Spatial variation in the structure of macrobenthic assemblages on intertidal
flats is known to be related to different environmental variables. Most of
the studies have observed that along the estuarine gradient, salinity is the
most important variable driving the patterns of the macrobenthic
assemblages. However, the great majority of studies have been done on single
estuarine systems in temperate regions. We investigated the relationship
between the macrobenthic assemblages in intertidal habitats and the
environmental variables along three tropical estuaries. From lower to upper
estuarine regions we sampled benthic macrofauna, salinity and sediments. The
structure of the benthic assemblages was primarily related to salinity.
There was a decrease in the number of taxa from the upper to the lower
estuarine regions, indicating important deviation from Remane's model of
estuarine diversity. There were important similarities of taxa abundance
along different estuarine salinity gradients which can be properly tested in
other tropical and temperate regions. We advocate that in order to adopt
general and robust management practices it is essential to identify broad
patterns and general rules governing estuarine systems.