Endangered Species

Introduction

A species whose numbers have declined so drastically that it is in danger of extinction throughout all or a significant part of its habitat is considered endangered. Extinct species no longer occur anywhere on Earth, and once they have disappeared, they are gone forever. Extirpated species have disappeared locally or regionally, but still survive in other regions or in captivity. Threatened species are at risk of becoming endangered in the foreseeable future. Drastic reductions in the population of a species or its complete disappearance diminish the bio-diversity of the ecosystems it inhabits and the planet as a whole.

Historical Background and Scientific Foundations

There are many reasons that a species may become threatened or endangered. Species have become extinct throughout the history of life on Earth due to selective pressures, natural climate changes, and catastrophic geologic events. However, the pace of extinction has accelerated dramatically in modern times due to human activities, and scientists estimate that present extinction rates are 1,000 to 10,000 times higher than the average natural extinction rate. Among the human activities that contribute to species endangerment are: land use practices, such as urban development, agricultural conversion, and deforestation; unsustainable levels of hunting or harvesting; habitat damage due to water, air, or soil pollution; intentional or accidental introduction of predators or diseases; and global climate change caused by humans.

An accurate assessment of the number of endangered species worldwide does not yet exist. This is due, in part, to the fact that the smallest, yet most multi-tudinous, species of plants, insects, and microorganisms have not been tallied. In addition, scientists believe that large numbers of as yet unknown (to science) and

unnamed species can be found in tropical rainforests. Since these forests are disappearing rapidly due to timber extraction and human population encroachments, all the species that inhabit these forests are likely to be endangered.

Since the number of species evaluated in the compilation of lists of endangered species is limited, the large numbers of plants and animals recorded on these lists is particularly alarming. IUCN-The World Conservation Union through its Species Survival Commission (SSC) has been assessing the status of species, subspecies, varieties, and selected subpopulations on a global scale for more than 40 years to highlight those at risk and promote their conservation. The IUCN Red Lists are intended to provide a comprehensive, apolitical, global approach for evaluating the conservation status of plant and animal species. The 2007 Red List of Threatened Species, released in September 2007, assessed 41,415 species. Of these species, 16,306 are threatened with extinction to a greater or lesser degree, an increase of nearly 200 species over the previous year. In addition, 65 species are found only in captivity or cultivation. According to the 2007 IUCN Red List, 25% of mammals, 12.5% of birds, 33% of amphibians, and 70% of the world's assessed plants are in jeopardy.

In the United States, species must meet a stringent set of criteria to be listed as endangered or threatened under the Endangered Species Act (ESA). In 2007, the U.S. Fish and Wildlife Service (FWS) listed 1,174 animal species and 1,921 plant species as threatened or endangered around the world. A listing under the ESA provides a species with a number of conservation benefits including protection from harm due to federal activities, restrictions on hunting and trade, development and implementation of recovery plans by the FWS (for species under U.S. jurisdiction), and protection of critical habitat.

Studies of species are often grouped by habitat. Freshwater ecosystems are among the most threatened. Marine species have historically been poorly covered in studies of endangered species due to the difficulties of studying these species in the world's vast oceans. Arid and semi-arid regions urgently need further study particularly since severe degradation of arid and semi-arid lands around the world is being accelerated by global warming. Global warming has also recently focused attention on polar regions, since one of the effects of global climate change appears to be accelerated melting of glaciers and Arctic ice. The plight of polar bears has attracted significant media attention.

Polar bears and other cold-loving species have very specialized adaptations for the harsh environments at the poles, and they have low tolerance for environmental change. Reductions in sea ice due to global warming influence not only the availability of polar bear hunting and denning habitat, but may impact the overall distribution and abundance of polar bears. Scientists have found evidence of polar bear drownings because some bears must swim longer distances (up to 60 mi/96 km) over open ocean in their search for food. In 2007, scientists studying the effects of climate and ice changes to help determine whether polar bears should be protected under the ESA estimated that two-thirds of the world's polar bears will disappear by 2050. These scientists concluded that polar bears are unlikely to be driven to extinction, but their habitat will contract significantly to the Arctic archipelago of Canada and areas off the northern coast of Greenland where sea ice persists even in warm summers.

