Mangrove restoration: Do we know enough?

Mangrove restoration projects have been attempted, with mixed results, thro ughout the world. In this paper, I first examine goals of existing mangrove restoration projects and determine whether these goals are clear and adequ ate, and whether or not they account for the full range of biological diver sity and ecological processes of mangrove ecosystems. Many restored mangrov e forests resemble forest plantations rather than truly integrated ecosyste ms, but mangrove plantations can be a first step toward mangrove rehabilita tion. Mangrove restoration projects that involve associated aquaculture or mariculture operations tend to be more likely to approximate the biological diversity and ecological processes of undisturbed mangrove ecosystems than are projects that focus only on the trees. These integrated restoration pr ojects also provide a higher economic return than do silvicultural projects alone. Second, I briefly assess whether existing ecological data are suffi cient to undergird successful restoration of mangal and define criteria for determining whether or not a mangrove ecosystem has been restored successf ully. These criteria include characteristics of vegetation (forest) structu re, levels of primary production, composition of associated animal communit ies, and hydrology. Finally, I suggest ways to improve mangrove restoration projects and identify key research needs required to support these efforts . Ecological theories derived from other wetland and upland systems rarely have been applied to either "basic" or "applied" mangrove forest studies, t o the detriment of restoration projects, whereas lessons from restoration o f the relatively species-poor mangrove ecosystems could be beneficially app lied to restoration projects in other contexts. An international database o f mangrove restoration projects would reduce the likelihood that unsuccessf ul restoration projects would be repeated elsewhere. Clear criteria for eva luating success, greater accessibility of information by managers in the de veloping world, intensified international cooperation, and application of r elevant ecological theories will improve the success rate of mangrove resto ration projects.