Carryover effects and climatic conditions influence the postfledging survival of greater sage-grouse.

Erik J Blomberg,Peter S Coates,Michael L Casazza,Daniel Gibson,James S Sedinger

doi:10.1002/ece3.1139

Erik J Blomberg, Peter S Coates + Show 3 more

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https://doi.org/10.1002/ece3.1139

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Abstract

Prebreeding survival is an important life history component that affects both parental fitness and population persistence. In birds, prebreeding can be separated into pre- and postfledging periods; carryover effects from the prefledging period may influence postfledging survival. We investigated effects of body condition at fledging, and climatic variation, on postfledging survival of radio-marked greater sage-grouse (Centrocercus urophasianus) in the Great Basin Desert of the western United States. We hypothesized that body condition would influence postfledging survival as a carryover effect from the prefledging period, and we predicted that climatic variation may mediate this carryover effect or, alternatively, would act directly on survival during the postfledging period. Individual body condition had a strong positive effect on postfledging survival of juvenile females, suggesting carryover effects from the prefledging period. Females in the upper 25th percentile of body condition scores had a postfledging survival probability more than twice that (Φ = 0.51 ± 0.06 SE) of females in the bottom 25th percentile (Φ = 0.21 ± 0.05 SE). A similar effect could not be detected for males. We also found evidence for temperature and precipitation effects on monthly survival rates of both sexes. After controlling for site-level variation, postfledging survival was nearly twice as great following the coolest and wettest growing season (Φ = 0.77 ± 0.05 SE) compared with the hottest and driest growing season (Φ = 0.39 ± 0.05 SE). We found no relationships between individual body condition and temperature or precipitation, suggesting that carryover effects operated independently of background climatic variation. The temperature and precipitation effects we observed likely produced a direct effect on mortality risk during the postfledging period. Conservation actions that focus on improving prefledging habitat for sage-grouse may have indirect benefits to survival during postfledging, due to carryover effects between the two life phases.

Highlights

The survival of young from independence to first breeding has a profound influence on both parental fitness and population persistence (Gaillard et al 2000; Etterson et al 2011; Nicolai and Sedinger 2012; Dybala et al 2013)
Ecology and Evolution published by John Wiley & Sons Ltd
We explored the effects of body condition and weather variables on postfledging survival of greater sage-grouse (Centrocercus urophasianus, hereafter sage-grouse; Fig. 1), a species of conservation concern in western North America (Knick and Connelly 2011)

Summary

Introduction

The survival of young from independence to first breeding has a profound influence on both parental fitness and population persistence (Gaillard et al 2000; Etterson et al 2011; Nicolai and Sedinger 2012; Dybala et al 2013). Survival during this life stage is generally lower and more variable than survival during adulthood (Clutton-Brock et al 1987; Owen and Black 1989; Martin 1995; Van der Jeugd and Larsson 1998; Ward et al 2004) and is inherently more sensitive to environmental variation and anthropogenic impacts (Robinson et al 2007; Reid et al 2003).

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