Linkages between resource availability, microorganisms and soil invertebrates

Abstract

The patterns and rates of organic-matter decomposition are determined by the qualities and quantities of the materials being decomposed, the “inoculum potential” of the decomposer organisms, the competitive and synergistic interactions between these organisms and by climatic variables (temperature and moisture). Using examples from a range of cool temperature forest ecosystems, interactions, particularly between soil fauna and microflora, but also with substrate quality, are discussed. Data are presented on inter- and intraspecific variations in chemical quality and leachability of various leaf litters. The effects of climatic factors on soil-litter biota, including freeze-thaw cycles, are discussed, and indicate that considerable biological activity occurs in decomposing litter during the rigorous winter period. Freeze-thaw cycles appeared to be less important than simple freezing and biological activity beneath snow. The litter layers of the forests described contain a rich mycoflora (typical of mor forest soils) with a high biomass which is greatly influenced by moisture conditions. Themacroinvertebrate fauna is impoverished, with lumbricids being absent. Mites, Collembola, nematodes and enchytraeids are the dominant taxa. As a result of this, faunal influences are probably restricted (both in time and space), and in this paper consideration is given to potential fungal-faunal interactions in litter and wood decomposition (and nutrient availability). The nutrient quality of fungi as food for soil fauna is considered, as are the impacts of fauna on microbial community, structure and on dispersal of fungi.