Elk forage and risk tradeoffs during the fall archery season

Abstract

During late summer and fall, elk (Cervus canadensis) need access to adequate nutrition to support physiological requirements for reproduction and overwinter survival. The archery hunting season often occurs during this period and can affect distributions of elk as they seek areas that minimize perceived harvest risk. Areas that confer lower harvest risk may provide relatively low-value nutrition, resulting in a potential tradeoff between minimizing risk and accessing adequate forage. We used radio-collar data collected from female elk during late summer and fall (Aug-Oct) and estimated resource selection models to evaluate the extent of this potential risk-nutrition tradeoff. To evaluate if elk exposed to a greater hunting risk altered selection for forage resources, we assessed the relationship between individuals' selection coefficients for forage and the proportion of their late-summer-fall home range accessible to hunters (our metric of hunting risk). Our results indicate that during the archery season, elk with higher-risk home ranges selected more strongly for areas farther from motorized routes than elk with lower-risk home ranges. Regardless of the level of risk, however, elk maintained or increased selection for areas with higher forage quality, suggesting that elk did not compromise access to nutritional resources during the archery season. Elk with higher-risk home ranges were also exposed to the poorest nutrition and increased their selection for areas with higher forage quality more strongly than elk with lower-risk home ranges during the hunting season. Elk with lower-risk home ranges had access to the highest nutrition, which may be due to the availability of concentrated sources of high-quality forage from irrigated agricultural areas on private lands that restricted hunter access. Resource agencies interested in encouraging elk to remain on public lands during the hunting seasons might consider closing motorized travel during the archery season to increase security on public lands, limiting hunter pressure on public lands, improving forage quality on public lands, and working with private land owners to enhance hunter accessibility and restrict elk access to high-quality forage resources. Ó 2019 The Wildlife Society.

Hiding Without Cover? Defining Elk Security in a Beetle‐Killed Forest

“…In addition to the selection for areas with higher canopy cover, security habitat in the Elkhorn Mountains was characterized by positive associations with increasing distances from motorized routes, relatively rugged slopes, and moderate slope angles of 18°. In general, these findings corroborate with other studies characterizing elk security and habitat (Lyon and Canfield , McCorquodale et al 2003, Ranglack et al , DeVoe et al ). Although the traditional definition of an elk security patch that has been broadly incorporated into forest management (i.e., contiguous areas of ≥100 ha located ≥0.8 km from an open motorized route; Hillis et al ) did not receive strong support among our candidate model set, our work lends credence to the importance of canopy cover and distance to motorized routes in defining elk security.…”

“…DMOT = distance to motorized route. and habitat , McCorquodale et al 2003, Ranglack et al 2017, DeVoe et al 2019. Although the traditional definition of an elk security patch that has been broadly incorporated into forest management (i.e., contiguous areas of ≥100 ha located ≥0.8 km from an open motorized route; Hillis et al 1991) did not receive strong support among our candidate model set, our work lends credence to the importance of canopy cover and distance to motorized routes in defining elk security.…”

“…For ruggedness we used the vector ruggedness measure (VRM), a unitless measure of landscape ruggedness integrating variation in slope and aspect (Sappington et al 2007). Following a large body of literature from regional studies modeling seasonal habitats and security areas for elk and other ungulates, we used a pseudothreshold (natural log) functional form for canopy cover, distance to motorized routes, and ruggedness, and a quadratic functional form for slope (Sawyer et al 2007;Proffitt et al 2010Proffitt et al , 2013Ranglack et al 2017;DeVoe et al 2019). We used a tiered approach to progress from univariate to multivariate models evaluating the traditional security metrics and landscape attributes.…”

“…Providing additional security areas on public lands through policy changes (i.e., road closures) or habitat improvement projects, has been highlighted as an important management objective to retain elk on public lands and reduce the redistribution of elk to private lands with reduced or eliminated hunting opportunity (Proffitt et al , Ranglack et al , DeVoe et al ). Although management paradigms have shifted to accommodate changes in land use practices and attitudes towards elk on private lands, managing for security areas on public lands has remained an important management objective (Ranglack et al ).…”

“…We expected to observe a decline in canopy cover in infested areas pre‐ and post‐pine beetle outbreak and a general reduction in canopy cover in infested forests relative to uninfested forests. With respect to elk security, given the anticipated loss of canopy cover associated with the pine beetle outbreak, we expected elk to use security areas characterized by large roadless areas (i.e., security patches) and rugged terrain, and we expected to observe an increase in selection for covariates associated with the traditional security paradigm for both sexes across the gradient of relative risk associated with the archery and rifle hunting seasons (Ranglack et al , DeVoe et al ).…”