Contribution of translocated greater sage‐grouse to population vital rates

Abstract

Range‐wide declines of greater sage‐grouse (Centrocercus urophasianus; sage‐grouse) populations have been attributed to long‐term habitat alteration and fragmentation. In areas that still exhibit suitable habitats and where population declines have been attributed to other threats (e.g., invasive predators), managers have successfully used translocations to augment declining wildlife populations. However, translocations to augment sage‐grouse populations have had limited success and the relative contribution of translocated sage‐grouse to declining populations is not well understood. From 2009 to 2012 we studied the vital rates of 34 resident (21 yearlings and 13 adults) and 60 translocated radio‐marked female sage‐grouse (30 yearlings and 30 adults) on Anthro Mountain in northeastern Utah, USA to determine the relative contributions of each group to population productivity. We used the encounter histories of the monitored sage‐grouse to construct nest survival models for program MARK to assess the impacts of age and residency status on annual survival and overall reproductive success in the population. Annual survival was not affected by age or residency status and averaged 0.40 (95% CI = 0.31–0.50). The yearling newly translocated females (translocated females during their first yr in the release area) exhibited the lowest nest initiation rates (0.50, 95% CI = 0.30–0.69), whereas adult resident and previously translocated (translocated females that survived ≥1 yr in the release area) females had the highest nest initiation (0.96, 95% CI = 0.88–0.99). Overall nest success (0.43, 95% CI = 0.30–0.55) and brood success (0.55, 95% CI = 0.41–0.69) were not affected by residency status or age. The adult resident and previously translocated females exhibited the highest overall reproductive success (0.22, 95% CI = 0.14–0.31) followed by resident yearling females (0.20, 95% CI = 0.12–0.29), and newly translocated adult females (0.18, 95% CI = 0.10–0.27). Newly translocated yearling females had the lowest overall reproductive success (0.12, 95% CI = 0.05–0.18). Survival of adult females is a major factor influencing sage‐grouse population stability. Although adult and yearling newly translocated females had similar survival rates, adult translocated females were more likely to raise a brood in their first year in the release area. Thus, managers should consider translocating a higher ratio of adult to yearling females in future translocation efforts to see a more immediate effect on population growth in the release area. However, because of the low vitals rates recorded in our study, managers should identify and mitigate the limiting factors affecting the resident population prior to implementing a translocation to augment declining populations. © 2017 The Wildlife Society.

Survival rates of translocated Gunnison sage‐grouse

“…Baxter et al (2008) reported survival of 0.60 (95% CI = 0.515–0.681) for female greater sage‐grouse in Utah during the first year following translocation. Also in Utah, survival of resident greater sage‐grouse (0.46, 95% CI = 0.31–0.63) was higher than survival of translocated sage‐grouse (0.36, 95% CI = 0.25–0.49; Duvuvuei et al 2017). Ebenhoch et al (2019) reported that in Washington, translocated male GRSG experienced lower survival than females.…”

“…Translocations were commonly used to manage North American grouse species, including greater sage‐grouse ( Centrocercus urophasianus ), with variable success (Reese and Connelly 1997). Recent evaluations of greater sage‐grouse translocation efforts have reported on demographic metrics as measures of success (Baxter et al 2008, Bell and George 2012, Gruber‐Hadden et al 2016, Duvuvuei et al 2017, Ebenhoch et al 2019). Among vital rates, survival (particularly female survival) strongly influenced long‐term population stability and growth rates (Taylor et al 2012, Dahlgren et al 2016).…”

Individual Variation in Temporal Dynamics of Post-release Habitat Selection

“…Translocation has been used as a management tool to augment declining sage-grouse populations across their range (Reese and Connelly, 1997;Baxter et al, 2008Baxter et al, , 2013Duvuvuei et al, 2017). Sage-grouse populations have undergone severe declines since the 1960s (Garton et al, 2011;Coates et al, 2021).…”

Field Methods for Translocating Female Greater Sage‐Grouse (Centrocercus urophasianus) with their Broods

“…In addition, individuals that stay in the release area often exhibit lower survival and reproductive rates than individuals within source populations (Patterson 1952, Toepfer and Eng 1990, Snyder et al 1999. Specifically, translocated pre-breeding females often fail to breed at the restoration site in the first year of their translocation (Baxter et al 2008(Baxter et al , 2013Duvuvuei et al 2017). Furthermore, extensive post-release movements, which are common among translocated grouse species, have been demonstrated to reduce survival (Kurzejeski andRoot 1988, Ebenhoch et al 2019).…”