Production and Harvest Production of wheat begins with the selection of the seed. So that high yields can be obtained, extreme care is taken to select only the highest-quality seed. For winter wheat, the seed is planted in the fall, generally at the time oftheaveragefirst frost. This timing allows the crop to make a stand before winter but is not so early that itbegins rank growthor starts to send uptall shoots. Spring wheat is generally planted as early as is practical in the spring, which is usually early March in the areas where spring wheat is normally grown. In the United States, almost all wheat is planted by drill- ing theseed intothe soil.Drilling providesfor the best germination and the least amount of winter killing. Harvest time for wheat is determined primarily by the moisture content of the grain. Most wheat in the United States is harvested with mechanical combines, and the ideal seed moisture for combine harvest is 12 to 13 percent. After harvesting, the grain is taken to the mill. During the milling process, the grain is washed and scoured to remove fuzz and foreign mate- rial. The grain is then tempered by soaking in water to toughen the bran. After tempering, the grain is crushed by a series of corrugated rollers. The bran, produced primarily inthe seed coat, is then separated from the starch. The milled flour is often chemically bleached to improve the color and baking quality and enriched with vitamins and minerals to replace those lost by removing the bran. The average flour yield is 70 to 74 percent of the weight of the grain. D. R. Gossett Further Reading Carver, Brett F. Wheat: Science and Trade. Ames, Iowa: Wiley-Blackwell, 2009. Fageria, N. K., V. C. Baligar, and R. B. Clark. Physiology of Crop Production. New York: Food Products Press, 2006. Kipps, M. S. Production of Field Crops: A Textbook of Agronomy. 6th ed. New York: McGraw-Hill, 1970. Martin, John H., Richard P. Waldren, and David L. Stamp. “Wheat.” In Principles of Field Crop Produc- tion. 4th ed. Upper Saddle River, N.J.: Pearson Prentice Hall, 2006. Metcalfe, Darrel S., and Donald M. Elkins. Crop Pro- duction: Principles and Practices. 4th ed. New York: Macmillan, 1980. Perkins, John H. Geopolitics and the Green Revolution: Wheat, Genes, and the Cold War. New York: Oxford University Press, 1997. Posner, Elieser S., and Arthur N. Hibbs. Wheat Flour Milling. 2d ed. St. Paul, Minn.: American Associa- tion of Cereal Chemists, 2005. Rather, Howard C., and Carter M. Harrison. Field Crops. 2d ed. New York: McGraw-Hill, 1951. Sleper, David A., and John Milton Poehlman. “Breed- ing Wheat.” In Breeding Field Crops. Ames, Iowa: Blackwell, 2006. Web Sites U.S. Department of Agriculture, Economic Research Service Wheat http://www.ers.usda.gov/Briefing/Wheat U.S. Department of Agriculture, Economic Research Service Wheat Data http://www.ers.usda.gov/Data/Wheat See also: Agricultural products; Agriculture indus- try; Corn; Green Revolution; Horticulture; Monocul- ture agriculture; Plant domestication and breeding; Rice. Wilderness Categories: Ecological resources; environment, conservation, and resource management; social, economic, and political issues Wilderness is an ecosystem resource. Unlike the Arctic tundra or the tropical rain forest, wildernesscannot be defined in termsof specific biological, geological, or cli- matological characteristics. In principle, wilderness can be any ecosystem that is relatively unmodified by human activity, but the term “wilderness” has gener- ally beenapplied to terrestrial as opposed to marineeco- systems. Background Characterizing wilderness as a natural resource may seem strange, but the same characteristics that make coal and oil natural resources make wilderness a natu- ral resource as well. The term “natural resource” ap- plies to any component of the natural world valued by humans. For most of human history, wilderness was not valuedas a resource. Wildernesswas eithera place 1336 • Wilderness Global Resources to be avoided, inhabited by wild beasts and dangerous to humans, or it was just leftover, unused land. As a species, humans havedevoted much collective energy to modifying environments to suit their desires, and wilderness is now relatively scarce. Sierra Club head and environmental activist J. Michael McCloskey has argued that wildernessis valued only when society has educated leaders, the economy produces surpluses, and wilderness is increasingly scarce. In the United States these conditions began to be met in the late nineteenth century in the aftermath of the Industrial Revolution. In much of the world, these conditions have not yet been satisfied. Wilderness Definitions The word “wilderness” means, literally, characterized by wild animals. It suggests an absence of agriculture, industry, roads, and structures—and of human civili- zation generally. Wilderness is a place, typically re- mote from civilization, where the natural fauna and flora have not been significantly modified by human activity, or in the words of the 1964 Wilderness Act, “Where the Earth and its community of life are un- trammeled byman, where manhimself is avisitor who does not remain.” Wilderness Values The values that make wilderness a