Relating Patterns of Land‐Use Change to Faunal Biodiversity in the Central Amazon

Large‐scale deforestation is threatening the diversity of tropical forests. Given the paucity of data on life‐history characteristics of tropical species, methods are needed to identify those species susceptible to extirpation following forest fragmentation. The approach developed in this paper provides a method to examine potential effects of forest fragmentation on biodiversity considering both land‐use changes and traits of susceptible species. Based on certain behavioral characteristics, the effects of forest fragmentation in the Brazilian Amazon were projected for nine groups of animals. The taxonomically diverse species were characterized by gap‐crossing ability and area requirements. The probability of local extinction due to destruction of habitat over a 40‐year period was estimated for these animal groups under three scenarios of land‐use practice, projected with a computer model. These scenarios include the typical land use of central Rondônia, Brazil, and two extremes of land‐use practice that bracket the range of possible agricultural land‐use changes. Animals with gap‐crossing ability proportional to area requirements respond similarly to fragmentation, regardless of their taxonomic affiliation. The available habitat for those species is proportional to the amount of remaining forest under all three agricultural management scenarios. In contrast, species that have large area requirements but that will cross only small gaps are more adversely affected by forest fragmentation. The available habitat for such species is reduced at a rate disproportionately greater than the rate of forest clearing. For a tropical frog, the effects of forest fragmentation were evaluated considering not only gap‐crossing ability and area requirement but also specialized habitat requirements and edge effects. For the worst‐case scenario of land management, gap‐crossing ability and area requirements of the tropical frog imply that only 60% of the forest remaining after seven years of management is suitable habitat. Considering breeding habitat requirements and possible edge effects further reduces the suitable habitat to 39% of the remaining forest. These reductions in the proportion of suitable forest area are likely to change with rate and spatial pattern of forest loss.