DURREN, BEVOLKERUNGSKOLLAPS UND BODENEROSION: EPIDEMIENUND UMWELTVERANDERUNGEN IN ZENTRALMEXIKO VOR 400 BIS 500JAHREN

摘要

Recently, there has been growing interest in historical megadroughts, arising from a variety of motivations; these include documentation of the past climatic record, impact of such climatic events on past environments and civilizations, the possibility of future megadroughts, and their interaction with the greenhouse effect (Hunt & Elliott 2002, Rees 2005). Here I show that the 16th century Mexican megadrought caused a population collapse resulting in abandonment of cultivated areas with consequences for soil erosion processes and environmental change. The relationship between climate and accelerated soil erosion (sediment yield) in central Mexico was modulated by population fluctuations in the areas of summer-rain-fed agriculture. In the 16th century, in central Mexico a climatically (megadrought) driven epidemic (cocolitzli) caused a population collapse which in turn resulted in an abandonment of cultivated land, reforestation/recovery of natural vegetation and retardation of soil erosion processes. There is no evidence from any central Mexican site that we have investigated, to suggest that climatic change and/or climatic hazards (e.g. droughts) had had a significant, direct impact on erosion rates.