resource in the modern world can be grouped into three broad cate- gories: experiential, ecological, and intellectual. Eco- nomic consequences arise directly or indirectly from each of these value groups. To many Americans the most obvious value of wilderness is experiential. Wilderness is a venue for hiking, hunting, backpacking, canoeing, camping, fishing, and photography. Wilderness provides recre- ational users opportunities for solitude, physical chal- lenges, emotional growth, and environmental educa- tion. Adventure-education programs are widespread in North America and include Outward Bound, Wil- derness VisionQuest, and the National Outdoor Lead- ership School. The proliferation of these programs and their preference for unmodified ecosystems is one measure of the experiential value of wilderness. The most direct experiential value of wilderness is outdoor recreation. Data about recreational use of wilderness are fragmentary at best. The most system- atic effort to estimate recreational use of national for - est and national park wilderness areas in the United States found irregular growth, from about 3 million visitor-days in 1965 to about 17 million in 1994. Reli - able subsequent estimates are unavailable, but ex- perts agree that aggregate wildernessrecreational use continues to grow in the United States. Popular areas are often crowded, and in some areas, wilderness managers have adopted quota and reservation sys- tems to reduce congestion. Although wilderness is often thought to exclude commercial enterprise, wilderness recreation has im- portant economic impacts. It supports guides, outfit- ters, recreational-equipment manufacturing and re- tailing, and ecotourism. It is not uncommon for wilderness recreationists to travel for hundreds or even thousands of kilometers to visit a particular wil- derness area. Not all wilderness users are recreational. Outside the United States and in Alaska, wilderness may pro- vide for the subsistence needs of indigenous peoples whose economies and cultures are dependent on wildland ecosystems. In the United States, the Alaska National Interest Lands Conservation Act of1980 spe- cifically authorized subsistence use of Alaskan parks and wilderness areas by local rural residents, mostly Alaskan native tribes. The ecological values of wilderness are less appar- ent butarguably more important.Wildernesscontrib- utes tocritical ecosystemservices suchas regulation of the hydrologic cycle, weather modification, pollina- tion, photosynthesis, and carbon sequestration. Wil- derness areas are particularly valuable for the conser- vation of complexnatural ecosystems, preservation of biological diversity, and protection for wilderness- dependent species. Specific wilderness ecosystems of global importancebecause oftheir ecosystemservices are under severe threat. Tropicalrain forestsare prob- ably the oldest, continuously functioning terrestrial ecosystems on Earth, and they are certainly among the most biologically rich. By most accounts, they are home to more than one-half of the world’s plant and animal species. Despite their global importance, trop- ical rain forests are being reduced by more than 200,000 square kilometers per year, with a concomi- tant loss of species numbering in the tens of thou- sands. One measure of the economic importance of global wilderness as a genetic repository is provided by the increasing energy expended there by the phar- maceuticals industry in search of natural compounds with medicinal value. The intellectual value of wildernesscomes in many varieties. Wilderness has important scientific value as Global Resources Wilderness • 1337 a natural baseline against which to measure the im - pact of human activity elsewhere. As relatively undis- turbed ecosystems become increasingly rare, their value to science will rise. To Americans, wilderness also has symbolic and historical value. Early Americans battled the wilder- ness for their very survival, and the country’s history as a people is told in terms of westward expansion and life on the frontier. The historian Frederick Jackson Turner argued that American democracy and the American character itself had been shaped by the country’s collective wilderness experience. It is no wonder that wilderness has come to be seen as a part of U.S. national heritage. For many, wilderness is a place of transcendence and spirituality, and the literature of wilderness is re- plete with references to the sacred. During his battle to prevent a dam in the wilderness of Yosemite Na- tional Park, Sierra Club founder John Muir famously compared flooding the Hetch Hetchy Valley with des- ecrating a temple. Reflecting the Judeo-Christian tra- dition, many Western authors and entrepreneurs have invoked images of Eden in reference to wilderness. Literature and the visual arts providea vicariousex- perience of wilderness for many Americans who may never visit a wilderness area in person. Edward Abbey introduced millions to the wilderness charms of the arid West. Sigurd F. Olson gave voice to the singing wilderness of boreal-forest canoe country. The wilder- ness images captured by photographers from Ansel Adams to David Muench have become a part of