Expert workshop to establish the current state of knowledge of & future evidence needs for the extent & condition of carbon stocks in Scottish peatlands

EXPERT WORKSHOP TO ESTABLISH THE CURRENT STATE OF KNOWLEDGE OF & FUTURE EVIDENCE NEEDS FOR THE EXTENT & CONDITION OF CARBON STOCKS IN SCOTTISH PEATLANDS

CR/2009/06

NOVEMBER 2009

Final Report

S.J. Chapman1*, R.R.E. Artz1, J.U. Smith2, P. Smith2

1 Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen AB15 8QH

2Institute of Biological and Environmental Sciences, School of Biological Science, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB41 3UU

* Project Manager

Project funded by the Rural and Environment Research and Analysis Directorate of the Scottish Government, Science Policy and Co-ordination Division.

The views expressed in this report are those of the researchers and do not necessarily represent those of the Scottish Government or Scottish Ministers

Contents

Glossary...... 3

1. Executive Summary...... 4 1.1. Background ...... 4 1.2. Methodology...... 4 1.3. Main Outcomes...... 4 1.4. Conclusion...... 6

2. Background...... 7

3. Objectives...... 7

4. Methods ...... 7

5. Questionnaire...... 8

6. Workshop...... 8 6.1. Introduction (SG)...... 8 6.2. RSPB Report summary (Richard Lindsay) ...... 8 6.3. ECOSSE 1 & 2 reports: summary of peatland stock estimates (Allan Lilly)...... 9 6.4. ECOSSE 1 & 2 reports: summary of model development (Jo Smith)...... 10 6.5. Questionnaire synthesis (Rebekka Artz) ...... 11 6.6. Empirical evidence base (Olivia Bragg - Facilitator)...... 11 6.7. Modelling development & challenges (Pete Smith – facilitator)...... 15 6.8. Evidence base for response of peatlands to change (Pete Smith – facilitator)...... 18 6.8.1. Hydro-electric/Wind power...... 18 6.8.2. Peat Extraction/Restoration ...... 18 6.8.3. Forestry/Agriculture ...... 19 6.8.4. Climate change/muirburn ...... 20 6.9. Critical gaps in knowledge base (Jo Smith – facilitator) ...... 20 6.9.1. New techniques ...... 20 6.9.2. Prioritization of research needs ...... 21 6.10. Next steps (SG) ...... 24

7. Priorities for Future Work ...... 25

8. Conclusions ...... 27 8.1. Current research on GHG emissions and sinks from organic soils in Scotland...... 27 8.2. Funders of research...... 28 8.3. Response of peatlands to change...... 28 8.3.1. Land use (including land management)...... 28 8.3.2. Climate change ...... 29 8.4. Knowledge gaps...... 29 8.4.1. The peatland carbon pool...... 29 8.4.2. Carbon dynamics in peatlands...... 30 8.4.3. Climate change ...... 30

1 8.4.4. Forestry...... 30 8.4.5. Erosion...... 30 8.4.6. Burning/Grazing...... 31 8.4.7. Wind farms and hydro schemes...... 31 8.4.8. Peatland restoration ...... 31 8.5. Future research needs ...... 31

References ...... 32

Appendices ...... 33

2 Glossary acrotelm surface layers of peat situated above the level of the lowest water table ArcGIS collection of Geographical Information System software products providing a standards-based platform for spatial analysis, data management, and mapping atmospheric emissions gases released from soil, or peat, to the atmosphere BES British Ecological Society BGS British Geological Survey blanket peat extensive areas of ‘climatic’ peatland, mainly in the hills and uplands, and covering as a 'blanket' bulk density dry weight of material in a unit volume of peat catotelm the deeper layers of peat that are normally permanently water-logged CEH Centre for Ecology and Hydrology CFLOW a carbon accounting model used in forestry diplotelmic peatland with distinguishable acrotelm and catotelm DOC Dissolved Organic Carbon ECOSSE Estimating Carbon in Organic Soils - Sequestration and Emissions eddy covariance method of large area, continuous gaseous flux measurement EO Earth Observation FCS Forestry Commission for Scotland fluvial fluxes movement of material via water courses GHG Greenhouse Gases, mainly carbon dioxide, methane and nitrous oxide grip drainage channel cut into peatland or moorland haplotelmic peat degraded peat with the acrotelm removed or compacted by drying out hydromorphology peatland shape as moulded by water table and water flow lagg margin of bog with ground water influence and fen vegetation LULUCF Land Use, Land Use Change and Forestry macrotope-nanotope used to describe the range of scales of peatland architecture microtopography variations in peat surface elevation at the scale of ca. 1-10 m MLURI Macaulay Land Use Research Institute muirburn the practice of periodic managed heather burning for land improvement NERC Natural Environment Research Council NSIS National Soils Inventory of Scotland organo-mineral soils where a thin organic layer (<50 cm* thick) overlays mineral material paleo-data information on past events gathered from analysis of the peat profile peat slide whole scale movement of a large body of peat down a slope peatland defined as a landscape with soil having an organic layer >50 cm* deep RSPB Royal Society for the Protection of Birds SEPA Scottish Environment Protection Agency SG Scottish Government SNH Scottish Natural Heritage SSKIB Scottish Soils Knowledge and Information Base TOC Total Organic Carbon WAG Welsh Assembly Government *50 cm in Scotland but 40 cm in England and Wales

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1. Executive Summary

1.1. Background The peatlands of Scotland represent a significant pool of carbon, which may be continuing to sequester carbon dioxide. It is important to have a good understanding of the susceptibility of this resource to both land use and climate change. As an aid to policy formulation and to assess research priorities, the SG (Scottish Government) wanted to know what the key evidence gaps were in our knowledge of peatland carbon.

1.2. Methodology A workshop was arranged with 21 experts who had specialist knowledge of the varied aspects of peatlands, particularly with reference to carbon dynamics. A first step was to assess the current state of knowledge and to find out who was working in this area. In advance of the workshop, a questionnaire was sent out to as wide an audience as possible who would be likely to have relevant information on peatland carbon pools and dynamics. 53 replies were collated, which gave data in varying detail on 31 study sites across Scotland. Part of the workshop remit was to assess the results of the questionnaire, discuss the outcomes of the SG-funded ECOSSE 2 (Estimating Carbon in Organic Soils - Sequestration and Emissions) report and also to discuss the main findings of a draft RSPB (Royal Society for the Protection of Birds) report on peatlands and carbon which had been compiled by Richard Lindsay. Conclusions from the latter are reflected in many of the outcomes given below.

1.3. Main Outcomes The peatland soil and habitat distribution across Scotland is reasonably well characterised. Data on peat depth is available for the major peat deposits but there are some areas of the centre, west and north-west of Scotland, largely covered in blanket peat, where information is scant. Data on bulk density and carbon content is even more patchy for Scottish peatlands and the total stock of peatland carbon in Scotland, determined in the ECOSSE 2 report (1620±70 Mt), was based upon pooled values. The assumption of their widespread applicability results in increased uncertainty in our soil C stock estimates.

Until about five years ago there were only about four sites where the greenhouse gas fluxes to the atmosphere (both carbon dioxide and methane) had been measured. Rather more data on aquatic fluxes (carbon losses to streams and rivers) was available. The past five years has seen an increase in measurements at various sites across the country though there are still only two sites where eddy covariance measurements (a method of continuous gaseous flux measurement that covers a relatively large area) are being made. Similarly, many sites now have data on aquatic fluxes and on vegetation condition. Unfortunately, much of this effort is not coordinated though current work at Auchencorth, Forsinard and Flanders Moss is attempting to address this. Work at Forsinard (in the Flow Country) is particularly critical as it represents the most extensive area of blanket bog in the UK and, in fact, in the world. Such coordination is important so that we can have a complete understanding of losses and gains of carbon and GHGs (Greenhouse Gases) from peatlands at a range of sites.

For Scotland, the principal carbon modelling activities have used the ECOSSE model, developed to simulate greenhouse gas emissions from the organic soils. The Durham peat model, specifically designed for estimating carbon budgets in blanket peat, has so far not been applied in Scotland. It would be useful to do this and to make comparisons between the outcomes of the two models.

