Context-dependence of long-term responses of terrestrial gastropod populations to large-scale disturbance

Abstract

Large-scale natural disturbances, such as hurricanes, can have profound effects on animal populations. Nonetheless, generalizations about the effects of disturbance are elusive, and few studies consider long-term responses of a single population or community to multiple large-scale disturbance events. In the last 20 y, two major hurricanes (Hugo and Georges) have struck the island of Puerto Rico. Long-term population trends of 17 species of terrestrial gastropod were evaluated to determine whether gastropods respond to hurricane disturbances in a consistent fashion. Some species increased, some decreased, and some exhibited no simple trend in density or spatial variability following disturbance. In addition, some species responded differently to the two hurricanes with respect to population density, absolute spatial variability, or relative spatial variability. Population responses probably hinge on trade-offs between sensitivity to microclimatic changes and resource availability resulting from the relocation of biomass from the canopy to the forest floor. The historical context within which a hurricane occurs may be as important, or more so, than the intensity of the storm, per se.