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Fig. 7 | Movement Ecology

Fig. 7

From: Quantifying effects of snow depth on caribou winter range selection and movement in Arctic Alaska

Fig. 7

a Relative selection strength [124] of population-level averages of integrated step selection analysis (iSSA; [119]) coefficient estimates for winters CAH caribou spent primarily on tundra (n = 114,631; blue points and 95% confidence interval (CI) error bars) and in mountainous boreal forest (n = 136,554; orange points and 95% CI error bars). Covariates in the iSSA model are log(step length), i.e., movement rate; the interaction between step length and snow depth in the starting point of a step (log(step length):snow depth); lichen proportion and snow depth at the endpoint of a step. Coefficient estimates greater than 1.0 (above the solid black line) indicate selection while estimates lower than 1.0 (below the solid black line) indicate avoidance. Coefficient estimates with 95% CI error bars that do not overlap the 1.0 line indicate that this relationship is statistically significant. The coefficient estimates below 1.0 for log(step length):snow depth indicate an inverse relationship between step length and snow depth. The winter habitats tundra (winters 2016/17, 2018/19, and 2019/20; blue) and mountainous boreal forest (winters 2014/15, 2015/16, and 2017/18; orange) roughly correspond to north and south of the CD, respectively. b Probability of use with varying lichen proportion when wintering on tundra (blue lines; dashed lines are 95% CI) and in mountainous boreal forest (orange lines; dashed lines are 95% CI). c Probability of use with varying snow depth (orange dashed lines are 95% CI) for winters spent in mountainous boreal forest. There was no statistically significant effect of snow depth on movement in winters on tundra. The probabilities are based on mean coefficients of iSSA only including snow depth and lichen proportion at the endpoint of a step (not scaled or centered datasets)

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