Factors conditioning the vegetation in the salt marshes of the atlantic coast of the Iberian Peninsula

Resumo

The zonation of saltmarsh vegetation is a universal phenomenon related to apparently simple physical and chemical gradients. Nonetheless, the relationship between these factors and the vegetation is seldom a direct one, but mediated through a number of other correlated variables. Of these ultimate variables, we have documented that elevation, salinity and redox potential are correlated with the vegetation gradient. Some possible factors have been considered are anoxia due to waterlogging (inundation of vegetated parts of the saltmarsh), direct toxic effect of salts (salinity), or the formation of potentially toxic ions (at low redox potential values). Interacting with those simple physical factors, there are some other factors that arise by the action of the biota itself. Therefore a number of biotic interactions contribute to the final result of plant distribution in salt marshes. Among them (many times, above them) the anthropogenic influence is conditioning the salt marsh vegetation through a number of different kinds of impacts. © 2011 Nova Science Publishers, Inc. All rights reserved.