Species diversity, endemism and distribution of land snails of the Western Ghats, India

Abstract

As elsewhere, invertebrate taxa have received little attention in conservation planning in India. The Western Ghats has been designated as a global biodiversity hotspot, one of only two such designations in India. We have assembled a database for land snail records in the region, incorporating both published records and the results of our own surveys over the last three years. Of the 269 species so far recorded, 75% are endemic to the region. Many species have very restricted ranges within the region. There is a decline in diversitv and local endemism from south to north. The southernmost division (8~·12°N) has much the richest recorded fauna (210 species), and the level of local endemism The latter is much lower in the central and northern divisions. There is thus considerable faunal turnover within the region. The overall level of endemism is higher than that recorded for other taxa, and our data have already been used to identify three local hotspots within the region. These results are discussed in terms of present climate and habitats, and in terms of environmental history. Comparisons are made with studies on other continents, and the impact of human activity by destruction and fragmentation of habitats is considered.