Facultative use of seasonal pools by American bullfrogs (Rana catesbeiana)

Abstract

Recent work has demonstrated the connection of seasonal pool-breeding amphibians to other local habitats such as forested wetlands and upland forests. However, the use of seasonal pools by facultative species is less well studied, particularly for highly aquatic species that breed in permanent waters such as American bullfrogs (Rana catesbeiana). Although movement between breeding ponds has been documented, evidence of bullfrog movement among breeding (permanent) and non-breeding (temporary) wetlands is scarce. Our objective was to determine the extent of bullfrog use of seasonal pools by examining movement patterns between breeding and non-breeding wetlands in Acadia National Park, Maine, USA. We examined patterns of bullfrog occupancy within one catchment using visual encounter surveys, mark-resighting, and radiotracking. Bullfrogs readily moved between wetlands with permanent and seasonal water regimes. Until pools completely dried, density of bullfrogs was greater in seasonal pools than in the permanent breeding ponds, underscoring the significance of seasonal pools as non-breeding habitat. The regularity of bullfrog use of seasonal pools throughout this study offers additional evidence for the role of seasonal pools as part of a habitat complex and highlights the importance of these habitats as features in a greater landscape context.