PUB - Publikationen an der Universität Bielefeld

Dispersal is a vital component of the life history of nearly all organisms. Theability to disperse determines the distribution and abundance of a species andthus its community dynamic at different sites. The scientific challenge is todesign standardized laboratory experiments that not only record the effects ofsingle factors but also include the multicausal nature of dispersal. Here we testedthe effect of the environmental factorsdensity, food availability and predation,and the combinations thereof on the dispersal of five free-living nematode speciesby performing experiments in two-patched systems. We hypothesized thatemigration is generally positively correlated with the intrinsic rate of naturalincrease and would decrease with increasing food availability and increase bothwith the presence of a predator and at higher initial population densities.These predictions were tested both using single-species tests with laboratorycultures and using intact natural nematode communities to investigate whetherenvironmental factors determine the composition of dispersing species. Theresults of our study revealed a positive correlation between dispersal and intrinsicgrowth ability, whereas the studied nematode species differed in their dispersalpatterns, both under control conditions and in response to bottom-up, top-down,and density-dependent stimuli. Despite the species-specific differences indispersal behavior in response to the environmental factors, the availability offood appeared as the main driver. This was particularly pronounced regarding anatural nematode community. Our experiments emphasize the central role offood availability in spatial structuring nematode communities.