Forage selection by mule deer: does niche breadth increase with population density?

摘要: Effects of population density mule deer Odocoileus hemionus on forage selection were investigated by comparing diet characteristics two subpopulations in southern California, USA, that differed during winter. Quality for deer, as indexed faecal crude protein, was higher at the lowdensity site than high-density winter, when densities different. similar summer both areas had comparable deer. Both outcomes are consistent with predictions from densitydependent diets Dietary niche breadth, however, a manner opposite to theory based under an ideal-free distribution. During differences between study sites pronounced, breadth along dietary axis area twice site. Generalist herbivores feeding primarily low-quality browse high winter would be expected increase their additional species plants they depleted food supply. Mule our study, decreased increased. We hypothesize rapidly eliminating high-quality forages heavy grazing, narrowed niche. Theoretical models changes dimensions, including distribution, need consider such empirical outcomes.