Large mammal biomass predicts the changing distribution of hunter-gatherer settlements in mid-late Holocene Alaska

Abstract

This study provides an ecological explanation for the distribution of Arctic Small Tool tradition (ASTt) settlements in Alaska and the origin of their arctic maritime adaptation. Theoretically grounded in the ideal free distribution (IFD) model, which predicts that higher ranked habitats will be occupied first and most continuously, we contend that the location of large mammals was a major factor influencing human dispersal and settlement decisions in the arctic and subarctic ecosystems of Alaska. We rank habitat suitability based on historic mammal population densities from wildlife ecology reports across predefined ecological zones in Alaska; we multiply densities by average animal weights per species to determine suitability rankings. Coastal habitats in Alaska are higher ranked than adjacent tundra habitats, but the interior boreal forest may have been the highest ranked, considering technological constraints of hunting aquatic species. The ASTt migration into Alaska created population pressure that promoted the colonization of the unoccupied Arctic coast and development of the dual, terrestrial-maritime economy. When pan-Alaska human populations declined around 3200–2500years ago low ranked tundra ecoregions were abandoned. As human populations recovered Alaska coasts became the most densely populated habitats. The adaptive logic entailed in the IFD provides a consistent evolutionary interpretation for settlement patterns documented in this region.