On the arid margin: the relationship between climate, humans and the environment. A review of evidence from the highlands of central Mexico.

There has long been speculation as to the relationship between climate, humans and the environment. Until recently, however, it has proved difficult to establish the degree to which these factors are interlinked. Here we draw on evidence that has recently emerged from a series of investigations in central México to evaluate the long-term human impact on the environment and to establish the impact that late Holocene changes in the climate have had on the indigenous populations that lived on the arid frontier of Mesoamerica. Data from these studies indicate that: 1) the indigenous peoples of central México had a significant and often detrimental impact on the landscape, causing widespread land degradation; 2) The onset of anthropogenic accelerated erosion coincided with the introduction of sedentary agriculture in this region; 3) Fluctuations in the climate of central México over the last 4,000 years have had a significant impact on the subsistence strategies of the population which extended its territory into the northern arid lands during wetter periods, but rapidly abandoned these areas when the climate became drier.