Abstract
Climate’s influence on late Pre-Columbian (pre-1492 CE), maize-dependent Native American populations in the midcontinental United States (US) is poorly understood as regional paleoclimate records are sparse and/or provide conflicting perspectives. Here, we reconstruct regional changes in precipitation source and seasonality and local changes in warm-season duration and rainstorm events related to the Pacific North American pattern (PNA) using a 2100-year-long multi-proxy lake-sediment record from the midcontinental US. Wet midcontinental climate reflecting negative PNA-like conditions occurred during the Medieval Climate Anomaly (950–1250 CE) as Native American populations adopted intensive maize agriculture, facilitating population aggregation and the development of urban centers between 1000–1200 CE. Intensifying midcontinental socio-political instability and warfare between 1250–1350 CE corresponded with drier positive PNA-like conditions, culminating in the staggered abandonment of many major Native American river valley settlements and large urban centers between 1350–1450 CE during an especially severe warm-season drought. We hypothesize that this sustained drought interval rendered it difficult to support dense populations and large urban centers in the midcontinental US by destabilizing regional agricultural systems, thereby contributing to the host of socio-political factors that led to population reorganization and migration in the midcontinent and neighboring regions shortly before European contact.
Highlights
The adoption of intensive agricultural practices allowed North American Pre-Columbian populations in the southwestern and eastern United States (US) to moderate subsistence shortfalls and thereby sustain larger populations with increasing socio-political complexity[1,2,3]
The first indications of discord at Mississippian settlements occurred at Cahokia and within the American Bottom, where some upland urban centers and smaller settlements alike were abandoned starting around 1150 CE during a severe drought, culminating in the whole of the central Mississippi valley being depopulated by 1350 CE
While climate has been suggested as a component of late Pre-Columbian Native American settlement patterns and population dynamics in the midcontinental US20–23, paleoclimate records with the length, temporal resolution, and proxy sensitivity required to identify the potential effects of past climate change on agricultural potential are scarce and provide conflicting climatic information
Summary
The adoption of intensive agricultural practices allowed North American Pre-Columbian populations (pre-1492 CE) in the southwestern and eastern United States (US) to moderate subsistence shortfalls and thereby sustain larger populations with increasing socio-political complexity[1,2,3]. A similar climate-agriculture-population dynamic has been suggested to explain the arc of midcontinental Native American populations associated with Mississippian and related archaeological cultures of the Ohio River Valley (i.e., Fort Ancient and Monongahela) between 1000–1450 CE10–12 These populations collectively expanded between 1000–1200 CE, developing large villages and socio-cultural/religious centers with higher population densities likely sustained by the adoption of intensive maze agriculture by 1000 CE12–14. Munoz et al.[23] identified suspected flood deposits in two lakes near Cahokia and suggested that increased regional precipitation and flooding after 1200 CE contributed to the collapse of Cahokia and other Mississippian city centers Though these contrasting climatic scenarios for the late Pre-Columbian period are not mutually exclusive, they do illustrate the need for paleoclimate records that capture geographically broad climate processes capable of influencing populations spanning a large region. The white box indicates the intersection between the REL and RMWL that defines average annual δ18Oprecip for Indiana
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
