Nearly 40 years of predator reduction efforts have not enhanced moose harvests, study says

Researchers analyzed harvest data to test hypotheses that nearly 4 decades of effort to reduce bear and wolf abundance was positively correlated with moose harvests.

Since 1994, Alaska Intensive Management (IM) law effectively has mandated predator reductions to achieve higher sustained yield for human harvest of wild ungulates for meat. Across nearly two-thirds of Alaska, moose (Alces alces) are the species targeted to benefit from IM of predators. For nearly four decades, efforts to comply with the IM law have involved predator-reduction programs for brown bears (Ursus arctos), black bears (U. americanus) and gray wolves (Canis lupus) in various parts of Alaska. The belief is that killing large numbers of these predators will enhance moose abundance and therefore, allow for better moose hunting opportunities. 

Contrary to this belief, a team of retired Alaska Department of Fish and Game and University of Alaska Fairbanks researchers recently concluded otherwise in a new study, “Efficacy of Killing Large Carnivores to Enhance Moose Harvests: New Insights from a Long-Term View”. Authors Sterling Miller, David Person, and Terry Bowyer set out to test the hypothesis that nearly four decades of effort to reduce abundance of brown bears, black bears, and gray wolves in a large area of the Interior and Southcentral Alaska was positively correlated with moose harvests in some time-lagged fashion. 

The scientific article, published in November 2022 in the peer-reviewed journal Diversity, concluded that there was no correlation between brown and black bear harvest and subsequent moose hunts. They also observed no differences in mean moose harvests during periods of officially designated wolf control.

These findings underscore the value of taking a long-term perspective, which in this case and in the opinion of the authors, “signals the need for further consideration for more well-rounded wildlife-management protocols in Alaska that consider more than just harvest of ungulates.”

Citation

Miller, S.D., Person, D.K., Bowyer, R.T. 2022. Efficacy of Killing Large Carnivores to Enhance Moose Harvests: New Insights from a Long-Term View. Diversity, 14, 939. https://doi.org/10.3390/d14110939

Abstract

We analyzed harvest data to test hypotheses that nearly 4 decades of effort to reduce abundance of brown bears (Ursus arctos), black bears (U. americanus) and gray wolves (Canis lupus) in an 60,542 km2 area in south-central Alaska (Game Management Unit [GMU] 13) was positively correlated with moose (Alces alces) harvests in some time-lagged fashion. Predator-reduction efforts were progressively more aggressive over decades (both de facto and officially designated predator control) and did not have clear starting points which complicated our post hoc analyses. We documented no positive correlations (p > 0.05) between harvests of brown and black bears and subsequent moose harvests for any time lag. Moose harvest was negatively correlated with the previous years’ wolf harvest, but the relationship was weak (correlation = −0.33, p < 0.05). Consequently, we reject our hypotheses that harvest of predators was positively correlated with moose harvests. We also observed no differences in mean moose harvests during periods of officially designated wolf control (2005–2020) and a previous period (p > 0.50). We recommend that predator reductions designed to improve hunter harvests of moose be conducted within a research framework that will permit improved interpretations of results and the implementation of an adaptive-management approach to achieve management objectives.

Select figures

Figure 2. Hunter harvests of moose and hunter and trapper harvests of wolves in Game Management Unit 13, in south-central Alaska, USA (moose = blue circles; wolves = red triangles). Our statistical analysis includes data from 1973 onward.

Authors and affiliations

Sterling D. Miller, Alaska Department of Fish and Game, Anchorage, AK 99519, USA
David K. Person, Alaska Department of Fish and Game, Juneau, AK 99802, USA
Terry Bowyer, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA

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