Impact of soil compaction and organic matter removal on soil fauna in the sub-boreal spruce zone of central British Columbia

Soil fauna communities were compared among three sites in the Sub-Boreal Spruce biogeoclimatic zone of central British Columbia. The short-term impact of soil compaction and organic matter removal on the soil fauna community was also examined.; Densities of most faunal elements were highest in the organic horizon and increased from spring to fall. Densities of spiders were higher at Topley, Hymenoptera were highest at Skulow Lake and Chilopoda, Pseudoscorpionida and Lumbricidae were highest at Log Lake. Numerically, Acari represented 70--80% of the mesofauna and Collembola accounted for 15--20%. Relative abundance of Prostigmata was significantly higher and both density and relative abundance of Oribatida were significantly lower at Log Lake.; Eighty-nine oribatid mite species were identified, including 11 new species recorded for Canada and 45 new species for British Columbia. Only sixteen species were common to all three sites. Oppiella nova (Oudemanns) was numerically dominant at all sites and for all seasons. Oribatid species richness was higher in the organic horizon than in the mineral soil. Skulow Lake had more species than the other two sites. Furthermore, more species were unique to Skulow Lake than Log Lake or Topley. Species composition of the organic horizon was highly similar among sites. Species richness in the mineral soil did not differ among sites; however, the oribatid species assemblage in the mineral soil at Topley differed from those of the other two sites.; Densities of most taxa did not differ between uncut forest control plots and stem-only harvested plots. Whole tree harvest and forest floor removal combined with heavy soil compaction significantly reduced densities of soil fauna. Loss of forest floor represented a substantial loss of habitat for most soil fauna. The forest floor apparently limited the impact of soil compaction and fluctuations in soil temperature and moisture. Structure of the macrofauna community did not change with treatment severity. However, relative abundance of Prostigmata and Mesostigmata increased with treatment severity while that of Oribatida decreased. Oribatid mite diversity and species richness was significantly reduced with treatment severity. Furthermore, the number of rare oribatid species and evenness decreased as treatment severity increased. Oppiella nova and Suctobelbella sp.nr. acutidens were the dominant species in the forest floor and mineral soil, regardless of treatment.