Mangrove plants are a diverse group which have been able to exploit a habitat (the intertidal zone) because they have developed a set of physiological adaptations to overcome the problems of anoxia, salinity and frequent inundation. Each species has its own capabilities and solutions to these problems and this may be the primary reason why on some shorelines mangrove tree species show distinct zonation as a consequence of variations in the range of environmental conditions across the intertidal zone. The mix of species at any location within the intertidal zone is therefore partly determined by the tolerances of individual species to physical conditions such as tidal inundation and salinity, but also may be influenced by other factors such as predation of their seedlings by crabs.

A cluster of mangroves on the banks of Vellikeel river in Kannur District of Kerala, IndiaOnce established, the roots of the mangrove plants help to impede water flow and thereby enhance the deposition of sediment in areas where it is already occurring. It is usually the case that the fine, anoxic sediments under mangroves act as sinks for a variety of heavy (trace) metals which are scavenged from the overlying seawater by colloidal particles in the sediments. In areas of the world where mangroves have been removed for development purposes, the disturbance of these underlying sediments often creates problems of trace metal contamination of seawater and biota.