Environmental Encyclopedia

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Environmental Encyclopedia 3

Wildlife

A stand of trees bursts into flames in Grand Teton National Forest in 1988. (Corbis-Bettmann. Reproduced by permission.)

national forests. The debate over which fires should be al-

lowed to burn and which should be suppressed undoubtedly

will continue for some time. See also Biomass; Biomass fuel;

Deforestation; Ecological productivity; Forest management;

Forest Service; Old-growth forest; Soil survey

[Ronald D. Taskey]

ESOURCES

OOKS

Barbour, M. G., J. H. Burk, and W. D. Pitts. Terrestrial Plant Ecology.

Menlo Park, CA: Benjamin/Cummings, 1980.

THER

Greater Yellowstone Pos-Fire Resource Assessment Committee, Burned

Area Survey Team. Preliminary Burned Area Survey of Yellowstone National

Park and Adjoining National Forests. 1988.

Lotan, J. E., et al. Effects of Fire on Flora. Forest Service General Technical

Report WO–16. Washington, DC: U. S. Government Printing Office,

1981.

National Wildfire Coordinating Group. Firefighters Guide. NFES 1571/

PMS 414-1. Boise: Boise Interagency Fire Center, 1986.

Wells, C. G., et al. Effects of Fire on Soil. Forest Service General Technical

Report WO–7. Washington, DC: U. S. Government Printing Office, 1979.

1517

Wildlife

It was once customary to consider all undomesticated

spe-

cies

of vertebrate animals as wildlife. Birds and mammals still

receive the greatest public interest and concern, consistently

higher than those expressed for reptiles and amphibians.

Most concern over fishes results from interest in sport and

commercial value. The tendency in recent years has been to

include more life-forms under the category of wildlife. Thus,

mollusks, insects, and plants are all now represented on

national and international lists of threatened and

endan-

gered species

People find many reasons to value wildlife. Virtually

everyone appreciates the aesthetic value of natural beauty or

artistic appeal present in animal life. Giant pandas (Ailuro-

poda melanoleuca), bald eagles (Haliaetus leucocephalus), and

infant harp

seals

(Phoca groenlandica) are familiar examples

of wildlife with outstanding aesthetic value. Wild species

offer recreational value, the most common examples of which

are sport

hunting

and bird watching.

Less obvious, perhaps, is ecological value, resulting

from the role an individual species plays within an

ecosys-

Environmental Encyclopedia 3

Wildlife

tem

. Alligators (genus Alligator), for example, create depres-

sions in swamps and marshes. During periods of droughts,

these “alligator holes” offer critical refuge to water-depen-

dent life forms. Educational and scientific values are those

that serve in teaching and learning about biology and scien-

tific principles.

Wildlife also has a utilitarian value that results from

its practical uses. Examples of utilitarian value range from

genetic reservoirs for crop and livestock improvement to

diverse biomedical and pharmaceutical uses. A related cate-

gory, commercial value, includes such familiar examples as

the sale of furs and hunting leases.

Shifts in human lifestyle have been accompanied by

changes in attitudes toward wildlife. Societies of hunter-

gatherers depend directly on wild species for food, as many

plains Indian tribes did on the

bison

. But as people shift

from hunting and gathering to agriculture, wildlife comes

to be viewed as more of a threat because of potential crop

or livestock damage. In modern developed nations, people’s

lives are based less on rural ways of life and more on business

and industry in cities. Urbanites rarely if ever feel threatened

economically by wild animals. They have the leisure time

and mobility to visit wildlife refuges or parks, where they

appreciate seeing native wildlife as a unique, aesthetic experi-

ence. They also sense that wildlife is in decline and therefore

favor greater protection.

The most obvious threat to wildlife is that of direct

exploitation, often related to commercial use. Exploitation

helped bring about the

extinction

of the

passenger pigeon

(Ectopistes migratorius), the great auk (Pinguinus impennis),

Stellar’s sea cow (Hydrodamalis gigas), and the sea mink

(Mustela macrodon), as well as the near extinction of the

American bison (Bison bison). In the late nineteenth and

early twentieth century, state and federal laws were passed

to help curb exploitation. These were successful for the most

part, and they continue to play a crucial role in

wildlife

management

Introductions of

exotic species

represent another

threat to wildlife. Insular or island-dwelling species of wild-

life are especially vulnerable to the impacts of exotic plants

and animals. Beginning in the seventeenth century, sailors

deliberately placed goats and pigs on ocean islands, intending

to use their descendants as food on future voyages. As the

exotic populations grew, the native vegetation proved unable

to cope, creating drastic

habitat

changes. Other species,

such as rats, mice, and cats, jumped ship and devastated

island-dwelling birds, which had evolved in the absence of

mammalian predators and had few or no defenses.

Pollution

is yet another threat to wildlife. Bald eagles,

ospreys (Pandion haliaetus), peregrine falcons (Falco peregri-

nus), and brown pelicans (Pelecanus occidentalis) experienced

serious and sudden population declines in the 1950s and

1518

1960s. Studies showed that these fish eaters were ingesting

heavy doses of pesticides, including DDT. The pesticides

left the shells of their eggs so thin that they cracked under

the weight of incubating parents, and numbers declined due

to reproductive failure. Populations of these birds in the

United States rebounded after regulatory laws curbed the

use of these pesticides. However, thousands of other

chemi-

cals

still enter the air, water, and

soil

every year, and the

effects of most of them on wildlife are unknown.

