Identifying important areas for the conservation of dwarf chameleons ( Brookesia spp.) in Tsingy de Bemaraha National Park, western Madagascar

Abstract

Many of Madagascar's endemic chameleon species have restricted ranges and require relatively intact forest for survival but information on their response to habitat degradation is generally lacking, especially in western deciduous forests. We assessed the abundance and density of endemic chameleons from nocturnal surveys of roosting animals in Parc National Tsingy de Bemaraha in western Madagascar. We found 444 Brookesia brygooi, 192 B. perarmata, 98 B. exarmata, 22 Furcifer nicosiai and two F. cf. petteri. The highest pooled density was for B. brygooi (53.2 ha-1), followed by B. perarmata (29.2 ha-1) and B. exarmata (18.7 ha-1). B. brygooi was ubiquitous, with the highest density and abundance in the disturbed Ankazomanga forest outside the Park, where the similarly sized B. perarmata was absent. B. perarmata, a species endemic to the Park, was abundant in three of the five survey sites, especially where there was a well-developed leaf litter and understorey. B. exarmata, a species endemic to the Bemaraha plateau, was associated with an open understorey and small protrusions of limestone karst. Spatial variation in the density of B. perarmata is an important consideration when interpreting monitoring data and this species is a conservation priority because of its restricted distribution and apparent sensitivity to forest degradation.