High dispersal capacity of cladoceran zooplankton in newly founded communities

The relative importance of local and regional factors to community buildup is a key question in community ecology. Dispersal capacity is an important regional determinant but is very difficult to assess. Instead, measuring colonization rates in newly created habitats can provide a reasonable approximation of dispersal capacities. We monitored cladoceran zooplankton colonization rates in 25 newly dug and isolated pools. During the first 15 months, an average of 4.2 cladoceran species colonized each pool. In total, 20 different species were found during this period in the pools, representing 40% of the total species richness observed during summer in well-established cladoceran communities in water bodies in the immediate neighborhood (within 3 km) of the studied new pools. Our results reveal high colonization rates of newly created habitats by cladoceran zooplankton, reflecting a high dispersal capacity in this group of organisms. We discuss these results in light of the extent and ecological and evolutionary impact of dispersal in aquatic organisms.