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1 November 2017 Environmental and ecological conditions at Arctic breeding sites have limited effects on true survival rates of adult shorebirds
Emily L. Weiser, Richard B. Lanctot, Stephen C. Brown, H. River Gates, Rebecca L. Bentzen, Joël Bêty, Megan L. Boldenow, Willow B. English, Samantha E. Franks, Laura Koloski, Eunbi Kwon, Jean-François Lamarre, David B. Lank, Joseph R. Liebezeit, Laura McKinnon, Erica Nol, Jennie Rausch, Sarah T. Saalfeld, Nathan R. Senner, David H. Ward, Paul F. Woodard, Brett K. Sandercock
Author Affiliations +
Abstract

Many Arctic shorebird populations are declining, and quantifying adult survival and the effects of anthropogenic factors is a crucial step toward a better understanding of population dynamics. We used a recently developed, spatially explicit Cormack–Jolly–Seber model in a Bayesian framework to obtain broad-scale estimates of true annual survival rates for 6 species of shorebirds at 9 breeding sites across the North American Arctic in 2010–2014. We tested for effects of environmental and ecological variables, study site, nest fate, and sex on annual survival rates of each species in the spatially explicit framework, which allowed us to distinguish between effects of variables on site fidelity versus true survival. Our spatially explicit analysis produced estimates of true survival rates that were substantially higher than previously published estimates of apparent survival for most species, ranging from S = 0.72 to 0.98 across 5 species. However, survival was lower for the arcticola subspecies of Dunlin (Calidris alpina arcticola; S = 0.54), our only study taxon that migrates through the East Asian–Australasian Flyway. Like other species that use that flyway, arcticola Dunlin could be experiencing unsustainably low survival rates as a result of loss of migratory stopover habitat. Survival rates of our study species were not affected by timing of snowmelt or summer temperature, and only 2 species showed minor variation among study sites. Furthermore, although previous reproductive success, predator abundance, and the availability of alternative prey each affected survival of one species, no factors broadly affected survival across species. Overall, our findings of few effects of environmental or ecological variables suggest that annual survival rates of adult shorebirds are generally robust to conditions at Arctic breeding sites. Instead, conditions at migratory stopovers or overwintering sites might be driving adult survival rates and should be the focus of future studies.

© 2017 American Ornithological Society.
Emily L. Weiser, Richard B. Lanctot, Stephen C. Brown, H. River Gates, Rebecca L. Bentzen, Joël Bêty, Megan L. Boldenow, Willow B. English, Samantha E. Franks, Laura Koloski, Eunbi Kwon, Jean-François Lamarre, David B. Lank, Joseph R. Liebezeit, Laura McKinnon, Erica Nol, Jennie Rausch, Sarah T. Saalfeld, Nathan R. Senner, David H. Ward, Paul F. Woodard, and Brett K. Sandercock "Environmental and ecological conditions at Arctic breeding sites have limited effects on true survival rates of adult shorebirds," The Auk 135(1), 29-43, (1 November 2017). https://doi.org/10.1642/AUK-17-107.1
Received: 14 June 2017; Accepted: 22 August 2017; Published: 1 November 2017
KEYWORDS
alternative prey hypothesis
Bayesian survival analysis
breeding dispersal
spatially explicit Cormack–Jolly–Seber models
true survival
waders
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