Spatial distribution of the epigeic species of earthworms Dendrobaena octaedra and D. attemsi (Oligochaeta: Lumbricidae) in the forest belt of the northwestern Caucasus

Abstract

Evaluation of the spatial distribution of 2 ecologically similar, but different, in terms of their spatial ranges, earthworm species,D. octaedra and D. attemsi, in the belt forests of northwestern Caucasus were based on our own natural data and using geographicinformation system (GIS) modeling of modern potential distributions. The quantitative records of earthworms were collected in beech,deciduous, dark coniferous, coniferous-deciduous, and pine forests (1028 geographic locations). Of the most important micrositesinhabited by the epigeic earthworms, 2 (plant litter and deadwood) were examined. It was demonstrated that there was high correlationof the 2 species with the humidity of the habitat and the presence of deadwood at different stages of decomposition, especially for D.attemsi, which lives mainly in deadwood in all of the forest types. The high correlation of these species to coniferous-deciduous forestsand dark coniferous forests was demonstrated on both the basis of the field data analysis and the GIS modeling results.