Midcontinental Native American population dynamics and late Holocene hydroclimate extremes

• DOI: 10.1038/srep41628
• Publication Date: 2017-01-31T10:26:25Z
• Authors: Broxton W. Bird; Jeremy J. Wilson; William P. Gilhoo...; Byron A. Steinman; Lucas Stamps
• Keywords: Proxy (statistics); Human settlement; Paleoclimatology

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 changes precipitation source and seasonality local warm-season duration rainstorm events related to Pacific North pattern (PNA) using a 2100-year-long multi-proxy lake-sediment record from US. Wet climate reflecting negative PNA-like conditions occurred during Medieval Climate Anomaly (950–1250 CE) adopted intensive maize agriculture, facilitating population aggregation development of urban centers between 1000–1200 CE. Intensifying socio-political instability warfare 1250–1350 CE corresponded with drier positive conditions, culminating staggered abandonment many major river valley settlements large 1350–1450 an especially severe drought. We hypothesize that this sustained drought interval rendered it difficult support dense US by destabilizing agricultural systems, thereby contributing host factors led reorganization migration midcontinent neighboring regions shortly before European contact.