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Survival of a polymorphic species in seasonally snow-covered forests
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  • Penelope Murphy,
  • Jonathan Pauli,
  • Amy Shipley,
  • Benjamin Zuckerberg
Penelope Murphy
University of Wisconsin-Madison

Corresponding Author:[email protected]

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Jonathan Pauli
University of Wisconsin-Madison
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Amy Shipley
University of Wisconsin-Madison
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Benjamin Zuckerberg
University of Wisconsin-Madison
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Color polymorphism is an adaptive strategy in which a species exhibits multiple color phenotypes in a population. Often times, phenotypes are variably suited to different environmental conditions which may buffer the population against variable conditions. Modern climate change is creating novel selective pressures for many species, especially in winter habitats. Few studies have quantified the benefits of polymorphism for allowing species to cope with climate-induced environmental change. We investigated how color polymorphism mediates selective pressures in ruffed grouse Bonasa umbellus, a widespread and winter-adapted bird species of North American forests. Ruffed grouse display phenotypic variation in plumage color, ranging from red to gray. Over five winter seasons (2015-2022), we monitored weather conditions, habitat use, and weekly survival for 94 ruffed grouse to test whether individuals had lower survival when grouse were phenotypically mismatched with snow cover (e.g., a gray bird on a snowless landscape or a red bird in snow). Grouse phenotypically mismatched with snow cover had lower survival, but only when winter survival rates were lowest. During winters of lower overall survival, red grouse exhibited higher survival during snow-free periods, whereas gray grouse had higher survival when snow was present. We also found that open habitat negatively impacted survival, regardless of color. While the effect of phenotypic mismatch was variable among years, it was a stronger predictor of winter survival than land cover features, suggesting that snow is an important habitat feature mediating overwinter survival. Our work offers an advancement in understanding how environmental variability affects geographic variation in and maintenance of multiple color phenotypes in seasonally-snow covered environments. Our finding that interactions between color morph and snow cover are important for conferring winter survival provides further evidence that color polymorphism may serve as a buffer against rapidly changing conditions and a pathway for persistence of polymorphic species.
16 May 2023Submitted to Oikos
22 May 2023Submission Checks Completed
22 May 2023Assigned to Editor
22 May 2023Review(s) Completed, Editorial Evaluation Pending
25 May 2023Reviewer(s) Assigned
08 Jun 2023Editorial Decision: Revise Minor
06 Jul 20231st Revision Received
07 Jul 2023Assigned to Editor
07 Jul 2023Submission Checks Completed
07 Jul 2023Review(s) Completed, Editorial Evaluation Pending
07 Jul 2023Reviewer(s) Assigned
08 Aug 2023Editorial Decision: Revise Minor
17 Aug 20232nd Revision Received
19 Aug 2023Assigned to Editor
19 Aug 2023Submission Checks Completed
19 Aug 2023Review(s) Completed, Editorial Evaluation Pending
23 Aug 2023Editorial Decision: Accept