The demand for water resulting from massive population and economic growth in the southwestern U.S. overwhelmed traditional uses of riparian areas. As a consequence, many of these uniquely-structured ecosystems have been altered or destroyed. Within recent years people have become increasingly aware of the many uses and benefits of riparian zones a

Riparian Areas of the Southwestern United States: Hydrology, Ecology, and Management provides hydrologists, watershed managers, land-use planners, educators, policymakers, and non-governmental organizations with a comprehensive account of the multiple benefits and conflicts arising from the uniquely structured ecosystems of arid and semi-arid regions. The text describes the inhabitants of southwestern riparian ecosystems and addresses the research, planning, and management concerns for these fragile ecosystems in relation to the impacts of water and sediment flows, livestock grazing, and other human activities, and the maintenance of key wildlife and fish habitats.

Woody wetlands constitute a relatively small but extremely important part of the landscape in the southwestern United States. These riparian habitats support more than one-third of the regionÕs vascular plant species, are home to a variety of wildlife, and provide essential havens for dozens of migratory animals. Because of their limited size and disproportionately high biological value, the goal of protecting wetland environments frequently takes priority over nearly all other habitat types. In The Ribbon of Green, hydrologists Robert H. Webb, and Stanley A. Leake and botanist Raymond M. Turner examine the factors that affect the stability of woody riparian vegetation, one of the largest components of riparian areas. Such factors include the diversion of surface water, flood control, and the excessive use of groundwater. Combining repeat photography with historical context and information on species composition, they document more than 140 years of change. Contrary to the common assumption of widespread losses of this type of ecosystem, the authors show that vegetation has increased on many river reaches as a result of flood control, favorable climatic conditions, and large winter floods that encourage ecosystem disturbance, germination, and the establishment of species in newly generated openings. Bringing well-documented and accessible insights to the ecological study of wetlands, this book will influence our perception of change in riparian ecosystems and how riparian restoration is practiced in the Southwest, and it will serve as an important reference in courses on plant ecology, riparian ecology, and ecosystem management.

The Clean Water Act (CWA) requires that wetlands be protected from degradation because of their important ecological functions including maintenance of high water quality and provision of fish and wildlife habitat. However, this protection generally does not encompass riparian areasâ€"the lands bordering rivers and lakesâ€"even though they often provide the same functions as wetlands. Growing recognition of the similarities in wetland and riparian area functioning and the differences in their legal protection led the NRC in 1999 to undertake a study of riparian areas, which has culminated in Riparian Areas: Functioning and Strategies for Management. The report is intended to heighten awareness of riparian areas commensurate with their ecological and societal values. The primary conclusion is that, because riparian areas perform a disproportionate number of biological and physical functions on a unit area basis, restoration of riparian functions along America's waterbodies should be a national goal.

"Volume 2 (this volume) describes wildlife and fish species, their habitat requirements, and species-specific management concerns, in Southwestern grasslands. This assessment is regional in scale and pertains primarily to lands administered by the Southwestern Region of the USDA Forest Service (Arizona, New Mexico, western Texas, and western Oklahoma)."--Abstract.

Volume 2. Wildlife and fish.

Grazing by wild and domestic mammals can have small to large effects on plant communities, depending on characteristics of the particular community and of the type and intensity of grazing. The broad objective of this report was to extensively review literature on the effects of grazing on 25 plant communities of the southwestern U.S. in terms of plant species composition, aboveground primary productivity, and root and soil attributes. Livestock grazing management and grazing systems are assessed, as are effects of small and large native mammals and feral species, when data are available. Emphasis is placed on the evolutionary history of grazing and productivity of the particular communities as determinants of response. After reviewing available studies for each community type, we compare changes in species composition with grazing among community types. Comparisons are also made between southwestern communities with a relatively short history of grazing and communities of the adjacent Great Plains with a long evolutionary history of grazing. Evidence for grazing as a factor in shifts from grasslands to shrublands is considered. An appendix outlines a new community classification system, which is followed in describing grazing impacts in prior sections.