Amer- ican culture through museum exhibits, exquisite art volumes, postcards, and calendars. To many people, simply knowing that wilderness exists and that it will be available tofuture generationsis worthsomething. As with other resources, the value of what remains evolves with the changing needs of society, and it in- creases with scarcity. For most of the twentieth cen- tury, wilderness was valued primarily as recreational space. In the latter half of the twentieth century, in- creased awareness of global climate change and mass extinction increased the value humans placed on wil- derness for ecosystem services such as carbon seques- tration and preservation of biological diversity. Wilderness Distribution No reliable inventory of the Earth’s wilderness exists. Every ecosystem has undergone a degree of modifica - tion from human activity, and there is no agreement on the degree of modification required to disqualify an areaas wilderness.Between 1987and 2003, various studies estimated the Earth’s remaining wild areas (excluding Antarctica) to be 17 percent (excluding Antarctica), 34 percent, 38 percent, 46 percent, and 52 percent of Earth’s land area. The more optimistic estimates allow for greater ecologicaldisturbance and human population densities of up to ten per square kilometer. Regardless of the definition employed, the remaining relatively undisturbed lands are found dis- proportionately in polar, arid, and alpine ecosystems, areas relatively hostile to human habitation and rela- tively poor in terms of biological diversity. Rapid pop- ulation growth and effective technologies for modify- ing the natural environment are shrinking global wilderness, and a relatively small proportion of these less disturbed lands have any kind of governmental protection. A 2002 study by Conservation Interna- tional noted that only 7 percent of the area it had identified as wilderness had any kind of legal protec- tion. Wilderness Preservation Wilderness is preserved in varying degrees in a variety of conservation systems around the world. Although total wilderness isshrinking, protectedlandscapes, in- cluding wilderness areas, are growing. In 2009, the World Database of Protected Areas reported growth in protectedareas generally from about 0.4percent of the Earth’s land area in 1964 to about 3.3 percent in 2007. There were about 1,650 national parks protect- ing about 353 million hectares in more than 140 coun- tries and more than 1,300 wilderness areas, covering 52 million hectares. Some of the most significant of the world’s natural areas have been granted interna- tional recognition asUnited NationsEducational, Sci- entific and Cultural Organization (UNESCO) World Network of Biosphere Reserves, Wetlands of Interna- tional Importance (Ramsar Sites), orUNESCO World Heritage Sites. In the United States, wilderness preservation, as a concept distinct from national parks protection, was pioneered by the Forest Service in the 1920’s, nur- tured by conservation groups such as the Wilderness Society, and eventually institutionalized by Congress in the Wilderness Act of 1964. The Wilderness Act de- fined wilderness as “an area of undeveloped Federal land retaining its primeval character and influence, without permanent improvements or human habita - tion, which is protected and managed so as to pre - serve its natural conditions.” Between 1964 and 2009, 1338 • Wilderness Global Resources the National Wilderness Preservation System grew to 756 units comprising 44 million hectares. Most of that increase resulted from passage of the Alaska National Interest Lands Conservation Act of 1980. Two-thirds of the total area and most of the largest wilderness units are in Alaska. Unlike the national park concept, the wilderness concept has notbeen widely emulated. Only Australia and Canada have designated significant numbers of large wilderness areas. Even in the United States, the system of designated wilderness areas fails to protect the full diversity of ecosystems. A 1988 analysis by George D. Davis concluded that only 157 of the 261 ecotypes occurring in the United States were repre- sented in the wilderness system. In 2005, using the less specific Bailey’s province-level ecosystem classifi- cation, GregoryH. Aplet andothers found forty-three of fifty-two ecoregions represented in the National WildernessPreservation System, some of them poorly represented. As with global wilderness, the U.S. Na- tional Wilderness Preservation System underrepre- sents ecosystems that are biologically rich and easily susceptible to human modification. Wilderness advo - cates often complain that American wilderness desig- nations protect mostly rock and ice. Wilderness Management Around theworld, mostwildernessis unmanagedand unprotected. In the UnitedStates, fourseparate agen- cies have the responsibility to manage wilderness ar- eas established within their respective jurisdictions. The National Park Service manages 40 percent of the wilderness system by area.The U.S.Forest Service,the U.S. Fish and Wildlife Service, and the U.S. Bureau of Land Management manage 33, 19, and 8 percent, re- spectively. However, the Forest Service remains the nation’s primary wilderness management