Review of Blanket Bog Management and Restoration TECHNICAL REPORT TO DEFRA PROJECT No. CTE0513 H O’Brien, J C Labadz & D P Butcher Nottingham Trent University School of Animal Rural & Environmental Sciences Brackenhurst Southwell NG25 0QF [email protected] 01636 817017 April 2007 CONTENTS 1 Introduction............................................................................................ 9 1.1 Principal Aims.................................................................................. 9 1.2 Objectives....................................................................................... 9 2 Methodology ......................................................................................... 10 2.1 Published Literature ....................................................................... 10 2.2 Grey Literature .............................................................................. 10 2.3 Interviews..................................................................................... 10 3 Blanket Bog: Definition, Classification and Characteristics........................... 12 3.1 Introduction .................................................................................. 12 3.2 Definition of Blanket Bog ................................................................ 12 3.3 Classification of Blanket Bogs .......................................................... 14 3.4 Blanket Bog Formation ................................................................... 16 3.5 Hydrology of Blanket Bogs .............................................................. 18 3.5.1 Infiltration and infiltration-excess overland flow.............................. 19 3.5.2 Saturation-excess overland flow ................................................... 20 3.5.3 Pipe flow and macropore flow....................................................... 20 3.5.4 Subsurface flow through the peat matrix ....................................... 21 3.5.5 Runoff generation in blanket bogs ................................................ 21 3.6 Peat Accumulation ......................................................................... 22 3.7 The Age and Origin of Blanket Bog in the British Isles......................... 23 3.8 UK Distribution of Blanket Bog......................................................... 24 3.9 UK Status – Protection and Designation ............................................ 25 3.10 Common Standards Monitoring and Condition Assessment .................. 26 3.10.1 Common Standards Monitoring ................................................ 26 3.10.2 Condition Assessment............................................................. 27 4 Management and Values of Blanket Bog ................................................... 28 4.1 Introduction .................................................................................. 28 4.2 The Value of Peatlands ................................................................... 28 4.3 Ecosystem Services of Blanket Bog .................................................... 29 4.3.1 Regeneration and Production Services of Blanket Bog ........................ 30 4.3.1.1 Production: Harvesting of Peat for Fuel....................................... 30 4.3.1.2 Production: Forestry................................................................. 31 4.3.1.3 Production: Grazing for Livestock............................................... 32 4.3.1.4 Production: Grouse Shooting ..................................................... 33 4.3.2 Regulation and Stabilsation Services of Blanket Bog .......................... 33 4.3.2.1Physical and Hydrological Function.............................................. 33 4.3.2.2 Potable Water Supply and Water Quality..................................... 34 4.3.3 Habitat Provision Services of Blanket Bog ...................................... 35 4.3.3.1 Wildlife Conservation Value ....................................................... 35 4.3.4 Cycling Services of Blanket Bog: Carbon Sequestration ...................... 35 4.3.5 Information/Life fulfilling Services of Blanket Bog ........................... 38 4.3.5.1 Landscape, Culture and Education Values ................................... 38 4.3.5.2 Visitor Access .......................................................................... 38 4.3.6 Purification and Detoxification ..................................................... 39 5 Blanket Bog Management and Causes of Degradation ................................ 40 5.1 Introduction .................................................................................. 40 5.2 Measurement of Blanket Bog Degradation......................................... 40 5.3 Causes of Blanket Bog Degradation – Natural Factors......................... 43 5.3.1 Wind Action ............................................................................... 43 5.3.2 Frost Action ............................................................................... 43 5.3.3 Drought .................................................................................... 44 5.3.4 Flowing Water ............................................................................ 46 5.3.4.1 Gully Erosion........................................................................... 47 5.3.5 Climate Change.......................................................................... 48 5.4 Causes of Blanket Bog Degradation Associated with Land Use and Management............................................................................................ 49 5.4.1 Controlled Burning...................................................................... 53 2 5.4.1.1 Methods of Controlled Burning................................................... 53 5.4.1.2 Guidelines for Controlled Burning on Blanket Bog......................... 54 5.4.1.3 Extent of Controlled Burning on Blanket Bog ............................... 56 5.4.1.4 Impact of Controlled Burning on Blanket Bog .............................. 56 5.4.2 Accidental or Wildfires................................................................. 60 5.4.3 Livestock Grazing ....................................................................... 61 5.4.3.1 Overgrazing ............................................................................ 61 5.4.3.2 Cattle .................................................................................... 66 5.4.4 Drainage (Gripping) .................................................................... 67 5.4.4.1 Effects of Drainage (Gripping) on Vegetation............................... 71 5.4.5 Afforestation .............................................................................. 73 5.4.6 Liming and Fertiliser ...................................................................... 76 5.4.7 Recreation ................................................................................. 78 6 Restoration of Blanket Bog...................................................................... 80 6.1 Introduction .................................................................................. 80 6.2 Blanket Bog Restoration ................................................................. 81 6.2.1 Objectives of Blanket Bog Restoration ........................................... 81 6.2.2 Principles of Blanket Bog Restoration ............................................ 81 6.3 Restoration of hydrological function.................................................. 84 6.3.1 Grip/Drain blocking........................................................................ 85 6.3.1.1 Methods of Grip Blocking .......................................................... 85 6.3.1.2 Results of Grip Blocking ............................................................ 93 6.3.2 “Natural” Gully blocking............................................................... 96 6.4 Re-vegetation of bare ground .........................................................100 6.4.1 Lime and Fertiliser Applications ...................................................104 6.4.2 Sphagnum re vegetation .............................................................106 6.5 Prescribed burning ........................................................................108 6.6 Grazing .......................................................................................109 6.7 Mitigation of Forestry Practices and Restoration of Afforested Sites .....111 6.8 Recreation ...................................................................................113 6.9 Agri-Environment Schemes and Policy .............................................114 7 Quanlitative Analysis and Evaluation of Interviews ....................................115 7.1 Introduction ......................................................................................115 7.2 The Definition of Blanket Bog and its Condition.................................116 7.3 The Value of Blanket Bog ...............................................................117 7.4 Threats to Blanket Bog ..................................................................119 7.5 Influence over Threats to Blanket Bog .............................................123 7.6 The Restoration of Blanket Bog.......................................................125 7.7 The Restoration of Hydrological Function and Appropriate Techniques .127 7.8 The Monitoring of Land Management and Restoration ........................128 7.9 Raising Awareness and Publicity .....................................................130 7.10 Knowledge Gaps and Future