Spatial acclimation of elk during population restoration to the Missouri Ozarks, USA

Abstract

Wildlife translocations are an important conservation tool but can be challenging for the animals. For translocations to be successful, animals must adjust to their release landscape. Investigating how animals acclimate to their release landscapes can improve post‐release monitoring and inform about the management needs of translocated populations. We investigated movements and resource selection dynamics of 106 elk (Cervus canadensis) during the first 6–8 years following their release to Missouri, USA in 2011–2013. We observed evidence of spatial acclimation as determined by cessation of changes in resource selection together with monthly range sizes and fidelity of individual elk. Females showed faster evidence of acclimation in their movements following release than males. Although range fidelity for both sexes stabilized within approximately seven months, range size stabilized within approximately three months for females and stabilization began within approximately 11 months for males. Selection for multiple resources by elk also largely stabilized within their first year following release. A simple refuge‐forage trade‐off alone did not explain acclimation in resource selection. Elk selected for high‐quality food plots across the temporal extent of restoration regardless of time since release, whereas their selection for cover resources during summer increased after elk acclimated. Together, spatial acclimation generally lagged behind physiological responses observed in this system, adding to the increasing evidence that translocated animals display acclimation patterns across trait‐specific time periods. Our approach demonstrates the utility of accounting for acclimation effects across multiple spatial response metrics for improving post‐release monitoring, evaluation, and management of restored wildlife populations.

Identifying temporal dynamics in post‐release survival of a restored large ungulate

“…Contrary to our expectations, elk stabilization in home range location and resource selection patterns (appearing around the 1year mark in Missouri:Pero, Palm, et al, 2023) occurred beyond the initial 5-month demographic acclimation period associated with most pronounced mortality risk. While resource selection patterns can be linked to mortality(DeCesare et al, 2014;Matthiopoulos et al, 2015), fitness effects of resource selection are likely less direct than those between prolonged elevations in physiological stress and movement rates.…”

“…Despite relatively few mortality events, we still observed evidence for strong post‐release effects during the initial 5‐month acclimation period and mixed support for our predictions regarding trait‐specific acclimation durations. We expected stabilization in survival to follow adjustment in finer scaled physiological stress (<2 months, Pero, Chitwood, Hildreth, Keller, et al, 2022) and spatial responses (range size [<6 months], range overlap and resource selection [<1 year], Pero, Palm, et al, 2023), as these processes may themselves influence survival patterns (Berger‐Tal et al, 2011; Boonstra et al, 1998; DeCesare et al, 2014; Haussmann & Marchetto, 2010; Hobbs, 1989). Although physiological stress (Teixeira et al, 2007) and animal movement behaviour (Berger‐Tal et al, 2019) are frequently implicated in increased mortality events and ultimate translocation failures, evidence is often lacking (Tarszisz et al, 2014).…”

“…acclimation, demographic rate estimation, reintroduction, restoration, survival, temporal dynamics, translocation, ungulate behavioural space use (<1 year, Pero, Palm, et al, 2023) acclimation periods identified in this system. To inform factors contributing to post-release survival, we additionally (1) considered the influence of release cohorts, age class, and sex on mortality risk, and (2) compared survival rates and sources of mortality observed during acclimation and post-acclimation periods.…”

“…In addition to the translocation process itself, survival of translocated wildlife is dependent on animals adjusting to sometimes exceptional amounts of variability in intrinsic and extrinsic factors encountered after release into novel landscapes (Berger‐Tal et al, 2022; Dickens et al, 2010). Such inevitable challenges inherent to translocation and post‐release processes can result in predictable temporal dynamics in population‐wide physiological (Dickens et al, 2010; Pero, Chitwood, Hildreth, Keller, et al, 2022), social (Pero, Chitwood, Hildreth, Berkman, et al, 2022; Poirier & Festa‐Bianchet, 2018), behavioural (Pero, Palm, et al, 2023; Picardi et al, 2021) and demographic (Armstrong et al, 2017; Hamilton et al, 2010; Panfylova et al, 2016) patterns in restored wildlife populations.…”

“…We evaluated temporal variation in elk Cervus canadensis survival following translocations to restore a population in Missouri, USA. We adopted a generalized survival modelling framework (Royston & Parmar, 2002) to characterize the dynamic post‐release survival response and approximate demographic acclimation duration (the period prior to stabilization in a response metric, sensu Pero, Palm, et al, 2023). Given that survival is a product of finer‐scaled biological responses such as physiology (Boonstra et al, 1998; McEwen & Wingfield, 2003; Haussmann & Marchetto, 2010) and behaviour (Berger‐Tal et al, 2011; DeCesare et al, 2014; Hobbs, 1989), we hypothesized acclimation in post‐release survival progresses more slowly than acclimation in physiological or behavioural responses.…”