agency, with responsibility for 59 percent of the wilderness area in the contiguous forty-eight states and the greatest number of wilderness users. Legal wilderness designation imposes use and management restrictions beyond those that would otherwise apply. The Wilderness Act prohibits roads, structures, commercial development, and motor use. Global Resources Wilderness • 1339 A train passes through the Alaskan wilderness on its journey to Denali. (©Tom Dowd/Dreamstime.com) Exceptions are made for existing mining, grazing, and reclamation use and for the administrative neces- sity of the managing agencies. Wilderness managers confront a number of diffi- cult challenges. The central challenge is to protect wilderness ecosystems so as to allow nature to take its course, but this is much more complex than it appears. In the United States, wilderness areas serve multiple, and often conflicting, purposes. Even recreational use takes a toll, causing erosion, introducing exotic plants, and sometimes starting fires. There is an obvious ten- sion between managing wilderness for naturalness and managing it for the pleasure of recreational visitors. Among the tough questions wilderness managers must confront are whether recreationaluse should be rationed, whether to control exotic or invasive spe- cies, whether to reintroduce species—often top pred- ators—that had been previously extirpated, whether natural fires should be extinguished or allowed to burn, and whether artificial fires should be ignited to compensate for the unnatural effects of decades of fire suppression. All these issues are complicated by the need to consider impacts outside the wilderness boundary. Nearby landowners may object to manage- ment choices designed to restore naturalness. In the United States,management decisions toallow natural fires to burn and to reintroduce wolves into ecosys- tems from which they were previously eradicated have provoked heated and prolonged controversies. Addi- tional complications arise because political compro- mises made in Congress have allowed a number of inappropriate uses to continue within wilderness boundaries: water impoundments, mineral develop- ments, recreational motorboat use, and even some aircraft use. The most significant inappropriate, but perfectly legal, use is commercial grazing, which has dramatically altered many wilderness ecosystems in the western United States. Managers are constrained in other ways. In most wilderness areas, the management of fish and wildlife is within the jurisdiction of state authorities. Finally, despite the increased difficulty and expense, manag- ers are often expected to do most of their work within wilderness areas without motor vehicles or power tools. Craig W. Allin Further Reading Allin, Craig W. The Politics of Wilderness Preservation. Westport, Conn.: Greenwood Press, 1982. Bergon, Frank, ed. The Wilderness Reader. New York: New American Library, 1980. Reprint. Reno: Uni- versity of Nevada Press, 1994. Callicott, J. Baird, and Michael P. Nelson, eds. The Great New Wilderness Debate. Athens: University of Georgia Press, 1998. Cordell, H.Ken, JohnC. Bergstrom,and J. M. Bowker, eds. The Multiple Values of Wilderness. State College, Pa.: Venture, 2005. Dawson, Chad P., and John C. Hendee. Wilderness Management: Stewardship and Protection of Resources and Values. 4th ed. Golden, Colo.: Fulcrum, 2008. Foreman, Dave. Rewilding North America: A Vision for Conservation in the Twenty-first Century. Washington, D.C.: Island Press, 2004. Hendee, John C., and Chad P. Dawson. Wilderness Management. 4th ed.Golden, Colo.:Fulcrum,2009. Kerasote, Ted, ed. Return of the Wild: The Future of Our Natural Lands. Washington, D.C.:Island Press, 2001. Lewis, Michael, ed. American Wilderness: A New History. New York: Oxford University Press, 2007. Martin, Vance G., and Cyril F. Kormos. Wilderness, Wildlands and People: A Partnership for the Planet. Golden, Colo.: Fulcrum, 2008. Nash, Roderick F. Wilderness and the American Mind. 4th ed. New Haven,Conn.: YaleUniversity Press, 2001. Robles Gil, Patricio, ed. Wilderness: Earth’s Last Wild Places. Washington, D.C.: Conservation Interna- tional, 2002. Scott, Doug. The Enduring Wilderness. Golden, Colo.: Fulcrum, 2004. Sellars, Richard West. Preserving Nature in the National Parks, a History. New Haven, Conn.: Yale University Press, 1997. Vale, Thomas R. The American Wilderness: Reflections on Nature Protection in the United States. Charlottesville: University of Virginia Press, 2005. Zeveloff, Samuel I., L. Mikel Vause, and William H. McVaugh. Wilderness Tapestry: An Eclectic Approach to Preservation. Reno: University of Nevada Press, 1992. Web Sites United Nations Environment Programme, World Conservation Monitoring Centre World Database on Protected Areas (WDPA) http://www.wdpa.org The WILD Foundation http://www.wild.org 1340 • Wilderness Global Resources Wilderness Institute at The University of Montana, Arthur Carhart National Wilderness Training Center, and Aldo Leopold Wilderness Research Institute Wilderness.net http://www.wilderness.net/ See also: Conservation; Conservation International; Deep ecology; Ecozones and biogeographic realms; Forest management; Forest