Diversity Patterns in the Tropics

Abstract

Subterranean habitats in the tropics host a high diversity of species that has been long overlooked.Specieshave beendiscovered at a fast pace over the last few decades. The patterns of habitat diversity differ from those of temperate regions in several respects. In the tropics, a significant contribution to overall subterranean diversity comes from anchihaline/marine and guano habitats. Troglobionts are moderately troglomorphic in the lowland tropics, whereas highly troglomorphic stygobionts are frequent. Troglomorphy levels and proportion of troglobiotic taxa increase with altitude and latitude, in parallel with a decrease in bats and guanobionts. Several taxa are unique to tropics and shared by all tropical regions, but there arealso great differences between regions. A major interest of subterranean fauna of temperate regions is its richness in relictual taxa: this is retrieved in the tropics, but to a lesser extent. On the whole, global diversity of obligate cave fauna in the tropics appears lower than that of the richest temperate regions. This may change however when biodiversity surveys of tropical caves begin totake into account microcrustacea and guanobionts.