Wolf predation on moose in Scandinavia: Local different effects on the moose population

Human harvest is the main mortality factor of the moose Alces alces population in Scandinavia. Since 1991, the Scandinavian wolf Canis lupus population has increased continuously and the wolf may be an important mortality factor of local moose populations in south-central parts of the Scandinavian Peninsula, especially inside the territory boundaries of established wolf packs. However, the size of the wolf packs (3-11) and the wolf pack territories vary, and so does the variation in the local moose population productivity and density. The presence of alternative prey species like the roe deer Capreolus capreolus is also highly variable. Thereby, on a local scale, the wolf predation on moose is suspected to have highly variable effects on the moose population and the human moose harvest in Scandinavia. As a case study, we have analyzed such differences by rough comparisons of data from two well-established wolf pack territories in southeastern Norway. Each winter, the annual wolf pack and territory sizes were estimated by ground tracking unmarked wolves on snow. The local moose population statistics were estimated by using moose hunter observations, harvest statistics and CERCIM. Compared to the northern territory, the moose density was about five times higher in the southern wolf pack territory. Contrary, the average wolf density in the southern territory was one third of the other. We conclude that, dependent on moose- and wolf densities, the local effects of wolf predation on moose populations could vary substantially in Scandinavia.