Abstract

Topic: Predator-prey interactions

Multispecies Interactions in Ljusdal Sweden: Part I Moose

Wiebke Neumann¹, Anders Johansson², Göran Ericsson³, Fredrik Stenbacka³

Swedish University of Agricultural Sciences, Skogsmarksgränd, Sweden
Sveaskog, Sweden
Department of Wildlife, Fish and Environmental Studies, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Umeå, Sweden

Abstract
Understanding reproduction and offspring survival is important for understanding population dynamics. In anthropogenic forest systems such as many parts of Europe, humans interfere with wildlife at multiple trophic levels, not only shaping the quantity, quality, and distribution of forage, but also controlling the population densities and distribution of herbivores and large carnivores. European wildlife managers therefore cannot rely on observations of multi-species predator-prey interactions in more natural systems. In multi-predator systems where humans act as ‘super-predators’, sustainable ungulate management relies on information on calf survival and cause-specific mortality to determine ungulate harvest rates. Previous research has emphasized the anti-predator behaviour of moose (Alces alces) in response to both predator presence and previous experience of calf loss as well as the compensatory effects of calf loss. Using a unique research infrastructure that allows individual-based studies of moose, brown bear (Ursus arctos), and wolf (Canis lupus), we quantify female moose reproduction, summer calf survival and cause-specific mortality of moose calves. Data from five calving seasons indicate that female reproduction is high in the study area, including both twin and tripling calving. Our preliminary results also show that bear predation on newborn calves largely determines summer calf mortality during the first two weeks of life. Furthermore, our data suggest that summer calf survival is positively related to higher bear harvest rates. In conclusion, our study indicates that female moose in this multi-predator forest landscape are in very good body condition during the rut, allowing them to become pregnant not only with twins, but also with triplets. High summer calf mortality due to predation reduces the number of calves available for the moose hunt in fall. In summary, our results indicate that whereas moose population in an area with multiple predator species and high predator densities may be sensitive to high harvest rates (due to lower recruitment rates), harvested adult female moose may be associated with higher slaughter weights.