Word: ecosystems
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Dates: during 1980-1989
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Realizing that if elephants vanish, so might tourists, some African nations are determined to slow down the killing. In addition, the animal is a vital part of Africa's unique ecosystem. For eons, elephants have knocked down trees, helping to give Africa its distinctive mix of forest and savanna and opening up the land for other big mammals...
...promised land, but they have merely produced a network of devastation. The soil that supported a rich rain forest is not well suited to corn and other crops, and most of the newcomers can eke out only an impoverished, disease-ridden existence. In the process, they are destroying an ecosystem and the millions of species of plants and animals that live in it. An estimated 20% of Rondonia's forest is gone, and at present rates of destruction it will be totally wiped out within 25 years...
Diversity is the raw material of earth's wealth, but nature's true creativity lies in the relationships that link various creatures. The coral in a reef or the orchid in a rain forest is part of an ecosystem, a fragile, often delicately balanced conglomeration of supports, checks and balances that integrate life-forms into functioning communities. Given the complex workings of an ecosystem, it is never clear which species, if any, are expendable...
...tropics the crucial question is how large a forest must be to sustain itself. If a park or protected area is too small to support some of its animal and plant life, the ecosystem will decline even with protection. As yet, no one knows the minimum critical size of a rain forest, but in 1979 Thomas Lovejoy, now at the Smithsonian Institution, set up a 20-year experiment with the cooperation of the Brazilian government to determine just that for the Amazon region. Among the findings: the smaller the forest, the faster the decline of insects, birds and mammals...
...only open after being exposed to intense heat. Ecologists expect the fires to help restore the park's depleted stands of aspen trees and increase the wide array of insects, birds and mammals that have found Yellowstone's aging forests increasingly inhospitable. "It's part of living in an ecosystem that is basically wild and uncontrollable," says Louisa Willcox of the Greater Yellowstone Coalition, which supports the natural-burn policy...