Service, U.S.; Forestry; Land management; National Park Service; National parks and nature reserves; Public lands; Wilderness Act. Wilderness Act Categories: Laws and conventions; government and resources Date: Enacted 1964; scope expanded significantly in 1976 and 1980 The Wilderness Act created a National Wilderness Preservation System, designated its first components, provided management direction for designated areas, and established a procedure by which new areas might be added to the system over time. Background The first national parks, national forests, national monuments, and national wildlife refuges were all es- tablished prior to World War I. Each set aside substan- tial areas of federal lands for conservation purposes, but those purposes differed from one system to the next. National forests emphasized scientific manage- ment of forest resources for economic purposes, na- tional parks focused on the preservation of scenic wonders and accommodation of tourists, national monuments handledthe preservationof archaeologi- cal resources, and wildlife refuges focused on the preservation of habitat for game species. Each of these systems contained significant de facto wilder- ness, but it was poorly protected and, after World War II, increasingly threatened by development. Fearing for the wilderness that remained, conserva- tion organizations,ledby HowardZahniser ofthe Wil- derness Society, proposed legislation to establish a Na - tional WildernessPreservation System. The proposed system was to be composed of undeveloped federal lands already managed for conservation purposes. Areas designated as wilderness were to remain within their respective conservation systems, but managing agencies would be required to preserve the wilderness character of areas under their jurisdiction. Efforts to pass a wilderness bill spanned a decade, but the essen- tial elements of this proposal were enacted in 1964. Provisions The Wilderness Act defined wilderness as “an area of undeveloped Federal land retaining its primeval character and influence, without permanent improve- ments or human habitation, which is protected and managed soas topreserve itsnatural conditions.”The act prohibited roads, structures, commercial activity, and motor use, but significant exceptions were made to benefit mining, grazing, and reclamation users of national forestlands. The Wilderness Act designated wilderness areas comprising 3.7 million hectares, se- lecting from lands that had already been classified as wilderness by the Forest Service, and it directed the secretary of agriculture and secretary of the interior to surveyundeveloped areas ofthe national forest, na- tional park, and national wildlife refuge systems and to propose additional wilderness areas for designa- tion by Congress. Impact on Resource Use Wilderness designation continues to be a controver- sial topic, especially on national forestlands where protecting the wilderness resource means forgoing the economic benefits of timber harvest and most mining and water resource development. In the na- tional parks these economic uses are generally pro- hibited regardless of wilderness status. Despite the controversy, the amount of wilderness protected con- tinues to grow. The Federal Land Policy and Manage- ment Actof 1976 added Bureau ofLand Management lands to those that are to be considered for wilderness designation. In 1980, the Alaska National Interest Lands Conservation Act more than doubled the area designated as wilderness, adding 22 million hectares. At the end of the twentieth century, the total area of federal land protected as wilderness exceeded 40 mil- lion hectares. That number has climbed to 43 million hectares, 55 percent of which was controlled by the National Park Service. Craig W. Allin See also: Wilderness; Wilderness Society; Wildlife. Global Resources Wilderness Act • 1341 Wilderness Society Category: Organizations, agencies, and programs Date: Established 1935 The Wilderness Society, founded by Aldo Leopold, works for the preservation of nature and the wise man- agement of natural resources. A special commitment of the society is the preservation of the Arctic National Wildlife Refuge. Background The WildernessSociety stresses the creation and pres- ervation of wilderness areas. It is unique among con- servation organizations in that the focus is exclusively on issues relatedto publiclands. Thesociety has estab- lished itself as a leader in environmental protection through lobbying and encouraging policy change. The Wilderness Society educates the public by sponsoring seminars, conferences, and workshops on the management of public land. It analyzes and cri- tiques administrative decisions that affect public land management and lobbies public officials on behalf of the proper use of public lands. Its representatives meet with members of Congress on preservation pro- grams and testify at legislative and oversight hearings before committees of the two houses of Congress on issues affecting public lands. Impact on Resource Use The Wilderness Society’s stated mission is “to protect wilderness areasand inspireAmericans tocare forour wild places,” based on science. Among the accom- plishments