Structural-functional organization of the soil mesofauna population in bogs and waterlogged forests of northwestern Karelia

Abstract

The soil mesofauna was studied in two ecological series (oligotrophic and mesotrophic) of bogs in northwestern Karelia. The earlier found differences in the structural-functional organization of the soil mesofauna in the bogs investigated were confirmed. The high indices of the taxonomic diversity and abundance of mesopedobionts were characteristic of the mesotrophic biogeocenoses. Among the factors limiting the activity of the mesopedobionts, the hydrothermal regime and soil acidity played the leading part. In the series of the bog biogeocenoses studied, the abundance of mesopedobionts increased with the increasing soil acidity, lowering the groundwater table and decreasing the content of sodium extracted by the ammonium acetate solution. Zoophages predominated in the trophic structure of the oligotrophic bogs due to the unfavorable conditions for large invertebrates there; in the mesotrophic bogs, myxophages were the dominants. The abundance of myxophages increased in the mesotrophic series simultaneously with the increasing nitrogen content in the soil mesofauna-inhabited soil horizons. In the mesotrophic biogeocenoses, saprophages were not numerous (one species of litter earthworms). Probably, in the bog soils, they are substituted for myxophages.