Impact of Moose Browsing on Boreal-type Forests of Isle Royale National Park
Snyder JD and Janke RA. 1976. Impact of Moose Browsing on Boreal-type Forests of Isle Royale National Park. The American Midland Naturalist. 95(1):79-92
Measurable long-range effects of moose browsing were found in a boreal-type forest at Isle Royale National Park. Overall forest density decreased while average basal area per tree increased. Total basal area and reproduction density were unaffected. Balsam fir densities were drastically reduced, especially in younger age classes. For the most heavily used site, the oldest firs affected are linked to the time of moose arrival on Isle Royale. Mountain ash densities were also drastically reduced. White spruce, unpalatable to moose, increased in density, possibly due to reduced competition from fir. Birch and aspen densities were relatively unaffected. Their stems were mostly out of reach of moose when these animals first arrived. Reduction in fir and mountain ash densities accounts for the reduction in total tree density. Total cover in the shrub layer was unaffected by browsing, but average stem height decreased. Taxus canadensis has almost disappeared on all browsed sites. Cover of low vascular plants and the ratio of windfalls to standing trees increased.
- Type
- Journal Article
- Authors
- Snyder, John; Janke, Robert
- Units
- ISRO
- Keywords
- balsam fir (Abies balsamea), Boreal Forest, Canada yew (Taxus canadensis), Moose (Alces alces), Plant Ecology