Factors influencing the seasonal phenology and composition of zooplankton communities in mountain temporary pools

Abstract In 2001 nine temporary pools of the northern Apennines (Italy) were visited on 13 occasions during the ice-free season (May to October). The aims of this research were to define the relationships between hydroperiod and other environmental variables and the Zooplankton. In total, 49 zooplankton taxa were identified: 36 rotifers, 5 cladocerans, 6 copepods and 2 anostracans. Our results indicate that hydroperiod is a major determinant affecting zooplankton species richness. The highest number of taxa was found in the pond having the longest duration. Distinctive species assemblages were observed in different habitat types: pools with the shortest hydroperiod were characterised by organisms with brief life cycles (e.g. rotifers) and/or typical of temporary habitat (e.g. anostracans). Of the physical and chemical characteristics, pH and chlorophyll-a appeared to have the largest influence on zooplankton distribution in the studied pools.