Impacts of mangrove vegetation on macro-benthic faunal communities
红树林植被对大型底栖动物群落的影响

Mangrove ecosystems, found on marine coasts of the sub-tropics and tropics, have high biological productivity and rich faunal diversity. Mangrove ecosystems provide organic matter and nutrients critical to marine benthic fauna, primarily through litter-fall which is a major component of the detrital food chain. The macro benthic fauna, in turn, provide an important link between mangrove detritus at the base of the mangrove food web and consumers at higher trophic levels. Benthic fauna also may modify the physical and vegetation structure of mangrove ecosystems. Thus, the community of macro benthic fauna needs to be considered in mangrove restoration if holistic ecosystem restoration is to be achieved. This overview examines the current knowledge of macro benthic fauna in mangroves, and the effects of mangrove vegetation on the faunal community in China. In mangroves, mollusks and crustaceans are the major components of the benthic fauna, and this is a common phenomenon all over the world. In China, the mollusks are represented by more species in most studies; this is similar to that in east coast of the Americas, but different from those in other geographic regions. Dominant fauna varies with mangrove regions, but some species such as Cerithidea cingulata, Littoraia elanostoma, sesarmid crabs and fiddler crabs are common, and some of them are dominant. The community structure of macro benthos seems to be influenced by environmental conditions such as hydroperiod, salinity and sediment texture, but the small-scale distribution pattern of benthic fauna mainly depends on the factors with respect to tidal regime and mangrove vegetation. This is due, in part, to the effects mangrove vegetation has on the chemical characteristics of sediment like the organic matter content, total N and pH. Perhaps more important is the role that mangroves play in providing a solid substrate for gastropods and shade that ameliorates the harsh conditions caused by high temperatures and high evaporation rates. These factors are responsible for making levels of secondary biological productivity and faunal diversity in mangroves comparable to those in seagrass meadows and salt marshes. Recent studies carried out in Jiulongjiang Estuary, showed that the total number of animal species within mangrove forests was greater than that of adjacent non-vegetated tidal flats with similar hydrological, topographical and edaphic conditions, indicating that mangrove vegetation promotes intertidal biodiversity. Studies in Jiulongjiang Estuary also demonstrated that mangrove areas with different vegetation ages or species can support different macro benthic assemblages, and the natural/mature mangroves generally support higher faunal biodiversity than the young or disturbed forest. Studies on mangrove rehabilitation and deforestation have further shown that Uca crabs are more abundant in open areas, while gastropods and sesarmid crabs are likely to prefer closed canopy, suggesting that so