By far the most critical threat to wildlife is habitat

alteration. Unfortunately, it is also more subtle than direct

exploitation, and thus often escapes public attention. Human

activities are altering some of the most biologically rich

habitats in the world on a scale unprecedented in history.

Tropical rain forests, for example, originally covered only

about 7% of the earth’s land surface, yet they are thought

to contain half the planet’s wild species. Other rich habitats

undergoing rapid changes include tropical dry forests and

coral reefs. As extensive areas of natural habitat are irrevoca-

bly changed, many of the native species that once occurred

there will become extinct, even those with no commercial

value.

Any species of wild animal has a set of habitat require-

ments. These begin with food requirements, adequate

amounts of available food for each season. Cover require-

ments are structural components that are used for nesting,

roosting, or watching, or that offer protection from severe

weather or predators. Water is habitat requirement that af-

fects wildlife directly, by providing drinking water, and indi-

rectly, by influencing local vegetation. The final habitat re-

quirement is space. Biologists can now calculate a minimum

area requirement to sustain a particular species of a given size.

Even in the absence of human activities, populations

of wild animals change as a result of variations in birth and

death rates. When a population is sparse relative to the

number that can be supported by local habitat conditions,

birth rates tend to be high. In such circumstances, natural

mortality

, including predation, disease, and starvation,

tends to be low. As populations increase, birth rates decline

and death rates rise. These trends continue until the popula-

tion reaches

carrying capacity

, the number of animals of

a particular species that can be sustained within a given area.

Carrying capacity, though, is difficult to define in prac-

tice. Variations in winter severity or in summer rainfall can,

between years, alter the carrying capacity for a particular

area. In addition, carrying capacity changes as forests grows

older,

grasslands

mature, or

wetlands

fill in through natu-

ral

siltation

. Despite these limitations, the concept of car-

rying capacity illustrates an important biological principle:

living wild animals cannot be stockpiled beyond the practical

limits that local habitat conditions can support.

Environmental Encyclopedia 3

Wildlife management

While all populations vary, some undergo extreme

fluctuations. When they occur regularly, such fluctuations

are called cycles. Cyclical populations fall into two categories,

the three- to four-year cycle typical of lemmings and voles,

and the eight- to 11-year cycle known in snowshoe hares

(Lepus americanus) and lynx of the Western Hemisphere

(Lynx canadensis). The mechanisms that keep cycles going

are complex and not completely understood, but the exis-

tence of cycles is widely accepted. Extreme populations fluc-

tuations that occur at irregular intervals are called population

irruptions. Local populations of deer tend to be irruptive,

suddenly showing substantial changes at unpredictable in-

tervals.

There are more species of wild plants and animals in

tropical rain forests than on arctic tundras. Such patterns

illustrate variations in the complexities of life-forms due to

climatic conditions. Measurement of

biodiversity

usually

focuses on a particular group of organisms such as trees or

birds. The most basic indication of species richness is the

total number of species in a certain area or habitat. A measure

of species evenness is more valuable because it indicates the

relative abundance of each species. As diversity includes

richness and evenness, an area with many species uniformly

distributed would have a high overall diversity.

Biodiversity is important to wildlife

conservation

well as to basic

ecology

. Comparisons of species diversity

patterns indicate the extent to which natural conditions have

been affected by human activities. They also help establish

priorities for acquiring new protected areas. See also Predator-

prey interactions; Wildlife refuge; Wildlife rehabilitation

[James H. Shaw]

ESOURCES

OOKS

Caughley, G. Analysis of Vertebrate Populations. New York: John Wiley &

Sons, 1977.

Kellert, S. Trends in Animal Use and Perception in 20th Century America.

Washington, DC: U.S. Department of the Interior, Fish and Wildlife

Service, 1981.

Matthiessen, P. Wildlife in America. 2nd ed. New York: Viking Books, 1987.

McCullough, D. The George Reserve Deer Herd. Ann Arbor, MI: University

of Michigan Press, 1979.

Wildlife management

Wildlife

laws are enforced by state and federal agencies,

usually known as wildlife departments or fish and game

commissions. In the United States, principal responsibility

for laws protecting migratory

species

and threatened and

endangered species

rests with the U.S.

Fish and Wildlife

Service

1519

Various nongovernmental organizations (NGOs) have

grown in membership and influence since the 1960s. NGOs

include private

conservation

groups such as the

National

Audubon Society

, the

National Wildlife Federation

, and

the

World Wildlife Fund

. Although they have no direct

legal powers, NGOs have achieved considerable influence

over wildlife management through fund raising, lobbying,

and other kinds of political action, as well as by filing lawsuits

concerning wildlife-related issues.

Depletion of native wildlife during the late nineteenth

century in the United States and Canada led to passage of

federal and state laws regulating the harvest and possession

of resident species. Congress passed the Lacey Act in 1900,

which made interstate shipment of wild animals a federal

offense if taken in violation of state laws, and so curbed

market

hunting

. A few years later, the Migratory Bird Treaty

Act was passed, establishing federal authority over migratory

game and insectivorous birds. This treaty was signed by

Great Britain on behalf of Canada in 1916 and became

effective two years later.

