Mangrove forests: a tough system to invade but an easy one to rehabilitate

Mangrove forests are tough ecosystems to invade because few species can tol erate the hydrological and edaphic conditions that prevail in mangrove habi tats. The small pantropical mangrove species pool is also the basis for ass erting that mangrove forests are easy to rehabilitate, at least in terms of tree species composition. The high complexity of the animal and microbial component of mangrove ecosystems is not addressed in this article. The foll owing questions are useful as a guide for evaluating the invasion of plant species into mangrove habitats: (1) Is the invading species a halophyte? (2 ) What conditions of the environment is the invading species occupying and how long,will those conditions last? (3) What is the geographic location of the invasion, does it penetrate the forest or is it only at the edge? (4) Is the invasion a short-term response to changes in microsite conditions? ( 5) Is the invasion the result of a long-term shift in the mangrove habitat? (C) 1999 Elsevier Science Ltd. All rights reserved.