Ecology of Desert Systems (eBook)

Walter G. Whitford (Autor)

eBook Download: PDF

2002 | 1. Auflage
343 Seiten
Elsevier Science (Verlag)
978-0-08-050499-5 (ISBN)

Infos

Conventional wisdom considers deserts stark, harsh regions that support few living things. Most people also believe that water alone makes the desert bloom. Ecology of Desert Systems challenges these conventional views.

This volume explores a broad range of topics of interest to ecosystem, population, community, and physiological ecologists. Climate, weather patterns, geomorphology, and wind and water processes are examined as variables that affect the distribution of biota through fundamental ecosystem processes. Descriptions of morphological, behavioral, and physiological adaptations of desert biota illuminate, through the lens of patch dynamics, principles for understanding observed patterns of primary production, nutrient cycling, and the effects of consumers. Desertification, and the techniques for monitoring and quantifying it, is examined within the framework of desert ecosystem patterns and processes.



* Focuses on the interactions of climate, soil, and biota along a spectrum of spatial and temporal scales
* Details the role of animals in desert ecosystems and landscape processes
* Examines watershed scale processes, the ecology of ephemeral lakes, and the ecological changes identified with desertification
* Outlines the fundamental concepts relevant to sustainable development of arid lands

Inhalt

Front Cover 1
Ecology of Desert Systems 4
Copyright Page 5
Contents 8
Foreword 12
Preface 16
Chapter 1. Conceptual Framework and Paradigms 18
1.1 Pattern and Process 19
1.2 Definition of Ecosystem 23
1.3 Landscape Units 26
1.4 Questions 27
1.5 Defining Deserts 28
1.6 The Pulse-Reserve Paradigm and the Autecological Hypothesis 29
1.7 Temporally Uncoupled Resources 31
1.8 The Soil Resource 31
1.9 Ecosystem Processes 33
1.10 Problems of Scaling 35
References 35
Chapter 2. Landforms, Geomorphology, and Vegetation 38
2.1 Desert Mountains and Hillslopes 39
2.2 Piedmonts, Alluvial Fans, and Bajadas 41
2.3 Ephemeral Streams 47
2.4 Basins and Flatlands 50
2.5 Desert Pavements and Stony Surfaces 53
2.6 Rivers and Floodplains 54
2.7 Sand Dunes and Sand Features 54
2.8 Landform Stability 57
References 57
Chapter 3. Characterization of Desert Climates 60
3.1 Seasonality 65
3.2 Spatial Effects 69
3.3 Predictability 70
3.4 Intensity, Duration, Frequency, and Return Time 72
3.5 Microclimate 75
References 78
Chapter 4. Wind and Water Processes 82
4.1 Wind Erosion 82
4.2 Redistribution of Rainfall 88
4.3 Splash Erosion-kinetic Energy of Raindrops 94
4.4 Infiltration and Run-off 95
4.5 Exchanges Among Landscape Units 101
4.6 Exchanges Within Landscape Units 103
4.7 Episodic Events 105
4.8 Ephemeral Ponds and Lakes 107
References 110
Chapter 5. Patch-Mosaic Dynamics 114
5.1 Seeds: Germination-Establishment Sites 114
5.2 Single Species Patches 119
5.3 Intraspecific Morphological Variation 120
5.4 Mosaics and Multi-species Patches 121
5.5 Competition versus Facilitation 123
5.6 Animal-produced Patches 127
5.7 Temporal Dynamics and Feedbacks 134
References 136
Chapter 6. Adaptations 140
6.1 Avoidance of Extremes 140
6.2 Physiological and Morphological Adaptations 150
References 168
Chapter 7. Primary Production 174
7.1 Measurement of Net Primary Production 174
7.2 Comparisons of Production Estimates with Mesic Ecosystems 177
7.3 Rain Use Efficiency 178
7.4 Below-ground Productivity 179
7.5 Models of AGNPP 180
7.6 Landscape Relationships 183
7.7 Productivity in Extreme Deserts 187
7.8 Productivity Linked to Rainfall 188
7.9 Productivity of Species and Functional Groups 189
References 195
Chapter 8. Consumers, Consumption, and Secondary Production 198
8.1 Secondary Production 198
8.2 Foliage Chewers and Browsers: Vertebrate and Invertebrate 202
8.3 Canopy Insect Communities 209
8.4 Surface Active Arthropods 215
8.5 Large Herbivores: Grazers 219
8.6 Granivory 223
8.7 Impacts of Rodents and Ants on Ecosystem Structure and Processes 230
8.8 Vertebrate Predators 232
8.9 Below-ground Food Webs 237
8.10 Ephemeral Ponds and Lakes 239
References 243
Chapter 9. Decomposition and Nutrient Cycling 252
9.1 Nutrient Limitations 252
9.2 Decomposition 254
9.3 Landscape Patterns of Nutrient Distribution 269
9.4 Resorption 274
9.5 Nitrogen Cycle 275
9.6 Other Potentially Limiting Nutrients 283
9.7 Role of Mycorrhizae 283
References 286
Chapter 10. Desertification 292
10.1 History of Desertification 294
10.2 Ecosystem and Landscape Consequences of Desertification 299
10.3 Resistance and Resilience of Desertified Landscapes 306
10.4 Desertification and Climate Change 307
10.5 Social and Economic Consequences of Desertification 308
10.6 Effects of Desertification on Biodiversity 310
10.7 Rehabilitation of Desertified Landscapes 312
References 318
Chapter 11. Monitoring and Assessment 322
1 1.1 Definitions 323
11.2 Existing Assessment and Monitoring Systems 323
1 1.3 Data for Assessment and Monitoring 326
1 1.4 Ecosystem Functions 327
1 1.5 Indicators 327
References 333
Chapter 12. Desert Ecosystems in the Future 336
References 342
Index 344

Produkt-Details

• Erscheint lt. Verlag: 25.3.2002
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Biologie ► Ökologie / Naturschutz
• Themenwelt: Naturwissenschaften ► Geowissenschaften ► Geografie / Kartografie
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• Themenwelt: Technik ► Umwelttechnik / Biotechnologie
• ISBN-10: 0-08-050499-X / 008050499X
• ISBN-13: 978-0-08-050499-5 / 9780080504995