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Most of the research effort in Scotland is being funded by either the Scottish Government or NERC (Natural Environment Research Council). Smaller scale studies have been funded by SNH (Scottish Natural Heritage), SEPA (Scottish Environmental Protection Agency), RSPB and Forest Research. Several universities and research institutes have an appreciable research effort in this area, supported by their own funding streams.

Peatlands are expected to respond to land use and climate change, as well as to changes in atmospheric deposition, particularly nitrogen. The major land use change impacts on peatlands were associated with forestry, peat use (extraction and restoration) and renewable energy (hydro-electric schemes and wind farms). Restoration would include grip blocking and the restoration of eroded areas. Muirburn was seen as a major land management tool. Drainage (gripping) is little practiced currently except where needed prior to other land use changes. However, in these cases the degree of subsidence is often not appreciated. For a future climate, if we assume a general rise in temperature then this is likely to increase both peat decomposition rates and evaporation rates. A drier climate could have a negative impact on peatland primary production and further increase decomposition rates. However, these effects could be reversed in areas currently experiencing excessive precipitation. There may be a greater susceptibility to fire. Intense rain in the winter may bring about greater erosion, peat instability and even peat slides. There is clearly a likely interaction between the effects of climate change and the land use pressures listed above. However, climate change is very likely to affect peatlands given that temperature and, particularly, rainfall are rate determining steps for its formation. Peatlands in good condition are more likely to be resilient to future climate change than those in poor condition.

The workshop was able to identify a number of gaps in our understanding of carbon in peatlands: • In terms of the carbon stock, more data on bulk density, particularly at depth, is required and peat depth values in areas where these are absent are needed. • A greater understanding of the carbon dynamics of peatlands is required. It would be particularly useful to be able to link peatland vegetation ‘condition’ to carbon flux values. This requires a coming together of both ecological and biogeochemical expertise. It should be recognised that the vegetation itself represents a significant carbon pool. Such studies should also take cognisance of the microtopography and how it relates to C fluxes. Similarly, they need to recognise whether a peatland is diplotelmic, i.e. having a distinguishable acrotelm and catotelm, or haplotelmic, i.e. having a degraded surface. Values for methane emission are limited to rather few sites and we need to understand more of the relative roles of bryophytes and vascular plants in the methane cycle. We still do not have a full understanding of the factors that drive carbon loss to waters. • The consequences of climate change on peatlands are difficult to predict. There are contrary hypotheses on the impact of temperature and the effects on vegetation and on microtope-nanotope architecture are not well understood. We need a better understanding of the impacts of drought on C sequestration and susceptibility to fire, as well as the impact of extreme rainfall events on peat instability and erosion. There are few peatland sites that climate modelling has been applied to and extrapolation to sites for which we have no gas exchange and/or peat accumulation rate data is a major difficulty. • There is a need to understand the carbon dynamics of existing forestry on peat and of what may happen in a second rotation or if we attempt to restore such sites back to active blanket peatland. Where forest drains are blocked as part of a restoration process, the resulting impacts on methane emissions are unknown. The time taken for afforestation to produce a net sink for carbon on organic soils is not fully understood. • The causes or triggers of peatland erosion are not fully understood; it is hard to establish when erosion started and hence the primary factors causing it. We do not know how effective different conservation or restoration practices might be or to what extent natural regeneration is an important process and how it might be encouraged. We have a very poor understanding of the fate of eroded peat. The mapping of erosion is still rudimentary though Earth Observation techniques may aid this.

5 • Few studies have looked at the impact of muirburn and of wildfire on peatland ecosystems, especially in relation to the soil-vegetation carbon balance. The influence of fire on DOC (Dissolved Organic Carbon) release is poorly understood. • The impacts of grazing on the C cycle are not well understood nor are what may be termed critical grazing levels for peatlands. • We have a limited understanding of the long-term impacts of energy generation schemes where these involve peat. The triggers of peat slides are poorly understood but very relevant to areas where large-scale peat works are implemented. • The impact of restoration practices on carbon cycling has not been studied in detail and it is not known how long it takes for a positive carbon balance to be achieved following restoration. Particular unknowns include methane release following the rewetting of formerly dry peatlands by drain blocking.

1.4. Conclusion The workshop produced a list of 28 areas for future work and these were prioritised and ranked. The main immediate priorities for research were to improve our understanding of the impact of afforestation and forest removal on soil C cycling and GHG emissions, to monitor GHG emissions and sinks from restoration efforts and to compile a peatland vegetation condition map for Scotland that would be linked to the potential for either carbon sequestration via ongoing peat accumulation or carbon loss via accelerated decomposition or erosion. There was merit in greater collation of existing data on stocks and condition as comparative data was often held by different organizations and for different sites or complementary data was held by different groups but for the same sites. A clear message from the workshop was that much benefit can be gained by co-ordinating all ongoing research effort. In the longer term, studies on the impacts of climate change were crucial as well as model development that would include feedback effects and the compilation of standard methodologies for peatland studies.

6 2. Background

The Scottish Government (SG) requires information on the state of current knowledge of the role of peatlands in GHG (greenhouse gas) emissions and sinks, and their reaction to changing climate and land use scenarios. This is important for the UK as a whole but for Scotland in particular.

Scotland’s soils are estimated to contain approximately 3000 MtC (Chapman et al., 2009) which is a major part of the carbon held in UK soils as most of the UK peatland resource is located in Scotland. It is important to know how land use change and climate change may affect the carbon held in Scotland’s soils and this workshop aims to report on areas of consensus in our scientific understanding of peatlands and to establish what the main evidence needs are to enable development of effective policies to protect this resource

The Scottish Soil Framework (2009) recommends the establishment of a group to review and co-ordinate research on organic soils in Scotland. As part of this process the SG would benefit from a summary of what research work is underway on the impacts of peatlands on GHG emissions and sinks and where the main gaps in our knowledge and understanding are.

3. Objectives

The objective was to hold a two-day expert workshop on the following topics related to Scottish peatlands and their contribution to GHG emissions/sinks:

• what research is being undertaken in Scotland and the UK into collating field data and developing models to predict the effects of land use and climate change on GHG emissions from organic soils?

• who are the main funders of research into peatlands in the UK?

• what are the main gaps in our knowledge on the response of peatland soils to external change?

• what are the main areas of consensus in our knowledge regarding the response of peatlands to land use and climate change?

• what research is needed to improve our understanding of the likely response of soil carbon to land use and climate change scenarios and to monitor these changes?

4. Methods

It was agreed to hold a two-day workshop which would consider the above five questions and to invite the participation of up to 20 external experts who would be able to cover stakeholder group interests (particularly SNH, SEPA, FCS and RSPB) as well as those with detailed knowledge of Scottish peatlands, or at least of blanket peat studies that were relevant to Scotland. The two days would deal with (i) the state of current knowledge and (ii) the response to change. Additionally, a highly relevant RSPB report, “Peatlands and Carbon: A Critical Synthesis” by Richard Lindsay, was currently in draft form (Lindsay, 2010) but made available to Steve Chapman for comment so that the key findings could be discussed at the workshop. Richard Lindsay was also invited to attend the workshop to present a synthesis.

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It was recognised that a few individuals and organisations would not be able to attend the workshop but were likely to hold valuable data on peatlands in Scotland and the UK. It was decided that a questionnaire would be sent out to as large a group as possible ahead of the workshop in order to capture this information and summarise it in time for the meeting.

5. Questionnaire

The questionnaire was sent to 79 individuals from 38 institutions. 53 responses were received, of which 32 were complete. These 53 responses included some duplicate information (as several groups were working on the same site) and were collated into 31 unique site responses. The collated information was then grouped on the basis of whether the response was for a major, nation-wide, dataset (e.g. National Soils Inventory of Scotland [NSIS_1]; NSIS Resampling [NSIS_2], the SNH Site Condition Habitat Monitoring data, SEPA Long Term Trends) or whether they constituted data from individual assessments of a small collection of, or individual, sites. The data were presented at the workshop based on the primary focus of the research carried out (e.g. soil C assessment, vegetation/condition monitoring, greenhouse gas or aquatic fluxes). The site returns were visualized on a Scottish map using ArcGIS to indicate sample numbers on a National scale. The results of the questionnaire as presented at the workshop can be found in Appendix 1. Questionnaire Summary. 6. Workshop

The workshop was held on 4th and 5th November 2009 at the Macaulay Land Use Research Institute in Aberdeen. A total of 21 attendees (Appendix 2) represented 16 organisations from government, university and research institutions and covered both science and policy interests.