Arid regions are getting hotter and drier, threatening the survival of plant and animal species already at their heat-tolerance limits. In marginal drylands, biodiversity is threatened by over cultivation. In the United States, for example, more than 50 species are now endangered in the Arizona desert, including some cactus varieties.

Marine and coastal waterways and freshwater systems also are vulnerable to climate changes. Freshwater fish have been seriously impacted with an estimated 20% of these fish species now extinct. Spawning and feeding habitats have changed. A number of salmon varieties are on the endangered species list due to habitat disruption, water pollution, and overfishing.

WORDS TO KNOW

BIODIVERSITY: Literally, “life diversity”: the number of different kinds of living things. The wide range of organisms—plants and animals—that exist within any given geographical region.

EXTINCTION: The total disappearance of a species or the disappearance of a species from a given area.

EXTIRPATED: The condition in which a species is eliminated from a specific geographic area of its habitat

HABITAT: The area or region where a particular type of plant or animal lives and grows.

THREATENED: When a species is capable of becoming endangered in the near future.

Plants have received less attention than animals, but they have not escaped the effects of climate changes. One quarter of all the wild potato species are predicted to be extinct within 50 years. Changes in rainfall patterns and increasing temperatures cause soil erosion and an increased leaching of soil nutrients. Wildfires are increasing in drier regions. In general, there are three main categories of potential effects of climate change on plant species. For plants existing in areas of climatic extremes, global warming may have drastic impacts, for example, forcing plants that require cold temperatures out of habitats like mountain peaks. If this is their only habitat, extinction will occur. Shifts in global biome distribution are another likely impact of global warming. Coniferous forests will shift farther north and grasslands and deserts will expand. Global warming also may alter how plants function in their existing environment by lengthening the growing season in some areas, especially in northern latitudes.

Impacts and Issues

Climate changes are affecting the environments inhabited by endangered species in many ways, including altering the timing of ecological events, such as the flowering of plants and the breeding of animals. Such changes are impacting the relationships of interdependent species whose interactions may be disrupted by differing rates of change. The habitats of species are shifting with the changing temperatures, but some habitats are disappearing rather than shifting. The species that inhabit these habitats may become extirpated from that region or may be driven to extinction.

Climate change impacts biodiversity by changing the distribution of species and threatening their survival as warm seasons grow longer. Global warming is reducing sea ice in polar regions and this melting is, in turn, accelerating global warming. Snow and ice reflect sunlight, but exposed darker land and ocean surfaces increase absorption of solar radiation. The melting ice caps in Greenland and Antarctica raise the sea level and add freshwater to the ocean. The added freshwater alters salinity and may cause shifts in ocean circulation.

Studies of threatened and endangered species are not consistent around the globe. The status of vertebrates is best documented with about 40% assessed. Species-rich environments, such as tropical forests and the oceans, are not well studied. What has become evident, however, is that species are declining fastest in tropical and subtropical regions and in the poorer regions of the world where conservation responses are often limited. Brazil, Indonesia, and the Philippines are among those regions.

A number of conservation organizations and governmental initiatives have been created to address the threats to Earth's biodiversity, including the World Summit on Sustainable Development, the international Convention on Biodiversity, and the United Nations Framework Convention on Climate Change and its Kyoto Protocol. More than 170 countries have signed the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES), which aims to ensure that international trade in specimens of wild animals and plants does not threaten their survival. Many individual countries have passed legislation to protect endangered species within their borders and to provide funding for recovery efforts. The World Wildlife Fund, Conservation International, and other similar nongovernmental organizations promote field research, sponsor species recovery efforts, and increase the public visibility of endangered species issues and their impact.

IN CONTEXT: POLAR BEARS AND THE ENDANGERED SPECIES ACT

Initial studies suggest that global climate change may already have taken a toll on Arctic polar bear populations. Polar bears require summer sea ice for hunting. Typically, polar bears swim between large and stable patches of sea ice, but the animals cannot swim long distances. Already researchers are noting thinner polar bears, decreasing birth rates, and declining cub survival rates in Arctic bear populations. The National Center for Atmospheric Research (NCAR) stated that, under a worst-case scenario, summer sea ice could disappear by 2040.

