Some pioneering projects in conservation biology are already reshaping scientists' ideas about extinction and its consequences. In the Amazon Basin near Manaus, Brazil, the World Wildlife Fund and Brazil's National Institute for Amazonian Research launched the Minima.! Critical Size of Eco systems project in 1979. Brazilian law re quires that 50 percent of the land in new cattle ranches remain forested; researchers worked with local ranchers as they cleared grazing land to create a set of forest reserves ranging in size from 1 to 10,000 hectares.

This huge experiment allows biologists to observe the process of extinction and species change when forest patches are isolated from once-continuous forest. The project will reveal for the first time the rates and patterns of species loss as the ecosystem approaches new equilibrium populations of plants and animals. Similar studies are needed in every type of habitat on every continent—a goal beyond the present capacity of the scientific community.

Another vital knowledge gap is how tropical forests recover after human disturbance. What happens when pasture or crop land is abandoned? What species will return? In late 1984, the Royal Society in Britain established the South-East Asian Rain Forest Research Program in Malaysian Borneo to answer these questions. In the forests of Southeast Asia, regeneration potential seems to depend on the scale of the disturbance; the smaller the disturbance, the quicker and more complete the recovery.

If such studies are to influence conservation decisions throughout the topics, they will have to be done on more than a piece meal basis. The scientific community is be ginning to recognize the need for large-scale, integrated studies of Earth's life-support systems, and tropical biology offers a promising starting point for such programs. Harvard University's Edward 0. Wilson advocates that the United States, the largest funder of tropical research, declare an "International Decade for the Study of Life on Earth" to focus scientific and financial re sources on the pressing problems of biological diversity. Though such a high-profile initiative has yet to take shape, an ambitious program, "Decade of the Tropics," now en joys broad international support. Separate studies of tropical savannas, soil biology and fertility, mountain environments, human adaptation to tropical conditions, and species diversity make up the program.

Despite these initiatives, conservation biology and tropical ecology remain the poor relatives of better-funded, more prestigious fields. A Society for Conservation Biology has been established, departments are springing up at universities, and a new journal, Conservation Biology, charts research progress, but the field remains outside the mainstream of science. The National Science Foundation, for example, has no program yet to fund work in conservation biology. This "applied" discipline remains beyond the bounds of the "basic" research the foundation's $1.6 billion budget sup ports.

In 1980, tropical biology research world wide received about $35 million, excluding work in applied areas of agriculture and forestry. With increasing attention to tropical environmental problems, biologist Peter Raven of the Missouri Botanical Garden estimates that the total may have risen to the $50 million to $75 million range by 1986.

Unfortunately, there is no systematic way to monitor this spending. Tropical biology is a fragmented field, and researchers in a variety of disciplines receive funding through many different agencies and programs. Five programs within the National Science Foundation's Division of Biotic Systems and Resources encompass tropical studies, but only 15 to 18 percent of the $60 billion division budget—$9 million to $11 million—funds tropical research. The Smithsonian Institution, which maintains a re search station in Panania, spent $17 million on tropical activities in 1986. The National Academy of Sciences, which does not fund research directly but helps set the national scientific agenda, recently created a Pro gram on Biodiversity that may give tropical studies the visibility needed to attract more generous support.

One way to strengthen research in critical tropical areas is to use development aid funds to train Third World students in conservation biology and help pay for national parks, species inventories, and natural re source management. But in the 'United States, development aid for scientific re search faces an uncertain future. Pressures to use foreign aid to promote political objectives and budget constraints resulting from the federal deficit have reduced science and technology programs in the U.S. Agency for International Development more than 22 percent over the last 2 years—a cut of $63 million. Even the budget for agricultural research, which enjoys widespread support, has been cut by 30 percent. Unless Japan or the European Community offsets shrinking U.S. support for overseas science, applied tropical studies could languish.

Given the enormous significance of tropical studies in helping nations come to terms with an era of biological change, the question of how to attract sufficient resources is an important one. Stanford University biologist Paul Ehrlich proposes quadrupling the level of funding for research in ecology, taxonomy and tropical studies through the National Science Foundation. Even at this level—roughly $200 million per year—tropi cal biology would remain a modest national priority beside multibillion dollar programs in biomedical research.

Tropical biology, the essential foundation for a response to the biological diversity crisis, is constrained by a legacy of neglect. The tropics and Earth's biosphere face profound changes in the course of the next human lifetime. Research agendas and science bud gets should reflect this challenge. Reweaving the fabric of biological diversity can scarcely begin as long as the strands remain uncounted and unknown.