Q. – question. A. – answer. C. – comment.

6.1. Introduction (SG)

The SG funded this work to try and get a better understanding of what evidence needs and gaps in knowledge there are for peatlands and who is undertaking relevant research in Scotland and the UK. Additionally, there is a need to move forward in a coordinated way. In order to enable better co-ordination of peatland research the SG needed to know who the key funders of relevant research are. Some key questions as part of this process are:

Q. Where is peat located in Scotland and how much of it is there and how much of it is protected?

Q. How does peat respond to changes in land use and climate?

Q. How should peat be managed in order to retain C stocks, provide clean water and maintain important habitats?

Q. What is the state of knowledge, the main uncertainties and how can these be addressed?

6.2. RSPB Report summary (Richard Lindsay)

The presentation given by Richard Lindsay is summarised in Appendix 3. Peatbogs and carbon - key issues. The points that came out during the presentation are given below. This report was

8 commissioned in 2009 by Clifton Bain at RSPB Scotland with funding support from Scottish Natural Heritage, Countryside Council for Wales, Natural England and the Forestry Commission. At the time of the workshop this report was still in draft form.

The report set out to rationalise the many inconsistences contained within various policy reports and scientific papers. Some could be seen as ‘differences in approach’ related to the objectives of the research, i.e. ecological vs. process studies, and also to the scale of investigation. The author is a peatland ecologist and not an expert on peatland carbon, biogeochemistry or modelling. However, ecological understanding was often found to be missing in research outputs dealing with, e.g., atmospheric emissions. This has caused confusion between ecosystem ecologists and biogeochemical and atmospheric scientists.

The extent of peatlands is dependent upon definitions; there are many more ways of defining ‘peat’ since the early peat and soil surveys that there are now a wide range of values for the extent of peatlands in the literature. There are few peat depth measurements and actual within- site measurements are not frequent, given that there can be enormous variation in depth at the microscale (<50 m). Most bulk density measurements used to estimate carbon density are taken from the upper 100 cms. The ‘Clymo’ model shows distinct changes in bulk density through the acrotelm (often much less in the top 12 cm then increasing with depth). However, this model doesn’t hold true in many UK peatlands. There are difficulties in bulk density determination, e.g. methane bubbles may affect bulk density within the catotelm. Many blanket bogs are ‘haplotelmic’, having greater bulk densities at the surface because of land-use impacts. There are difficulties in bulk density determination, e.g. methane bubbles may impact bulk density within the catotelm. There is also a need to describe and quantify microtopography; there is currently no system for describing and classifying microtope patterns, and, in particular, nanotope units are often missing from the literature.

In terms of the peatland carbon cycle, we need to know the quantity of peat passing from the acrotelm to the catotelm (residence time). Methane shunts act through vascular plants (for example, the tussock-forming Trichophorum); the overall effect of this on net C balance is not fully understood. Competitive interactions between methane-shunting plants and Sphagnum or other bryophytes are largely unstudied.

Subsidence in peatlands is often not taken into account when considering the impact of drainage. Water table data taken relative to only the peat surface sometimes do not show this, leading to erroneous assumptions about the impact of drainage on peat and carbon. When compared to the carbon stored in coniferous plantations on peat, it is not widely understood that the biomass in living bogs may contain as much carbon as is stored in the biomass of the forest- peat system, especially when considering a budget that includes the C in the bryophyte layer in the natural state. Note too must be taken of carbon lost from peat through long-term oxidation of the peat by the plantation. On burning, there are important unanswered questions about the time required for recovery in blanket bog environments.

6.3. ECOSSE 1 & 2 reports: summary of peatland stock estimates (Allan Lilly) The PowerPoint presentation is given in Appendix 4. Estimation of the peatland C stock.

Two significant pieces of research, referred to as ECOSSE 1 (jointly funded by the SG and WAG; Smith et al., 2007) and ECOSSE 2 (funded by the SG; Smith et al., 2009) were primarily aimed at estimating the total peatland carbon stock within Scotland and at developing a model of carbon turnover in highly organic soils. ECOSSE 1 gave initial estimates of total stock based upon a synthesis of peat depth data and also formulated the ECOSSE (Estimating Carbon in Organic Soils - Sequestration and Emissions) model. ECOSSE 2 further examined the C stock values in more detail and attempted to ascribe some uncertainty to the estimates as well as applying the ECOSSE model to predict C value changes due to land use change across Scotland (Modelling aspects are covered in more detail in the next section).

9 There is still some unquantified uncertainty regarding the C stock estimates. Firstly, the estimation of error on the peatland area values may be improved by more closely examining detailed mapping at larger scales and comparing them with the 1:250,000 scale. Secondly, some upland map units (e.g. those comprising moraine fields) can contain substantial areas of peat but these so far have not been fully characterised. Where these moraines are found on sloping ground, the extent and depth of the peat decreases with slope angle. Based upon an analysis of variance of existing peat depth data, it is possible to estimate the number of peat depth samplings in data poor areas. To obtain a precision of ±10 % on the mean will require 145 and 250 depth samples for 95 and 99% confidence limits, respectively.

6.4. ECOSSE 1 & 2 reports: summary of model development (Jo Smith) Jo Smith, lead author of the ECOSSE 2 report, was invited to summarise model development. The PowerPoint presentation is given in Appendix 5. ECOSSE 1 & 2 – Modelling developments.

Models used to estimate GHG emissions are of two types: static models, which use simple relationships to describe interactions observed in a dataset, and dynamic models, which describe the changes that occur over time, usually representing the individual processes occurring in the system. Because static models are based on current observations, they cannot usually cope with varying environmental conditions. Dynamic models describe the underlying processes and so can extrapolate beyond the current conditions. However, the commonly applied soil models, such as RothC, were developed using data from mineral soils and cannot currently simulate soils with large organic carbon contents. ECOSSE has been developed from the RothC model to include additional processes that are more important in organic soils. Following the approach of RothC, the ECOSSE model compartmentalises different types of organic matter into discrete ‘pools’, because a continuum of soil organic matter, although closer to reality, is difficult to apply in field conditions. Each pool is homogenous in activity with first order decomposition. The ECOSSE model uses a RothC equilibrium run to determine the initial size of the pools, which then defines the overall rate of decomposition.

The ECOSSE model includes N as well as C. It is designed to simulate soil C and N turnover at national as well as field scale using land use, weather data and soil survey information. This allows evaluation of the model performance against field data to be used to define the uncertainty of the model simulations at national scale. When ECOSSE was evaluated against NSIS data, the uncertainty in the simulations was 11% of the change in soil C, suggesting that the uncertainty in the national simulations should be taken to be ~11%.When compared to the estimates of GHG losses provided by CEH (Centre for Ecology and Hydrology), the correlation between the two approaches was highly significant and on average the result for the different land use changes differed by -3%. This provides confidence in the model simulations at the national scale because very similar results are obtained by these two very different approaches.

ECOSSE can now be used to answer policy relevant questions. However, problems still exist with modelling some land-use changes, largely due to insufficient soils data. In particular, insufficient data to characterise the soils under forestry land use mean that simulations of changes in soil C associated with land use changes between semi-natural and forested land should not be considered as being reliable, especially on upland organic soils. Because there is insufficient evidence to separate out soil characteristics for uncultivated soil types into semi- natural and forested soils, the characteristics of the soil horizons are assumed to be equivalent under semi-natural and forestry land use (Lilly et al., 2004). However, the experimental evidence also suggests that the thickness of the litter layer is significantly larger in soils under forestry than under semi-natural land-use. A larger litter layer is therefore assumed in the soils data held in SSKIB (Scottish Soils Knowledge and Information Base) resulting in the whole profile of a typical soil under forestry always containing more carbon than under semi-natural land use. In many soils, this will be an accurate assumption. However, in some soils, particularly upland

10 organic soils that have usually been drained before afforestation, the increased aeration due to drainage may result in an increased rate of soil organic matter decomposition and so a lower C content in the soil profile under forestry. Further research is needed on forested soils to fill this gap.

