How do free-ranging domestic herbivores reduce competition within owner-determined herds?

Abstract

Highlights • Goats only joined patches during the wet season when feed was readily available. • Goat herds split into subherds more frequently in the dry season. • Interindividual distance increased in the dry season. • Individuals in large herds reduced competition more than those in small herds.

Behavioural Indicators of Intra- and Inter-Specific Competition: Sheep Co-Grazing with Guanaco in the Patagonian Steppe

“…We showed an effect of dry biomass availability and sheep density on feeding behaviour and bite rate, as well as an effect of sheep density on vigilance and other behaviours. Our results suggest that the current high densities of sheep herds above carrying capacity in some sites increase intraspecific competition, leading to changes in sheep feeding behaviour [ 18 , 20 , 22 , 23 ]. Although the presence of a possible competitor species could potentially increase these negative effects due to interspecific competition [ 26 , 41 , 82 ], we found no evidence of any negative effect caused by the presence of guanaco co-grazing with sheep in the sites under study.…”

“…Contrary to wild herbivores, domestic herbivores are usually spatially confined, with population densities determined by productive interests rather than environmental constraints, predisposing them to increased intraspecific competition if trophic resources are limited [ 16 , 17 ]. In gregarious wild herbivores, when intraspecific competition increases, individuals tend to move away or split into smaller subgroups to avoid and decrease competition, but these mechanisms may fail if densities are artificially maintained at high levels [ 17 , 18 ].…”