Height and species as factors determining browsing of shrubs by wapiti.
The scrub layer was studied in 11 selected areas of Riding Mountain National Park, Manitoba, which are used as winter range by wapiti (Cervus canadensis manitobensis) and moose (Alces alces). 23 shrub spp. were identified and 15 were sufficiently abundant to be included in analyses. The number, frequency, constancy, importance value, cover value and ht. of each of the spp. were measured using a line transect method. Browsing was assessed by presence or absence of browsing, and by a numerical browse index. There was no significant correlation between the number of plants of a particular shrub sp. present and its use as browse, but plant ht. was significantly correlated with use. Plants within the ht. range 1-2 m were generally preferred; use as browse decreased rapidly outside these limits. Although there were some differences in browse use among spp. in any given ht. range, such differences were few and inconsistent. Ht. appeared to be the most important factor determining use.