C. Projected carbon savings could be subdivided into habitats to assess if significant savings could be made from relatively small land areas.

6.5. Questionnaire synthesis (Rebekka Artz)

The PowerPoint presentation is given in Appendix 1. Questionnaire Summary.

A brief synthesis of the results of the questionnaire that had been sent out was given and further comment invited. In summary, various field data exist covering to differing degrees the extent, condition and C sequestration potential within peatlands. There have been some major surveys (some used in ECOSSE), e.g. Scottish peat surveys, NSIS, SEPA monitoring sites (lochs, rivers), SNH condition monitoring, Forest Research BioSoil sites. In addition there have been many smaller (more local) surveys, variously focussing on GHG exchange, aquatic C fluxes, peat depth and/or spatial soil C, hydrology, patterning and hydromorphology, vegetation condition/monitoring and sites with manipulations.

Q. During the NSIS_2 sampling, what sampling was done on peat?

A. Depth was probed to 2 m (but it was not possible to probe deeper than this). However, bulk density was only sampled to around 1 m.

Q. Was the vegetation classification done as per Birse and Robertson?

A. Yes.

Q. For the SEPA data for lochs, the TOC/DOC appear to be going down for most; is this correct?

A. The data presented show mostly no trend in Lochs monitored for >5 years and those sites with declining trends are mostly situated in the far North and North-West. The river data appears to concur with trends (>50 % of sites showing increased TOC) seen elsewhere in the UK.

6.6. Empirical evidence base (Olivia Bragg - Facilitator)

The following questions were posed:

Q. Have we missed any major areas of research? Q. Are there any major issues in cross-comparison of data? (We are seeking experiences of researchers reviewing evidence base) Q. Is standardisation required in reporting? For which types of data is this critical? Q. Can we come to a consensus regarding our confidence in, and the completeness of, datasets with regards to current status of C stocks and fluxes?

These were addressed in a round-the-table discussion session. The following comments and follow-up questions were compiled from flipcharts and notes.

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Q. Missed literature/areas of research?

A. SNH commissioned a report on geodiversity with the British Geological Survey (BGS).

A. SEPA contacted BGS during the compilation of the State of Scotland’s’ Soils report. Their peat maps are based on >1 m depth definition vs. the Scottish Soil Survey soil maps (>50 cm) so a comparison may be useful (although it appears that the 1 m definition was not strictly enforced and dependent on expert judgement).

A. There are missing data for forestry on peat. The Scottish Forest Alliance (funded by BP), for example, holds data for 14 sites in Scotland (a mix of FCS, RSPB Scotland and Woodland Trust Scotland properties) with forest biomass data, as part of their remit to develop woodland cover. There is a 200 year (!) monitoring programme funded by endowment. Finally, RSPB hold data on forest development on peat and other data sets for the Flow Country. FR also hold data on peat condition post restoration (incl. site hydrology etc).

A. The commercial Forestry industry holds data. There appears to be a willingness to share these if a common body was available.

A. Books recommended by Richard Lindsay dating from 1981 look at long term (paleo scale) impacts of wet and dry climatic cycles on C storage by patterning changes between hummock forming systems and pool structures (Barber, 1981; Ivanov, 1981). These perspectives need to be rediscovered.

12 Q. Major issues in cross-comparison?

Q. How much peat do we have in Scotland and what is the error on the current estimate?

A. The sources of error have been calculated as part of the ECOSSE 2 project. Caveats are that the error on depth includes values determined by expert judgement, which may have a bias, and that bulk density and carbon content are based upon samples which are spatially restricted.

A. The current estimate maybe adequate, especially if confidence limits can be attached, however model projections more important.

A. Several options for filling data gaps for upland blanket peat could be explored. Information about peat below 1 m depth is needed, particularly on the density of the peat.

Q. First, how do we define ‘peat’?

A. Definition of peat varies between studies and this leads to total estimates that differ up to ×2 in magnitude.

C. There is a real requirement here for standardisation of reporting parameters. This issue also arises in DOC reporting (see later).

Q. There is the question of diminishing returns for further sampling effort. Is it better to spend the money elsewhere?

A. The soil carbon content of soils is extremely important for driving soil organic matter models at national scale. Although it is feasible to spin up the models using estimates of plant inputs to the system, because plant inputs are not well known at the national scale, a measurement of current soil carbon provides the most reliable way to estimate the activity of organic matter at this scale.

A. Some examples of major data gaps are for upland blanket peat. There are peat depth development data available on different slopes/topographies (e.g. in the hydromorphological datasets). A statistical model of depth vs. slope could be used to give depth values where none exist. Change in stocks and emissions possibly require different datasets (we also need data on specifically damaged bog). We need better data on peat with depths of > 1 m.

Q. Depth surveys are planned in the centre and west of the country but where exactly to do it?

A. We need to know where change may occur and this may require a different approach.

Q. There is a question of how bulk density changes with depth. Vegetation changes over time may impact on this. Map units are sometimes vague in giving an indication of depth. There are some map units where there a major transitions in bulk density (e.g. Abernethy Forest, Glensaugh). Certainly, data on slope vs. depth is required.

A. ECOSSE 2 outlines a geostatistical approach based on kriging to resampling in order to give optimum efficiency (cost effectiveness) for sampling effort. Validation of this can be tested on e.g. wind farm sites.

13 Q. Major issues in cross-comparison (continued)?

Q. It is important to distinguish haplotelmic vs. diplotelmic peat in terms of their relative bulk density. Can we produce a map of both or at least of bog ‘condition’?

A. Certainly, there are site condition monitoring data that could be used to identify areas with haplotelmic vs diplotelmic peat. However, we need to know whether ‘condition’ relates to carbon sequestration or not.

A. Aerial photography can be used for condition; it can indicate, e.g., whether an area is afforested, burnt or gripped. A lot of work on peat erosion has been done using this approach.

A. Important to characterize Sphagnum (diplotelmic) blanket bog.

A. Sphagnum has a special spectral pattern that can be detected by remote sensing.

C. Julia McMorrow (Manchester) is currently working on this for the Pennines. There are also data for Shetland that are not yet digitised.

C. Some time back NCC produced maps of ‘condition’ which included the Pennines and some areas of Scotland. These were based upon satellite imagery within areas of BGS peat and located areas of continuous colour. Comparison with a field survey gave good correlations. This could be used to map ‘active bog’. These data were collected but current whereabouts is uncertain and they are not digitized yet.

C. CSM (Climate System Model) monitoring is in relation to previous state; a lot of work has been done on erosion by aerial mapping.

Q. Does supporting vegetation, i.e. lagg etc., need to be considered here? Often, in Scotland, this does not include Sphagna due to other pressures, e.g. agricultural encroachment?

Q. Is standardisation required in reporting? For which types of data is this critical?

C. Knowledge of absolute peatland carbon stocks are important to put soils in context vs. other carbon sources such as emissions from fuel use for transport, electricity generation, etc.

C. There is a problem of harmonising systems between Scotland, England and Wales, and Northern Ireland, e.g., there are differences in the basic definition of what is classified as peat.

C. There is also the example of DOC methodology where different fractions are measured by different workers.

C. There are no standard methods for organic soil analysis.

14 Q. Can we come to a consensus regarding our confidence in, and the completeness of, datasets with regards to current status of C stocks and fluxes?

C. There are very few sites where carbon dioxide and methane emissions are measured. There are not enough to make comparisons.

