Tropical mangrove ecology: Physical and biotic factors influencing ecosystem structure and function

Our understanding of the ecology of tropical mangals has strong practical implications for the management and conservation of these threatened ecosystems. Earlier models of tropical mangals proposed overwhelming influences by physical forces and processes such as the tidal regime or geomorphology on ecosystem structure and function. Recent findings from especially the Indo-Pacific mangals suggest also considerable influence from biotic agents and processes such as sesarmine crab feeding and bioturbation activities in shaping the ecology of tropical mangals. I argue that more research attention should be paid to the study of the interplay between physical and biotic influences in the ecology of tropical mangals. Examples in litter dynamics and community determination are given to illustrate how biotic influences may respond to changes in the physical setting of mangals. This necessitates an approach integrating the two sources of influences. Despite decades of increased research effort, answers to many fundamental questions concerning practical management issues of tropical mangals are still largely unavailable. The often-acclaimed functions and values of tropical mangals also have to be critically assessed in the light of existing and future data. It is proposed that research effort should also be targeted towards the assessment and mitigation of the predicted impacts of urgent problems faced by tropical mangals (e.g. conversion to aquaculture ponds, pollution) in order to secure their long-term conservation and wise management.