Effets de trois scénarios de régénération de la sapinière boréale sur les passereaux nicheurs, les petits mammifères et le lièvre dAmérique

We compared wildlife utilization of recent clearcuts subjected to three regeneration scenarios commonly used in boreal balsam fir (Abies balsamea (L.) Mill.) forests: natural regeneration, plantation of black spruce (Picea mariana (Mill.) BSP) followed by herbicide release (glyphosate), and plantation of black spruce followed by manual release (brushsaw). The wildlife species studied were songbirds, small mammals and the snowshoe hare (Lepus americanus Erxleben). Surveys were conducted during the 2 years preceding and the 5 years following conifer release. The abundance of songbirds decreased the second and third years after both types of release, and the abundance of the red-backed vole (Clethrionomys gapperi Vigors) was reduced for 2 years following herbicide release. Snowshoe hares rarely used the stands during the 8 to 10 years that followed logging, so conifer release did not affect them. In this study, the short- and mid-term effects of the regeneration scenarios on wildlife may have been mitigated by the poor quality of clearcuts as wildlife habitats at the time of release and by the fact that plantations, like naturally regenerated sites, had a heterogeneous vegetation and a well-developed herb and shrub cover. In the humid balsam fir forest, where vegetation growth is slow and snow cover deep, the size and distribution of clearcuts would have greater effects on wildlife in the short and mid term than the regeneration scenario used for forest renewal. A landscape management approach inspired by natural disturbance dynamics is proposed as a mitigation measure.