and their habitats.  It has been responsible for saving a number of species, including the California Condor (Gyps californianus), Black-footed Ferret (Mustela nigripes), Whooping Crane (Grus americana) and numerous other animals and plants.  The law has helped fund research, captive breeding, protection in the wild, reintroduction programs, land acquisition and law enforcement protection. 
 
     The law must be reauthorized regularly by Congress, however, and at these times, efforts to weaken or even fail to authorize it threaten its effectiveness and very existence.  The strong support the law has received from the US public is not always evident in the halls of Congress, where commercial interests and lobbyists have had considerable influence.  To date, the law has survived, although it has been amended and weakened somewhat since its enactment.  The blocking of listings on the Endangered Species Act by its opponents has become the major means of thwarting the Act.  Lawsuits have been filed by both opponents and proponents of the law demanding either delisting of species or listing and critical habitat designation.  A virtual impasse has resulted in a moratorium on listing new species which the Department of the Interior declared in 2000.
 
     Many listings have been thwarted by commercial interests.  In a recent case, a proposal to list the Lynx (Lynx canadensis) on the Endangered Species Act was not acted upon by the Fish and Wildlife Service without a lengthy struggle.  This species has greatly declined from its once large range in the lower 48 states.  Heavy trapping for its valuable fur and logging of its habitat of mature pine forests have reduced its populations to fewer than 1,000 animals.  The majority of Lynx remain in Montana, Idaho, Washington and Maine.  Although the Fish and Wildlife Service's (FWS) own biologists found this population to be endangered, they were overruled by headquarters whose bureaucrats decided to refuse to list the species on the Endangered Species Act (Cushman 1998).   Petitions by conservationists urging Endangered Species Act listing for the Lynx were ignored, and only when a lawsuit was filed against FWS did the tide begin to turn in this endangered cat's favor.  Conservationists won the suit in 1997, but the FWS, in an unprecedented action, declined to list the Lynx, stating that other species had higher priority for listing.  Loggers and commercial timber companies oppose listing the Lynx, fearing that areas would be set aside as critical habitat where no tree cutting would be allowed, and many conservationists believed that FWS had succumbed to these pressures.  Finally, in February 1998, the Service and several conservation groups reached an agreement to list the Lynx on the Endangered Species Act to take effect in 1999 (Cushman 1998).  President Clinton declared a moratorium on new road building in national forests lands in 2000, which will greatly aid the Lynx and other threatened species of these forests, such as the Wolverine and Marten.
 
     The Public Employees for Environmental Responsibility (PEER) issued a report in December 1997 accusing the FWS of failing to protect more than 300 species awaiting listing.  Only listings of plants have increased in recent years, leaving a growing number of animals in need of federal listing (Stein et al. 2000).   The Nature Conservancy's biological surveys have uncovered a far greater number of endangered and threatened species in the United States than are listed by the Endangered Species Act, especially plants.
 
     On the positive side, an increase in the number of endangered species added to the Endangered Species Act has been seen in recent years.  The Endangered Species Act, in spite of shortcomings, is vital to the preservation of endangered species in the United States, and it is in grave danger of being weakened so much that it will become ineffective.  Various proposals in 2001 made by the Bush Administration would make it nearly impossible for citizens to sue the government to force listing of endangered species (Jehl 2001).  The majority of species on the Endangered Species Act were listed as a result of citizen suits (Jehl 2001, Gorov 2001).  The Fish and Wildlife Service claims to be unable to perform its duties because of the large number of legal challenges.  The law has not been reauthorized since 1991, and proposed changes might leave actions regarding endangered species to the discretion of the Department of the Interior, rather than basing them on biological status.  Under the new plan, citizens could petition for listings, but the government would not have to respond promptly, nor would it have to act on designating critical habitats for endangered and threatened species (Gorov 2001).  So little money--$6.4 million--is budgeted for listing that a stalemate is inevitable.  Other proposals by the Bush Administration would cut overall spending on endangered species programs by $11 million, leaving the Office of Endangered Species without the means to accomplish its purpose (Gorov 2001).
 
     A number of private organizations have aided in preserving endangered and endemic plants not listed on the Endangered Species Act.  The Nature Conservancy and its state Natural Heritage Programs have purchased or arranged purchase of hundreds of thousands of acres of land for threatened plants.  Arboretums and botanical gardens, such as the Missouri and the New York Botanical Gardens, also are active in this regard.  Lady Bird Johnson helped found the extremely effective organization, the National Wildflower Research Center, which aids in the conservation of wildflowers.  In the northeast, the New England Plant Conservation Program has spent six years collecting seeds from some 500 rare plants for a seed bank.  The New England Wild Flower Society has been instrumental in this program, and many sanctuaries throughout the region are preserving threatened plants. 
 
     The actions of individual states under their state endangered species laws and Natural Heritage Programs have also been crucial to the survival of many species that are threatened within a state or region, but might not qualify for federal listing.  Programs to reintroduce Bald Eagles (Haliaeetus leucocephalus), Peregrine Falcons (Falco peregrinus), threatened fish and River Otters (Lutra canadensis) have brought back these species in many areas where they had been eliminated by pesticides, over-trapping, pollution or water projects.  Many programs have involved cooperation between state and federal endangered species officials.
 
