Comparison of the effects of hydrological disturbance events on benthos and plankton salt marsh communities

The effects of hydrological disturbance events have been compared between macrozoobenthos (organisms 1 mm) and zooplankton communities (organisms 50 mm) in a Mediterranean salt marsh (Emporda` wetlands, NE Iberian Peninsula). Two different benthic communities related to different habitat types have been identified: one for the more environmental stable habitat type (permanent waters, higher surface and sand content, and low salinity) characterised by the dominance of the amphipod Corophium orientale; and a second one characteristic of more stressed environments (with temporary waters, and higher salinity) characterised by the dominance of the dipteran Chironomus gr. salinarius. In contrast, no characteristic zooplankton species were identified for these different habitat types. Hydrological disturbance events resulted in different changes on benthos and plankton communities. In benthic communities hydrological disturbances caused a decrease in the characteristic dominant species, whereas in plankton environments an increased dominance of certain species of rotifers and ciliates (Synchaeta and Eutintinnus) were found. Additionally, the damage caused by the disturbances (severity) varied among habitat types, and patterns observed after a disturbance were different for benthos and plankton communities. In benthic communities, a higher severity was observed in the most environmental stable habitat type while the others had lower severity. In contrast, plankton communities in the more environmental stable habitat type were less damaged than in stressed environments. The same disturbance event did not necessarily cause similar severity on plankton and benthos.