Influence of herbicide-induced habitat alteration on vegetation and snowshoe hare populations in sub-boreal spruce forest.
The hypothesis that herbicide-induced habitat alteration would reduce snowshoe hare (Lepus americanus) populations in early- to mid-successional (<25 years post-treatment) stages of sub-boreal spruce forest, was tested by intensive population sampling and monitoring of vegetation in replicate control and treatment blocks near Prince George, British Columbia, Canada from 1988 to 1991, and index line surveys of hares in 10 paired control-treatment blocks. Herb biomass and cover recovered to control values by 2-3 yr post-treatment. Shrub and tree biomass and cover were little affected in a 'conifer release' treatment where coniferous species dominated these layers. In a 'backlog conversion' treatment, the dominant deciduous trees and shrubs were relatively slow to recover. Herbicide-induced habitat alteration in optimum habitat seemed not to affect abundance of snowshoe hares during summer and autumn. Post-harvest forest habitats 10-20 yr old may have sufficient and persistent vegetative structure, particularly those with a high component of coniferous species, to support hare populations regardless of herbicide treatment.