Variations in macrobenthic fauna of mangrove and unvegetated habitats in an Amazon estuary

Comparisons between vegetated and unvegetated intertidal habitats have led to the paradigm that benthic fauna are more abundant and diverse in the former. Mangroves are the dominant vegetation in estuarine intertidal zones of northern Brazil, however until now; there are no studies that investigated the macrobenthic fauna between vegetated and unvegetated intertidal habitats of estuaries at Amazon region. This study aimed to characterize the community structure of the macrobenthic fauna between an intertidal mudflat (non-vegetated area) and mangrove (vegetated area) of an estuarine gradient of salinity in the Amazon coast. Overall, finer sediments were found at the vegetated area and increased toward lower estuary. Overall, higher density and richness were found in the vegetated area and the values increased toward the lower estuary. The same pattern was found at the non-vegetated area. In general, our results showed the formation of a gradient of organism distribution along the estuary. Also, the results showed that the presence of the vegetation influences macrofaunal patterns.