A. A problem exists in using foreign (e.g. Finnish) datasets for extrapolation. (Issues such as frost-heaving disturbance rarely apply in a UK context)

C. There is a need to coordinate data collation from all key organisations

A. The current JNCC exercise is identifying research gaps in soil C.

A. Common objectives in this regard should be the National Ecosystem Assessment and the Living With Environmental Change (LWEC) initiatives.

Q. As well as harmonising the science, there is also the issue of ‘harmonization’ of policy; do policy makers across the various administrations talk to each other?

A. Not as much as they should do

C. On ‘harmonising’ policy, it is important to link science, policy and practice. An example would be the research hub on the uplands (Aberdeen University, Leeds University, Durham University and CEH).

C. The Scottish soil focus group meeting aims to look at gaps in soil research –There is always the problem of resources and the time needed for coordination.

C. We need to get more involvement between funders and science to develop and maintain field based research projects and infrastructure, e.g. monitoring and large scale manipulation experiments (and not always with small projects).

C. There is a special need to have funding that keeps monitoring going.

C. On resources: to achieve priority policy outcomes it may be advantageous for funding bodies to consider pooling of (and ring fencing of) resources. This could include UK wide commercial funders. There are timescale and policy requirement issues but these could aid directed long-term monitoring and prioritisation of required research.

6.7. Modelling development & challenges (Pete Smith – facilitator)

The following questions were posed:

Q. Have we missed any major pieces of model development? Q. Which areas within models are not yet fully addressed? Q. Which of these are the most pressing? Q. What empirical data might be required and at what scale? Q. Are there areas where empirical data that are critical for model input are confusing or contradictive? (We are seeking model developers’ experiences) Q. Are there any major issues regarding further development – e.g. essential empirical data requirements?

15 C. A particular problem for modelling is that papers are always demanding concise reports such that there is no space for the additional data that might be required by modellers. Perhaps this should be reported elsewhere.

Q. Why can’t we have this vital information?

C. There is a need for a Web-based refereed journal on data. Funders often stipulate that actual data should be archived.

C. Webportals designed to contain metadata will be brought in by the EU. There are already some meta database examples, such as the DEFRA inventory (based on INSPIRE), the paleo repository, the Fluxnet community repository (which is a citable publication). Perhaps this could be suggested to e.g. BSSS?

C. We should agree on and publish methodologies on organic soil analysis; but who would do it?

C. ECOSSE would benefit from a vegetation component, including vegetation condition.

A. There are currently some issues with the timescales at which vegetation vs soil C pools change – this could lead to an erroneous replacement in the model of soil C pools (long-lived) by vegetation C (short-lived). The timescales at which such processes operate would have to be matched to be modelled correctly.

C. And should include microtopography.

A. Yes, this could be done, if the data was available. Scaling of models is already being used: e.g. the integrated emissions budget for some sites is modelled by a distributed modelling algorithm that incorporates some topographical units. The issue is the scale requirement for model outputs – this differs dependent on the policy outcome to be addressed. At this point, there are severe data constraints at the national level.

Q. Is it possible to model muirburn?

A. Currently we cannot model impacts of muirburn with ECOSSE, but this is, in principle, possible. The data gaps here are related to the effects of burning on soil physics e.g. increase in hydrophobicity, and levels of inorganic C inputs.

Q. And drainage changes?

A. The model can, in principle, do this. For example, water table alterations in ECOSSE are designed to be constrained to accommodate this – the challenge is knowing what happens to the hydrology at the catchment scale. A lot of data is currently being recorded on wind farm projects.

C. Other biogeochemical feedbacks, e.g. atmospheric deposition of sulphur and/or nitrogen on e.g. CH4 emissions, are not yet taken into account. Methane emissions are as yet not modelled and data on this GHG is generally lacking.

C. Post-construction monitoring is also going on but this needs to be government-steered in order to encourage data sharing.

C. Macrotype-nanotype terminology needs to be understood and applied to modelling. There is a possibility here to integrate with groups that research the stability of peatland patterning that could inform long-term integrated emission modelling.

16 Q. What will be the impact of climate change? Will it be the same as the effects of burning in the South Pennines?

A. Peatlands in Scotland are in a better condition.

C. All our peatlands are disturbed.

Q. How much Scotland-specific data do we have to address these potential changes?

Q. What happens to carbon, not just vegetation?

Q. Can badly disturbed (cracked) peat be restored?

A. Restoration can reduce a loss, not just provide a sink.

A. The impacts of climate change were written about in books in 1981 dealing with peatland hydrology (Barber, 1981;Ivanov, 1981). Effects were always as thought. Wetter bogs would give rise to more pools and poorer carbon accumulation. Drier bogs, which would be hummock-dominated, could accumulate more carbon. Work by Paul Hughes at Southampton supports this. Such paleo-scale feedbacks as not yet part of our models, but would benefit models of e.g. post-harvested peatland restoration effects.

Q. Can other people use the ECOSSE model?

A. Yes, in theory. The aim was to keep the model as simple as possible, including the inputs.

A. In practice the model takes a lot of computing power which makes it more difficult to run. Also there are data constraints as access is required to soils data, climate data, etc., for the model to run.

C. Summing up: i. The model needs to remain simple ii. A vegetation model would be useful but some compromise on nanotypes would be needed iii. The drivers impacting peatlands will be covered tomorrow iv. Real data is needed on these driver impacts

C. There are other models, e.g. bioclimatic models which may be very useful. Some cross comparison is already underway. Similarly, hydrological models need to be looked at in relation to runoff monitoring as there are a lot of conflicting DOC data. There are some issues regarding timescale compatibilities here in terms of model comparisons.

C. Unravelling the confusing data trends on DOC could be aided by DOC radiocarbon dating, such work is in progress.

C. It is important for microforms and water-table to be included in the model.

C. ECOSSE is driven by hydrology, therefore a topographic index is important, including impacts on run-off.

17 6.8. Evidence base for response of peatlands to change (Pete Smith – facilitator)

Break-out sessions covered four topics: Hydro-electric/wind power, Peat extraction/restoration, forestry/agriculture and climate change/muirburn. The sessions were challenged with considering the following questions:

Q. What types of data do we need for addressing each pressure, e.g. monitoring, research project, remote sensing, modelling? Q. Is there a given consensus for the direction of change under different climate scenarios? Q. Can we model any of these scenarios at this point? What other data are required? – Do we need any major new initiatives or can small studies suffice to plug data gaps? Q. Is there enough evidence to predict effects of other impacts? Q. What areas of research need to be prioritised given the national and international importance of any of these pressures? Q. Do we need targeted monitoring of existing sites or new experiments?

6.8.1. Hydro-electric/Wind power

Hydro could be a large scale scheme coving a whole peat catchment. Typically the peat would be covered in 1-2 m water together with general disturbance. The overall effects were unknown. There are currently 2 major hydro schemes on peat catchments, with maybe 2-3 more in the pipeline. Small-scale schemes might be located adjacent to individual households in remote areas; the driver is the cost of fossil fuels. Impacts would be local with trenching and new vehicle tracks. Flooding effects during construction are a major source of uncertainty.

Wind farms would potentially have bigger impacts on peat. For the floating roads commonly used, the impacts are unknown. Perhaps there are options for better designs that would minimize impacts. A timetable considering impact on peat and actions for mitigation and remediation is required during the construction process, possibly even before decisions on the wind farm siting are made, to enable integration with site engineers so as to minimise road construction impacts. Grid connection is a separate planning process which may have its own impact. This is currently unknown, but needs to be tied in to the construction process

C. Some engineers are testing draining blanket bogs to increase flow through turbines.

Q. Is there a problem with methyl mercury?

A. There is much less mercury around in Scotland cf. England.

6.8.2. Peat Extraction/Restoration

Peat is lost through crofting on a domestic scale, industrial scale peat cutting for horticulture and fuel and extraction by the whisky industry. We need to know the extent of the damaged peat and habitat areas and what the prime areas with good restoration potential are, as opposed to those that may be problematic. The reasons for restoring were often initially for biodiversity (vegetation), regulation of catchment hydrology or water quality (control of DOC), not for carbon. There is a need for a peat condition map for Scotland and more joined-up thinking. If we look at work in England it is at least three years ahead. It is expensive to cover all measurements; a cost-benefit analysis is required. There are priorities for tree removal, grip blocking, treating burnt areas. Better to have joined up monitoring with perhaps fewer sites but more comprehensive measurements. There is a requirement for adequate controls and baseline data.

