Limnetica 35

The biogeographical principle that larger areas contain more species than smaller areas has more often been assumed than tested. In this sense, contradictory results have been published in studies on the relationship between water body size and species richness in temporary waters. Pond size can have an effect on the structure and composition of the macrofauna community, but this effect can be modified by other environmental factors such as water trophic state, habitat structure and spatial connectivity within the ecosystem. We sampled the aquatic macrofauna (from midges to amphibians) from a network of twelve Mediterranean temporary ponds in southwestern Portugal with a strong size gradient (245-78 652 m²), also taking into account three environmental factors that can modulate the relationship between pond size and community structure: connectivity, water trophic state and habitat structure. Our aim was to test the importance of pond size in macrofaunal structure and composition. Pond size was not related to any of the three environmental factors included in this study. Our results noted an unclear relationship between pond size and macrofauna, since we found a significant effect on community composition but did not find an effect on community structure parameters such as richness, taxonomic diversity or body size diversity. The high connectivity among ponds seems to be a plausible explanation for the observed pattern.