Structural and dynamical roles of preindustrial people in food webs of the North Pacific

Background/Question/Methods Aleut lived on Sanak Island, near the tip of the Alaska Peninsula, continuously for ~6000 years.  They appear to have had relatively sustainable patterns of culture and habitation based on a local economy directly tied to ecosystem goods and services.  We integrate data from the Sanak Archipelago on the trophic interactions among species in intertidal, terrestrial, freshwater, and marine habitats with detailed information from middens on human diets over thousands of years.  Using a food-web analysis and modeling framework, we explore the topological and dynamical roles that Aleut played in the Sanak ecosystem, and the potential impact of such roles on persistence and stability of this preindustrial coupled human-natural system.
Results/Conclusions Network structure analysis suggests that the Aleut had unique roles, compared to other species, in terms of both their topological position and their feeding dynamics within the food web. For example, the Aleut were strong generalists and omnivores, feeding on many taxa across all trophic levels; they fed on taxa from all four habitat types; they did temporal, spatial, and trophic-level prey switching; and they had the potential to be highly efficient in their gathering and consumption of other taxa.  Non-linear dynamical modeling suggests conditions under which food webs that include a species with these types of characteristics can promote, or inhibit, the persistence and stability of a complex ecosystem.  This modeling framework is generic and may be extended to considering the sustainability of complex ecosystems with human involvement in other pre- and postindustrial contexts.