Spatial and temporal distribution of call activities of two Gephyromantis species (Mantellidae) along forest–farmbush habitat in Ranomafana, Madagascar

Abstract

Understanding how changes in land use affect the distribution, abundance and behaviour of organisms is an increasingly important question in ecology. We investigated the distribution and the differential calling behaviour of two diurnal terrestrial frogs, Gephyromantis decaryi (Near Threatened) and Gephyromantis enki (Data Deficient) (Mantellidae), across a disturbed forest and farmbush area at the border of Ranomafana National Park (Madagascar), in a selectively logged forest. We used five transects of 300 m that encompass habitats of equal length. We found that G. enki is rather a forest species while G. decaryi occurs more abundantly in farmbush. While detection was relatively constant inside forest, it depended on time of sampling in secondary vegetation: more G. enki calls were recorded in the morning while more G. decaryi calls were recorded in the afternoon outside forest. These findings bring new information to the habitat requirement and the calling behaviour of the two species. Results suggest the need for different study design recognising that the two species may have different calling behaviour. It also implies the importance of secondary vegetation around protected areas for threatened species.