Read the following text and sum up the measures taken to preserve the wildlife.

 

 

Wildlife Conservation

 

The activities of human beings and human population growth have increased the danger for wildlife. Some species of plants and animals have greatly declined in numbers, others are now extinct. Thus, human beings created the need for conservation.

Various species have become extinct even before people appeared on the
earth. In the past, however, other species developed and replaced those that died off, and the total variety of life did not diminish. Today human activities kill off species with no hope for their replacement, and so the variety of life decreases.

Beginning with the late 1800's, growing concern for the world's vanishing wildlife has lead to increased conservation action. The governments of many nations have passed protective laws and set aside national parks and other reserves for wildlife. Nowadays there are more than 1200 national parks, wildlife reserves and similar protected areas throughout the world. The measures taken have saved the American bison, the pronghorn antelope, and many of the rare plants found on such islands as the Hawaiian and Galapagos islands. Several hundreds species of animals and thousands of species of plants, however, still face the danger of extinction.

Wild biologists use three main classifications for animals and plants that face possible extinction: endangered, threatened, and rare.

Endangered species face the most serious threat of extinction. They require direct human protection for survival. The California condor is endangered because only about 50 birds of this species still exist, most of them in captivity. In 1987 wildlife biologists captured what was then the last remaining wild California condor. Since then, more than 25 California condors have been born and raised in captivity, and scientists have released some of these birds into the wild.

Threatened species are generally abundant in some areas, but still face serious dangers. These dangers may result from unfavourable changes in the environment. They also may be due to extensive hunting, fishing, or trapping, or even to collecting by enthusiasts. The grey wolf, a threatened species, is plentiful in some places. But its overall numbers worldwide are being steadily reduced by hunting, trapping and poisoning.

Rare species have small populations. They live in protected environments, and their numbers are not decreasing. For example, the Torrey pine tree is classified as rare. It grows only in two small areas of Southern California, but human actions do not threaten its survival.

An animal threatened by too much hunting can be protected by laws that forbid or regulate such killing. These laws may specify when a certain species may be hunted or how many of the species can be killed. Laws can also protect plants endangered by over-collection. If an entire habitat requires protection, the area may be made a national park or wildlife refuge. On the other hand, a species may become too numerous – the problem that occurred with elks and hippopotamuses in national parks. The numbers of such a species must then be reduced, either by controlled hunting or by restoring its natural enemies where they have become scarce.

If a species can no longer survive in its natural environment, it may be raised in captivity. This method saved the Hawaiian goose. Likewise, conservationists hope to save the black-footed ferret. This small mammal once lived throughout
the Great Plains of North America, but its population declined sharply during the 1900's. Scientists captured all known ferrets in the 1980's and began breeding them in captivity. In 1991, they began releasing the ferrets into the wild, where these animals have established new populations.

A species threatened by disease may be helped by sanitation measures in its habitat. Rare plants can be maintained in botanical gardens, or their seeds can be saved in seed banks for future planting.

The success of wildlife conservation to a great extent depends on the understanding of the way in which a species lives, and how it relates to everything, both living and nonliving, in its environment.

 

 

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