The objective of the proposed research object is to study the colonization of zooplankton species in twenti-five newly created pools in order to determine which factors are responsible for the structuration of zooplankton communities. Potential factors as regional species richness, distance to neighbouring pools and pond characteristics (morfometric, abiotic and biotic) will be investigated. Furthermore we want to investigate if these factors are also valid for structuring the genetic omposition of local populations. In experimental designs we want to investigate in how far invaseion of new species is successful in a gradient of evoluating resident communities.