The U.S. Minerals Management Service released a report that documented the drowning deaths of at least 4 polar bears off of the Alaskan coast in September 2004. The report asserted that warmer than average temperatures prompted record melting of sea ice, stranding hunting polar bears. The report prompted several environmental organizations—including the Center for Biological Diversity, the Natural Resources Defense Council (NRDC), and Greenpeace—to sue the U.S. government for failing to take action on an earlier petition to have polar bears evaluated for inclusion as a threatened species under the Endangered Species Act. Environmental groups and researchers asserted that the U.S. government failed to address the question of adding polar bears to the threatened species list because of a policy of downplaying the possible effects of global climate change. Under the act, the secretary of the interior should have responded within 90 days and opened the issue for public comment. Government officials claimed that they were actively studying polar bear populations for over two years.

Under a court settlement, the U.S. Department of the Interior announced that it was formally proposing to designate polar bears as a threatened species. Identifying polar bears as threatened could give environmental groups more power to challenge current standards governing carbon dioxide emissions and other leading contributors to climate change.

Although extremely limited when compared to the enormity of the problem, there have been some success stories. The California condor has been successfully returned to the wild as a result of a concerted captive breeding and release program, and the black-footed ferret is making a comeback in the western prairies of the United States due to a similar program. A wide range of recovery initiatives extending over several decades resulted in the removal of the bald eagle from the U.S. endangered species list in 2007. In Canada, a red squirrel population seems to be adapting successfully to changing climate conditions. Scientists studying these squirrels have found that they now produce offspring on average 18 days earlier in the year than their great-grandmothers did, probably due to warmer spring temperatures. These squirrels provide some of the first hard evidence that mammals can adapt to a warmer world in a few generations.

Primary Source Connection

This article discusses how climate change may affect the production of baseball bats. For decades, ash from the Northeastern and Midwestern United States has been the wood of choice for baseball bats. Warmer temperatures could cause ash wood to become softer, and some fear the species could be wiped out.

BALMY WEATHER MAY BENCH A BASEBALL STAPLE

RUSSELL, Pa. —Careers at stake with each swing, baseball players leave little to sport when it comes to their bats. They weigh them. They count their grains. They talk to them.

But in towns like this one, in the heart of the mountain forests that supply the nation's finest baseball bats, the future of the ash tree is in doubt because of a killer beetle and a warming climate, and with it, the complicated relationship of the baseball player to his bat.

“No more ash?” said Juan Uribe, a Chicago White Sox shortstop, whose batting coach says he speaks to his ash bats every day. Uribe is so finicky about his bats, team-mates say, that he stores them separately in the team's dugout and complains bitterly if anyone else touches them.

At a baseball bat factory tucked into the lush tree country here in northwestern Pennsylvania, the operators have drawn up a three-to-five-year emergency plan if the white ash tree, which has been used for decades to make the bat of choice, is compromised.

In Michigan, the authorities have begun collecting the seeds of ash trees for storage in case the species is wiped out, a possibility some experts now consider inevitable.

As early as this summer, federal officials hope to set loose Asian wasps never seen in this country with the purpose of attacking the emerald ash borer, an Asian beetle accused of killing 25 million ash trees in Michigan, Illinois, Indiana, Ohio and Maryland since it was spotted in the United States five years ago.

In late June, officials found signs of the ash borer's arrival in Pennsylvania, setting off a new alarm for the makers of baseball bats, most of which come from this rocky, cool range on the New York border.

Along with the ash borer beetle, a warming of the local climate could also affect the ash used for bats, some scientists say. As temperatures rise, the ash wood that now makes an ideally dense but flexible bat might turn softer because of a longer growing season. Eventually, some scientists predict, the ash tree could vanish from the region.

A warmer climate could also aid the emerald ash borer's invasion, some scientists contend, although others disagree, by creating stressed trees and the possibility of a quicker reproduction cycle in the beetle.

“We're watching all this very closely,” said Brian Boltz, the general manager of the Larimer & Norton company, whose Russell mill each day saws, grades and dries scores of billets destined to become Louisville Slugger bats. “Maybe it means more maple bats. Or it may be a matter of using a different species for our bats altogether.”

