Introduction

Abstract

Living organisms on Earth are being subjected to massive disruptions in the form of wholesale exchanges of species among regions, introduction of alien predators and pathogens, overharvesting, habitat destruction, pollution, and, in the future, perhaps also climate change. Changes in land use in the tropics are creating extensive areas of agricultural lands and early successional patches at the expense of late successional and climax communities. Along with these changes are major reductions in population sizes and extinctions of species that depend upon the habitats that are being destroyed. Rates of forest destruction are higher in tropical regions today than elsewhere on Earth (Green and Sussman 1990, Whitmore and Sayer 1992, Wilson 1992, FAO 1993, Skole and Tucker 1993). The consequences of these changes are poorly known. Unfortunately, losses of species that may accompany forest destruction are irretrievable, and habitat loss, although reversible, can be recovered only slowly and with difficulty.