Resource partitioning between Caucasian chamois and domestic sheep in mountain pastures of the eastern Caucasus, Dagestan, Russia

Abstract

Feeding and spatial distribution of Caucasian chamois and domestic sheep were studied in the eastern Caucasus. Trophic analysis showed that the chamois diet consisted of 12 herbaceous species and 21 for sheep. Chamois selected forbs and fabaceous species, whereas sheep foraged less selectively. The trophic niche breadth (averaged) of sheep was significantly greater (9.75) than that of chamois (4.33). Trophic niche overlap reached 86% in spring and 56.6% in autumn, and the summer spatial niche breadth of chamois was lower (0.83) than that of sheep (1.46). The spatial niche overlapping of both species was low (17%). Five environmental parameters made the highest contributions to interspecific differences. Chamois habitats in spring were characterised by a lower total phytomass level and higher-calorie herbaceous group biomass (forbs, fabaceous) than in sheep-grazing areas, whereas in autumn, the high-calorie herbaceous-group biomass was higher in chamois habitats than in sheep pastures. We deduce that the chamois spatial pattern is a potential response to sheep presence; chamois moves to difficult-to-reach habitats. Therefore, ecological segregation could be potentially expected due to divergence along the spatial axis of the ecological niche.