The ecosystem Precise data on global mangrove resources are scarce. The majority of the subtropical and tropical coastline is dominated by mangroves. Estimates are that there are some 16 million ha of mangrove forests worldwide. The general distribution of mangroves corresponds to that of tropical forests, but extends further north and south of the equator, sometimes beyond the tropics. However, over the past several decades, the global area in mangroves has increasingly diminished as a result of a variety of human activities, such as overharvesting, freshwater diversion and conversion to other uses.
Mangrove forests are vital for healthy coastal ecosystems.
A primary factor of the natural environment that affects mangroves over the long term is sea level and its fluctuations. Other shorter-term factors are air temperature, salinity, ocean currents, storms, shore slope, and soil substrate. Most mangroves live on muddy soils, but they also grow on sand, peat, and coral rock. If tidal conditions are optimal, mangroves can flourish far inland, along the upper reaches of coastal estuaries. Evolutionary adjustments to varying coastal marine environments have produced some astounding biological characteristics within mangrove plant communities.