IN THE LAST 20 years, the size of tropical rainforests and the number of animals in them has declined drastically, although money for conserving those forests has become more plentiful. We have made protecting the forests an international priority, but we are not doing a good job of it.     The problem is that many conservationists have embraced the goal of sustainable development, which is badly defined and may well be unworkable Economic growth-a component of most definitions of development-usually requires the consumption of at least some nonrenewable resources; and even where stable systems of agriculture can be constructed around renewable resources, those systems inevitably displace natural ecosystems.     In any case, we cannot achieve both sustainable development and conservation's original goal of protecting largely un- spoiled habitats. The pressures of human population growth and general economic development have led people to clear forests to make farms, plantations, roads, and towns. Nonetheless, conservationists continue to support development, out of financial and political expediency.     During the 1960's and early 1970's, two major international conservation groups -IUCN- The World Conservation Union and the World Wide Fund for Nature, known in the United States as the World Wildlife Fund--began or adopted many conservation projects in tropical regions, and the number of parks and other protected areas in rain forests began to increase markedly. As the quantity of projects grew, IUCN racked up a substantial budget deficit; it was bailed out in 1976 by the newly founded United Nations Environment Programme.     From1hat point on, IUCN, the W.W.F., and UNEP became regular collaborators. UNEP, founded to improve the condition of the human environment, supplied much of the financial support for a strategy of world conservation that was formulated by IUCN and published, in 1980, as a joint report by the three organizations. Rather than focusing on the creation of nature reserves around the world -the original goal of IUCN- the strategy stressed the concept of sustainable development.     Another new source of money for conservation in the 1970's was development organizations such as the U. S. Agency for International Development and the World Bank. Those organizations faced increasing criticism because so many of the projects they sponsored in the tropics-such as new dams and highways-were disrupting the environment. In response, they began to make money available for projects that linked development with conservation-in at least one case, in Nigeria, involving agricultural development inside a forest reserve. Why a Prime Model for Saving Rain Forests Is a Failure By John F. Oates     Politicians in developing countries supported the new integration of conservation with development, because they had felt that international agencies were giving wildlife protection precedence over economic development for humans. Naturally, conservation groups, which had previously relied chiefly on donations from individuals, were happy to have the additional funds, Linking conservation and development seemed to be a solution that would benefit everyone involved, as well as protect natural ecosystems. THE MARRIAGE of conservation and development has been a disaster for much of tropical nature. Most of the integrated conservation-and-development projects that I know of have failed to protect the environment, and they have rarely achieved sustainable development either. Like the majority of pure development projects, they are designed to fit the short-term financial strategies of their sponsoring agencies. The projects typically have three-to-five- year budgets, even though conservation efforts should focus on the very long term. Large amounts of money are released over short periods of time, promoting lavish and unsustainable spending, and sometimes corruption. Most of the projects are managed by highly paid consultants, often resented by local professionals, whose salaries can be less than one-thousandth that of a consultant.     The projects usually emphasize local economic and agricultural development. But if the work is at all successful, it both increases the impact on the ecosystem of the people already in the area and attracts migrants. As Andrew Noss, a scientist at the Wildlife Conservation Society, said in a review of one project in the Central African Republic, many Africans will readily move, even to a remote area, to exploit new economic opportunities.     Because most international agencies' policies stress helping people, rather than preserving the environment, few integrated conservation-and-development projects make the rigorous policing of protected areas a high priority. Those in charge of the projects typically believe that if people have viable economic alternatives, they will voluntarily refrain from exploiting forest resources, By contrast, land-management policies in developed countries do not rely on that comforting idea, based on the myth that humans will attempt to live in harmony with nature if given the chance. Instead, industrialized countries recognize the human tendency to exploit any available resource until it is exhausted; as a result, they have zoning regulations.     As John Terborgh, a tropical ecologist at Duke University, and others have made clear, we are on the verge of a crisis. Many animal species in the tropics face extinction, as their ecosystems are reduced to smaller and smaller fragments, each of which is under increasing pressure from human-population growth and economic development. Strong action is necessary to prevent the crisis, and academics can play a role in the solution. SCIENTISTS such as Terborgh and the primatologist Thomas Struhsaker, also at Duke, have become convinced, as I have, that a much greater effort must be made to protect tropical parks and reserves from human interference-while some large, relatively untouched natural ecosystems remain. Without better protection, through policing of the sites and enforcement of laws against exploiting the resources, many of those ecosystems and the species they sup. port will soon be gone forever. Many tropical countries have already set aside about 5 percent of their land area as reserves. Turning over that amount of land to development would have only a marginal economic effect for humans, yet it would have a devastating impact on millions of other species.     The money to create new parks, and to protect them and the existing ones, would probably have to come, for the time being, Information Resource: The Chronicle of Higher Education from the citizens of rich countries, given hat the economies of many developing countries -particularly in Africa- are not in good shape.     Through their governments' financial support of organizations such as the World lank, the citizens of developed countries are now subsidizing the conservation-and-development projects that are harming rain forests. If that money were allocated instead to independent trust funds, income from the funds could pay indefinitely for he basic protection of many tropical parks. Some organizations, such as conservation International, have already helped establish trust funds for tropical conservation.     Such investments should be accompanied by increased efforts to instill a greater appreciation for nature -beyond its material value- among people, especially children, in developing countries. That is not a hopeless cause. Children everywhere tend o be fascinated by animals and plants, and hat interest can lead to public support for protecting nature. India is an excellent example of a densely populated country whose citizens, though mostly very poor, how widespread respect for other living things and generally support government-run conservation areas.     Teaching science and natural history in primary schools can be an effective way to reach children. Natural-history books are now in short supply in many tropical countries, as are movies and videos about wildlife. Spending money on educational resources would be an excellent investment; so would improving the often awful zoos in cities of developing countries, and including exhibits on conservation.     Finally, biologists should be more vocal in their criticism of current conservation policies. Only a few, such as Terborgh and Struhsaker, have so far made public statements about the lack of logic; and the danger, in promoting sustainable development.     Over the years, many academics have refrained from directly criticizing international conservation organizations on the round that those groups are only trying to do their best under difficult circumstances -if we undermine them, who will be left to fight for conservation? Many biologists working in the tropics have also depended for their research funds on conservation organizations, a practice that surely has inhibited criticism.     Before it is too late, more academics should apply the critical thinking in which hey are specially trained to the problems of tropical conservation, and speak out bout the logical flaws in current policies. Biologists in particular have an obligation o do what they can to preserve nature. They are the experts, the logical defenders of the natural world. John F. Oates is a professor of anthropology at Hunter College and the Graduate Center of the City University of New York. {His most recent book is Myth and Reality 0 the Rain Forest: How Conservation strategies Are Failing in West Africa, published last fall by the University of California Press.