The long-term impacts of clear-cut logging on insect communities in the boreal mixedwood forests of northeastern Ontario

grantor: University of TorontoLarge-scale clear-cut logging in the boreal forest may contribute to the loss of insect biodiversity through reductions in the amount of older, undisturbed forest and through stand-level decreases in structural heterogeneity. To investigate the long-term effects of clear-cutting on insect communities, hymenopteran and dipteran communities were surveyed with Malaise traps during the summer of 1998 in 12 mature (30-50 year old) post-logged and 12 unlogged boreal mixedwood stands in northeastern Ontario. Unlogged stands yielded a significantly higher abundance of Dolichopodidae (long-legged Ries), several Syrphidae (hoverflies) species, and the Syrphidae larval wood-inhabiting guild. These differences were predominantly due to the older ages of the unlogged stands which supported different habitat features, though some evidence of a logging effect per se was found. These results demonstrate the need for maintaining features characteristic of older forests in post-logged stands, and suggest a potential loss of insect species characteristic of older forests, particularly species dependent on downed woody debris, in the face of continued clear-cut logging activities.M.Sc.F