Spatial Ecology of Scaphiophryne gottlebei in the Canyons of the Isalo Massif, Madagascar

The Rainbow Frog Scaphiophryne gottlebei lives within the humid canyons that cross the Isalo Massif, central-southern Madagascar. Knowing that a single haplotype dominates the largest part of its distribution range raised questions about the dispersal ability of the species. We affixed external radio transmitters to 36 individuals of S. gottlebei to understand whether the adults of this species actively displaced from the canyon they inhabit. We studied 13 males and 7 females in 2009 and 7 males and 9 females in 2011 over two periods (November-December 2009 and January-February 2011). Study sessions were chosen due to the different meteorological conditions: the first is the beginning of the rainy season, which corresponds to the start of reproduction; and the second being the end of the rainy season, which corresponds to a wetter period during which individuals are more likely to be feeding in order to increase body weight. Our results revealed that there is no significant difference in the activity patterns between sexes and that rain and temperature stimulate the dispersal rate. The distance covered by the individuals did not differ between males and females; the range varied from a few centimeters to approximately 50 m, although two individuals displaced more than 100 m in a single day. These data suggest that individuals of this species are quite phylopatric to the canyons they inhabit. The generalized haplotype sharing observed might then be explained by passive dispersal of larvae and metamorphosed individuals during the intense cyclonic floods.