Leaf Litter Translocation and Consumption in Mangrove Ecosystems: the Key Role Played by the Sesarmid Crab Neosarmatium malabaricum

Nutrient cycling in mangrove forests is strongly linked to detrital processing of leaf litter, as compared to direct herbivorous consumption. Sesarmid crabs play a key role in detrital pathways in mangrove forests by processing a large amount of leaf litter produced in the ecosystem. We studied the rate of leaf litter translocation and consumption by a sesarmid crab, Neosarmatium malabaricum, through an ex situ experiment simulating field conditions. We supplied weighed senescent leaves of Aegiceras corniculatum, Avicennia officinalis, Excoecaria agallocha and Rhizophora mucronata to the crab. When provided separately, the crab translocated leaf litter of E. agallocha the maximum, and that of Rhizophora mucronata the minimum to the burrows. When litter mixed together was provided, the rate of translocation was the highest. The crabs consumed up to 80.24% of the litter that they translocated. We found this species capable of translocating 4.39 ±1.68 g of leaf litter m^-2 per day and that its population had the potential to translocate 1.81 times more leaf litter than the ecosystem produced, based on comparisons of translocation rate, density of N. malabaricum and leaf litter production in the study area. Our experiments emphasize the key role played by this crab in detrital pathways of mangrove ecosystem.