Abstract

Topic: Predator-prey interactions

Moose harvest in relation to wolf territory density – changes over time

Camilla Wikenros¹, Håkan Sand¹, Ane Eriksen², Petter Wabakken², Johan Månsson¹, Cecilia Di Bernardi¹, Barbara Zimmermann²

Department of Ecology, Grimsö Research Station, Swedish University of Agricultural Sciences, Grimsö, Riddarhyttan, Sweden
University of Inland Norway, Koppang, Norway

Management of ungulates is challenging due to the various factors that need to be considered, such as environmental conditions, predation, and conflicting interests among stakeholders. We examined long-term moose (Alces alces) harvest data (1995-2020) in Sweden and Norway, which share populations of wolves (Canis lupus) and moose. We tested how wolf establishment and variation in wolf territory density affected moose harvest density and composition (age and sex). We also analyzed how the presence of an additional carnivore, the brown bear (Ursus arctos), along with habitat composition, latitude, and infrastructure correlated with harvest density to improve our understanding of factors influencing moose harvest. As a response to wolf establishment, hunters in Sweden almost instantly reduced the harvest of moose. In areas with average wolf territory densities, harvest density was on average 37% (Norway) and 51% (Sweden) lower than in areas without wolves. This was a result of management actions to reduce the total moose mortality as well as to maximize productivity in the population in response to increased wolf territory density. In later years, however, harvest became decoupled from wolf territory density in several areas, likely in an attempt to reduce local moose densities and browsing damage in young forest stands. When investigating other potential factors, total moose harvest and the proportion of calves in the harvest were both positively correlated with the proportion of young forest in the area. An increased proportion of agricultural land was linked to both a higher total harvest and greater proportion of calves, likely due to increased roe deer (Capreolus capreolus) densities diverting predation from moose to roe deer. The total harvest was negatively related to increased brown bear density. Also, the location and characteristics of wind power establishments impacted on moose harvest. The ability to adjust to new conditions is key in wildlife management where conflicting societal objectives such as forestry, hunting and carnivore conservation occur. Knowledge of management strategies and goals in bordering countries and/or management units that share populations of game species, and a constructive dialogue between stakeholders based on empirical knowledge on population parameters is one way to improve wildlife management.