Forest or meadow: the consequences of habitat on female arctic ground squirrel condition

• Main Authors: Werner, Jeffery R, Krebs, C.J., Donker, S.A., Sheriff, M.J.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: NRC Research Press (a division of Canadian Science Publishing) 2015
• Subjects: Arctic; Arctic ground squirrel; Urocitellus parryii
• Online Access: http://hdl.handle.net/1807/69822; http://www.nrcresearchpress.com/doi/abs/10.1139/cjz-2015-0100

Body condition of animals influences the likelihood of surviving harsh environmental conditions, successfully reproducing and resisting disease. The sum of these individual components of fitness, in turn, have consequences for the growth and persistence of wildlife populations. Here we compared the body mass and condition of adult female arctic ground squirrels, Urocitellus parryii (Richardson, 1825) (an obligate hibernator) in source and sink habitats. We tested the hypothesis that adult females would be in poorer condition in the boreal forest than in adjacent meadows. We found that, during spring, postpartum females in forests weighed less (405 ± 7g (SE) vs. 437 ± 11g) and were in poorer condition (mean residual of mass over structural size = -11.0 ± 10.2g vs. 20.5 ± 6.1g) compared to females in meadow source habitat. However, by the onset of entrance into hibernation in August, forest squirrels had reached parity with meadow squirrels and no difference was found in mass (519 ± 13g vs. 520 ± 15g) or condition (residual index = -0.01 ±0.01 vs. 0.03 ±0.01). We suggest that, for squirrels in formerly occupied boreal forests a) poor spring body condition decreased reproductive success, and b) achieving compensatory growth, via increased foraging, comes at the costs of higher predation risk. These costs likely contributed to the recent local extinction of AGS in boreal forest habitat. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.