Other protective measures soon outlawed market

hunting and regulated sport hunting. Hunters are now re-

quired to purchase hunting licenses, the proceeds of which

help pay salaries of game wardens, and game harvests are

now regulated chiefly through hunting seasons and bag lim-

its. These are imprecise tools, but the resulting harvests are

generally conservative and excessive ones are rare.

In 1973, the

Endangered Species Act

conferred fed-

eral protection on listed species, resident as well as migratory.

Three years later, the United States became one of the first

nations to sign the Convention on International Trade in

Endangered Species (CITES), in which more than 100 na-

tions pledged to regulate commercial trade in threatened

species and to effectively outlaw trade in endangered ones.

Although laws regulating the taking or possession of

wild animals are essential, they are not sufficient by them-

selves. Wildlife populations can only be sustained if adequate

measures are taken to manage the habitats they require.

Habitat

management can take three basic approaches: pres-

ervation, enhancement, and restoration. Preservation seeks

to protect natural habitats that have not been significantly

affected by human activity. The principal tactic of preserva-

tion is exclusion of mining, grazing by livestock, timber

harvesting, oil and gas exploration, and environmentally

damaging recreational practices. Federally-designated

wil-

derness

areas and national parks use habitat preservation

as their principal strategy.

Habitat enhancement is designed to increase both

wildlife numbers and

biodiversity

through practices that

improve food production, cover, water, and other habitat

components. Enhancement differs from preservation be-

cause improvements are often achieved through artificial

Environmental Encyclopedia 3

Wildlife management

means, such as nest boxes, the cultivation of food plants,

and the installation of devices to regulate water levels. Most

state wildlife management areas and many national wildlife

refuges practice enhancement.

Habitat restoration seeks to reestablish the original

conditions of an area that have been substantially altered by

human use, such as farming. Most

land use

practices result

in a simpler

biological community

, so many of the original

species must be reintroduced. Although not a precise science,

in the future this kind of restoration will likely be more

widely used to expand rare types of habitat. Costa Rica is

using restoration to create more tropical dry forests, and

The

Nature Conservancy

in the United States has used it to

reestablish tallgrass

prairie

habitat.

Although the strategies used in wildlife management

usually involve regulation of harvests and manipulation of

habitats, the objectives of most management plans are de-

fined in terms of population levels. Most game management,

for example, seeks to increase production of game. Many

people assume that game production rises with game popula-

tions. In reality, game production is maximized by improving

habitat conditions so as to raise the

carrying capacity

for

a particular game species. Rather than let populations reach

that, modern wildlife managers harvest enough game to keep

the population below it, and this practice results in healthier

populations with lower rates of natural

mortality

and higher

rates of reproduction. Hunters may take more animals from

a population managed at a population level below carrying

capacity than they can from one managed at it.

Some wildlife populations are managed to minimize

the damage they can inflict upon crops or livestock. Some

animal-damage control is done by reducing the wildlife pop-

ulation, usually through

poisoning

. But just as game popula-

tions become more productive when reduced below carrying

capacity, so animals that inflict crop or livestock damage

often compensate for population reductions with higher rates

of reproduction, as well as higher survival rates for their

young. This compensatory response to control, together with

increased public pressures against uses of poisons, has led

to refinements in animal-damage control. The trend in re-

cent years has been toward methods that prevent damage,

such as special fencing or other protective measures, and

away from widespread population reductions. When lethal

measures are taken, wildlife managers have tended to endorse

selective removal of offending individuals, particularly in

large carnivorous species.

For

rare species

, those endangered, threatened, or

declining, managers attempt to increase numbers, establish

new populations, and above all, preserve each rare species’

gene pool

. Legal protection and habitat improvement are

important means for managing rare species, just as they are

for game animals; in addition, rare species are helped by

1520

captive propagation done under cooperative agreements be-

tween zoos and the U.S. Fish and Wildlife Service. Although

expensive, captive propagation can increase numbers quickly

by using new technologies such as artificial insemination

and embryo transfers. Once the numbers in captivity have

been built up, some of the population can then be reintro-

duced into suitable habitat. Wildlife managers prepare wild

animals bred in captivity for reintroduction through

accli-

mation

, training, and by selecting favorable age and sex

combinations.

Rare species often face long-term problems resulting

from reductions in their gene pools. When any species is

reduced to a small fraction of its original numbers, certain

genes are lost because not enough animals survive to ensure

their perpetuation. This loss is known as the bottleneck

effect. Rare species typically exist in small, isolated popula-

tions, and they lose even more of their gene pools through

the

inbreeding

that results. The

Florida panther

(Puma

concolor coryi), a nearly extinct subspecies of cougar, exhibits

loss of size, vigor, and reproductive success, clear indications

of a depleted gene pool, the result of the bottleneck effect

and inbreeding.

Managers try to minimize the loss of gene pools by

striving to prevent severe numerical reductions from oc-

curring in the first place. They also use population augmen-

tation to systematically transfer selected individuals from

other populations, wild or captive, to encourage outbreeding

and can replenish local gene pools.

Modern wildlife managers tend not to concentrate on

perpetuating one species, focusing instead on maintaining

entire communities with all their diverse species of plant

and animal life. Maintenance of biodiversity is important

because wild species exist as ecologically interdependent

communities. If enough of these communities can be main-

tained on a sufficiently large scale, the long-term survival of

all of its species may be assured.

