Effect of Forest Mosaic on the Functional Diversity of Earthworms (Oligochaeta, Lumbricidae) in the Forest-Steppe Belt of the Ob River Region (Novosibirsk Oblast)

Abstract

This paper discusses earthworm (Lumbricidae) populations inhabiting forb–fern pine forests and fern birch–aspen forests prevailing in the forest-steppe belt of the Ob River region (Novosibirsk oblast) in relation to the forest mosaic. A detailed analysis of the structure of earthworm complexes has made it possible to identify individual species and living forms biotopically confined not only to certain forest types, but to forest microsites as well. Pine forests are mostly predominated by Asian earthworm species, while birch–aspen forests are mostly predominated by cosmopolitans. Differences between earthworm populations inhabiting various microsites in population density and biomass are more pronounced in forest openings than in undercrown and intercrown spaces, especially in pine forests. An analysis of earthworm populations inhabiting fallen deadwood has made it possible to identify distinctive features of their structure: in pine forests, incomplete deadwood earthworm complexes complement soil earthworm complexes; in birch–aspen forests, fallen deadwood represents a distinct microsite with a fully featured earthworm complex.