Riparian Ecosystem Recovery in Arid Lands

Book excerpt: Riparian ecosystems are declining throughout the southwestern United States, where many have disappeared completely; yet progress toward checking their decline has been marginal, and the results of only a few recovery projects have been evaluated. In this guidebook, Mark K. Briggs has filled this gap in riparian conservation literature. Based on his experiences gleaned from evaluating the results of many riparian rehabilitation projects, Briggs presents these results in a manner that biologists, hydrologists, government planners, resource managers, and other concerned citizens can immediately apply toward developing site-specific recovery strategies. The book opens with a review of watershed characteristics and an examination of drainage systems, then proceeds to determining the causes of riparian decline. It introduces five factors that have a significant effect on the results of riparian rehabilitation--natural regeneration, water availability, channel stability, direct impacts such as livestock grazing and recreational activities, and soil salinity--and offers case studies that demonstrate how revegetation has been used both effectively and ineffectively. It also discusses strategies other than revegetation that may be effective in improving the ecological condition of a site. Many of the strategies presented are also relevant to nonarid climates and to urban areas. By emphasizing evaluation of riparian ecosystems, so that the causes of degradation can be understood, and by offering general approaches that can be tailored to specific situations, Riparian Ecosystem Recovery in Arid Lands takes a holistic approach to riparian recovery that will enable users to better judge whether recovery expenditures are likely to produce desired results. An unprecedented work, it will substantially add to efforts across the Southwest and elsewhere to restore these unique and priceless ecosystems. CONTENTS 1 An Overview: Background on Riparian Ecosystems / Lessons Learned from Past Riparian Recovery Efforts / An Evaluation Strategy / Defining Some Important Terms 2 Considering the Damaged Riparian Area from a Watershed Perspective: Case Study 1: Rincon Creek / Taking Advantage of Available Information / Getting to Know the Watershed / Getting to Know the Stream 3 Impacts within the Riparian Zone: Livestock / Case Study 2: Sheepshead Spring / Recreation / Competition from Nonnative Species / Wildlife 4 Natural Recovery in Riparian Ecosystems: Case Study 3: Aravaipa Creek / Factors Influencing Natural Recovery / Case Study 4: McEuen Seep / Autoecology of Selected Southwestern Riparian Tree Species / Case Study 5: Boulder Creek 5 Water Availability: Case Study 6: Box Bar / How Groundwater Decline Occurs / Evaluating Groundwater Conditions / Revegetating Riparian Ecosystems Characterized by Groundwater Decline 6 The Drainageway: Channel Instability and Riparian Ecosystems / Case Study 7: Babocomari River / Channel Dynamics / Strategies for Evaluating Channel Stability / Developing Recovery Projects along Unstable Alluvial Stream Channels 7 Soil Salinity and Riparian Ecosystems: Effects of Soil Salinity on Plant Growth / The Soil Survey / Soil Salinity and Revegetation 8 Developing the Recovery Plan: Developing Project Objectives / Selecting the Best Site / Local, State, and Federal Permit Requirements / Identifying Model Areas / Critical Components of the Recovery Plan / Community Involvement / Demonstration Sites / Postproject Evaluation and Monitoring