From a practical standpoint, there are simply not

enough resources or time to develop management plans for

each of the earth’s 4,100 species of mammals or 9,000 species

of birds, not to mention the other, more diverse life-forms.

The tedious process of listing threatened and endangered

species is slow and often achieved only after the species is

on the brink of

extinction

. Recovery becomes expensive and

despite heroic efforts, may still fail.

If biodiversity management succeeds, it may reduce

the loss of wild species through proactive, as opposed to

reactive, measures. Many North American songbirds, partic-

ularly those of the eastern woodlands and the prairie regions,

are experiencing steady declines. Even familiar game species,

including the northern bobwhite quail (Colinus virginianus)

and several species of duck, are becoming less abundant.

The causes are complex and elusive, but they probably relate

Environmental Encyclopedia 3

Wildlife refuge

to our failure to stabilize habitat conditions on a sufficient

scale. If wildlife managers can reverse this trend, they may

stop and ultimately reverse these declines. See also Defenders

of Wildlife; Migration; Overhunting; Predator control; Res-

toration ecology; Wildlife refuge; Wildlife rehabilitation

[James H. Shaw]

ESOURCES

OOKS

Kohm, K. A., ed. Balancing on the Brink of Extinction: The Endangered

Species Act and Lessons for the Future. Washington, DC: Island Press, 1991.

Matthiessen, P. Wildlife in America. 2nd ed. New York: Viking Books, 1987.

Shaw, J. H. Introduction to Wildlife Management. New York: McGraw-

Hill Book Co., 1985.

Soule, M., and B. A. Wilcox, eds. 1980. Conservation Biology. Sunderland,

MA: Sinauer Associates, 1980.

Wildlife refuge

When President

Theodore Roosevelt

issued an executive

order making Pelican Island, Florida, a federal bird reserva-

tion, he introduced the idea of a

national wildlife refuge

Nearly 90 years later, Roosevelt’s action has expanded to a

system of more than 400 national

wildlife

refuges with a

combined area of over 90 million acres (36 million ha).

Roosevelt’s action was aimed at protecting birds that

used the islands. Market hunters had relentlessly killed

egrets, herons, and other aquatic birds for their feathers or

plumes to adorn women’s fashions. The first national wildlife

refuge, like other

conservation

practices of the early twenti-

eth century, emerged in reaction to unregulated market

hunting

. Pelican Island became a sanctuary where wild ani-

mals, protected from gunfire, would multiply and then dis-

perse to repopulate adjacent countryside.

States followed suit, establishing protected areas

known variously as

game preserves

, sanctuaries, or game

refuges. They were expected to function as breeding grounds

to repopulate surrounding countryside. Although protected

populations usually persisted within the boundaries of such

refuges, they seldom repopulated areas outside those bound-

aries. Migratory waterfowl enjoyed some success in repopu-

lating because they could fly over unsuitable habitats and

find others that met their needs. Nonmigratory or resident

species

often found themselves surrounded by inhospitable

tracts of farmlands, highways, and pastures. Dispersal

chances were limited. Resident populations, particularly

those of deer and other large herbivores, built up to unhealthy

levels, depleting natural foods, becoming infested with heavy

parasite loads, and leaving the animals susceptible to starva-

tion. In short, refuges proved to be too small and too scat-

1521

tered to compensate for changes in the overall landscapes

imposed by expanding human populations.

Yet elements of the refuge idea proved to be sound,

even critical, under some conditions. The U.S.

Fish and

Wildlife Service

administers the National Wildlife Refuge

System and, in keeping with its legal responsibilities, de-

signed the system to provide crucial

habitat

reserves for

migratory waterbirds. Roughly 80% of the refuges in this

system were established to provide breeding grounds, win-

tering grounds, or

migration

stopover sites for aquatic mi-

grants. The task of providing

critical habitat

for threatened

and

endangered species

, another area of federal commit-

ment, has been added to this mission.

As wildlife researchers learned more about habitat

needs, survival rates, and the dispersal abilities of birds and

mammals, wildlife managers began to redefine refuges more

in terms of meeting habitat needs than in providing sanctuary

from hunters. Without considering habitat quality both on

the refugeitself and along its boundaries, no level of protection

from gunfire could ensure perpetuation of native wildlife.

Pelican Island is a true island off the Florida coast;

other refuges are, or soon will be, habitat islands surrounded

by a sea of farms, ranches, forest plantations, shopping malls,

and suburbs. There is increasing evidence that even those

refuges providing the highest quality habitat may simply be

too small to sustain many of their wild species under condi-

tions of isolation.

But how much is enough? How large must a habitat

refuge be to ensure that its populations will survive?

Nature

provides a clue through an experiment that began 10,000–

11,000 years ago at the end of the last

ice age

. As the

glacial ice melted, sea levels rose. Coastal peninsulas in the

Caribbean and elsewhere became chains of islands as the

rising waters covered lower portions of the peninsulas.

The original peninsulas presumably had about the

same number of vertebrate species as did the adjacent main-

land. By comparing the numbers of birds, mammals, reptiles,

and amphibians present on the islands within historical times

with those on adjacent mainlands, biologists have found that

the islands contain consistently fewer species. Furthermore,

the number of species that a given island maintained was

correlated directly to island size and inversely to distance

from the mainland.

