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Harvest and density-dependent predation drive long term population decline in a northern ungulate
  • Robby R. Marrotte,
  • Brent Patterson,
  • Joe M. Northrup
Robby R. Marrotte
Trent University
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Brent Patterson
Ontario Ministry of Natural Resources and Forestry
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Joe M. Northrup
Ontario Ministry of Natural Resources and Forestry
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Abstract

The relative effect of top-down versus bottom-up forces in regulating and limiting wildlife populations is an important theme in ecology. Untangling these effects is critical for basic understanding of trophic dynamics and effective management. We examined the drivers of moose abundance by integrating two sets of observations to create one of the largest existing spatiotemporal datasets on ungulate population dynamics globally. We documented a 20% population decline. At high density, moose were regulated by intraspecific competition. Predation primarily limited population growth, except at low density, where it was regulating. Harvest was largely additive and contributed to population decline. Our results provide strong evidence for density dependent predation, highlighting that population dynamics are context dependent and vary strongly across gradients in climate, forest type and predator abundance. These results clarify longstanding questions in population ecology and highlight the complex relationships between natural and human-caused mortality in driving ungulate population dynamics.

Peer review status:UNDER REVIEW

25 May 2021Submitted to Ecology Letters
26 May 2021Assigned to Editor
26 May 2021Submission Checks Completed
27 May 2021Reviewer(s) Assigned
22 Jun 2021Review(s) Completed, Editorial Evaluation Pending