Species richness and distribution of copepods and cladocerans and their relation to hydroperiod and other environmental variables in Donana, south-west spain

Twenty-five sites located in five wetland zones within Donana, south-west Spain were studied for copepod and cladoceran species richness and composition in relation to habitat characteristics from January to March 2004. The gamma-diversity of copepods and cladocerans combined varied between wetland zones, which differed significantly in conductivity, surface area and abundance of vegetation. However, there were no significant differences between zones in local species richness of either copepods or cladocerans or the two combined. Species richness was significantly higher in sites with intermediate hydroperiods (duration between 3 and 5 months) than in sites with shorter or longer hydroperiods. CCA analyses performed separately for copepods and cladocerans extracted conductivity, surface area, and vegetation cover as the main factors structuring species composition of both groups. Ours is one of the first studies of zooplankton in the natural marshes of the Donana World Heritage Site, and we recorded five species new to the Donana area.