Over the past thirty years, late Quaternary environments in the arid interior of western North America have been revealed by a unique source of fossils: well-preserved fragments of plants and animals accumulated locally by packrats and quite often encased, amberlike, in large masses of crystallized urine. These packrat middens are ubiquitous in caves and rock crevices throughout the arid West, where they can lie preserved for tens of thousands of years. More than a thousand of these deposits have been dated and analyzed, and middens have supplanted pollen records as a touchstone for studying vegetation dynamics and climatic change in radiocarbon time (the last 40,000 years). Now, similar deposits made by other mammals like hyraxes are being reported from other parts of the world.

This book brings together the findings and views of many of the researchers investigating fossil middens in the United States, Mexico, Africa, the Middle East, and Australia. The contributions serve to open a forum for methodological concerns, update the fossil record of various geographic regions, introduce new applications, and display the vast potential for fossil midden analysis in arid regions worldwide. The findings presented here will serve to foster regional research and to promote general studies devoted to global climate change. Included in the text are more than two hundred charts, photographs, and maps.

In prehistoric times, the Santa Cruz River in what is now southern Arizona saw many ebbs, flows, and floods.  It flowed on the surface, meandered across the floodplain, and occasionally carved deep channels or arroyos into valley fill. Groundwater was never far from the surface, in places outcropping to feed marshlands or ciénegas. In these wet places, arroyos would heal quickly as the river channel revegetated, the thriving vegetation trapped sediment, and the channel refilled. As readers of Requiem for the Santa Cruz learn, these aridland geomorphic processes also took place in the valley as Tucson grew from mud-walled village to modern metropolis, with one exception: historical water development and channel changes proceeded hand in glove, each taking turns reacting to the other, eventually lowering the water table and killing a unique habitat that can no longer recover or be restored.

Authored by an esteemed group of scientists, Requiem for the Santa Cruz thoroughly documents this river—the premier example of historic arroyo cutting during  the late nineteenth and early twentieth centuries, when large floodflows cut down through unconsolidated valley fill to form deep channels in the major valleys of the American Southwest. Each chapter provides a unique opportunity to chronicle the arroyo legacy, evaluate its causes, and consider its aftermath. Using more than a collective century of observations and collections, the authors reconstruct the circumstances of the river’s entrenchment and the groundwater mining that ultimately killed the marshlands, a veritable mesquite forest, and a birdwatcher's paradise.

Today, communities everywhere face this conundrum: do we manage ephemeral rivers through urban areas for flood control, or do we attempt to restore them to some previous state of perennial naturalness? Requiem for the Santa Cruz carefully explores the legacies of channel change, groundwater depletion, flood control, and nascent attempts at river restoration to give a long-term perspective on management of rivers in arid lands. Tied together by authors who have committed their life’s work to the study of aridland rivers, this book offers a touching and scientifically grounded requiem for the Santa Cruz and every southwestern river.