STRUCTURE OF THE SPECIES DIVERSITY OF SOIL SPRINGTAILS (HEXAPODA, COLLEMBOLA) IN PINE FORESTS OF THE CAUCASUSAND RUSSIAN PLAIN: A MULTI-SCALE APPROACH
The structure of collembolan diversity in green-moss pine forests in the Caucasus Mountains and over 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 the same habitats at different locations and in different regions made it possible to compare the structure of the diversity of geographically remote areas despite an incomplete study of their faunas. The results showed that species richness on all spatial scales in the mountains is about twice as high as on the plain. According to additive partitioning, differences in species composition in areas of different sizes increased proportionately with the distances between them. Differences in the species composition of Collembola of similar habitats within a region were mainly related to species replacements, while variations between different regions occurred according to different species richness values. The ratio of regional to local faunal species lists in the mountains was higher than in the plain. Nevertheless, the forest fauna of springtails in the Caucasus seems to have failed to preserve its original diversity. The rarity of endemic Collembola species even in natural reserves suggests a high-degree 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 can be assumed to have served as one of the sources of Collembola colonization of the Russian Plain's forests in the Holocene.