Collembolan community structures in a continental psammic habitat of south-west Germany

Abstract

The present study reports for the first time on the collembolan community composition and structure across a successional gradient in a continental sand habitat. Nine sites – ranging from open sands to a woodland site – in southwest Germany were sampled. Increasing vegetation corresponded significantly with increasing organic matter and nutrient content as well as decreasing pH of the sandy soils, showing a clear eutrophication of the sands along the gradient. Parallel to increasing successional status, the registered microarthropod densities increased and showed a strong shift in group composition. Specifically, the collembolan densities and species numbers also generally increased along the gradient. The open sands showed extremely species-poor communities and strong eudominances of single species, whereas up to 20 species in balanced community structures were found in the most developed sites. Specialised, psammophilous species were largely limited to the open sands and short-grass sites, whereas eurytopic, thermophilous species were for the most part limited to and were dominant in the more highly vegetated and eutrophied sites. Correlation analyses showed a significant connection between soil eutrophication and distribution of these species. Psammophilous taxa, on the other hand, were limited to the nutrient-poor, abiotically extreme sites, which also showed potentially low faunistic competition. These results can be related to theories of A-selection of arthropods from extreme habitats.