Fauna and population structure of springtails (Hexapoda,Collembola) in zonal forest-steppe biotopes of the Middle Volga River basin

A total of 92 springtail species were revealed in forest-steppe areas of the Privolzhskaya Lesostep nature reserve. The considerable part of the species (25–40%) are inhabitants of steppe and open sites with the predominance of soil forms. The specific features of the chernozem soil fauna are determined by the rare species occupying deep soil layers. In different forest-steppe biotopes, the springtail communities are similar in the species composition but differ in the structure. Steppe and forest types of communities were distinguished. When the steppe is forested, the most drastic changes in the collembolan population are revealed in the transitional shrub zone. The marginal community is characterized by the most even structure and a variable set of dominants.