Walking the line: Investigating biophysical characteristics related to wildlife use of linear features

The study areas consisted of caribou ranges in west-central and north-western Alberta and British Columbia, Canada. The west-central area included four caribou ranges – Little Smoky, A la Peche, and the Alberta portions of Redrock-Prairie Creek and Narraway outside of protected areas (-117˚ W to -120˚ W, 53˚ N to 55˚ N). The north-western area included the Chinchaga range on both sides of the provincial border (-117˚ W to -122˚ W, 56˚ N to 58˚ N; Fig. 1). The areas totaled 47,100 km2 and contained over 92,943 km of linear features, including seismic lines, pipelines, and inactive forestry roads. The primary goal of field data collection was to collect information on human use of linear features. Using a geographic information system (GIS) and a random number generator, we selected linear features that intersected access roads. We created a unique identifier for each linear feature (LineID) and established three plots at 0m, 100m, and 500m away from the intersecting access road. We visited all west-central and north-western seismic line sampling sites in June–October 2014, 2015, and north-western pipeline sites in August 2017 to record wildlife and human linear feature use, collect field measurements of linear feature and surrounding forest characteristics, and identify vegetation taxa. On the linear feature (‘online’), we identified tracks, scat, and any other wildlife and human sign. We classified canines (wolves and coyotes, C. latrans), bears (black bears, U. americanus, and grizzly bears, U. arctos), and deer (white-tailed deer, O. virginianus, and mule deer, O. hemonius) at the genus level and caribou, moose, and elk at the species level. To account for weather impacts on tracks and signs, we assigned a confidence level to each observation, and only included observations assigned confidence levels of ‘reasonably certain’ and ‘certain’ in statistical modelling. We measured an average online lateral vegetation cover from cover board measurements taken in both directions from the plot, measured average vegetation height, recorded soil moisture, and the presence/absence of human and game trails (see Pigeon et al., 2016 for details). In the surrounding forest (‘offline’, 15m from the linear feature), we again measured lateral vegetation cover and average tree height. To record vegetation composition data, we established online 10m2 and 1m2 subplots at the plot 100m from the access road; we only recorded vegetation composition data within this plot because of limited time and resources for field data collection. Within these subplots, we identified and recorded the percent ground cover of vegetation taxa used as forage by bears and caribou alternate competitors. We standardized and scaled continuous and percent variables prior to modelling.