Maize adoption and intensification in the central Illinois River valley: An analysis of archaeobotanical data from the Late Woodland to Early Mississippian periods (A.D. 600-1200)

We consider the causes and timing of maize (Zea mays) intensification in the central Illinois River valley and argue that an understanding of changes in maize production requires a consideration of changes occurring in the entire plant subsistence system. To this end, we explore trends in the collection and production of plant foods from the Late Woodland (A.D. 600-1100) to Early Mississippian periods (A.D. 1100-1200). The plant data reveal a stepwise decrease in nut collection during the Late Woodland period, and again during the transition to the Early Mississippian period. This pattern is accompanied by statistical increases in maize abundance, indicating an intensification of maize production around A.D. 1100. We consider these patterns in light of similar maize increases occurring throughout the Eastern Woodlands and evaluate several possible interpretations related to population pressure, climate change, competitive generosity, and cultural emulation, the latter which appears to have been inspired by prolonged contact between local populations and Mississippian groups in the greater Cahokia area