David A. Wardle

Acknowledgments vii
Chapter 1: Introduction 1
Chapter 2: The Soil Food Web: Biotic Interactions and Regulators 7
Controls: Top Down, Bottom Up, and Productivity 9
Regulation by Resources and Predation in Soil Food Webs 16
Litter Transformers, Ecosystem Engineers, and Mutualisms 37
The Functionality of Soil Food Webs 43
Stability and Temporal Variability 48
Synthesis 53
Chapter 3: Plant Species Control of Soil Biota and Processes 56
Plant Species Effects on Soil Biota 57
Links among Plant Species, Soil Biota, and Soil Processes 68
Temporal and Spatial Variability 73
Plant Traits, Strategies, and Ecophysiological Constraints 83
Soil Biotic Responses to Vegetation Succession 97
Synthesis 103
Chapter 4: Belowground Consequences of Aboveground Food Web Interactions 105
Individual Plant Effects 106
Dung and Urine Return 114
Effects of Palatability Differences among Plant Species 117
Spatial and Temporal Variability 130
Consequences of Predation of Herbivores 132
Transport of Resources by Aboveground Consumers 134
Synthesis 136
Chapter 5: Completing the Circle: How Soil Food Web Effects Are Manifested Aboveground 138
The Decomposer Food Web 140
Nitrogen Transformations 152
Microbial Associates of Plant Roots 157
Root Herbivores 169
Physical Effects of Soil Biota 173
Soil Biotic Effects on Aboveground Food Webs 175
Synthesis 181
Chapter 6: The Regulation and Function of Biological Diversity 183
Assessment of Soil Diversity 184
Stress and Disturbance as Controls of Soil Diversity 187
Biotic Controls of Diversity 194
The Enigma of Soil Diversity 203
Diversity of Soil Organisms over Larger Spatial Scales 205
Biodiversity and Ecosystem Function 209
Synthesis 236
Chapter 7: Global Change Phenomena in an Aboveground-Belowground Context 239
Species Losses and Gains 240
Land Use Changes 253
Carbon Dioxide Enrichment and Nitrogen Deposition 265
Global Climate Change 281
Synthesis 292
Chapter 8: Underlying Themes 295
References 309
Index 387