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Table 2 Terms used in the step selection function with the associated predictions

From: Roads constrain movement across behavioural processes in a partially migratory ungulate

Model terms


Forest Density + Forest density: Time of day

Selection of more forested areas during the day and more open areas during night time [8]

Slope + Slope2

Selection of flatter areas [31]. A quadratic term was added to evaluate selection of slopes with intermediate steepness

Elevation difference + Elevation difference2

Selection of steps with low elevation difference – i.e. low elevation gain/loss (i.e. around zero)


Selection of areas with higher NDVI values. A quadratic term was added to evaluate selection of intermediate values, especially during migration [57]

Road crossings

General avoidance of road crossings [51]

Road crossings: Time of day

Road crossings should be avoided at all times of day, but particularly during the day and twilight, when traffic is more intense [40, 47]

Road crossings: Forest density

Road crossings should occur preferentially in more forested areas [19, 51]

Road crossings: Movement mode

Road avoidance should be strongest for resident individuals, intermediate for migrants and weakest for dispersers

log(Step length)

Statistical estimator of the parameters of the assumed step-length distribution [4]

log(Step length): Sex

Control to account for potentially different step lengths between sexes

Road crossings: log(Step length)

Control to account for the fact that longer steps are more likely to cross roads

Road crossings: Sex

Control to account for potentially different road avoidance between sexes