Organic Soils in the UK Overseas Territories and Crown Dependencies. Peat from Penguins to Palm Trees

WHY DO WE NEED TO KNOW ABOUT PEAT

CONDITION IN THE OTs AND CDs?

BECAUSE IMPROVED MANAGEMENT OF PEATLANDS IN THE OTs AND CDs COULD HELP TO MIGITATE CLIMATE CHANGE

Introduction The UK has 14 Overseas Territories (OTs) and 3 Crown Dependencies (CDs). The Falkland Islands contain large areas of organic soils, with smaller areas in the Isle of Man and the Caribbean OTs. Where sufficient data are available GHG emissions from the OTs and CDs which have ratified or are likely to ratify the UN Framework Convention on Climate Change and the Kyoto Protocol are included in the UK GHG inventory. We review current understanding of organic soils in these areas.

Janet Moxley janmox@ceh.ac.uk (CEH), Chris Evans (CEH), Nicole Archer (BGS), Mary-Ann Smyth (Crichton Carbon Centre)

References:FAO (2007) The world’s mangroves 1980 – 2005. FAO Forestry Paper 153.Manx Upland Steering Group (2013) Issues and Opportunities.IUCN (2011) Brief summary of the state of peatlands in British Overseas Territories and Crown Dependencies . UK Committee Peatland Programme.Weissert, L.F. and Disney, M. (2013). Carbon storage in peatlands: A case study on the Isle of Man. Geoderma 204-205, 111-119.Wilson, P; Clark, R; McAdam, J.H; and Cooper, E.A. (1993) Soil Erosion in the Falkland Islands: an assessment. Applied Geog. 13 329 – 352.

The Falkland IslandsEstimates of peat area vary between 282 kha (BGS and CEH, unpublished data) and 548 kha (Wilson et al, 1993). The BGS/CEH estimate assumes that all valley-bottom deposits, and 33% of upland organo-mineral soils on shallow slopes, are peat, based on new field survey data. Falkland peatlands comprise a mixture of upland blanket bog covered with Astelia pumila, White grass (Cortadelia pilosa), Diddle Dee (Empetrumrubrum), and white grass-dominated valley mire. Rainfall is low, resulting in only low presence of Sphagnum magellanicum, and (combined with high wind speeds) in high susceptibility to erosion. The main pressures are from grazing by large numbers of sheep, use of prescribed fire for vegetation management, dredging of stream channels to increase drainage, wildfires, effects of historic bomb craters, domestic peat extraction, and the use of turf banks as windbreaks. Peat distribution has been mapped, but peat condition has not been documented. Because of this Grasslands in the Falklands are currently considered to be undrained, so emissions from peatland drainage are only reported from Cropland and Settlement on peat. Carbon loss in 2014 reported in the UK Land Use, Land Use Change and Forestry (LULUCF) Inventory was 4.73 ktC which may significantly under-estimate actual losses.

BGS superficial geology map for the Falklands, re-classified to show areas of peat occurrence Red – Upland and coastal deep peatBrown – Valley peatPeach – Upland organo-mineral soils containing significant deep peat Grey – Non peat areas Source: Digmap GB-50 V7-22. British Geological Survey materials ©NERC [2016]).

Caribbean TerritoriesThe Caribbean islands contain a range of wetland habitats on organic soils, including wet forest, freshwater swamps and mangrove swamps. An unknown area has been reclaimed, degraded, or modified. FAO (2007) report 7.8 kha of mangrove in the Cayman Islands which may be threatened, or already lost due to development of the islands for tourism. (IUCN,2011)

Bermuda contains a small area of peat in marsh savanna and wet “hammock” scrub/woodland of which 58 % is reported to be drained for agricultural use and landfill sites. (IUCN,2011)

Other Caribbean OTs are also likely to have small areas of organic soil in mangrove swamps. The organic soils associated with mangrove swamps are not true peats, but are made up of layers of woody material, which may decay into peat in favourable conditions

There is no detailed mapping of organic soils in the Caribbean OTs and no documentation of their condition. No LULUCF emissions are reported for these administrations due to lack of data.

Source: Digmap GB-50 V7-22. British Geological Survey materials ©NERC [2016]).

Low peat habitats include bog pools, wet woodland, man-made ditch systems and fen grassland. Ballaugh Curragh is a RAMSAR protected area.

Upland peatlands are Sphagnum-dominated bog, heath and acid grasslands. These areas are managed for grazing and recreation. Some conifer plantations also occur on peat There is some managed burning, and evidence of historical peat cutting as well as continued peat cutting at one site. (Manx Upland Steering Group, 2013).

No emissions from peatland drainage in the Isle of Man are reported in LULUCF inventory due to lack of data on peat condition.

The Isle of Man9% of the Isle of Man is covered by shallow peats <0.5m, located mainly in the highlands and on the edges of valley bottoms (Weissert and Disney, 2013). However, deeper peat >1 m only covers 0.5 kha as shown below.

Conclusion Understanding of the extent and condition of organic soils in OTs and CDs is less comprehensive than for the rest of the UK. This limits development of policies

and management practices which maintain carbon stocks. It also limits the UK’s ability to report on emissions from drainage and rewetting of organic soils. More comprehensive survey and mapping of the extent and condition of organic soils in the OTs and CDs is desirable.

Funding from BEIS (TRN860/07/2014) is gratefully acknowledged. CEH would also like to thank Shaun Russell (Bangor University) for his contribution to the Falkland field survey

Photos: C. Evans

Photos: M-A Smyth