During the last 150 years, two species of mesquite trees in the Southwestern United States have become increasingly common in what formerly was desert grassland. These trees have spread from nearby watercourses onto relatively xeric upland areas, decreasing rangeland grass production. Management attempts to limit or reverse this spread have been largely unsuccessful. This paper reviews studies regarding mesquite natural history and management strategies, emphasizing studies published during the past decade. Mesquite possess a deep root system and are capable of fixing atmospheric N, rendering them capable of accessing resources unavailable to other plants in open rangeland. Their seeds, which remain viable for decades, have a hard exocarp and require scarification before germination. Consumption by cattle provides a means of scarification and seed dispersal, and is a major factor contributing to the spread of mesquite in open rangelands. Increases in atmospheric CO2 and winter precipitation during the past century also contribute to enhanced seed germination. Removal techniques have included herbicides, prescribed burning, grazing reduction, and mechanical removal. For increased effectiveness of these techniques, management goals must be clearly articulated; these goals include complete removal, no removal, and limited removal. Of these, limited removal appears the most feasible, using an initial herbicide application followed by periodic prescribed burning.

The Changing Mile, originally published in 1965, was a benchmark in ecological studies, demonstrating the prevalence of change in a seemingly changeless place. Photographs made throughout the Sonoran Desert region in the late 1800s and early 1900s were juxtaposed with photographs of the same locations taken many decades later. The nearly one hundred pairs of images revealed that climate has played a strong role in initiating many changes in the region. This new book updates the classic by adding recent photographs to the original pairs, providing another three decades of data and showing even more clearly the extent of change across the landscape. During these same three decades, abundant information about climatic variability, land use, and plant ecology has accumulated, making it possible to determine causes of change with more confidence. Using nearly two hundred additional triplicate sets of unpublished photographs, The Changing Mile Revisited utilizes repeat photographs selected from almost three hundred stations located in southern Arizona, in the Pinacate region of Mexico, and along the coast of the Gulf of California. Coarse photogrammetric analysis of this enlarged photographic set shows the varied response of the region's major plant species to the forces of change. The images show vegetation across the entire region at sites ranging in elevation from sea level to a mile above sea level. Some sites are truly arid, while others are located above the desert in grassland and woodland. Common names are used for most plants and animals (with Latin equivalents in endnotes) to make the book more accessible to non-technical readers. The original Changing Mile was based upon a unique set of data that allowed the authors to evaluate the extent and magnitude of vegetation change in a large geographic region. By extending the original landmark study, The Changing Mile Revisited will remain an indispensable reference for all concerned with the fragile desert environment.

Global problem or treasure? This question has accompanied the widespread and controversial mesquite tree wherever it grows and is studied around the world. In this comprehensive reference to the genus Prosopis, rangeland scientist Rodney Bovey has gathered and synthesized years of research in a book that reflects our current state of knowledge about the biology, morphology, and management of mesquite. Environmentally adaptive, the mesquite is considered by many to be an invasive or a pest species, and Bovey addresses the concerns about mesquite encroachment worldwide. But he also explains its ecological importance in the prevention of erosion and desertification and in providing food and habitat for wildlife. In addition, Bovey traces the uses of mesquite by humans and discusses the economics of growing and harvesting mesquite. A handy guide to the names, locations, distributions, habitat, structure, and uses of several species of mesquite is included in this benchmark publication for ecologists, range managers, biologists, landowners, and students of agriculture and ecosystem science.