Abstract

Topic: Predator-prey interactions

Multispecies Interactions in Ljusdal Sweden: Part II Brown Bears and Wolves

Aimee Tallian¹, Jenny Mattisson², Fredrik Stenbacka³, Wiebke Neumann³, Håkan Sand³, Anders Johansson⁴, Jonas Kindberg², Ole-Gunnar Støen²

Norwegian Institute for Nature Research, Høgskoleringen 9 7034 Trondheim, NO
Norwegian Institute for Nature Research
Swedish University of Agricultural Sciences
Sveaskog

Abstract
Brown bears and wolves are two of the most wide-spread large carnivores in the Northern Hemisphere. Several populations of bears and wolves have recently recovered in parts of Europe, including Scandinavia. The recovery of large carnivores can have widespread impacts on their primary prey species, ranging from behavioral shifts to population limitation. The moose population in Sweden has declined in recent years, likely from a range of factors including shifting hunter harvest practices. Although the moose population is declining nation-wide, the decrease is seemingly more pronounced in areas where moose overlap with brown bears and wolves. Increased predation pressure in these areas creates the potential for a predator-pit, i.e., when prey are held at low density equilibrium they are unable to escape from. It is therefore critical that managers in Scandinavia are provided both accurate and up-to-date information about the ecology of the local bear and wolf population and their effects on prey species such as moose. Our current collaborative study capitalizes on ongoing research efforts from three species-specific projects in the Ljusdal and Härjedalen Municipalities of Gävleborg and Jämtland Counties, respectively. This represents a unique opportunity to study interactions between multiple predators and their prey, i.e., bears, wolves, moose, and potentially red deer. Here, we discuss the main objectives from the predator side of the collaborative effort and present the latest results from the ongoing study. Our mail goals are to: 1) quantify brown bear and wolf predation rates on moose, 2) explore and quantify drivers of bear and wolf kill rates, and 3) explore multispecies interactions and behavior. This study is particularly important in the context of the shifting paradigm from single species to multispecies management. Furthermore, this project is proposed at a key moment in time; the bear population is currently undergoing a human-driven reduction in population size via legal hunter harvest. Conducting our study during this window provides a rare opportunity to study predator-prey interactions during a known large-scale system perturbation.