Composition of Diets Selected by Sitka Black-Tailed Deer on Channel Island, Central Southeast Alaska.

摘要

Composition of diets selected by tame but free-ranging deer in a natural forest environment was studied throughout a 24-month period and summarized by mean monthly percentage composition on the basis of dry-matter intake. A modification of the standard bite-count method of diet determination was used. All forages were identified by species and plant part (leaf, twig). Major forages comprising the diet were identified seasonally and considered in relation to their role in the nutritional ecology of the deer. Overall, a simple but consistent pattern was evident in the data. When green, leafy forages (herbs and shrub leaves) were available, they were consistently targeted by the foraging deer, but as they became less available in winter, and especially with their burial by snow, diet composition shift ed to less digestible woody forages (shrub twigs and conifer foliage) supplemented with highly digestible arboreal lichens. Although a wide array of potential forages are available during the growing season, dietary options shrink to a narrow range of important evergreen forbs, a few ferns, shrub twigs, and lichens in winter.