Such uncertainty does not sit well with professional players, some of whom shun (or break) bats that have failed them and worship those that have sent balls out of the park. (Some widely suspect that the well-known players get the best-quality wood, and the rookies, something softer.) Baseball, after all, is a game of routine, of instinct, of superstition.

The magic in a perfect bat is not easy to define. “You can't describe it—it's a feel,” said Scott Podsednik, an outfielder for the White Sox. “When you pick it up and take a couple of swings with it, you just know.”

After batting practice one morning, Podsednik's team-mate Uribe sheepishly confirmed his lectures to his bats (his beloved “Hoosier HB 23” models). “I tell them: ‘do your job and if you don't do your job, I'm going to have to go back to the Dominican Republic,’” Uribe said in Spanish. “Sometimes they listen; sometimes they don't.”

For much of a century, ash was the wood that ruled the realm of baseball bats, but it has faced threats before: First, competition from aluminum and composite bats (which whisked away much of the youth and amateur market but are barred from professional baseball) and then, in the past decade, from the sugar maple.

When it became known that Barry Bonds of the San Francisco Giants, who is closing in on baseball's career home-run record, was using maple bats, change swept through baseball's clubhouses.

Some bat makers say professional players are now about evenly divided between ash and maple, which is more expensive and which some players (catchers, especially) say tends to explode more violently when a bat breaks.

“Maple is all the rage with the young players coming up now,” said Tom Hellman, the clubhouse manager for the Chicago Cubs, whose responsibilities include ordering bats and keeping track of them. “But the older players still want their ash.”

Science has never definitively established whether ash makes the optimal bat. Terry Bahill, an engineer at the University of Arizona and a co-author of “Keep Your Eye on the Ball: Curveball, Knuckleballs and Fallacies of Baseball,” said researchers could measure how much energy was dissipated when a bat struck a baseball and how much force was required to bend a bat.

“But in the end,” Mr. Bahill said, “we can't tell you which bat is going to be more effective because a human being is going to be swinging this bat. So the players making decisions about bats are making them on feelings, not scientific data.”

Some scientists, however, do see a threat to the quality of the northern white ash posed by rising temperatures over a period of decades. Ash that grows in the warmer Southeastern States is held to be softer, in part because of the longer growing season, said Ron Vander Groef, who runs a factory in Dolgeville, N.Y., which make Rawlings bats.

There are also some concerns that the numbers of white ash trees in the North could significantly decline. Louis R. Iverson, a research landscape ecologist with the United States Forest Service, has helped map how habitat changes could affect 134 tree species by the end of the century. In a worst-case scenario, the white ash (and the sugar maple) diminish in numbers and shift farther north.

Still, the emerald ash borer, or Agrilus planipennis Fairmaire, is the most immediate threat. Discovered in the United States near Detroit in 2002, the beetles, which are shiny green, will destroy a tree in two to three years. The larvae tunnel inside the trees, cutting off water and food.

The ash borer is native to Asia, where the trees are naturally resistant to it.

“It just doesn't look good,” Dan Herms, an associate professor of entomology at Ohio State University, said of the prospect of stopping the beetle in this country. “The current technology won't be able to stop it.”

Dr. Herms strongly disputes any link between the ash borer and climate change, saying that the beetle has survived in a wide range of temperatures in Asia.

For now, the baseball bat makers are bracing for the worst. At the mill in Russell, even as machines cranked and hummed with ash billets last month, state investigators were barring the movement of wood from four Western Pennsylvania counties after adult beetles were discovered.

Some suppliers say they are harvesting trees years earlier than planned because of the ash borer's arrival.

In the end, baseball players may be faced with switching to, and holding conversations with, bats made of maple or some new wood yet untested by the hardball.

Monica Davey

davey, monica. “balmy weather may bench a baseball staple.” the new york times. july11, 2007.

See Also Desert and Desertification; Extinction; Forests and Deforestation; United Nations Environment Programme (UNEP.)

BIBLIOGRAPHY

Web Sites

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Miriam C. Nagel