America's wildlife winners and losers of the twentieth century
provided by Environmental Defense Fund
ince colonial times, wildlife in America has faced two periods of crisis, one at the close of the 19th century, the other at the close of this century. And yet, these times of crisis have also been times of great hope for the future of our embattled wildlife.
The last quarter of the 19th century witnessed the end of the last, great flocks of passenger pigeons and herds of bison, the near-extinction of sea otters, ruthless campaigns to rid the West of its wolves, grizzlies, and other large predators, and insatiable commercial markets for the feathers and flesh of all manner of birds. The modern environmental movement began in response to this destruction of wildlife, and thankfully succeeded in stopping some of the worst abuses. Today, a network of national wildlife refuges, parks, and forests, as well as numerous laws and treaties, provide a safety net of sorts for American wildlife.
As we approach the end of this century, as much as a third of our total flora and fauna is currently in danger of extinction -- more than at any time since the end of the Ice Age. Over-exploitation -- the bane of conservationists at the turn of the century -- is no longer a major threat to most animals (with the notable exception of some fisheries). Instead, it has been replaced by three far more ruthless and indiscriminate killers: habitat destruction, nonnative or alien species, and pollution.
It's a grim situation, but by no means a hopeless one. A new Executive Order from the White House is designed to curb the accidental or intentional release of foreign plants and animals in the United States. Reducing this "alien invasion" will go a long way toward preventing many plants and animals from becoming endangered. The White House and Congress are both talking about creating a permanent source of funding for the starved Land and Water Conservation Fund, which would be used to purchase new parks and open space. The US Fish and Wildlife Service has instituted a "safe harbor" program that allows landowners to restore habitats for endangered species without incurring additional regulatory burdens; thus far, over a million acres of land have been enrolled in the program.
As the yearand the centuryand the millennium draw to a close, it's time to look back on the species that have done well and the ones that haven't. In that spirit, here's our list of America's Wildlife Winners and Losers of the Twentieth Century:
Wildlife Winners of the Century
1. Bald eagle
The widespread use of DDT and other persistent pesticides in the years after World War II caused populations of bald eagles, peregrine falcons, ospreys, and other birds to crash. The pesticides interfered with the birds' reproduction, causing them to lay infertile eggs or eggs with shells so fragile they collapsed under the weight of the incubating parent. The bald eagle population in the Lower 48 dropped to fewer than 450 pairs in the 1960s, and the eagle was added to the endangered species list in 1967. The banning of DDT, coupled with the protection of nesting sites and reintroduction programs made possible under the Endangered Species Act, set the stage for the eagle's recovery. In 1998, the breeding population of eagles in the Lower 48 totaled 5,748 pairs. This past summer, the Interior Department announced that it would remove the eagle from the endangered species list, an auspicious beginning for the new millennium.
2. White-tailed deer
As improbable as it seems today, the white-tailed deer was in danger of disappearing from large parts of the United States at the beginning of the 20th century. Unregulated hunting, combined with extensive deforestation, had eliminated deer from most of their historic range. Fewer than half a million remained in the nation. The imposition of game laws, the regeneration of the eastern forests, and (unfortunately) the extirpation of major deer predators such as wolves and mountain lions, allowed this graceful animal to stage one of the century's biggest comebacks. Today, some 17 to 25 million whitetails prowl the forests, fields, and suburbs of America. In many areas, white-tailed deer have become so abundant that they are now pests, destroying farm crops, consuming backyard vegetable gardens, decimating native wildflowers, and impeding the regeneration of forests by consuming young hemlocks and yews.
3. Brown-headed cowbird
Like the white-tailed deer, the brown-headed cowbird is an example of a native species that has succeeded all too well. A member of the blackbird family, the cowbird is a brood parasite -- it lays its eggs in the nests of other bird species, at the expense of the hosts' own eggs and offspring. Prior to the arrival of European settlers, cowbirds were largely confined to the central plains, where they followed the roaming herds of bison, eating the insects stirred up by them. The clearing of the forests for pasture and farmland, as well as the introduction of domestic livestock, enabled cowbirds to spread to new areas and increase in abundance. The expansion of rice farming in the South also has benefited cowbirds by providing them with an abundant new food source for the winter: waste grain left in the fields after harvest. More cowbirds, of course, mean that more nests of other birds are being parasitized. In recent decades, cowbird parasitism has been a key factor in the near-extinction of the Kirtland's warbler, black-capped vireo (see "Wildlife Losers"), and least Bell's vireo. The survival of all three species now depends upon ongoing efforts to control cowbird numbers in key breeding areas. In addition, cowbird parasitism is thought by many scientists to be one reason why populations of forest-dwelling warblers, vireos, tanagers, and other songbirds have been declining in many parts of the East.