18 There is currently no model that assesses the long term C sequestration benefits of restorative management. An assessment of the areas with greatest potential for restoration is required, at a level that includes the socio-economic and ecosystem service benefits. There is no single assessment of a restoration project in Scotland in terms of emissions monitoring that aids model development, the problem is often that such projects are not generally set up with a fully replicated experimental design. Consensus on the direction of restoration practices is still lacking, although there are some recent examples attempting this.

6.8.3. Forestry/Agriculture

There is conflicting information on the benefits of forestry for carbon sequestration. Much depends upon the depth of peat. There is data out there but not all is available in the public domain. We need collaboration between researchers and between organisations, and ‘jig-saw’ funding. Unfortunately different methods have been used in data collection so we need standardization. We see a lack of communication between different policy groups. Forest Research has initiated a lot of work. However, current pressures are away from peats and onto organo-mineral soils, short-rotation cropping and biofuels. There are questions over the effects of both stump and brash removal; the latter is sometimes good, sometimes not.

Q. What is the future of existing planting on deep peat? Will there be a second rotation or what?

Q. What are the limitations with SSKIB?

A. Unless we collect more data on forested soils and for more soil series we cannot improve on the SSKIB data for afforested soils that is used as input into ECOSSE. A further 12 sites (from the Biosoil sampling) will not inform SSKIB adequately. We should note that historically most soil sampling was done on cultivated land as the main focus of the Soil Survey at that time was in improving agricultural productivity.

C. There is a requirement for more information on both stocks and dynamics of stock changes. ECOSSE relies on stock estimates. Within SSKIB, stocks on afforested soils always come out higher than the semi-natural stock, which is not realistic. This is due to the methods used to determine C stocks of afforested soils (see section 6.4)

A. There is a working group (SG plus FC ) on soil carbon under forestry to review the status.

A. New data is coming on-stream together with ongoing experiments.

A. There is a need to set up a meeting on this (to include MLURI and perhaps a modeller). This could be incorporated into a planned FC meeting. . There is a need to understand models better and to have wider stakeholder expertise so as to get models workable and appropriate.

C. CFLOW, used in the LULUCF, has some problems in predicting forest effects.

C. What about agricultural land-use on peat soils - e.g. large areas of Caithness that were formally peatland have been improved for agriculture? Is this covered adequately?

19 6.8.4. Climate change/muirburn

There are big uncertainties in applying climate change models, such as the Hadley Centre model HadCM3, to peatlands; basically the resolution of climate change prediction is too coarse.

There is considerable value in looking at paleo data – looking at past climate (either warming/cooling or wetting/drying). We need long-term monitoring (beyond the usual 3-5 years) and include damaged areas as well as ‘pristine’ sites. There is a need for experimental sites (to reduce reliance on purely model predictions) and to include vegetation changes (succession). There is also no data on whether peatlands show signs of adaptation to climatic change; most climatic projections assume this does not take place.

With Muirburn, there are major issues for modelling as identified earlier, e.g. inorganic C inputs and physical alterations to peat, as well as potential changes in post-fire vegetation succession with different burn scenarios. There are very few actual data of intensity, frequency or severity of the currently applied burning practices and of their effects. Muirburn can have different effects depending upon the burn intensity (‘hot’ or ‘cold’). More research is required for Scotland; England are ahead on this (Yallop et al., 2009), partly driven by the fact that English peatlands are in much poorer condition. Again there is the value of paleo-data – e.g. charcoal layers and vegetation burns following a burn. MLURI (Macaulay Land Use Research Institute) have concluded that there in currently insufficient data available (Note: Richard Bradshaw at Liverpool has a project on this). Few papers have looked at the recovery process (that of Ed Maltby is moderately long-term; Alistair Hamilton has done recent research in NW Sutherland on fire impacts on blanket bog and monitoring recovery rates from different fires).

Q. Are there alternative ways to kick the system into an alternative state (to overcome the cycle of having to rely on muirburn)?

A. The value of increases in Sphagnum may be promoted by the provision of invertebrates for grouse.

C. Vegetation succession and carbon models cannot be linked due to lack of data (there is a research gap on the carbon dynamics of vegetation succession). However, they could be linked in ECOSSE.

6.9. Critical gaps in knowledge base (Jo Smith – facilitator)

6.9.1. New techniques

A short discussion was held on novel techniques. These included: • Satellite imagery (discussed above), i.e. use of sphagnum to define potential areas of carbon-accumulating peats. How should we determine areas of degrading peats? – gas flux measurements from large scale projects (towers, planes, infrared 2 beam system). • Near infrared imagery to classify severity/time since last burn. • Ground-truthing. • LiDAR (deemed unfeasibly expensive at the resolution required as low altitude flight costs are prohibitive. However, used a lot in England, and produces very useful data at high resolution, e.g. to monitor changes in peat volume, due to erosion or restoration for instance). • Shielded vs unshielded ground penetrating radar (GPR). The frequency of the antenna determines the depth of probing. EU is now legislating against unshielded

20 antennae. Waterfilled spaces are problematic and there are further methodological issues in peat. • Tomography (electrical resistance or resistivity) as a 2-D profiling technique is unlikely to be useful. • New ways to utilise the paleo archive data, e.g. to determine successional changes after burning? Problematic if the burn did not record in the peat layers, also there are periods without peat accumulation. Some cross comparison of pollen vs. plant cuticular wax biomarkers are ongoing. • BGS (British Geological Survey) have completed a study of physical methods at Talla. • ECOSSE 2 reviewed some of these issues as well • EO has the potential to gather data on both GHGs: (http://www.scotland.gov.uk/Publications/2009/12/15084401/0) and the extent of peat erosion: (http://www.scotland.gov.uk/Publications/2009/11/06110108/0)

C. There is poor coordination at a host of levels.

C. Demonstration sites would be very useful.

C. There would be merit in looking at methanogenic populations.

6.9.2. Prioritization of research needs

An exercise that extrapolated the main research priorities from the discussion sessions was undertaken. The following points were identified:

• Peat depth measurements (& spatial variability) – Bulk density – %C • Survey information on peats – Standard methodologies needed for peat and hydrology survey – Little data in some areas of Scotland – Proportions of peats in map units may be small so get missed – Areas of degraded peatlands unknown – More long term studies needed on impact of climate change • Forestry – More information on forest soils and forest management (e.g. Impact of stump removal / brash removal) – Impact of afforestation / forest removal on soil C / net GHG emissions – Collation of existing data access to forest soils data (needs collaboration of researchers and funders) • Restoration – Monitoring of restoration (including control on-site) – Combine socio-economic analysis of timing of restoration (cost/benefits of restoring) – Critical review of management techniques for restoration (e.g. Worrall et al – in press) – Timescales of carbon budgeting for restoration • Muirburn – Depth of drying / burning – Fate of plant and peat C after incineration – Changes in vegetation • Renewable schemes – Changes in hydrology

21 – Changes associated with different types of access tracks constructed on peatlands – Bioenergy / SRF / SRC (what are the pressures/ opportunities; policy drivers) • Impact of grazing – Dependence on plant communities – Critical grazing levels • Understanding tradeoffs between GHG emissions and other ecosystem services such as energy production • Full GHG budget – Methane production /oxidation (measurement and understanding) – Nitrous oxide • Model evaluation – Data – Feedback

These were expanded into 28 priorities and workshop participants were then asked to identify their top three priorities, which were then assembled. The votes were weighted according to the rank given (3 points weight for a top 1 priority etc.). The result of this initial ranking exercise is given in Table 1 below. After this exercise, it was suggested that this be repeated, by ranking these priorities according to the most immediately pressing requirements and those that ought to be addressed in the medium term (see Section 7.)

