Niche preferences of tree-climbing crabs in Singapore mangroves

Abstract

Six species of crabs are known to climb mangrove trees in Singapore: the non-burrowing Selatium brockii, Metopograpsus gracilipes, and M. latifrons, and the burrowing Episesarma spp.: E. versicolor, E. chengtongense, and E. singaporense. Despite the apparent spatial overlap of their habitat, an examination of the diet, distribution in the mangrove, and spatial strategy of these crabs reveals that members of the three genera occupy different niches. The algivorous tree-dwelling S. brockii and algivorous habitual tree-climbing Metopograpsus spp. are mainly found in the sandbank zone, whereas the herbivorous, facultatively tree-climbing Episesarma spp. dominate the main forest and the mud lobster mound system.