ADAPTIVE STRATEGIES OF COLONIZATION OF THE SOIL STRATUM BY ANIMALS

Heterogeneity of the soil medium is considered as a factor determining taxonomic and ecological variations of the soil fauna in the course o f evolution. Differences between spatial niches occupied by groups of invertebrates of different size are analyzed in terms of their respira tion characteristics. The formation of three mechanisms of gas exchang e is discussed, with soil animals taken as an example. Ethological and ecological adaptation of large soil animals for formation and mainten ance of aerated space in the mineral soil mass is considered. Air-fill ed macropores are the main factor allowing population of deep horizons of the soil profile by aerobiotic animals. A hypothesis on the coloni zation of the soil stratum by terrestrial animals from the soil surfac e is substantiated.