22 Table 1. Results of the initial ranking exercise

Rank Priority Score 1 Compile a Peat condition map for Scotland (including habitat 19 condition, soil C stock*, hydrological condition, etc.) 2 Monitoring of restoration (including control on-site, success 19 criteria) 3 Impact of afforestation / forest removal on soil C / net GHG 12 emissions 4 Compilation of Standard methodologies for peat and hydrology 7 surveys (including remote sensing) 5 Information on forest soils and forest management (e.g. Impact 7 of stump removal / brash removal) 6 Model development: to include feedbacks (eg. vegetation 7 succession) 7 Long term studies on impacts of climate change 6 8 Collation of existing data (needs collaboration of researchers 6 and funders) 9 Fate of plant and peat C after incineration 5 10 Model evaluation using more detailed studies on eco-hydrology 5 and GHG / C balance 11 Data on depth of drying / burning effects 4 12 Understanding tradeoffs between GHG emissions and other 4 ecosystem services such as energy production 13 Measurements of/ understanding methane production/oxidation 4 in the context of full GHG budgets 14 Define proportions of peats in map units that may be small so 3 get missed (complex topography) 15 Changes in hydrology due to impact of renewable energy 3 schemes 16 Peat depth & spatial variability - specifically bulk density 2 measurements 17 Combine socio-economic analysis of timing of restoration 1 (cost/benefits of restoring) 18 Changes associated with different types of access tracks 1 constructed on peatlands (and other infrastructure) 19 Land use change effects on organo-mineral soils 1 20 Peat depth & spatial variability - specifically %C measurements 0 21 Gain survey data from under sampled areas of Scotland 0 22 Critical review of management techniques for restoration (eg 0 Worral et al – in press) for Scottish scenario 23 Define Timescales of carbon budgeting for restoration 0 24 Gather evidence on changes in vegetation due to muirburn 0 25 Bioenergy / SRF / SRC (what are the pressures/ opportunities; 0 policy drivers) 26 Grazing - Dependence on plant communities 0 27 Critical grazing levels 0 28 Understanding Nitrous oxide production in the context of full 0 GHG budgets *Will require elements of 16 and 20.

23 C. Feedback on prioritization exercise; the first three had a clear preference (with the first two being equal in score):

i. Peat condition ii. Restoration monitoring iii. Impact of afforestation/forest removal

C. Erosion has rather been missed out (see points by R. Lindsay).

C. SNH has commissioned work on erosion as does the SG (e.g. http://www.snh.org.uk/publications/on-line/comm-reports/cc_10.asp).

6.10. Next steps (SG)

Coordination is required for both research and monitoring. There are serious potential gaps in our understanding, or at least description, of emissions and sinks in the LULUCF (Land Use, Land Use Change and Forestry) inventory, which does not include a proper assessment of soil carbon. Soils policy development requires reliable knowledge and data on peats. For habitat management we need to know the impact of policy on carbon. We need to know what research is needed and how to coordinate this research effort in Scotland. Sufficient and coordinated funding mechanisms to fill our key knowledge gaps are important. There is a need to know who else is doing this type of work and collectively can we start to provide answers to these questions.

24 C. Policy timescales sometimes come well before the research radar starts to operate, hence is not able to deliver timely funding to answer the questions.

C. Funders need to allocate money to get answers and articulate what they require clearly. This area of research has not been well funded in the past. Funders need to have a realistic appreciation of what can be done immediately based on previous resource allocation, and what can be done in next 5-10 years with appropriate (i.e. substantial) investment.

C. The skills, expertise and even the networks are often available but what is needed is strategic focus on critical data collection. Data quality is always related to the questions asked at the time of tender and the resource allocated to it.

C. Picture is less pessimistic

C. There is a need for large-scale monitoring experiments, e.g. building upon the CEH Carbon Catchment Programme.

C. Moor House (North Pennines; CEH-led monitoring site for the Environmental Change Network monitoring programme) is a good example. We want fewer reviews and more data points.

C. Is there a need for clarity on how current work is hitting knowledge gaps. Is work being carried out in the right places and for right reasons. Are these places (e.g. Flows) available/able to support future research proposals. Are there other peats (places) where we should be starting work - thinking about climatic/geographical spread of sites across different peat types.

C. There is a plea for interdisciplinary research; plant species are key. The weight of interest has shifted over the past thirty years from vegetation studies to more hydrological and biogeochemical work – there is a concern that current work omits ecological knowledge. Vice versa, some ecological work omits hydrological and biogeochemical knowledge. There are many interdisciplinary studies in the planning and funding review stage. More can be achieved through collaborative funding initiatives.

Q. Do we all agree that coming to a natural state is best for peatlands?

A. There is no consensus on this. Evidence base is there. But may be conflicting at NGO and policy level and this creates interpretation issues. These can be caused by differences in the individuals’ scientific background. The best mechanism to integrate these should be through scientific advisory group.

C. Funding streams need to be more inclusive of potentially competing bidders.

C. There may be a need for an ecosystems services handbook for peatlands. Funders still have no mechanism to pull this together. Would this be a challenge for, e.g., the BES (British Ecological Society) Mires Research group?

7. Priorities for Future Work

The 28 suggested priorities for future work identified at the workshop were used in a secondary ranking exercise, carried out using a LimeService based questionnaire. The 21 workshop delegates were invited to rank the 28 priorities, both according to their perception of whether they should be addressed immediately (within the next 5 years; Table 2) or in the medium term

25 (5-10 years; Table 3). 18 delegates completed this survey, of which one was returned by Excel spreadsheet. The ranked responses were weighted according to the rank given to each priority by the individual delegates (a number 1 rank for a particular priority carried a weight of 28 points, a ranking of 28 carried a weight of 1) and the total score for each priority was calculated both on the basis of all ranks, and on the basis of the top 5 ranks of each individual respondent. The reason for the second scoring was a comment made by two respondents that they found it difficult to attribute a ranking to the priority groups beyond their perceived top 5 priorities.

Table 2. Immediate (<5 years) priorities

Rank Priority 1 Impact of afforestation / forest removal on soil C / net GHG emissions 2 Monitoring of restoration (including control on-site, success criteria) 3 Compile a Peat condition map for Scotland (including habitat condition, soil C stock, hydrological condition etc) 4/5* Compilation of Standard methodologies for peat and hydrology surveys (including remote sensing) 4/5* Collation of existing data (needs collaboration of researchers and funders) * Shared rank as the summary of all 28 responses placed this priority at rank 4 while the summary only considering the top 5 placed this priority at rank 5 (and vice versa).

Table 3. Medium term (5-10 years) priorities

Rank Priority 1 Long term studies on impacts of climate change 2/3* Impact of afforestation / forest removal on soil C / net GHG emissions 2/3* Compile a Peat condition map for Scotland (including habitat condition, soil C stock, hydrological condition etc) 4 Monitoring of restoration (including control on-site, success criteria) 5/5$ Model development: to include feedbacks (e.g. vegetation succession) / Compilation of Standard methodologies for peat and hydrology surveys (including remote sensing) * Shared rank as the summary of all 28 responses placed this priority at rank 2 while the summary only considering the top 5 placed this priority at rank 3 (and vice versa). $ Shared rank as the summary of all 28 responses (first value) slightly differed from the summary only considering the top 5 (second value).

The full sets of rankings are given in Appendix 6. Full list of priorities ranked by score.

Further comments that were received following the ranking exercise were:

• “As immediate actions, an inventory of peat condition and rapid advice on and start of systematic monitoring of peatland restoration and management is needed. Also the integration and alignment of research, science and practice seems key to allow for long term success. Secondly, there are detailed studies on detailed questions. Most importantly the Scottish Government should adopt a holistic ecosystem approach and therefore not only focus on carbon but also assess synergies and trade-offs with other ecosystem services. In the long term, it will be pivotal to monitor changes with and land use change to enable adaptive management. Model integration of vegetation will be beneficial to improve predictions and spatial accuracy”. • “Data collection is needed - the evidence to support many policy needs does not exist. Integrated long-term monitoring and experimental sites are a particular priority”. • “I don’t understand how a priority ranking list of 28 items for the next five years can be any different in a 10 year phase so I’ve made both the same. Sorry if I’ve missed something”. • “I think some of the categories should be combined e.g. Impacts of burning/muirburn, Sustainable grazing levels for peatlands. Also the two Peat Depths priorities could be

26 combined. Monitoring of restoration needs to be explicit in that it includes drain blocking, forestry removal, and other restoration techniques/types e.g. revegetating, eroding peat surfaces, peatlands damaged by fire, etc.”

