FOREST FRAGMENTATION IN THE HUMID TROPICS - A CROSS-NATIONAL ANALYSIS

While habitat destruction always causes species extinctions, the rate of extinction may be highest in those habitats which become the most f ragmented as they decline in size. For this reason, knowledge about th e patterns and origins of rain forest fragmentation in the tropics may prove useful in efforts to preserve biodiversity. This paper calculat es the degree of fragmentation in the tropical rain forests of 51 nati ons containing 83 per cent of the world's tropical forests. By these m easures, West Africa and Central America have the most fragmented trop ical rain forests in the world. Not surprisingly, rain forests in the Amazon basin are the world's least fragmented. Some patterns of tropic al deforestation appear to produce more fragmentation than others. A t wo-stage least squares analysis of these data suggest that deforestati on driven by smallholders is most likely to produce highly fragmented forest habitats. The implications of these findings for policy and for further research are briefly discussed.