Harvesting and site preparation impacts on soil microarthropods

The impacts of various current and alternative harvesting and site preparation practices on: soil microarthropod abundance;distribution, and species diversity are being studied in boreal mixedwood sites in northern Ontario. In general, in the absence of site preparation treatments, numbers of mites decreased after clear-cutting. Collembolan numbers were unaffected by harvesting, but clear changes in species diversity as a result of different harvesting practices-were identified; Population densities and species diversity in partial cuts tended to resemble values obtained in the uncut forest, rather than in clearcuts. Preliminary results indicate that screefing and mixing treatments had dramatic effects on the numbers of both Collembola and mites and on the species diversity of the collembolan fauna; Plots treated by strip mixing showed more signs of recovery than those subjected to the screefing treatment. No deleterious effects on the soil microfauna were evident in plots treated with herbicide (Velpar(R)).