Transformations of earthworm communities during post-logging successions in the forests of the Northwest Caucasus

Abstract

The paper presents study findings of the earthworm population at three phases of postlogging succession of coniferous–broad-leaved forests in the Northwest Caucasus (heads of the Pshekha and Belaya rivers). Three types of forest communities corresponding to the stages of forest vegetation succession were examined: early stage – aspen–hornbeam–honeysuckle smallgrass forests, intermediate stage – fir–hornbeam small-grass forests, late stage – beech–fir deadcover forests. Type of soil: brown forest soils. It has been shown that during the post-logging succession significant changes in the earthworm community occur only at the late stage, when the biomass of anecic worms increases significantly. Only at the late stage there are four stable morpho-ecological groups of Lumbricidae, despite the fact that at this stage the structure of ecological-cenotic plant groups becomes simpler and oligodominant dead-cover communities with a predominance of boreal species are formed. At all stages, species with the CrimeanCaucasian type of habitat (D. schmidti, D. mariupolensis) are prevalent. Demographic structure of the earthworm community in all types of forests is stable, represented by different ontogenetic states with a significant predominance of juvenile worms (65–78%).