Why these study regions?

Nomadic hunter-gatherer groups—that is, those who move throughout their lives and do not spend extended periods of time in the same place—have historically used and continue to use the resources of the environments they inhabit. The regions we study exhibit environmental variations that may have been significant for their ancient inhabitants. These differences include the availability of water, rock shelters, and high-quality raw materials (see, for example, the figures below), which could have been used during their movements. Water availability in these environments has also fluctuated over time, as demonstrated by paleoenvironmental studies conducted in our study regions by George Brook (University of Georgia) and María Virginia Mancini (University of Mar del Plata), which have been correlated with data from other researchers.