Sharing the bounty-Adjusting harvest to predator return in the Scandinavian human-wolf-bear-moose system

• Published in: Ecological Modelling
• Main Authors: Jonzén, Niclas, Sand, Hakan, Wabakken, Petter, Swenson, Jon E., Kindberg, Jonas, Liberg, Olof, Chapron, Guillaume
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2013
• Subjects: Biological Sciences; Large carnivores; Demography; Management; Predator-prey; Hunting; Structured models; Ungulates; Alces alces; Canis lupus; Ursus arctos
• Online Access: https://lup.lub.lu.se/record/4061429; https://doi.org/10.1016/j.ecolmodel.2013.05.017

The increase and range extension of wolves (Canis lupus L) and brown bears ( Ursus arctos L) in Scandinavia inevitably impacts moose (Alces alces L.) populations and, as a consequence, the size and composition of the hunter harvest must be adjusted. We used a sex- and age-structured moose population model to delineate optimal harvest strategies under predation and to compare the resulting harvest composition with the strategy commonly implemented in practice. We examined how much moose density or adult sex ratio needs to change to fully compensate for losses to predation. We found a harvest allocation pattern in commonly used practical management across calves, bulls and cows that indicated a trade-off strategy between maximising the number of shot moose, the yield biomass and the number of shot prime bulls. This strategy performed quite well with respect to all yield measures and yielded an age structure most similar to the strategies maximising harvest biomass and prime bulls. Unless predation pressure was very high, the harvest loss could be completely compensated for by allowing a higher moose density. In other situations the current hunting strategy was not possible to implement and the moose density needed to sustain predation even without hunting increases dramatically. An alternative option to balance the predation loss was to accept a more female-biased sex ratio in the winter population. Hence, it may be possible to keep 50% calves in the harvest and still obtain the same total harvest if the proportion of bulls in the harvest is increased to compensate for predation. The increase of large carnivores competing with moose hunting creates conflicts and will inevitably reduce harvest yield unless hunting strategies change. We show how increased moose density and redistribution of the harvest towards bulls can mitigate this conflict and we provide a web-based tool, where stakeholders can compare the long-term effects of alternative management decisions and eventually adjust their hunting strategy ...