Springtail Assemblages (Hexapoda, Collembola) of the Forest-Steppe Ecotone in the 'Privolzhkaya Lesostep' Reserve

摘要

When steppe phytocenosis is replaced by forest, the springtail fauna remains similar, but significant differences in the structure of assemblages are observed. The transitional zone (steppe shrubs) is revealed, where types of the springtail assemblagechange explosively. In comparison with other assemblages of the ecotone, col-lembolan assemblages of the transitional zone are distinguished by dynamic changes (composition of dominating species and spectra of life forms significantly change from year to year) and mostly leveled species composition and ecological structure. No species typical only of this zone were found. In this ecotone, the "marginal effect" is developed not as an increase in species richness, but in changes of the structure of collembolan assemblages.