A naturally heterogeneous landscape can effectively slow down the dispersal of aquatic microcrustaceans
Abstract
Several studies have suggested that aquatic microcrustaceans are relatively efficient dispersers in a variety of landscapes, whereas others have indicated dispersal limitation at large spatial scales or under specific circumstances. Based on a survey of a set of recently created ponds in an area of approximately 18 x 25 km, we found multiple indications of dispersal limitation affecting the community assembly of microcrustacean communities.
Spatial patterns in the community composition were better explained by the geomorphological structure of the landscape than by mere geographic distances. This suggests that ridges separating the network of valleys act as dispersal barriers, and as such may channel the dispersal routes of the studied taxa and, likely, also of their animal vectors.
Dispersal limitation was further supported by a strong positive relationship between species richness and the abundance of neighboring water bodies, suggesting that isolation affects colonization rates. Finally, the apparent dispersal limitation of microcrustaceans is further corroborated by the observation of low colonization rates in newly dug experimental ponds in the study area.