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Report, 2013

Restoration of wolverines: Considerations for translocation and post-release monitoring

Aber, Bryan C.; Callas, Richard; Chapron, Guillaume; Clark, Jospeh; Copeland, Jeffrey; Giddings, Brian; Inman, Robert; Jake, Ivan; Kahn, Rick; Long, Clinton; Magoun, A.; Mattisson, Jenny; McCauley, Deborah; McKelvey, Kevin; Miller, Michael; Monello, Ryan; Oakleaf, Bob J.; Odell, Eric; Persson, Jens; Wolfe, Lisa


Successful reintroduction of wolverines to historically occupied, suitable habitat could function as a major proactive step toward improving wolverine status and genetic diversity in the contiguous United States. However, because wolverine reintroduction has not been previously attempted, there is a need to assemble information to develop the most appropriate techniques in case this management option becomes desirable and politically feasible. In this document we describe pros and cons of various approaches (and identify obvious nonstarters) and advocate an adaptive approach for reintroductions. We find this preferable to a more prescriptive approach because the “right” answer is largely unknown without prior experience. We suggest that ongoing assessment and modification of capture, transport, and care of captive animals is used to ensure the highest probability of survival and site fidelity. Wherever possible, activities should be undertaken in a manner that maximizes the ability to learn from experiences and adapt to improve. Protocols will likely change as more information and experience is accumulated. We suggest sourcing wolverines that maximize genetic diversity of the reintroduced population after consideration of other factors such as the sustainability of removals from source populations and matching habitat and prey between source and relocation sites. A mixture of wolverines from multiple locations including Alaska, British Columbia, Yukon Territory, and Northwest Territory would provide a broad genotypic representation. Additional areas that provide unique genetic material (e.g., Manitoba, Nunavut) could also prove beneficial but would require careful selection due to smaller source populations and differences in habitat/prey/mortality sources. Total numbers translocated from any one site should be carefully considered based on locally available data. Our consensus regarding the number of wolverines to move during an initial translocation was strong for a larger number of individuals over several years (i.e., >10/year for multiple years) rather than a smaller, more conservative number. This approach would protect against stochastic failure and reduce time to reestablishment. To determine season of capture and method of release most likely to be successful, we considered effects that translocation may have on wolverine survival, site fidelity, and reproduction. Consensus formed around winter captures (Oct–Dec) followed by a provisioned release (release into natural snow-covered chambers where supplemental food has been placed) after a short stay at a captive transfer facility. The option of retaining pregnant females at a captive facility until or just prior to parturition (Feb 1 or later if ultrasound or other information is available) may help improve site fidelity. This could be particularly useful if large movements away from the reintroduction site are deemed to be a problem. Because same-year reproductions may occur and are valuable for improving site fidelity, genetic diversity, and successful establishment of a population, careful consideration of how to release males, if at all, is warranted (some species have been reestablished by moving pregnant females and allowing male offspring to mature, disperse, and breed). We provide details of aspects to consider during capture, handling, inspection, and transportation of wolverines. We also briefly discuss monitoring of translocated populations.

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Publisher: Wildlife Conservation Society