Mangroves are an assemblage of salt-tolerant trees and plants that exist in the intertidal coastal zones of countries in the tropics and sub-tropics. Healthy mangroves can greatly assist the sustainable existence of local coastal villagers because of the wealth of ecosystem goods and services they provide. However, a significant proportion of this ecosystem has been degraded or converted to other land uses. Many government mangrove agencies are realising that because of the diffuse nature of this ecosystem and limited government resources, they need to work with local communities that are based within or near these forests, encouraging some form of community management and involvement to counter mangrove losses.
The overall goal of this research was to explore some of the barriers that inhibit successful community mangrove management, across two countries in Southeast Asia in order to contribute to the discussion about how best to enable this process. The first objective was to assess whether communities were able to rehabilitate mangroves successfully and the role of government assistance within this. The second objective was to study in a more qualitative, detailed manner how villagers carried out this rehabilitation work and to identify the knowledge and understanding that underpinned their decisions, contrasting these with actual outcomes.
Environmental organisations typically encourage protection of existing mangroves over rehabilitation of degraded areas because rehabilitation projects have uncertain outcomes, and the full suite of ecosystem benefits are only provided by mature stands. Therefore, a third objective was to explore how communities preserve their own mangroves and inhibit cutting of mangrove through the development of their own management rules, or the use of national law. A final objective was to help independent organisations to assist mangrove communities by suggesting a simple method that would allow comparison and therefore ranking of the status of mangroves across a group of communities, to indicate which were most in need of, and likely to benefit from, outside assistance.
Outcomes from the first two objectives suggested that inappropriate targets, set centrally by mangrove agencies, together with gaps in villager and mangrove agency field office staff knowledge of mangrove ecosystems, have led to sub-optimal rehabilitation outcomes. Almost all rehabilitation projects relied on planting rather than assisting natural regeneration, and much of this planting proved either unnecessary or was conducted in inappropriate locations. There was confusion about the suitability of mudflats for planting, normally considered below an appropriate tidal elevation for mangrove establishment. Effective tidal flushing and drainage was demonstrated to have a significantly positive effect on planting results. Villagers were aware of the possibility of rehabilitating some sites simply by improving the hydrology, but this appeared not to result in activities on site to improve site topography or hydrology.
Consideration of the community management rules of this sample of villages suggested that many of the principles suggested by terrestrial community forest researchers hold true in a mangrove environment, particularly the need for strong social capital and effective leadership, but as has been suggested previously, local context and parameters play such a significant role that the wider application of these conclusions should be done with caution.
Finally, to help external organisations that wish to assist mangrove communities, I have suggested a series of indicators for the development of mangrove quality and sustainability criteria, that when combined with other bio-physical measures, are easier to aggregate and assess than some of the existing terrestrial forest indicators. A suggested indicator weighting system is proposed, which with further testing in mangrove ecosystems other than river deltas, might provide a simple way to prioritise the location of mangrove management interventions.