Why were Pacific-drainage Athabaskan communities generally less mobile than Mackenzie River communities?

Pacific-drainage Athabaskan communities were generally less mobile than those in the Mackenzie River region because their environment provided more reliable and abundant food resources. Specifically, the salmon streams that drain into the Pacific Ocean offered a consistent food supply that served as a natural gathering place for these groups.1

In contrast, the Mackenzie River communities relied on food resources that were distributed quite thinly across the subarctic landscape, necessitating greater mobility to avoid exhausting local supplies. While the Pacific-drainage groups were able to establish more stable settlements and developed more complex social stratification due to their reliable food sources, the Mackenzie River groups maintained highly mobile, kin-based band structures as a survival strategy in their more challenging environment.12