4. Gray wolf
Prior to the arrival of settlers from Europe, gray wolves occurred from Alaska to Mexico, and from the Atlantic to the Pacific. They were hated and feared by most settlers, who persecuted them with a vengeance. By 1960, the only wolves remaining in the United States were in Alaska and northern Minnesota. Protection under the Endangered Species Act enabled the Minnesota population to grow and expand; it also allowed a few wolves to move safely south from Canada and recolonize the northern Rockies. In 1995, after years of prodding from environmentalists, the federal government reintroduced wolves in Yellowstone National Park and in wilderness areas of central Idaho. The results have been spectacular: more than 200 adult wolves now roam the wildlands of Yellowstone and central Idaho, and last spring, about 120 pups were born in the two areas. Tourists from around the world have been flocking to Yellowstone to catch a glimpse of them. The reintroduction of the gray wolf has cost less, succeeded better, and generated fewer conflicts with livestock than virtually anyone predicted when these efforts began.
5. Gray whale
One of the easiest whales to hunt because of its slow speed and preference for inshore waters, the gray whale was driven close to extinction by whalers. A population along the Atlantic coast vanished in the early 18th century; another population in Asia has been reduced to a few hundred individuals; and a third population along the Pacific coast of North America -- the well-known population that migrates from feeding grounds in the Bering and Chukchi seas to breeding grounds off the coast of Baja California -- numbered no more than a few thousand at the start of the 20th century. Protection for this Pacific coast population has enabled it to stage a remarkable recovery. It is now estimated to number 23,000 individuals, which is equal to if not greater than the population prior to exploitation. The Pacific gray whale was taken off the endangered species list in 1994.
6. Northern elephant seal
From the blubber of a single 18-foot elephant seal, a seal hunter could extract more than 210 gallons of oil, which was used to fuel lamps. For this reason alone, North America's largest seal was brought to the brink of extinction. By the start of the 20th century, fewer than 100 individuals were left. Protection came not a moment too soon. Today, over 125,000 elephant seals crowd the beaches of California and Baja California, earning this species the title of "comeback kid of the century."
7. Whooping crane
Our tallest bird has been the subject of what is perhaps the longest running and highest profile conservation effort for any imperiled species in the United States. Whooping cranes once nested on the northern prairies south to present-day Iowa and Illinois, with scattered numbers elsewhere in the Southeast, but hunting and the destruction of wetlands took a heavy toll on them. By the 1940s, approximately 20 cranes remained. The whooping crane was added to the endangered species list in 1967. Aggressive enforcement of the Endangered Species Act's stiff penalties against killing cranes, protection of the birds' winter habitat along the Texas coast and their migratory stopover sites along the Platte River, and a captive breeding program have all been used to bolster the population. More recently, federal and state officials have attempted to create a new, non-migratory population of cranes in Florida. As a result of all these efforts, the wild population of whooping cranes now exceeds 250, which is probably more than at any time this century. Although the whooping crane is by no means out of danger, it nonetheless represents one of this century's greatest success stories in wildlife conservation.
Among the nation's least-loved species, cheatgrass is nonetheless one of this century's biggest winners. Native to the Old World, it was accidentally brought to the United States and Canada in the late 1800s. Once on this continent, cheatgrass "rode the rails," dispersing its seeds via grain shipments, livestock feed and bedding, and animal dung. Its spread was also facilitated by threshing machines, which were moved from farm to farm without being cleaned. In some places, range experts even planted it deliberately in order to replenish overgrazed rangelands. Cheatgrass is a highly flammable plant that dies and dries out in the spring, creating ideal fuel for summer wildfires. The summer fires, in turn, sweep through the shrublands, killing or damaging native plants, and creating new opportunities for the cheatgrass. Inventories show that cheatgrass currently dominates tens of millions of acres of what was once sagebrush steppe in the West. Alien species like cheatgrass are second only to habitat degradation as a cause of (native) species endangerment in the United States -- and more unwelcome plants and animals are crossing our borders every year aboard planes, trains, ships, and automobiles.
