Relationship between latitude (untransformed) and age-zero annual growth as explained by the top-ranked model using AIC_c (Table 3).

<p>The shaded area represents the smoothed 95% CI using t-based approximations. County and district abbreviations are as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0172011#pone.0172011.g001" target="_blank">Fig 1</a>.</p

Sources for Eastern Massasauga life history information including locality and study years.

<p>Sources for Eastern Massasauga life history information including locality and study years.</p

Relationship between latitude (untransformed) and size–fecundity (natural log back-transformed) as explained by the top-ranked model using AIC_c (Table 3).

<p>Female size was held constant at 55.2 cm SVL based on the average size of adult females in Cass County, Michigan. The shaded area represents the smoothed 95% CI using t-based approximations. County and district abbreviations are as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0172011#pone.0172011.g001" target="_blank">Fig 1</a>. The image of dam and offspring was taken within minutes of parturition in Cass County, Michigan (Photograph credit, E. T. Hileman).</p

Candidate model sets for life history variables.

<p>Bolded 95% confidence intervals exclude zero and therefore indicate the standardized effect size for a given explanatory variable is informative. For models with two predictor variables, the standardized effect size and 95% CI for the first and second variable are in the first and second row associated with that model. Model abbreviations are the same as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0172011#pone.0172011.t002" target="_blank">Table 2</a>.</p

Relationship between mean annual precipitation (untransformed) and neonate mass as explained by the top-ranked model using AIC_c (Table 3).

<p>The shaded area represents the smoothed 95% CI using t-based approximations. County and district abbreviations are as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0172011#pone.0172011.g001" target="_blank">Fig 1</a>.</p

Relationship between latitude (untransformed) and the proportion of gravid females as explained by the top-ranked model using AIC_c (Table 3).

<p>The shaded area represents the smoothed 95% CI using t-based approximations. County and district abbreviations are as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0172011#pone.0172011.g001" target="_blank">Fig 1</a>.</p

Locations of Eastern Massasauga study sites (counties/districts shaded black) and the approximate historic range of the Eastern Massasauga (gray shading, from http://www.iucnredlist.org/).

<p>County and district codes: IA = Bremer, IA; IL.1 = Clinton, IL; IL.2 = DuPage, IL; IL.3 = Cook/ Lake, IL; IL.4 = Piatt, IL; IL.5 = Warren, IL, IL.6 = Will, IL; IN.1 = Hendricks, IN; IN.2 = LaGrange, IN; IN.3 = Marshall, IN; MI.1 = Barry, MI; MI.2 = Cass, MI; MI.3 = Kalkaska, MI; MI.4 = Lenawee, MI; MI.5 = Oakland, MI; MI.6 = Van Buren, MI; MI.7 = Washtenaw, MI; NY.1 = Genesee, NY; NY.2 = Onondaga, NY; OH.1 = Ashtabula, OH; OH.2 = Champaign, OH; OH.3 = Clark, OH; OH.4 = Greene, OH; OH.5 = Greene/ Warren, OH; OH.6 = Hardin, OH; OH.7 = Trumball, OH; OH.8 = Wyandot, OH; ONT.1 = Bruce, ONT; ONT.2 = Essex, ONT; ONT.3 = Muskoka, ONT; ONT.4 = Beausoliel Island, ONT; ONT.5 = Parry Sound District (1995–1996), ONT; ONT.6 = Parry Sound District (1992–2009), ONT; ONT.7 = Regional Municipality of Niagara, ONT; PA = Butler/ Venango, PA; WI.1 = Buffalo, WI; WI.2 = Juneau/ Monroe, WI. Reprinted and modified from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0172011#pone.0172011.ref150" target="_blank">150</a>] under a CC BY license, with permission from [Collin P. Jaeger], original copyright [2016] (See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0172011#pone.0172011.s003" target="_blank">S3 File</a>).</p

Snout‐vent length plotted against capture day‐of‐year of Eastern Massasaugas captured during 2006–2014 in Cass County, Michigan.

<p>Seven distinct age classes are evident: age 0 (blue) includes recently born animals prior to their first hibernation; age 1 (gray) includes animals captured following their first hibernation, but prior to their second hibernation; age 2 (black) includes animals captured following their second hibernation, but prior to their third hibernation, and so on; age 3 (white); age 4 (orange); age 5 (red); age 6 (yellow). Age 1 begins to overlap with age 2 in August (~ DOY 225).</p

(A) Number of study sites, number of explanatory variables per model, and number of candidate models possible and (B) specific candidate models used in analyses of Eastern Massasauga life history response variables.

<p>(A) Number of study sites, number of explanatory variables per model, and number of candidate models possible and (B) specific candidate models used in analyses of Eastern Massasauga life history response variables.</p

Relationship between mean annual precipitation (untransformed) and adult female size as explained by the top-ranked model using AIC_c (Table 3).

<p>The shaded area represents the smoothed 95% CI using t-based approximations. County and district abbreviations are as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0172011#pone.0172011.g001" target="_blank">Fig 1</a>.</p