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March 6, 2012; 109 (10)

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Cover image: Connected to the Nile’s floodwaters, the oasis pictured here was developed after 280 BCE by Ptolemy II, son of one of Alexander’s generals. Cultivation and productivity in the region were expanded through a regulator dam that controlled the influx of Nile water, while an outer ring of master canals helped secure irrigation for new lands. The article by Karl W. Butzer, part of the Critical Perspectives on Historical Collapse Special Feature, reports that a succession of plague, reduced Nile floods, and mismanagement, led to the collapse of the upstream canals, depopulation, and widespread abandonment, illustrating the ecological dereliction of a landscape that did not fully recover until about 1900 CE. See the Perspective by Karl W. Butzer on pages 3632–3639. Image courtesy of Karl W. Butzer and John Oswald (University of Texas at Austin, Austin, TX).

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