Wildlife Losers of the Century
1. Passenger Pigeon
Once the most abundant bird on the planet, with flocks that literally darkened the sky, the passenger pigeon was the victim of relentless, ruthless overhunting, coupled with the clearing of the eastern forests. By the end of the 19th century, it was on the brink of extinction. And less than one hundred days into the new century, on March 24, 1900, the last wild passenger pigeon was killed in Pike County, Ohio. The last captive individual, an aged female named Martha, died at the Cincinnati Zoo on September 1, 1914. Today all that remains of this once-abundant species are the written accounts of the early naturalists, a few stuffed specimens, and the term "stool pigeon," which once referred to passenger pigeons that were captured and tethered and used to lure other passenger pigeons to the ground where they could be netted.
2. Turgid-blossom pearly mussel
This obscure little creature, now believed extinct, stands for something more: the wholesale destruction of America's freshwater fauna over the course of this century. In general, our freshwater species -- fish, mussels, dragonflies, etc. -- are disappearing at a much faster rate than our terrestrial species, despite laws like the Clean Water Act. Approximately two-thirds of North America's freshwater mussels, for example, are either extinct or gravely imperiled. The turgid-blossom pearly mussel once inhabited twelve rivers in Arkansas, Missouri, Tennessee, and Alabama, but river impoundments, siltation, and pollution steadily reduced its range. In the early 1970s, the last known population lived in the upper reaches of the Duck River, in central Tennessee, precisely where the Tennessee Valley Authority intended to put a dam. Most freshwater mussels cannot survive in the murky, still waters that are created by dams. The US Fish and Wildlife Service, unwilling to block the construction of the dam for the sake of a rare mussel, delayed putting this species on the endangered list until after the dam was completed. By that time, of course, it was too late: the turgid-blossom pearly mussel was gone.
3. Snake River sockeye
The poster child for the Northwest's dwindling salmon populations may well be the Snake River sockeye. Historically, few salmon traveled as far or climbed as high as the intrepid sockeyes of the Snake River, which for countless generations journeyed 900 miles from the Pacific Ocean through the Columbia River and up the Snake River to their ancestral spawning grounds in Idaho's Redfish Lake. A difficult journey in the best of times, it has become a near impossibility in recent decades due to dams, water diversions, logging, grazing, and other activities that have degraded and destroyed salmon habitat. By the time the Snake River sockeye was granted protection under the Endangered Species Act in January 1992, the population was down to a handful of individuals. A captive breeding program is underway, and state and federal authorities have promised to take action to improve salmon habitat. Whether these actions will be enough to halt or even reverse the decline is open to debate. At the present time, the future of the Snake River sockeye, and that of many other salmon stocks in the Pacific Northwest, looks bleak.
According to scientists at the Interior Department, North America's grassland birds have shown steeper and more widespread declines over the past quarter century than any other group of birds. The bobolink, a colorful member of the blackbird family, is a case in point. Occurring in hay fields, grasslands, and pastures across much of the United States, it is declining in most of its range. In Illinois, for example, bobolinks declined by a staggering 93 percent between 1966 and 1991. This sharp drop can be attributed to two factors: the conversion of pastures and hay fields to row crops, and a trend toward cutting hay fields earlier in the season, when the bobolinks are still nesting. There is some cause for optimism, however. The Department of Agriculture's Conservation Reserve Program pays farmers to retire tens of millions of acres of highly erodible soils from crop production and plant them with cover (mostly grass). Bobolinks and other grassland birds have found much of this newly restored habitat to their liking.