     Habitat Conservation Plans (HCPs) are agreements worked out between landowners and the Fish and Wildlife Service for listed endangered species under a 1982 amendment to the Endangered Species Act.  In essence, they are the result of deals made among developers, state and county officials, Fish and Wildlife Service representatives and local citizen groups on large tracts of land, in which portions of endangered species' habitats are protected, while development is allowed on the rest.  HCPs are a permanent contract that cannot be amended, even if biological information is revealed showing that they were in error.  These HCPs have been the center of much controversy, considered by some conservationists to compromise the principles of the Endangered Species Act, and by others to be an excellent means of protecting species.  HCPs are not presently published in the Federal Register prior to signing by the Secretary of the Interior, which would subject them to public comment. 
 
     In 1997, a team of 119 scientists, financed by the National Science Foundation and the American Institute for Biological Sciences, carried out careful appraisals of signed HCPs and reported on their conclusions.  They found that crucial scientific knowledge was lacking about many of the species involved in these agreements (Yoon 1997).  They also found misuse of scientific methods and biological data which will end in harming, rather than helping, many species (Yoon 1997).  Dr. Peter Kareiva, a University of Washington ecologist who organized the study, concluded that many HCPs should not have been written, and only about half correctly employed science (Yoon 1997).  Of 206 HCPs examined in total, 44 of them in detail, one-third lacked information as basic as life span of species, and the vast majority did not include data on rates of population rise and decline and habitat changes (Yoon 1997).  The most glaring problem seen by the scientists was the failure of HCPs to correctly assess the impact of losses to species' populations, mainly as a result of untested methods of appraising impacts.  One plan proposed to protect Utah Prairie Dogs (Cynomys parvidens) by moving animals to a new location using a method already known to result in the deaths of 97 percent of the relocated animals within three months (Yoon 1997).  An HCP for the Desert Tortoise (Gopherus agassizi) in Nevada allowed the killing of hundreds of these threatened reptiles by bulldozing their burrows and habitat, while protecting only minimal amounts of habitat. 
 
     A major problem faced by those trying to save endangered species is the fact that the vast majority live on privately owned land, and arrangements must be made with owners to insure the survival of these species.  Many people believe that protecting these species involves major restrictions on the use of their land and, therefore do not want to enter into Habitat Conservation Plans.  Ideally, however, protecting a threatened butterfly or plant on a private ranch, for example, would only involve identifying the habitat, the host plants for the butterfly, and preventing destruction through excavations or other major alteration of the land.  In many cases, cattle grazing is compatible with protection of rare species, since the land is not plowed, which can destroy plant life.  Ranchers in southern Arizona have cooperated in protecting the land through preventing overgrazing and maintaining riverbank vegetation and springs for rare frogs and birds.  For many endangered species, conservation easements are an excellent solution for their protection.  These easements involve the payment of funds to the landowner by private organizations, or local, state or federal governments to let the land remain undeveloped and help enhance it as wildlife habitat.  This is an especially good solution for farmers who are afraid of losing their land after years of crop failure or low market prices.  Innovation has marked many arrangements now being made to protect endangered and endemic species.
 
     The US public as a whole supports the protection of endangered species, which helps explain the Endangered Species Act's survival under strong opposition.  Polls conducted in November 1994 by Peter D. Hart Research Associates found that 57 percent of the public wanted to maintain the Endangered Species Act in its present form, and only 32 percent wanted to relax requirements.  A September 1995 CNN poll asked which was more important, saving endangered species or saving jobs:  48 percent replied endangered species, and 40 percent, jobs.  A Gallup poll carried out for CNN in April 2001 found that support remained strong.  It asked Americans whether they supported environmental and wildlife protection even if it meant higher prices or more jobs, and again, a majority supported conservation.  They were also asked to rank environmental protection in terms of its importance as an issue, and most placed it near the bottom of the list.  When asked whether it would be an important issue in 25 years, however, the majority said it would be among the most important issues.  This reflects a failure to understand the ongoing wave of extinctions that is eliminating many of the Earth's most fragile plants and animals and its possible effect on humans. 
 
     Thus, education is extremely important, especially its role in relating American lifestyles and waste of resources to the extinction and endangerment of species.  A 2001 film, "Natural Connections" (Howard Rosen Productions, shown on PBS), addresses this issue as well as the gradual diminution of biodiversity.  The overconsumption that Americans take for granted impoverishes nature in the US as well as in other countries that export their tropical hardwoods; cut flowers; leather from cows grazed in former rainforests; non-organic, sun-grown coffee; minerals; and handcrafts from scarce materials to this country.  Other products are manufactured as a result of polluting the environment and, like coated paper cups or pulp magazines, are used once and thrown away.  To maintain such a throw-away lifestyle, millions of trees are cut each year in the United States and elsewhere, disrupting ecosystems and threatening wildlife.  Pollution is created from mines that poison rivers, and manufacturing and power plants that spew dioxin and greenhouse gases into the air.  The urgency that gave rise to legislation early in the 20th century that protected native birds and other wildlife from overexploitation for commercial purposes was enacted after the extinctions of the Passenger Pigeon and Carolina Parakeet, and near-extinction of the American Bison (Bison bison) and other animals from 19th century slaughters.  It would be tragic if a similar wildlife or environmental catastrophe were needed to spur strong action to preserve the world's genetic and biological heritage.


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