Traversing the Southern Canadian Rocky Mountains: A Least Cost Path Analysis

The Kootenai people of southern Canada historically traversed the Rocky Mountains, often several times annually, to hunt bison on the eastern front ranges. Some routes across this complex landscape were more energetically efficient than others so that archaeological and historical sites accumulated along least cost paths (LCP) as predicted by spatial analysis. We produced 12 least-cost path models traversing the Southern Canadian Rocky Mountains (SCRM) using varying degrees of landscape cost, ranked them for stability, and combined them into a final composite model. We expanded this composite LCP model into 3- and 5-km buffers within which we compared counts of historical and archaeological sites (total n = 5,651 points) to counts of equivalent quantities of randomly distributed points. High densities of land use indicators tend to follow paths across the SCRM predicted by the LCP model, creating persistent patterns of travel and land use. The results of this analysis indicate that human movements across the SCRM have been strongly influenced by the avoidance of high travel cost topography over multiple centuries. More broadly, our findings suggest that humans tend to optimize their patterns of spatial movement for energetic efficiency, consistent with predictions of behavioral evolution.