A record of sustained prehistoric and historic land use from the Cahokia region, Illinois, USA

A high-resolution paleoecological study of Horseshoe Lake, adjacent to Cahokia Mounds State Historic Site, reveals that sustained prehistoric land use began abruptly around 450 CE and intensified over centuries before the rise of Cahokia. The research, combining palynological and carbon isotope data, documents rapid forest clearance followed by the proliferation of indigenous seed crops, peaking between 900 and 1200 CE. A major flood event around 1200 CE coincides with agricultural contraction and Cahokia's decline, suggesting environmental factors may have played a role in its downfall.

Munoz, S. E., Schroeder, S., Fike, D. A., & Williams, J. W. (2014). A record of sustained prehistoric and historic land use from the Cahokia region, Illinois, USA. Geology, 42(6), 499–502. https://doi.org/10.1130/g35541.1