Habitat Management

Wildlife managers affect a particular species by manipulating the plant cover, food, and water sup­plies of its habitat. Because different animals pre­dominate in different stages of ecological succes­sion, controlling the stage of ecological succession of an area's vegetation en­courages the presence of certain animals and dis­courages others. For example, quail and ring-necked pheasant arc found in weedy, open are* that are characteristic of early-successional stages. Moose, deer, and elk predominate in partially open forest, such as an abandoned field or meadow adja­cent to a forest; the field provides food, and the forest provides protective cover. Other animals such as grizzly bears, California condors, and big­horn sheep, require undisturbed climax vegetation. Wildlife managers control the stage of succession with techniques such as planting certain types of vegetation, burning the undergrowth with con­trolled fires, and building artificial ponds.

Management of Migratory Animals

International agreements must be established to protect migratory animals. Ducks, geese, and shore-birds, for example, spend their summers in Canada and their winters in the United States and Central America. During the course of their annual migra­tions, which usually follow established routes called flyways, they must have areas in which to rest and feed. Wetlands, the habitat of these animals, and must be protected in both their winter and summer homes.

Management of Aquatic Organisms

Fish with commercial or sport value must be managed to ensure that they are not overexploited the point of extinction. Freshwater fish such as trout and salmon are managed in several ways. Fishing laws regulate the time of year, size of fish.

Habitat Management

Wildlife managers affect a particular species by manipulating the plant cover, food, and water sup­plies of its habitat. Because different animals pre­dominate in different stages of ecological succes­sion, controlling the stage of ecological succession of an area's vegetation en­courages the presence of certain animals and dis­courages others. For example, quail and ring-necked pheasant arc found in weedy, open are* that are characteristic of early-successional stages. Moose, deer, and elk predominate in partially open forest, such as an abandoned field or meadow adja­cent to a forest; the field provides food, and the forest provides protective cover. Other animals such as grizzly bears, California condors, and big­horn sheep, require undisturbed climax vegetation. Wildlife managers control the stage of succession with techniques such as planting certain types of vegetation, burning the undergrowth with con­trolled fires, and building artificial ponds.

Management of Migratory Animals

International agreements must be established to protect migratory animals. Ducks, geese, and shore-birds, for example, spend their summers in Canada and their winters in the United States and Central America. During the course of their annual migra­tions, which usually follow established routes called flyways, they must have areas in which to rest and feed. Wetlands, the habitat of these animals, and must be protected in both their winter and summer homes.

Management of Aquatic Organisms

Fish with commercial or sport value must be managed to ensure that they are not overexploited the point of extinction. Freshwater fish such as trout and salmon are managed in several ways. Fishing laws regulate the time of year, size of fish

and maximum allowable catch. Natural habitats are maintained to maximize population size; this .ikhides pollution control. Ponds, lakes, and streams may be restocked with young hatchlings from hatcheries.

Traditionally, the ocean's resources have been considered common property, available to the first people to exploit them. As a result, many marine fish have been severely reduced in numbers by commercial fishing. To protect this dwindling re­source, the national sovereignty of coastal waters now extends 200 miles from the shoreline, meaning that these waters are owned, or under the control of, whatever nation borders the coastline. This ruling provides governments with the opportunity to regulate and control fishing, which should help the populations of endangered and threatened fish to increase. Habitats for marine organisms can be con­structed by dumping such benign wastes as old tires and building materials offshore. Such refuse— sometimes called artificial reefs—provides cover for fish and points of attachment for algae, corals, and other sedentary organisms.

Whales During the 19th and 20th centuries, many whale species were harvested to the point of commercial extinction, meaning that so few re­main chat it is unprofitable to hunt them. Al­though commercially extinct species still have liv­ing representatives, their numbers are so reduced that they are endangered.

In 1946 the International Whaling Commis­sion set an annual limit on killed whales for each whale species in an attempt to secure sustainable whale populations. Unfortunately, these limits were set too high, resulting in further population declines during the next 20 years. Conservationists began to call for a worldwide ban on commercial whaling; such a ban went into effect in 1986. Whaling still occurs, however, because of a loop­hole in the ban that allows countries to harvest whales for research purposes and then use the meat for domestic consumption. Although a few coun­tries still use this loophole and allow the harvest of whales, they may soon bow to international pres­sure and discontinue whaling. Unfortunately, it may be too late for some whales, because their numbers are so low that they may become extinct in the next few years.