1. Overview -- 1.1. Problems and challenges -- 1.2. Hypotheses and questions -- 1.3. Modeling framework -- 1.4. The structure of this book 2. Physical processes -- 2.1. Characteristics of semi-arid ecosystems -- 2.2. Water-heat-carbon cycles -- 2.3. The abiotic and biotic properties of semi-arid soils -- 2.4. Land-atmosphere interactions -- 2.5. Soil water dynamics -- 2.6. Vegetation community composition -- 2.7. Equilibrium and shift -- 2.8. Summary and discussion 3. Conceptualizations -- 3.1. Approximation of semi-arid ecosystems -- 3.2. Ground-surface processes -- 3.3. Rootzone processes -- 3.4. Below-rootzone processes -- 3.5. Plant growth and senescence -- 3.6. Topsoil erosion -- 3.7. Summary and discussion 4. Mathematical models -- 4.1. Overview -- 4.2. Comparisons of existing models -- 4.3. Model selection -- 4.4. Development of new algorithms -- 4.5. Measures of model performance -- 4.6. Model parameterization and calibration -- 4.7. Summary and discussion 5. Case studies -- 5.1. Study sites -- 5.2. Long-term soil moisture responses to climate and livestock grazing -- 5.3. The effects of climate and livestock grazing on precipitation consumption -- 5.4. Topsoil erosion as influenced by climate and vegetation coverage -- 5.5. Retardation effects of a dry soil layer on soil water evaporation -- 5.6. Grass productivity as influenced by climate and livestock grazing -- 5.7. Interactive effects of land use and soil on water and sediment yields -- 5.8. The effects of biocrusts on water balance and soil erosion -- 5.9. Resilience and degradation of semi-arid ecosystems -- 5.10. Summary and general conclusions 6. Overall conclusions and discussion -- 6.1. Major findings -- 6.2. Broad discussion -- 6.3. Further research Appendix A. Derivation of equation (3.26) -- Appendix B. Derivation of equation (3.35) -- Appendix C. Derivation of the first part of equations (4.13).
Water-soil-vegetation dynamic nexuses affect, and are affected by, both human activity and climate change. Inappropriate land management practices can result in soil and vegetation degradation, which in turn will likely alter natural hydrologic processes, leading to more frequent and severe flooding and drought. In response, an altered hydrologic condition tends to prompt soil erosion by wind and water, which can cause further vegetation degradation or even loss. Such nexuses will likely become more interwoven in changing climate because the non-stationary climate can further deteriorate the already-altered hydrologic condition. So far, our understanding is incomplete regarding how such nexuses maintain or break equilibriums between water, soil, and/or vegetation in terms of eco-environmental resilience. This book: 1) conceptualises the interrelated physical processes of water-soil-vegetation systems; 2) introduces mathematical models for simulating the processes; and 3) develops a variety of modelling cases of selected systems across the world.
Researchers and graduate students.
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The author, Xixi Wang, PhD, PE, Fulbright Scholar, is currently Professor and Graduate Program Director in Department of Civil and Environmental Engineering at Old Dominion University, Norfolk, Virginia, USA. He has extensive teaching and research experience in hydrology, hydraulics, and water resources. His current research interests include effects of climate change versus human activity on water resources, water-soil-vegetation nexus and equilibrium in changing climate, and watershed hydrology and stormwater management. He has authored or co-authored a variety of peer-reviewed journal papers, conference presentations, technical reports, books, and book chapters. He has been a registered professional engineer in North Dakota (#5145) since 2003 and Texas (#99798) between 2007 and 2011 and obtained various honours and awards.
9780750340205 9780750340199
10.1088/978-0-7503-4020-5 doi
Arid regions--Mathematical models. Nature--Effect of human beings on--Mathematical models. Human ecology--Mathematical models. Hydrogeological modeling. Hydrology & the hydrosphere. Environment and energy.