The most likely explanation for this pattern is that the

smaller the island, the less likely that species will survive in

isolation over long periods of time. The greater the distance,

the less likely that wild animals will re-colonize the island

by making it across from the mainland.

Shouldwe consider this analogyrealistic? After all,most

refugesare surrounded by land, notwater. Several studies from

national parks in the American West, areas protected from

both hunting and habitat alterations, have compared the

Environmental Encyclopedia 3

Wildlife rehabilitation

number of large mammal species surviving in the parks. These

studies show consistently that the bigger the park, the greater

the number of surviving species of large mammals.

Large carnivores such as

wolves

, bears, lions,

tigers

and jaguars need the largest expanses of protected areas.

Because they attack livestock (and occasionally humans),

large carnivores have long been subjected to persecution.

However, there are biological reasons for their rarity as well.

Any given level in the

food chain/web

can exist at only a

tiny fraction of the abundance of the level beneath it. It may

take 100 or more moose (Alces alces) to support a single

wolf (genus Canis) or 1,000 Thompson’s gazelles (Gazella

thomsonii) to sustain one lion (Panthera leo). These condi-

tions mean that large carnivores occur at low levels of abun-

dance and range over large areas. Simulation models that take

into account the areas needed for long-term perpetuation of

lions or bears suggest that even the largest national parks

and other protected areas may be too small. Either the pro-

tected areas themselves will need to be expanded substantially

or the populations will have to be aided by reintroduction

of individuals from outside the protected zones.

Although large carnivores remain controversial, they

also offer popular appeal to a growing segment of the public.

Refuges, parks, and other protected sites large enough to

support a population of tigers or wolves, even for a short

time, will almost certainly be large enough to meet the needs

of other wild species as well. Thus, Project Tiger in India

helped sambar (Cervus unicolor) and chital deer (Axis axis)

populations by defining areas as tiger preserves.

In the United States and Canada, people tend to think

of national parks as scenic areas for tourism and

recreation

But national parks also act as refuges by protecting wildlife

from direct exploitation and by attempting to preserve origi-

nal habitat conditions. The

grizzly bear

(Ursus arctos)once

ranged from the western prairies to the Pacific Ocean. By

the end of World War II, the only grizzly bear populations

in the lower 48 states occurred in and around two large

national parks:

Yellowstone National Park

and Glacier.

Had it not been for these parks, the grizzly bear would have

become completely extinct in the United States, exclusive

of Alaska, during the first half of the twentieth century.

Worldwide standards for refuges, parks, and other

protected areas have been developed by the United Nations

(UN), the

IUCN—The World Conservation Union

, and

the IUCN’s World Commission on Protected Areas. These

agencies compile listings every five years according to three

general criteria. To be included, an area must be at least

2,500 acres (1,000 ha) with the exception of offshore islands

of at least 250 acres (100 ha), have effective legal protection

and adequate de facto protection, and be managed by the

highest appropriate level of government.

1522

The 2000 tally by the IUCN/UN lists over 30,000

protected areas with a total area of 5.1 million sq mi (13.2

million sq km), about 9.5% of the earth’s land surface, or

roughly the size of China and India combined. Of the 193

major habitat types, 183 are represented by at least one

protected area.

The number of internationally recognized areas of pro-

tected habitats grew from about 1,800 in 1970 to nearly

7,000 by 1990 and 30,000 by 2000. This expansion resulted

from improved cooperation between nations and from the

growing realization that without protected areas, the earth’s

wildlife would be in peril. During the next quarter century,

the list of protected areas will likely continue to grow, espe-

cially in developing nations. They will become increasingly

valued for tourism and for national prestige. The effective-

ness of refuges in the more distant future will depend on

population growth

and on how quickly people shift from

extractive to sustainable

land use

practices. The current

tendency to view habitat protection as the antithesis to eco-

nomic development will fade as people recognize the impor-

tance, both ecologically and economically, of maintaining

the world’s wildlife.

[James H. Shaw]

ESOURCES

OOKS

Shafer, C. L. Nature Reserves: Island Theory and Conservation Practice.

Washington, DC: Smithsonian Institution Press, 1990.

Western, D., and M. C. Pearl. Conservation for the Twenty First Century.

New York: Oxford University Press, 1989.

World Resources Institute. World Resources 1992–93. New York: Oxford

University Press, 1992.

THER

1990 United Nations List of National Parks and Protected Areas. Gland,

Switzerland: IUCN—The World Conservation Union, 1990.

Wildlife rehabilitation

is the practice of saving injured,

sick, or orphaned wildlife by taking them out of their

habitat

and nursing them back to health. Rehabilitated animals are

returned to the wild whenever possible. Although precise

estimates of the numbers of wild animals rehabilitated are

impossible to obtain, the practice seems to be expanding in

nations such as the United States and Canada. The National

Wildlife Rehabilitators Association (NWRA), an interna-

tional group formed in the early 1980s, estimates that its

members treat about 500,000 wild animals annually, with

at least twice that number of telephone inquiries.

