Patterns of cattle and sheep losses related to large carnivores and other causes in the outfields of Norway

Abstract

Large carnivore populations have increased in many areas of Europe, resulting in socio-political conflicts, especially in areas with extensive outfield grazing systems. In Norway, the occurrence of large carnivores, especially brown bears (Ursus arctos) and grey wolves (Canis lupus), are largely separated from outfield grazing areas via carnivore management zones. However, the overall drivers of livestock losses in the outfields and the contribution of large carnivores are not well understood. Here, we investigated (1) correlates of cattle and sheep losses across organized grazing areas of Norway to evaluate which factors, including large carnivore densities, livestock density, the size of the grazing area, tick density, landscape characteristics, and climatic variables, are responsible for livestock losses in the outfields, and (2) spatio-temporal correlates of cattle losses suspected of being attacked by large carnivores. Based on our analyses investigating cattle and sheep losses in organized outfield grazing areas, we found no evidence that large carnivore densities correlated with cattle losses, but the proportion of sheep losses increased with increasing large carnivore densities, especially of bears and wolverines (Gulo gulo). Importantly, factors other than large carnivores, such as tick density and landscape composition, were related to higher probabilities of cattle losses. Our study provides important information concerning the overall causes of livestock losses in the outfields, indicating that large carnivores contribute little to total cattle losses.