of the Wilderness Society are wilderness bills passed in nearly all fifty states, as well as federal legislation including the Wilderness Act (1964) and the Alaska National Interest Lands Conservation Act (1980), which established twelve new national parks, eleven new wildlife refuges, and twenty-five wild and scenic rivers in Alaska. The Wilderness Society has been involved in every aspect of national forest plan- ning and helped pass oil-spill liability legislation. It has been involved with other conservation organiza- tions in protecting areas such as the California desert, the Florida Everglades, and the Greater Yellowstone ecosystem. Grace A. Banks Web Site Wilderness Society http://wilderness.org/ See also: Land management; Leopold, Aldo; Public lands; Wilderness; Wildlife. Wildlife Category: Plant and animal resources Wildlife can encompass a broad range of organisms. Maintaining wildlife species is essential because of the roles they play in providing ecological resources, func- tional ecosystems, food and clothing, and recreation. They also serve as indicatorsof environmentalquality. Background Prior to 1937, the term “wild life” was defined primar- ily as only vertebrate species with some economic value. The term “wildlife” (as one word) was adopted and describedin 1937in the Journalof Wildlife Manage- ment. At this time, wildlife became known as a diverse array of organisms, including all vertebrates and the other organisms with which they interact. Because wildlife can encompass such a broad range of taxa, it has diverse values associated with it, including provid- ing recreation, food and clothing, and ecological re- sources for humans and serving as components of ecosystems and indicators of environmental quality. Hunting for Recreation, Subsistence, and Trade Recreational hunting of “game species” is a tradi- tional value of wildlife. AsAldo Leopoldmentioned in Game Management (1933), one objective of managing “wild life” was to provide “an opportunity to hunt.” Hunting of some vertebrate species provides an op- portunity for people to continue a traditional sport; it is also a population management technique that wild- life managersuse to control locally abundantanimals, to adjust sex and age ratios of populations, and to col- lect biological information from harvested animals. Data collected from harvested wildlife can be used in making management decisions intended to help per- petuate the species and hunting. The concept of re - quiring people to possess a hunting license to pursue game species was first adopted in the United States in 1342 • Wilderness Society Global Resources Michigan and NorthDakota in 1895. In addition to hunting, wildlife also provides nonconsumptive forms of recreation such as viewing and pho- tographing. For many people throughout the world, wildlife has served as a source of food and clothing as well as a product to besold or traded for other goods. For example, the buffalo was used for hundreds—or thousands— of years as a staple for food, clothing, and other artifactsby American Indi- ans in the Great Plains. It was also used by western travelers in the United States during the 1800’s. This use of wildlife in the United States changed with the passage of the Lacey Act in the United States in 1900. This piece of legislation had a significant impact on the conserva- tion of many wildlife species because it prohibited the interstate trade of wildlife and wildlife products. Many local people in developing regions of the world continueto consumemeat fromwildlife species as a staple food and to use animal skins. For example, the Agta people in the Philippines have pursued wild- life species such as birds, lizards, and deer to fulfill some of their food requirements and to trade with other groups of people for agricultural crops. There is also a multibillion-dollar local and international trade of wildlife species and products including meat, furs, skins, animal parts, and items manufactured from these materials. During 1967 and 1968, for ex- ample, an estimated 620,000 birds, mammals, rep- tiles, and amphibians were traded internationally for approximately $1.9 million. Ecological and Environmental Aspects Each wildlife species also plays important roles in the functioning of ecosystems. As wildlife species interact with other living and nonliving things in a geographic area, they modify environmental conditions. These modifications help create optimal habitat conditions for other wildlife species. For example, in the Seren- geti ecosystem, optimal habitat conditions for the Thomson’s gazelle and some of the other relatively small herbivores is created by larger herbivores (ze - bras, wildebeest) migrating before the gazelle and cropping the longer, coarser grasses so the gazelle’s preferred foods of shorter grasses and forbs are avail- able. Wildlife species are also used as indicators of the health of the environment. Specifically, they are used to monitor the presence of contaminants (bald ea- gles), trends in wildlife populations (songbirds), and relative habitat quality for other species (game spe- cies), communities, and ecosystems. When wildlife species are used as environmental