Structure of the Species Diversity of Soil Springtails (Hexapoda, Collembola) in Pine Forests of the Caucasus and the Russian Plain: a Multi-Scale Approach

Abstract

The structure of Collembola diversity in green-moss pine forests in the Caucasus Mountains and the Russian Plain was compared. The study was based on intensive multi-scale sampling ranging from several square centimeters to a hundred square meters. Repeated samplings in similar habitats in different localities and regions allowed us to compare the springtail diversity structure in geographically remote areas despite incomplete knowledge of their faunas. Species richness on all the spatial scales was found to be about twice as high in the mountains as on the plain. According to additive partitioning, differences in species composition in differently sized areas increased in proportion to the distances between them. Differences in springtail species composition in similar habitats within a region were mainly related to species replacements, while variation between different regions occurred due to different species richness values. The ratio of regional to local faunal species lists was higher in the mountains than on the plain. Nevertheless, the forest springtail fauna in the Caucasus seems to have lost some of its original diversity. The rarity of endemic springtail species even in natural reserves suggests a high level of incompleteness of the regional species pool on the Russian Plain. Since the same widespread species are numerous in both regions while the species richness is higher in the Caucasus, the montane forests of the latter region probably served as a source of colonization of the Russian Plain’s forests by Collembola in the Holocene.