Wildlife rehabilitation differs from

wildlife manage-

ment

in the sense that rehabilitators focus their attention

on the survival of individual animals, often without regard

Environmental Encyclopedia 3

Edward Osborne Wilson

to whether it is a member of a

rare species

. Wildlife manag-

ers are principally concerned with the health and well-being

of wildlife populations and rarely concentrate on individuals.

Wayne Marion, formerly of the University of Florida,

has summarized the advantages and disadvantages of wildlife

rehabilitation. Rehabilitation facilities give the public a place

to bring injured or orphaned wild animals while giving veter-

inary students the opportunity to treat them. They also save

the lives of many animals that would otherwise die; experi-

ence gained through the handling and care of common

spe-

cies

may be put to use when rarer animals need emergency

care. But rehabilitation, according to Marion, is expensive,

and common species constitute the large majority of animals

saved. Rehabilitated wildlife also lose their fear of humans

and risk catching diseases from other animals.

Besides routine care for injured or orphaned animals,

rehabilitation groups often organize rescues of wild animals

following catastrophes. When the oil tanker

Exxon Valdez

ran aground in 1989, spilling 11 million gallons of crude oil

into

Prince William Sound

, the International Bird Rescue

Research Center (IBRRC) directed a rescue operation in-

volving 143 boats. Over 1,600 birds representing 71 species

were rescued alive. Survival rates varied by species, but overall

roughly half of the birds were eventually returned to the

wild. Rehabilitators also recovered 334 live sea otters from

areas affected by the spill, cleaned and treated them, and

returned 188 to the wild.

Wildlife rehabilitation should become more integrated

with conventional wildlife management in the future, espe-

cially when catastrophes threaten

endangered species

Meanwhile, an important role of rehabilitators is in educa-

tion. Rehabilitated animals who have lost all fear of humans

or who are permanently injured cannot be returned to the

wild. Such individuals can be used to teach school children

and civic groups about the plight of wildlife by bringing rare

animals, such as the

bald eagle

peregrine falcon

display at talks. See also Game animal; Nongame wildlife;

Nongovernmental organizations

[James H. Shaw]

ESOURCES

ERIODICALS

Maki, A. W. “The Exxon Valdez Wildlife Rescue and Rehabilitation

Program.” North American Wildlife and Natural Resources Conference Transac-

tions 55 (1990): 193–201.

Marion, W. R. “Wildlife Rehabilitation: Its Role in Future Resource Man-

agement.” North American Wildlife and Natural Resources Conference Transac-

tions 54 (1989): 476–82.

Willingness to pay

see

Shadow pricing

1523

Edward O. Wilson Jr. (Photograph by John Chase/

Harvard. Reproduced by permission.)

Edward Osborne Wilson (1929 – )

American zoologist and behavioral and evolutionary biol-

ogist

Edward Osborne Wilson was born on June 10, 1929, in

Birmingham, Alabama, and is one of the foremost authori-

ties on the

ecology

, systematics, and

evolution

of the ant.

Wilson developed an interest in

nature

and the out-

doors at an early age. Growing up in rural, south Alabama,

near the border of Florida, young Wilson earned the nick-

name “Snake” Wilson by having collected most of the 40

snake

species

found in that part of the country. He began

studying ants after an accident impaired his vision and has

been studying them for over 50 years, having progressed

from amateur to expert with relative swiftness. His formal

training in the biological sciences resulted in his receiving

the Bachelor of Science degree in 1949 and Master of Science

in 1950 from the University of Alabama. He received his

Ph.D. in 1955 from Harvard University.

Wilson’s work on ants has taken him all over the

world on numerous scientific expeditions. He has discovered

several new species of these social insects, whose current tally

of named species numbers nearly 9,000. Wilson estimates,

however, that there are probably closer to 20,000 species in

the world, and those species comprise over a million billion

Environmental Encyclopedia 3

Wind energy

individuals. Much of his work on this fascinating group of

insects have been synthesized and published in a monumen-

tal book he co-authored with Bert Ho

lldobler in 1990, sim-

ply entitled The Ants.

Besides hundreds of scientific papers and articles, Wil-

son has published several other books that have been the

focus of much attention in the scientific community. In

1967, Robert H. MacArthur, a renowned ecologist, and

Wilson published The Theory of Island Biogeography, a work

dealing with island size and the number of species that can

occur on them. The book also examines the evolutionary

equilibrium reached by those populations, the implications

of which have been more recently applied to the loss of

species through tropical

deforestation

. In 1975, Wilson

published his most controversial book, Sociobiology: The New

Synthesis, in which he discussed human behavior based on

the social structure of ants. His book On Human Nature,

also relating

sociobiology

and human evolution, earned

him a Pulitzer Prize for General Nonfiction in 1979. Biophi-

lia won him popular acclaim in 1984, as have his more recent

books dealing with the threats to the vast diversity of species

on earth, Biodiversity, published in 1988, and The Diversity

of Life, published in 1992. Wilson again won the Pulitzer

for General Non-fiction in 1991 for his work The Ants.

He was also awarded the 1997

Earthwatch

Global Citizen

Award, the 1998 Zoological Society of San Diego

Conser-

vation

Medal and 100 Champions of Conservation, 20th

Century by the

National Audubon Society

(1998). Wilson

was named Humanist of the Year in 1999 by the American

Humanist Association.

[Eugene C. Beckham]

ESOURCES

OOKS

lldobler, B., and E. Wilson. The Ants. Cambridge: Belknap Press, 1990.

