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  • Title: The impact of population pressure on conservation and development.
    Author: Collins NM.
    Journal: Res Reprod; 1984 Jan; 1(1):1-2. PubMed ID: 12265923.
    Abstract:
    In many parts of the world high population levels and growth rates are responsible for hunger, disease, and poverty. Humans are not the only species suffering the consequences of the increasing numbers of people. The search for agricultural and grazing land, the depletion of forests and woodlands for timber and fuel, and the intensified use of chemicals for pest control, pasture improvement, and crop productivity all combine to degrade the environment, forcing the retreat and extinction of wild animals and plants. All organisms, including humans, depend upon environmental resources which are shared with other animals and plants. Overpopulation by 1 species inevitably depletes the resources of all of them. Many animals and plants have methods which prevent overcrowding and competition with other individuals of their own species. Humans have escaped many of nature's constraints by developing agriculture, industrialization, and medicine, bypassing the safety valves which regulate other species. Population growth in the industrial nations of the northern hemisphere since the industrial revolution frequently has been very high and has now stabilized at less than 1%. The environmental cost has been great and is still serious because of increasingly intensive use of the land. Many species have been severely reduced in numbers. Humans are the greatest single factor in the loss of species. In industrialized nations, powerful machines and chemicals change habitats and entire landscapes. In developing countries, a vast army of rural people do the same. The demands of populations are so great that even the basic need for firewood causes severe destruction of tropical woodlands and shrub formations. In 1980 the 1200 million people in the developing world who use wood as their primary fuel consumed wood faster than it was naturally replaced. Soil erosion, loss of fertility, and desertification follow. More species than ever before might become extinct as humans disrupt the most complex of all earth's biological communities--the equatorial rain forest. At the end of the century about 88% of the world's present rain forest area will remain, but most of it will be in the huge forests of Brazil and Zaire. Land hungry shifting cultivators are clearing 7.5 million hectares of closed canopy forest every year. With too many people on too little land, the traditional fallow periods are markedly fore-shortened and the forest cannot rebuild its store of nutrients. Some species adapt well. Yet, the number of endangered species could escalate to unprecedented proportions, many being familiar vertebrates. A table shows the number of extinctions of full species of birds and mammals alone between 1600 and 1970. Dependence upon wild species should not be underestimated. Resource conservation is essential for sustainable development.
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