LAUSR

Disarticulated fish remains are frequently recovered from late preHispanic and early historic archaeological sites in the Middle Rio Grande basin of central New Mexico, but they are rare during earlier time periods. Increased aquatic habitat quality brought on by wetter climatic conditions may have impacted Ancestral Pueblo foraging goals related to risk minimization, leading to an uptick in fish exploitation. Wetter stream conditions can increase the number of different energy channels that help support fish populations and increase ecological stability, which makes fish less risky to pursue for human foragers. Here, we illustrate how to identify stable ecological communities in the archaeological record using stable carbon and nitrogen isotope values of fish bones recovered from archaeological sites in the Middle Rio Grande. We find that energy derived from terrestrial C4 plants—a stabilizing “slow” allochthonous energy source—was important for the Middle Rio Grande aquatic food web during the late preHispanic/early historic period. This result suggests that fish populations were supported by a broader resource base and were thus more stable and less risky to pursue for Ancestral Pueblo people.