Photo: Karine Savard

From the standpoint of protecting litter-dwelling insects, clearcutting and scarification are among the forestry practices that should be avoided in mixedwood forests. Small-gap harvesting is the best silvicultural approach.

A study conducted by researchers at the Canadian Forest Service and the Université du Québec à Montréal in yellow birch and fir mixed forests of the Portneuf region examined the effect of silvicultural practices on rove beetles (family Staphylinidae), which belong to the order Coleoptera. Nearly 9,500 specimens, representing 116 species, were captured. Six species accounted for 82% of all the individuals collected. Given their sensitivity to disturbances, these insects are good candidates for investigating the effect of natural disturbances and forest management practices on biodiversity.

The findings show that small-gap (28 m diameter) harvesting without ground scarification produces the best results in terms of maintaining the natural balance of litter insect populations. These small gaps more closely approximate the type of natural disturbances that occur in the ecosystems concerned. Indeed, deciduous forest renewal occurs when old, large-diameter trees are uprooted and fall, creating openings in the canopy. The study also showed that even a light scarification treatment is deleterious to litter-dwelling insects.