Rainforests of the seas

Tropical mangroves are salt-tolerant 'rainforests' which occur at the interface of land and sea (Ball, 1996). They can occur on sand, mud, rock or on corals although they are best developed on deltaic silts at the mouths of large river systems. Mangrove communities are not floristically as diverse as terrestrial rainforests because the necessary adaptations to this precarious environment have only occurred in relatively few species in a handful of plant families. Thus, only about 70 species are characteristic members of this saline tropical rainforest community. The specific features needed to deal with this tropical intertidal environment include (i) an ability to tolerate salt; (ii) a tolerance of waterlogging and the anoxic soil conditions that accompany this phenomenon; and (iii an ability to withstand tidal buffeting from wind, waves and tidal currents. Each of these features is briefly reviewed and the habitat values of this tidal rainforest are discussed.