5. Black-tailed prairie dog
The four species of prairie dogs that inhabit the grasslands of western North America are critical components of those ecosystems. By creating a vast network of burrows and by continually clipping the grass around their colonies, prairie dogs create a diversity of habitats supporting many other species of plants and animals. Among the animals associated with prairie dog colonies are a number of rare and declining species, including the black-footed ferret, swift fox, mountain plover, sage grouse, and burrowing owl. The settlement of the western grasslands had severe consequences for prairie dogs due to poisoning, land conversion, and overgrazing by livestock. Of the four species, the black-tailed was by far the most numerous. In its heyday, it occupied more than a hundred million acres of the central plains along the eastern side of the Rockies, from Canada to Mexico. Its total population must have numbered in the hundreds of millions, if not billions. Since settlement of the West, it has suffered a 98 percent reduction in range and now survives only in scattered locations. It is being considered for listing as a threatened species. Ranchers continue to exterminate prairie dogs throughout the West, under the belief that these animals compete with livestock for forage. Yet studies show that prairie dogs actually prevent shrubs from encroaching on grasslands, thereby benefiting the ranchers. Moreover, their habit of clipping the grass around their colonies improves the quality of the grass and forbs for livestock. Prairie dogs also are shot for "sport" and target practice.
In the summer of 1973, two students from the University of Hawaii stunned the ornithological world when they discovered a previously unknown species of songbird living in the remote rainforests of Maui. The po'ouli was the first new bird species to be discovered in the United States since the beginning of the century. Estimates placed the total population at around 140 individuals, all occurring within an area of rainforest totaling less than 2 square miles. In recent years, however, the po'ouli population has crashed, probably because feral pigs have destroyed much of the vegetation where the birds live. Diseases spread by nonnative birds brought to the Hawaiian Islands by well-meaning people may be contributing to the decline as well, along with predation by rats. The most recent census turned up only three remaining po'ouli, and the species seems destined for extinction in the near future. To some degree, however, the demise of the po'ouli comes as no surprise: The Hawaiian Islands have one of the highest proportions of extinct or endangered species of any comparably sized area on earth. The reason for this epidemic of extinction is a combination of habitat destruction and the widespread release of nonnative or alien species.
7. Black-capped vireo
At the turn of the century, black-capped vireos could be found in shrublands from central Kansas south through Oklahoma and Texas into northern Mexico. But, like many other songbirds, it is a prime target of the brown-headed cowbird (see "Wildlife Winners"), which parasitizes the nests of other birds. Heavy rates of nest parasitism by cowbirds, coupled with the destruction and degradation of its shrubland habitat by developers and livestock, landed the black-capped vireo on the endangered species list in 1987. Today, the only sizeable populations left in the United States occur in the Hill Country of Texas. Fortunately, cowbird control programs in a number of key vireo nesting areas have dramatically reduced the rate of nest parasitism and allowed vireo populations to expand. A loser in the 20th century, the black-capped vireo may well emerge a winner in the 21st.
8. Longleaf Pine
When the Spanish began exploring North America in the 16th century, nearly pure stands of stately longleaf pines covered about 74 million acres in the southeastern coastal plain, from Virginia south to Florida and west to Texas. Frequent summer wildfires, spawned by lightning storms or set by Indians, kept oaks and other hardwoods from crowding out the fire-resistant longleaf pine. Today, less than 3 percent of the original longleaf pine forest ecosystem remains, and most of that is in a highly degraded condition. Four factors contributed to the demise of this uniquely American ecosystem. First, at the turn of the century, the longleaf forests were heavily logged but not replanted with longleaf pine. Other species of trees then grew up on these sites. More recently, much of the remaining longleaf forest has been harvested and replaced with other, faster-growing pine species preferred by the forest products industry. Second, prior to the development of petroleum-based substitutes, settlers used the tar, pitch, rosin, and turpentine of longleaf pines to lubricate wagon axles, waterproof sails, caulk leaks, and protect the hulls of ships against shipworms; vast acres of long-leaf pine trees were literally bled to death. Third, for much of the 19th century, large numbers of feral hogs roamed the South, eating longleaf seedlings. Finally, due to fire suppression, much of the remaining acreage of longleaf pine has become overgrown with hardwoods. Numerous plants and animals associated with the longleaf pine ecosystem have suffered severe population declines due to demise of these forests, foremost among them the endangered red-cockaded woodpecker.