original_query: What evidence suggests that there was a decline and/or reorganisation in human population early in the Younger Dryas period in North America?
query: What evidence suggests a decline and/or reorganization in the North American Paleo-Indian population at the start of the Younger Dryas?
answer: A study of Paleoindian demography initially found no evidence of population decline at 12,900 ± 100 BP, contradicting impact event predictions.  However, a critique argued this was an insensitive population proxy.  A later paper presented three approaches to population dynamics, concluding a significant decline and/or reorganization early in the Younger Dryas, followed by a resurgence later in the period.