Bridging the gap between pest control and conservation through effective management of Columbian ground squirrels Urocitellus columbianus in a national park
Creators: Lorentz, Brianna M
Publisher: name: University of Alberta Library
Year: 2023

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<li> Infrastructure development can displace wildlife and lead to human-wildlife conflict, which typically requires non-lethal solutions when it occurs in protected areas. The Columbian ground squirrel (Urocitellus columbianus) is a small burrowing mammal that is prevalent in the mountain parks near human habitation and so it is frequently a source of human-wildlife conflict and is impacted by infrastructure development. Translocation and deterrence from burrows are two potential tools to mitigate these conflicts but their efficacy is not well-studied or understood.</li>
<li> We addressed this issue in Jasper National Park where we trapped, marked, and monitored the presence of 61 marked Columbian grounds squirrels (hereafter ‘squirrels’). We translocated 31 animals in four groups of sympatric individuals to a prepared release site and compared their apparent survival to that of 30 squirrels that were not translocated using Kaplan-Meier estimates. We evaluated hazards associated with translocation, age and sex classes, and year of translocation using Cox proportional hazards analysis. We tested the effect of deterrence on squirrel activity by blocking 157 burrows at two sites with wooden stakes, pool noodles, or a combination of stakes and hardware cloth and monitored them for signs of re-entry. At one site, we used logistic regression to estimate the probability of re-entry based on blocking method and whether the burrow was regularly sprayed with a scent deterrent (coyote, Canis latrans, urine). At both sites we also investigated the change in re-entry events over the 8-week monitoring period using a chi-square test.</li>
<li> Apparent annual survival, measured as detection at the release site, between July 2020 and May 2022 was 75% for control squirrels and 8.7% for translocated squirrels. As binary comparisons, hazards were higher for translocated squirrels in both years with no difference in hazards between sex or age classes. The likelihood of burrow re-entry was not predicted by any of block type, the use of spray, or their interaction; similarly burrow isolation did not predict reentry likelihood. There was a greater number of re-entry events in the first half of the monitoring period at one site and a greater number in the second half at the other site. </li>
<li> We suggest that retention and apparent survival was lower for translocated squirrels because of increased rates of predation, conflict with conspecifics, or dispersal from the site. Cost-effective mitigation for this species may include robust deterrence with sturdy materials, but the ethical use of this method may require that suitable habitat is available or augmented nearby. Mitigation of conflict involving squirrels might begin with increased public awareness of the ecological roles of squirrels to support greater tolerance of squirrel activity, particularly in protected areas. When squirrels must be removed from an area quickly and lethal management is undesired, translocation is unlikely to support survival comparable to resident squirrels. Deterrence success may be enhanced by reducing local habitat attraction (e.g., mowed lawns), augmenting adjacent habitat (e.g., by providing fertilizer, cover or starter burrows), and maintained with fertility control, which has been applied to other species of ground-dwelling rodents.</li>
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