Wilson, Edward O. Biophilia. Cambridge: Harvard University Press, 1984.

———. The Diversity of Life. Cambridge: Harvard University Press, 1992.

———. Insect Societies. Cambridge: Belknap Press, 1971.

———. Sociobiology: The New Synthesis. Cambridge: Belknap Press, 1975.

ERIODICALS

Lessen, D. “Dr. Ant.” International Wildlife 21 (1991): 30–34.

Wind energy

The ultimate source of most energy used by humans is the

sun.

Fossil fuels

, for example, are substances in which

solar

energy

has been converted and stored as plants or animals

that have died and decayed. When energy experts look for

alternative energy sources

, they often search for new ways

to use solar energy. Wind energy, although not technically

1524

classified as solar energy, is produced by the sun, and when

converted accounts for approximately 1–2% of the total en-

ergy of the sun.

When sunlight strikes the earth, it heats objects such

as land, water, and plants, but it heats them differentially.

Dark-colored objects absorb more heat than light-colored

ones and rough surfaces absorb more heat than smooth

ones. As these materials absorb more or less heat, they also

transmit that heat to the air above them. When air is warmed,

it rises into the air until it reaches approximately 6 mi (10

km) and then spreads toward the North and South Poles.

The rising air is replaced by cooler air, leaving a low pressure

area that attracts winds from the north and south. This

movement of air results in winds, and their direction is

affected by the rotation of the earth. For these reasons, some

types of

topography

and some geographic regions are more

likely to experience windy conditions than others, and from

the standpoint of energy production, these areas are reserves

from which solar energy can be extracted.

Devices used for capturing the energy of winds are

known as windmills. The wind strikes the blades of a wind-

mill, causing them to turn, and the solar energy stored in

wind is converted to the kinetic energy of moving blades.

That energy, in turn, is used to turn an axle, to power a

pump, to run a mill, or to perform some other function.

The amount of power that can be converted by a windmill

depends primarily on two factors: the area swept out by the

windmill blade and the wind speed. One goal in windmill

design, therefore, is to produce a machine with very large

blades. But, the power generated by a windmill depends on

the cube of the wind speed, and so in any operating windmill,

natural wind patterns are by far the most important consider-

ation.

Farmers have been using windmills to draw water from

wells

and to operate machinery for centuries, and the tech-

nology has been traced back to the seventh century

A.D.

the early twentieth century, windmills were a familiar sight

on U.S. farms. More than six million of them existed, and

some were used to generate electricity on a small scale.

As other sources of power became available, however, that

number declined until the late 1970s, when no more than

150,000 were still in use.

In the 1970s, windmills were not considered part of

the nation’s energy equation. Fossil fuels had long been

cheap and readily available, and

nuclear power

was widely

regarded as the next best alternative. The 1973

oil embargo

by the

Organization of Petroleum Exporting Countries

(OPEC) and the Three Mile Island nuclear disaster in 1979

changed these perceptions and caused experts to begin think-

ing once more about wind power as an alternative energy

source.

Environmental Encyclopedia 3

Wind energy

Wind turbines at Tehachapi Pass, California. (Source unknown. U.S. Department of Energy, Washington, DC.)

During the 1970s, both governmental agencies and

private organizations stepped up their research on wind

power. The National Aeronautics and Space Administration

(NASA), for example, designed a number of windmills,

ranging from designs with huge, broad-blade fans, to ones

with thin, airplane-like propellers. The largest of these ma-

chines consists of blades 300 ft (100 m) long and weighing

100 tons, which rotate on top of towers 200 ft (60 m) tall.

At winds of 15–45 mi per hour (25–70 km per hour) these

windmills can generate 2.5 megawatts (MW) of electricity.

Under the best circumstances, modern windmills achieve an

energy-conversion efficiency of 30%, comparable or superior

to any other form of energy conversion.

As a result of changing economic conditions and tech-

nological advances, windmills became an increasingly popu-

lar energy source for both individual homes and large energy-

producing corporations. With dependable winds of 10–12 mi

per hour (16–20 km per hour), a private home can generate

enough electricity to meet its own needs. The 1978 Public

Utilities Regulatory Policies Act requires

electric utilities

purchase excess electricity from private citizens who produce

more than they can use by alternative means, such as wind

1525

power. “Wind farms,” consisting of hundreds of individual

windmills, are able to generate enough electricity to meet

the needs of small communities. By the late 1980s, more

than 70 wind farms had begun operation in Vermont, New

Hampshire, Oregon, Montana, Hawaii, and California.

North America has large wind reserves. Twelve

states—North Dakota, South Dakota, Texas, Kansas, Mon-

tana, Nebraska, Wyoming, Oklahoma, Minnesota, Iowa,

Colorado, and New Mexico—contain as much as 90% of

the U.S. wind potential. It is estimated that North Dakota

alone has enough wind to supply 37% of the electricity used

in the entire United States in 1999. The largest number of

wind farms in the United States are found in California

(about 95% of U.S. capacity), and the greatest concentration

of them are located at Altamont Pass east of San Francisco.

