Part 1 Introduction 1

Chapter 1 Peat and Peatlands 3

1.1 Introduction: wetlands and peatlands 3

1.2 Peat and peatland definitions and terminology 3

1.3 Scientific classification systems 5

1.4 Fens and bogs: a key concept 6

1.5 Hydromorphological peatland classification 7

1.6 Mire distribution 15

1.7 Summary 23

Chapter 2 Peat Landforms and Structure 24

2.1 Introduction: peat landforms 24

2.2 Landform development: form, process and time 24

2.3 Description of peat landforms 26

2.4 Landform survey techniques 28

2.5 Peat landform survey: an example from Scotland 32

2.6 Hydrology and peat landforms: the groundwater mound hypothesis 35

2.7 Summary 38

Part 2 Peat land Processes 39

Chapter 3 Peatland Hydrology and Ecology 41

3.1 Introduction 41

3.2 Hydrology and water balance 41

3.3 Water movement within peatlands 43

3.4 Outflows 44

3.5 Hydrochemistry 51

3.6 Chemical processes within peatlands 53

3.7 Ecology and ecohydrology 57

3.8 Limiting factors for plants and animals 57

3.9 Environmental gradients 60

3.10 Summary 72

Chapter 4 Origins and PeatInitiation 73

4.1 Introduction: time and peat growth 73

4.2 Frameworks for peat growth 73

4.3 Pathways to peal growth: terrestrialisation and paludification 74

4.4 Evidence for the origins of peatlands 74

4.5 Examples of peat initiation 80

4.6 Blanket mire initiation in the British Isles 80

4.7 Causes of paludification in other mires 84

4.8 Human impact as a cause of peat growth in other peatlands 86

4.9 Tropical peat initiation 87

4.10 Beavers and peat initiation 90

4.11 Summary 91

Chapter 5 Peat Accumulation 92

5.1 Introduction 92

5.2 Peatland cycles one peat accumulation 92

5.3 Productivity 94

5.4 Decay 100

5.5 Models of peat accumulation 104

5.6 Variability in long-term accumulation rates 110

5.7 Summary 113

Part 3 Changes in Peat lands 115

Chapter 6 The Peatland Archive Palaeoenvironmental Evidence 117

6.1 Introduction 117

6.2 The range of evidence and some general principles 117

6.3 Reasons for Palaeoenvironmental studies on peatlands 120

6.4 Measuring time peatland chronologies 121

6.5 Survey and stratigraphy 129

6.6 Biological evidence of past changes 130

6.7 Physical and chemical characteristics 137

6.8 Multi-proxy approaches 141

6.9 Summary 141

Chapter 7 Autogenic Change 143

7.1 Introduction: long-term change 143

7.2 Autogenic anti allogenic causes of change 143

7.3 Hydroseral succession 145

7.4 Reversals and other successions 149

7.5 Processes of terrestrialisation and the transition to bog peat 150

7.6 Lateral expansion and the development of peal land landscapes 153

7.7 ‘Mature’ peatlands and erosion 155

7.8 Cyclic regeneration 156

7.9 Pattern development 156

7.10 Plant-mediated changes 161

7.11 Physical processes in cold climate peatlands 164

7.12 Summary 165

Chapter 8 Allogenic Change 166

8.1 Introduction 166

8.2 Climate 166

8.3 Fire 169

8.4 Hydrological factors 173

8.5 Volcanic influences 175

8.6 Climate reconstruction from peat 176

8.7 Summary 133

Chapter 9 Peatland-Environment Feedbacks 184

9.1 Introduction 184

9.2 Catchment hydrology 184

9.3 Water quality 186

9.4 Peatlands and global climate 192

9.5 Carbon budgets and gas exchange 194

9.6 Impacts of management and climate change on carbon cycling 198

9.7 Summary 203

Part 4 Resource Management 205

Chapter 10 Values Exploitation and Human Impacts 207

10.1 Introduction: peatland values 207

10.2 Economic values mid exploitation 207

10.3 Wildlife conservation values 209

10.4 Functional values 210

10.5 Value to society 210

10.6 Conservation and ‘wise use’ of peatlands 210

10.7 Impacts of recent human disturbance: drainage as a key process 212

10.8 Peat extraction 214

10.9 Forestry 219

10.10 Agricultural reclamation 225

10.11 Effects of fragmentation 225

10.12 Pollution 227

10.13 Recreation and other disturbance 229

10.14 Long-term anthropogenic disturbance 229

10.15 Summary 230

Chapter 11 Conservation Management and Restoration 231

11.1 Introduction 231

11.2 Naturalness disturbance and conservation 231

11.3 Management options for disturbed peatlands 233

11.4 Semi-natural peatlands habitat management 234

11.5 Restoration and rehabilitation 242

11.6 Restoration of cutover ombrotrophic mires 244

11.7 Restoring other damaged systems 253

11.8 The future for peatlands in the twenty-first century 255

References 258

Index 289