Individual Variation in Temporal Dynamics of Post-release Habitat Selection

Simona Picardi,David K Dahlgren,Brian J Smith,Steven R Mathews,Peter S Coates,Nathan Ranc

doi:10.3389/fcosc.2021.703906

Abstract

Translocated animals undergo a phase of behavioral adjustment after being released in a novel environment, initially prioritizing exploration and gradually shifting toward resource exploitation. This transition has been termed post-release behavioral modification. Post-release behavioral modification may also manifest as changes in habitat selection through time, and these temporal dynamics may differ between individuals. We aimed to evaluate how post-release behavioral modification is reflected in temporal dynamics of habitat selection and its variability across individuals using a population of translocated female greater sage-grouse as a case study. Sage-grouse were translocated from Wyoming to North Dakota (USA) during the summers of 2018–2020. We analyzed individual habitat selection as a function of sagebrush cover, herbaceous cover, slope, and distance to roads. Herbaceous cover is a key foraging resource for sage-grouse during summer; thus, we expected a shift from exploration to exploitation to manifest as temporally-varying selection for herbaceous cover. For each individual sage-grouse (N = 26), we tested two competing models: a null model with no time-dependence and a model with time-dependent selection for herbaceous cover. We performed model selection at the individual level using an information-theoretic approach. Time-dependence was supported for five individuals, unsupported for seven, and the two models were indistinguishable based on AICc for the remaining fourteen. We found no association between the top-ranked model and individual reproductive status (brood-rearing or not). We showed that temporal dynamics of post-release habitat selection may emerge in some individuals but not in others, and that failing to account for time-dependence may hinder the detection of steady-state habitat selection patterns. These findings demonstrate the need to consider both temporal dynamics and individual variability in habitat selection when conducting post-release monitoring to inform translocation protocols.

Highlights

Most animals select for areas that have been previously visited – their familiar space (Wolf et al, 2009; Avgar et al, 2015; Ranc et al, 2020b)
We evaluated individual variation in temporal dynamics of habitat selection after release in a novel environment using a population of greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) translocated from Wyoming, USA, to North Dakota, USA, as a case study
Using data for translocated greater sage-grouse, we showed that temporal dynamics of post-release habitat selection may manifest in some individuals but not in others, and that not accounting for time-dependence may hinder correct interpretation of habitat selection patterns

Summary

Introduction

Most animals select for areas that have been previously visited – their familiar space (Wolf et al, 2009; Avgar et al, 2015; Ranc et al, 2020b) This behavioral process has been shown to provide benefits in terms of resource acquisition (Merkle et al, 2014; Ranc et al, 2021) and reduction of predation risk (Gehr et al, 2020). Translocated animals experience an unfamiliar landscape and often undergo a phase of behavioral adjustment after being released in a novel environment (Berger-Tal and Saltz, 2014; Berger-Tal et al, 2020). The transition from exploration to exploitation has been termed post-release behavioral modification (PRBM; Berger-Tal and Saltz, 2014)

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