Foraging niche characteristics of horses, sheep and goats in an alpine meadow of the Indian Central Himalaya.
Abstract
Data on plant species foraged, foraging hours, bite rate, bite size and species DM removed per species per bite were collected in tussock grass-forb (Grass-F), forb-tussock grass (Forb-G), Trachydium-forb (Forb), Rhododendron-Cassiope and early successional communities from May to Sep. 1988-89 in a moderately foraged Central Himalayan alpine meadow at Baideni-Ali (3250-4000 m alt.) in order to study the foraging niche characteristics of horses, sheep and goats. The 3 animals together grazed 30 plant species, of which 20 were grazed by horses, 22 by sheep and 16 by goats. The averaging foraging hours (5.2-13.2), bites/minute (23-51) and mg DM/bite (59-99) for horses, sheep and goats were significantly different in different communities and months. The foraging search cost, defined as distance walked/unit DM eaten, was 15.4, 8.1 and 1.2 km/kg in goats, sheep and horses, respectively. Of the total intake of horses (3.25 kg DM/day), the Forb community accounted for 40%. Sheep (0.74 kg/DM day) had a similar consumption pattern to horses, whereas goats (0.40 kg DM/d) consumed little in the Forb community and about 50% of their intake from the Grass-F community. Forbs were the largest dietary category for all animal species. The selection ratio varied from 0.7 to 11.3 for forbs, 1.0 to 7.2 for sedges and 1.1 to 2.5 for grasses. Response breadth (in terms of species grazed) was similar for horses and sheep (0.46 vs. 0.43) and somewhat wider for goats (0.49). Grazing pressures below the carrying capacity of the community increased botanical diversity.