indicators, wildlife managers make two assumptions. First, they assume that monitoringthe populationstatus ofan individual species provides a reliable assessment of habitat qual- ity. Second, they assume that if the population of a wildlife species used as an indicator is increasing or decreasing, other species with similar requirements will have similar fluctuations in their populations. Because of the vast number of wildlife species and the fact that they all have unique seasonal require- ments for food, cover, water, space, and the relative proximity ofthese components to one another, it isof- ten more economical and efficient to monitor the rel- ative quality of wildlife habitat or health of ecosystems by monitoring a few wildlife species. When wildlife species are used as indicators of environmental condi- tions, managersselect a few species with different hab- itat requirements and monitor them intensively in- stead ofattempting to know the specific requirements of all species in an area and monitor their popula - tions. Global Resources Wildlife • 1343 The Bengal tiger is found in several countries in central Asia. (©iStockphoto.com) Unknown Potential Many wildlife species are still relatively unknown in terms of the ways they may be beneficial to humans in the future. Because each species has a different set of genetic material, conserving as many species as possi- ble may prove useful in addressing future human health problems. Numerous wildlife species have been investigated by scientists for their pharmacological effects in treating illnesses (marine organisms, ar- thropods) andhave beenused in biomedical research (toads, primates). Finally, the disappearance of wildlife species through human activities—over hunting, encroach- ment of human development into wildlife habitats, deforestation, pollution, and a host of other anthro- pogenic modifications of the environment, has accel- erated over the past century and has resulted in, and will continue to contribute to, ecological conse- quences for both the world’s biomes and the re- sources on which humans have come to rely. Henry Campa III Further Reading Allen, Durward.Our Wildlife Legacy. Rev.ed. New York: Funk & Wagnalls, 1962. Bertrand, Gerard A., John A. Burton,and Paul Sterry. HarperCollins Complete North American Wildlife: A Photo Field Guide. New York: HarperCollins, 2003. Brokaw, Howard P., ed. Wildlife and America: Contribu- tions to an Understanding of American Wildlife and Its Conservation. Washington, D.C.: U.S. Government Printing Office, 1978. Elton, Charles, Mathew A. Leibold, and J. Timothy Wootton. Animal Ecology. Chicago: University of Chicago Press, 2001. Fulbright, Timothy E., and David G. Hewitt, eds. Wild- life Science: Linking Ecological Theory and Management Applications. Boca Raton, Fla.: CRC Press, 2008. Goodall, Jane, and Marc Bekoff. The Ten Trusts: What We Must Do to Care for the Animals We Love. San Fran- cisco: HarperSanFrancisco, 2002. Leopold, Aldo. Game Management. Drawings by Allan Brooks. New York: C. Scribner’s Sons, 1933. Re- print. Madison: Universityof Wisconsin Press, 1986. Manfredo, Michael J., et al., eds. Wildlife and Society: The Science of Human Dimensions. Washington, D.C.: Island Press, 2008. Sinclair, Anthony R. E., John M. Fryxell, and Graeme Caughley. Wildlife Ecology, Conservation, and Man - agement. 2d ed. Malden, Mass.: Blackwell, 2006. Wildlife Conservation Society. State of the Wild, 2008- 2009: A Global Portrait of Wildlife, Wildlands, and Oceans. Edited by Eva Fearn. Washington, D.C.: Is- land Press, 2008. Web Site National Wildlife Federation http://www.nwf.org/wildlife See also: Biodiversity; Conservation; Conservation biology; Ecosystems; Endangered species; Leopold, Aldo; Species loss; United Nations Convention on In- ternational Trade in Endangered Species of Wild Fauna and Flora; Wetlands; Wildlife biology. Wildlife biology Category: Scientific disciplines Wildlife biologists study the life cycles, behaviors, re- quirements, ecology,and populationsof wild animals. Definition Wildlife biology is a subcategory of the biological sci- ences concerned with nondomesticated animals and their interactions with living and nonliving compo- nents of their environments. Overview While “wildlife” includes all animals that have not been domesticated by humans, it is sometimes re- stricted to birds and mammals, excluding other verte- brate andnonvertebrate species.As apractical matter, wildlife biologists may focus on one species or groups of species, but all wild animals should be included within the sphere of wildlife biology. Conservation bi- ology, comprising both plants and animals, can be considered, with regard to the latter, a subdivision of wildlife biology concerned with nondomesticated an- imals that have become endangered or threatened by environmental changes, particularly those associated with human activities. Wildlife biology involves the study of wild animals from conception to death, including their strategies and behaviors for dealing with survival and reproduc- tion. Itis alsoconcernedwith their nutritional anden - vironmental requirements and their ecological niches. It focuses on their natural home or