Mangroves in the Great Barrier Reef World Heritage Area: current status, long-term trends, management implications and research

Mangroves are a coastal marine environment, characteristically biomass-dominated by trees. They support a high biodiversity of marine and terrestrial biota, as well as providing a haven for estuarine fauna, and a nursery ground for other fauna ranging from flying foxes, seabirds, to offshore fish and crustaceans. The uses and benefits of mangroves equate to our direct use of some of these biota but it also includes other indirect benefits such as protection of coastal foreshores and estuarine margins from erosion. Mangrove environments in, and adjacent to, the Queensland GBRWHA are in relatively good condition, although there are clear indications that pressures on them are increasing rapidly. Localised impacts are accumulating to a point where large areas, once thought to be able to withstand change, are now threatened. And, detrimental changes appear to exceed societies' current responses to protect mangrove environments and to reduce the overall impact of the growing number of smaller impacts. Human activities affect the establishment, growth, survival and biodiversity of mangrove plants, and their impacts range from: direct removal and damage of mangrove plants; conversion of mangrove lands to other uses; construction of breakwaters and other alterations to water courses and local hydrology effecting depositional planes and sediment levels; changes to air and water quality as increased dust, turbidity, temperature and the addition of chemicals; catastrophic events of pollution bringing long-term impacts like large oil spills; and the introduction of exotic pests and pathogens from land and sea sources. Pressures on mangrove environments are real, and there is an increasing obligation on environmental management authorities to clearly describe coastal and estuarine areas according to the best scientific advice. Based on these descriptions, the next step would be to apply protection status, and in particular, designating specific areas for total protection with surrounding areas as buffers. There has never been such a profound urgency to have coastal management plans in place if we wish to preserve rare natural stands, especially adjacent to more populated areas in the region. The obligation on management authorities extends to their taking a leading role in advising Governments on the uniqueness, fragility, vulnerability and ecological tolerance of mangrove ecosystems, as well as on their benefits. And, once management authorities and all interest groups have made decisions about which areas are to be preserved, future develop proposals cannot be a matter of compromise between special action groups and developers since it is the environment we wish to preserve which ultimately must determine where the limits of change are set. In appreciation of the urgency, it is also recommended that we continue to fill gaps in our knowledge and understanding of mangrove forests by further supporting long-term monitoring programs investigating, in particular: ecological processes; loss of mangrove area; and the restoration of damaged mangrove stands