Responses of soil mesofauna communities and oribatid mite species to site preparation treatments in high-elevation cutblocks in southern British Columbia

Abstract

Summary Five years after operational preparation of planting sites in high-elevation clearcuts, we studied the densities of soil Acari and Collembola to determine whether their response was related to the level of disturbance. In the forest floor (the organic horizon overlying the mineral soil), Acari and Collembola densities were lower in the burned sites than in the untreated sites. In the upper mineral soil, there were no differences in Acari density among untreated, burned, and scalped planting sites, but Acari density was lower in mounded sites which were the most severely disturbed at the micro-site level. For Collembola, density was lower in burned and mounded sites than untreated sites. Treated sites all had generally reduced soil nutrient levels compared to untreated sites. In the forest floor, 23 species of oribatid mites were identified. Oppiella nova and Platynothrus septentrionalis dominated the forest floor in untreated sites while Liochthonius brevis and Quadroppia quadricarinata dominated the forest floor in burned planting sites. Twenty-four oribatid mite species were collected from the upper mineral soil. There were significantly more species in the upper mineral soil of untreated than of mounded, burned or scalped sites. Five species ( L. brevis , Platynothrus sibiricus , Q. quadricarinata , Suctobelbella sp. nr. acutidens , and Synchthonius crenulatus ) dominated the upper mineral soil in untreated sites, Synchthonius crenulatus and L. brevis in burned sites, Neoliochthonius occultus and Suctobelbella sp. nr. sarekensis in scalped sites and O. nova , Cultrobates sp., and Suctobelbella palustris in the mounds. The results suggest that disturbance effects on mites and collembola persist into the 5th year after site preparation in these forest types.