habitat, including 1344 • Wildlife biology Global Resources cover,food, water, and breeding sites. The end goal of wildlife biology is the integrative understanding of the factors that influence populations ofwild animals. The ultimate application of the field is wildlife man- agement, in which humans intervene to maintain ap- propriate populations (populations that do not ex- ceed the area’s carrying capacity) of wild animals in a particular area. James L. Robinson See also: Animal domestication; Conservation biol- ogy; Ecology; Ecosystems; Wildlife. Wind energy Category: Energy resources Wind energy has been a significant energy resource in human history, from its use by ancient sailboats to its employment in modern large-scale electrical genera- tors. In the twenty-first century, it is one of the fastest- growing energy sources in the world. Wind energy is a clean, renewable, and free power source that is a viable alternative to fossil fuels, which pollute the environ- ment and promote global warming. Background The energy of the wind was captured by humans as early as the fourth century b.c.e., when the Egyptians used wind to propel sailboats on the Nile River. Soon, there were sailing vessels in the Mediterranean Sea. Windmills, machines that convert wind into mechani- cal power, were used to pump water and mill grain in ancient times. In a windmill, wind blows on sails or blades radiating from a windshaft (cylindrical part on which the sails turn), which produces mechanical en- ergy when it rotates. The first documented wind de- vice was a Persian windmill shown in drawings from about 500 c.e. This windmill was the horizontal axis type, with a horizontal wheel holding the sails, a verti- cal windshaft, and vertical sails made of bundles of reeds or wood. These windmills spread throughout the Middle East and into China. During the twelfth century, the first European windmills appeared in England and France. These wooden machineswere called postmills, because they had a central vertical post. They had a horizontal windshaft, hada revolvingplatformatop thepost, and were rotated by hand. In the fourteenth century, a larger and sturdier windmill called the tower mill was developed. The tower mill had a stationary body that supported a rotatable wooden cap, to which the rotor was attached. The blades faced the wind, and there was storage space for the grain at the base. This wind- mill was popular in Holland, where windmills were used for land drainage. Between 1300 and 1850 c.e., windmills provided about 25 percent of Europe’s in- dustrial power. They were used for grinding dyes, spices, and paint pigment as well as for irrigation and grain milling. In the nineteenth and early twentieth centuries, windmills played an essential role in the development of the western and Great Plains regions of the United States. In 1854, Daniel Halladay designed small, multibladed, and inexpensive windmills that were sturdy enough forthe Great Plains.American farmers and homesteaders used windmills to pump under- ground water to the surface. Windmill-generated water wascrucialfor livestock, human use, crop irriga- tion, andsteam locomotives. Windmillsmade thearid Great Plains bloom, opening up the West to towns, farms, and most important, the transcontinental rail- road. Windmills were responsible for changing cattle ranching from a nomadic to a stable business and transforming the Great Plains into a breadbasket. Be- tween 1880 and 1930, approximately 6 million wind- mills were installed in the western United States and the Great Plains. As Europe and the United States became industri- alized, the steam engine gradually replaced water- pumping windmills in Europe, and electricity replaced wind power in rural America. The Rural Electrifica- tion Act of 1936 provided low-cost federal loans for bringing electricity into rural areas. Low-cost power from town and regional electric generators became available, and power lines were extended to remote areas of the country. In 1935, only 11 percent of the farms in the United States had electric service, but by the early 1970’s, about 98 percent did. Meanwhile, scientists developed larger windmills, called wind turbines, that could generate electricity. In 1890, in Denmark, P. LaCour built the first wind- mill capable of generating electricity. In 1941, Palmer Putnam built the world’s largest wind turbine on a windy mountaintop called Grandpa’s Knob in Ver- mont. This nearly 230-metric-ton generator served an entire townby feeding electricpower into the existing local utility grid. Global Resources Wind energy • 1345 . square kilometers per year, with a concomi- tant loss of species numbering in the tens of thou- sands. One measure of the economic importance of global wilderness as a genetic repository is provided by. preservation of scenic wonders and accommodation of tourists, national monuments handledthe preservationof archaeologi- cal resources, and wildlife refuges focused on the preservation of habitat. Aldo Leopold, works for the preservation of nature and the wise man- agement of natural resources. A special commitment of the society is the preservation of the Arctic National Wildlife Refuge. Background The