Diet Overlap Between Livestock and Wild Herbivores in the Greater Himalaya

Understanding the niche usage and dietary habits of wild ungulate populations is crucial to monitoring their response to livestock grazing and changes in habitat quality. Livestock grazing is common throughout the Himalaya and may reduce available forage for wild ungulates, but few studies have assessed the impact of livestock grazing on the diets of wild herbivores in the Greater Himalaya. We assessed forage availability and used microhistological analysis to compare the diet composition of livestock (domestic goats and sheep) and 2 wild herbivores (blue sheep Pseudois nayaur and musk deer Moschus sp.) in the Uttarkashi district of Uttarakhand, India. We calculated the diet preference and niche breadth of each species and the diet overlap between each pair of species. Our results suggest that musk deer may browse trees more than previously understood. In addition, blue sheep consumed fewer graminoids in the autumn than has been previously published. The seasonal increase in shrub and herb consumption by blue sheep during the winter may be amplified and shifted to earlier in the year as a result of reduced graminoid availability after intensive livestock grazing. We recommend monitoring livestock numbers in the study area and limiting livestock to current numbers to avoid further reducing forage availability.