Island-wide distribution of Sri Lankan primates based on a questionnaire survey of residents

Abstract

Five primate species, representing three genera and 12 subspecies, occur in Sri Lanka. We conducted an island-wide questionnaire survey of primate presence/absence, based on a 5x5 km grid with three questionnaires administered to residents in each cell. Respondents were queried on the presence of Slender Lorises, Toque Macaques, Sri Lankan Sacred Langurs and Purple-faced Langurs in their neighbourhood. Results indicated that Slender Lorises and Toque Macaques were distributed over 88% and 90% of Sri Lanka, respectively, including the wet and dry zones, but with patchy wet-zone distributions. Sri Lankan Sacred Langurs were present over 86% of the island but absent from large parts of the wet zone. Purple-faced Langurs were distributed over 53% of Sri Lanka with a disjunct distribution consisting of a patchy dry-zone presence and a more uniform wet-zone distribution. The maps presented are the first based on a systematic island-wide survey. We discuss the implications of the observed distributions for primate taxonomy and conservation