The wind farms at Altamont Pass date to the early 1980s,

when a state study declared it the most promising site for

windmills, and a 25% state and federal tax credit encouraged

11 different developers to build 3,800 windmills there. By

the time those credits expired, wind power had proven itself

to be an inexpensive source of electricity for northern Cali-

fornia. In 1993, a single company, U.S. Windpower, oper-

Environmental Encyclopedia 3

Windscale (Sellafield) plutonium reactor

ated 4,200 windmills at Altamont Pass, dependably generat-

ing 420 megawatts of electrical energy. By 1995 California

produced enough wind power to supply all of San Francisco’s

residents with electricity. Technology improvements have

reduced the cost of wind power, and also have increased the

efficiency and durability of wind power stations. From about

25 cents per kilowatt-hour (KWH) in 1980, wind energy

costs declined to about 5 cents per KWH by 1995 at sites

with strong winds, making it competitive with fossil fuel

energy.

By the mid-1990s, wind energy had become the fastest

growing source of energy in the world. Global wind electric

capacity doubled between 1995 and 1998, and doubled again

by 2001, reaching 23,300 megawatts in 2001. The 2001

world wind energy total was enough to power about 10

million households in industrialized countries. Since the

early 1990s, the U.S. share of world wind power has declined,

as countries including Japan, Germany, Denmark, Spain,

and India dramatically increased their wind power produc-

tion. The European Wind Energy Association estimates

that the

European Union

will reach 60,000 MW in wind

power production by 2010.

Cheap fossil fuel prices and changing government tax

breaks for

renewable energy

caused wind energy produc-

tion to stagnate or decline in the United States in the mid-

to late 1990s. However, the year 2001 saw record U.S. wind

installations, and the U.S. share of global capacity rose for

the first time since 1986. New installations include ones in

Texas (900 MW), in Oregon and Washington along the

Columbia River (1,300 MW), Pennsylvania, and Palm

Springs, California. A 3,000 MW wind farm was being

planned in South Dakota, and the nation’s first offshore

wind farm was being designed for operation off the coast

of Cape Cod, Massachusetts.

A trend in wind power is offshore production, particu-

larly in Europe. Offshore wind farms are being explored due

to fewer available land sites, as well as higher and more

consistent winds offshore. Engineers are studying means of

capturing offshore wind power. In coastal urban areas, wind

farms could be built offshore on floating platforms. The

electricity generated could be sent back to land on large

cables or used on the platforms to generate

hydrogen

from

seawater, which could then be shipped to land and used as

a fuel.

Like any energy source, wind power has some disad-

vantages, and these are some of the reasons why wind power

has not already become more popular. The most obvious

disadvantage is that it can be used only in locations that

have enough wind over an extended part of the day. Storage

of energy is also a problem. Wind is strongest in spring and

autumn when power is least needed and weakest in summer

and winter when demand is greatest. Other drawbacks in-

1526

clude controversies over the appearance of wind farms and

the claim that they spoil the natural beauty of an area.

Concerns have also been raised about the noise they produce

and the electromagnetic fields they create. Finally, wind

farms cause the death of untold thousands of birds each

year, because birds use the same windy passages in their

flight patterns that are good for energy production.

Around the world, wind power will become increas-

ingly important as concerns increase over global warming

and the

pollution

caused by the burning of fossil fuels, and

as technology makes it cheaper and more available. By 2001

the United States had lost the technological edge in wind

energy to other countries that have made wind energy a

higher priority in their national energy plans. Wind energy

technology has often been funded by governments, as the

United States did in the 1970s, and shown favorable technol-

ogy gains. During the 1980s, the Reagan and Bush adminis-

trations both took a different view about the development

of alternative energy sources. Both presidents believed that

the federal government should have little or no role in this

type of research, and comparatively little progress was made

for a decade in the development of U.S. wind power.

[David E. Newton and Douglas Dupler]

ESOURCES

OOKS

Asmus, Peter. Reaping the Wind: How Mechanical Wizards, Visionaries,

and Profiteers Helped Shape Our Energy Future. Washington, DC: Island

Press, 2001.

Gipe, Paul.Wind Energy Basics: A Guide to Small and Micro Wind Systems.

White River Junction, VT: Chelsea Green Pub. Co., 1999.

THER

Danish Wind Industry Association. Guided Tour on Wind Energy. April 17,

2002 [cited July 5, 2002]. <http://www.windpower.org/tour/index.htm>.

Energy Information Administration. Energy Consumption by Source, 1989–

2000. May 7, 2002 [cited July 5, 2002]. <http://www.eia.doe.gov/emeu/

aer/overview.html>.

Sawin, Janet. Losing the Race for Wind Power: How the U.S. Can Retake

the Lead and Solve Global Warming. Greenpeace USA. March 2002 [cited

July 5, 2002]. <http://www.greenpeaceusa.org/climate/pdfs/windrep-

ort.pdf>.

RGANIZATIONS

American Wind Energy Association, 122 C Street, NW, Suite 380,

Washington, DC USA 20001 (202) 383-2500, Fax: (202) 383-2505,

Email: windmail@awea.org, <http://www.awea.org>

European Wind Energy Association, Rue de Trone 26, B-1000 Brussels,

Belgium +32 2 546 1940, Fax: +32 2 546 1944, Email: ewea@ewea.org,

<http://www.ewea.org>

Windscale (Sellafield) plutonium

reactor

The Windscale nuclear reactor was built in the 1940s near