Deserts and Desert Environments

Julie Laity is a Professor at California State University, Northridge, USA. Her work has focused on deserts, looking at aeolian, fluvial, and groundwater systems, and the impact of environmental degradation on wind-blown sand and dust events. Her research on groundwater-sapping systems and wind erosion has been used to aid our understanding of Martian environments.

"All chapters of the book are preceded by a short introduction, which is very useful. The book isrichly illustrated in the form of both black-and-white and colour photos (but the colour figuresduplicate the black-and-white ones!), graphs and diagrams . . . taken all together, the book can be recommended to graduate students and researchers dealing with deserts; sedimentology is certainly not the main topic, but much information is very useful to increase the insight into the conditions that control the sedimentological processes in this environment." (Society for Sedimentary Research, 2011) "I would recommend Deserts and Desert Environments as a useful starting point for any undergraduate student wishing to explore a range of dryland environments and landforms for the first time. The well-illustrated and accessible nature of this text-book will suit them well". (The Geographical Journal, 1 March 2010)"Each chapter of the book is preceded by a short introduction, which is very useful. The book is richly illustrated in the form of both black-and-white and colour photos (but the colour photos duplicate the black-and-white ones!), graphs and diagrams." (Geologos, July 2010)

• Preface xii1 Introduction: defining the desert system 11.1 Defining the desert system 11.2 Evolution of deserts 21.3 Indices of aridity 61.4 Desert surfaces 81.5 Tectonically stable and unstable deserts 81.6 Deserts of the past 91.7 Changing human perspectives on deserts 122 Deserts of the world 142.1 Introduction: the extent of global aridity 142.2 Global deserts 143 The climatic framework 483.1 Introduction: classification of deserts by temperature 483.2 Weather data 483.3 Atmospheric controls: surface boundary layer 503.4 Temporal and spatial variability of climatic influences 644 The hydrologic framework 714.1 Introduction 714.2 The water balance in deserts 714.3 Water budgets 734.4 Surface runoff and floods 844.5 The chemical quality of surface and soil water 894.6 Water resources 904.7 Case study: the waters of the Tigris-Euphrates Basin and the impact of modern water management 945 Lake systems: past and present 985.1 Introduction to desert lakes 985.2 Types of lake 985.3 Lakes of the global arid environment 1066 Weathering processes and hillslope systems 1226.1 Introduction 1226.2 Weathering 1226.3 Weathering forms 1266.4 Duricrusts 1286.5 Desert varnish 1346.6 Hillslope processes 1366.7. Composite surfaces (pediments) 1457 Desert soils and geomorphic surfaces 1487.1 Introduction 1487.2 The nature of soils in arid and semiarid regions 1487.3 Soil description and classification 1497.4 Soil characteristics of arid regions 1507.5 Inorganic and biological soil crusts 1527.6 Spatial heterogeneity in soil properties and the ecohydrology of patterned vegetation zones 1567.7 Surface volume changes 1587.8 Surface types: hamada and stone pavements 1598 Water as a geomorphic agent 1688.1 Introduction 1688.2 Groundwater sapping in slope and valley development 1688.3 Piping processes in channel and slope evolution 1718.4 Fluvial processes 1728.5 Fluvial landforms 1799 Aeolian processes 1869.1 Introduction 1869.2 Near-surface flow 1879.3 Wind processes 1919.4 Landforms of accumulation: sand sheets, zibar, and sand stringers 1959.5 Landforms of accumulation: dunes 1979.6 Ripples 21310 Landforms of aeolian erosion and desert dust 21610.1 Introduction 21610.2 Deflation features: desert depressions and pans 21610.3 Ventifacts 21810.4 Yardangs and ridge and swale systems 22110.5 Desert dust 22511 Plant communities and their geomorphic impacts 23711.1 Introduction: characteristics of desert ecosystems 23711.2 Adaptations to desert conditions 23811.3 Plant communities and ecotones 24511.4 Succession in desert plant communities 25111.5 Dune communities 25211.6 Vegetation type and density and relationship to geomorphic processes 25312 Animal communities 25912.1 Introduction: environmental requirements 25912.2 Effects on geomorphic processes 26412.3 Hydrologic impacts 26512.4 Effects of the geomorphic activity of animals on plant communities 26613 Desertification and the human dimension 26713.1 Desertification: introduction and terminology 26713.2 Climate change and desertification 26813.3 Anthropogenic causes of desertification 26913.4 Water resources: a rural and urban problem 27513.5 Case study: the Aral Sea 28013.6 Discussion 283References 285Index 320