8. Conclusions

Here we summarise the main conclusions and recommendations of the whole workshop process. This will be done by referring back to the original five questions that the workshop has attempted to answer. Inevitably, time and space devoted to these questions has not been equal and it is the premise that the more important issues and areas of concern have had the more consideration. Many more detailed statements, suggestions and research proposals can be found within the relevant sections of the report and these are too numerous to repeat.

8.1. Current research on GHG emissions and sinks from organic soils in Scotland

Historically, a great detail of information on peatland distribution across Scotland was gathered during the early peat surveys at the Macaulay Institute (1940s – 1970s) and during soil surveys (1940s – 1980s). This included some data on peat depth as well as carbon content though this data is less well represented spatially. More recent point data was gathered during the NSIS_1. SEPA holds long-term data for TOC (Total Organic Carbon) and DOC (Dissolved Organic Carbon) on over 50 river sites and over 200 lochs, many of which will contain peatland within their catchment. SNH hold data on site condition at over 550 peatland sites across Scotland under phases 1 and 2 of the CSM (Common Standards Monitoring). Specific sites where GHG emissions have been investigated in detail have been few; past studies of CO2 and CH4 fluxes were carried out at Ellergower Moss, Bad à Cheo, Loch More and Deepsyke Head. One study has investigated methane only but based on aircraft measurements across the whole country. Specific sites where detailed aquatic fluxes have been monitored in the past are slightly more numerous and usually cover much more extended periods; the most extensively investigated areas have been the Ochils, the Trossachs and Glen Dye.

Current research (within the last five years) has seen an intensification of studies covering most aspects. NSIS_2 now includes bulk density, which was largely omitted in earlier samplings, and this has been supplemented by the Forest Research BioSoil sites. CO2 and CH4 fluxes have been monitored at Auchencorth, Forsinard, Flanders Moss, Whim Moss, Middlemuir Moss, Glensaugh and Ullapool. At some sites N2O has also been measured. Both Auchencorth and Forsinard benefit from Eddy covariance measurements in addition to the chamber-based approach commonly used. Most of the studies return at least monthly data and the eddy covariance method gives a continuous trace. Recent detailed DOC measurements have been made at Auchencorth, Forsinard, Flanders Moss, Whitelee and Girnock.

In addition to the above, there are a number of smaller surveys that have been listed, Thus there are 17 sites where we have more detailed spatial peat depth and/or C data, 13 sites that have had detailed hydrological surveys, 19 sites which have recorded patterning and hydromorphology, 35 sites where vegetation condition has been assessed and 3 sites that have ongoing manipulation experiments, viz. Flanders Moss, Forsinard and Whim Moss.

The above listings should not be considered as being exhaustive since it has relied upon the survey returns which ran at 67%. Additionally, there may have been individuals who were not included in the survey. Nevertheless, the consensus is that we have included here at least the major studies that have been carried out within Scotland. It is clear from the various datasets

27 that there has not been much in the way of coordination of the different approaches such that the data can be easily collated. Measurements of peat C stock, vegetation condition, GHG emissions and fluvial fluxes have all been at different sites. More recently this has been addressed and studies such as those at Auchencorth, Forsinard and Flanders Moss are attempting to cover most aspects. A suggestion is that we needed a coordinating body, or some form of Peat Science group, to act as a focus for discussion, coordination, knowledge exchange, etc.

Model development for Scotland has been largely confined to the ECOSSE model, developed by Aberdeen University. This soil carbon flux model is a direct development from Roth C which was found to be unsatisfactory for mineral soils with moderately high organic matter content and unworkable for highly organic soils. Field scale evaluation shows good agreement between ECOSSE and measured soil C and N stocks and annual fluxes while comparison with CEH estimates of national CO2 emissions shows good agreement across land uses. This gives confidence that national simulations can be used to assess the impact of climate change and potential mitigation options. Further work is required to fully implement the CH4 and DOC components of the model. Since the model does not include a vegetation component, adding this may be useful though there may be a lack of good quality data specific to peatland vegetation and hydromorphological types, which would be needed for model parameterization. It should also be noted that ECOSSE is not specific to just peatlands. The Durham peat model, used for estimating the C budgets of blanket peat, has been applied to peatlands in the Pennines but not so far to Scottish locations.

8.2. Funders of research

The Scottish Government itself is clearly a major funder of peatland research in Scotland. However, there is a considerable body of results being collected by CEH that is NERC-funded. Any work by BGS will also come through this funding stream. SEPA is funding work on aquatic C fluxes while SNH has been sponsoring studies into peat erosion as well as its ongoing responsibilities for peatland vegetation condition. RSPB is increasingly involved in supporting work on C fluxes, peatland condition and impacts of restoration measures in the peatlands they hold in the Flow Country while Forest Research are looking at implications of forestry on peatlands or organo-mineral soils. It should also be recognized that several universities have appreciable research effort in this area, supported by their own funding streams.

A clear message from the workshop and a key outcome is that much benefit can be gained by co-ordinating this research effort and a strategic approach is required to enable this.

8.3. Response of peatlands to change

8.3.1. Land use (including land management)

The major land use change impacts on peatlands were associated with renewable energy (hydro-electric schemes and wind farms), peat use (extraction and restoration) and forestry. Muirburn was seen as a major land management tool. Also restoration would include grip blocking and the restoration of eroded areas. Drainage (gripping) is little practised currently except where needed prior to the foregoing land use changes.

Both wind farms and hydroelectric schemes result in major peat disruption during construction. Access roads and tracks need to be minimized and are potential causes of ongoing peat loss.

28 While some effects can be predicted or modelled in broad terms, only ongoing monitoring of sites can provide definitive values of C cycling impacts. Predicting the long-term impacts of ‘floating’ roads is difficult as is the precise assessment of peat-slide risk. Flooding impacts on peatland areas are little understood both in terms of GHG release and the potential for peat translocation and deposition in reservoirs (The report by R. Lindsay gives more details on this based upon Canadian and Finnish studies (Lindsay, 2010)).

Peat is lost from extraction sites though current industrial scale cutting in Scotland is fairly limited (ca. 2000 ha). Further areas are subject to domestic cutting though the scale of this is minor. Of greater significance are those areas that have been drained and cut in the past and now lay abandoned. Natural regeneration is slow and may not proceed in drained areas. Restoration efforts have been limited and even less is known of the impacts of restoration on the C cycle. Some work is progressing on restoration (tree removal and drain blocking) in the Flow Country.

Forestry policy has moved away from planting on deep peats and current efforts are focussed on organo-mineral soils. However, questions remain regarding the current impacts of forests as they mature on peatlands and what will happen at the end of the present rotation, either restoration back to peatland or second rotation?

The impacts of muirburn are poorly understood and most information has come from studies in the Pennines. This makes modelling impacts of burning difficult and more data relevant to Scotland is required, particularly on the impacts on Sphagnum and its recovery, and on DOC losses. There may be some value in studying paleo-data – the records of past burns.

8.3.2. Climate change

There is some difficulty in applying climate change projections to peatlands as the spatial resolution is too coarse. However, if we assume a general rise in temperature then this is likely to increase peat decomposition rates to CO2, DOC and CH4. At the same time warmer may mean drier, which could further increase CO2 and DOC loss, decrease CH4 emission and have a negative impact on peatland primary production. Altered precipitation patterns may cause longer summer drought periods which again may decrease C fixation, either directly or via vegetation succession or by increasing decomposition rates. There may be a greater susceptibility to fire. Intense rain in the winter may bring about greater erosion, peat instability and even peat slides. There is clearly a likely interaction between the effects of climate change and the land use pressures listed above. Peatlands in good condition are more likely to be resilient to future climate change than those in poor condition. There is an alternative view that suggests that some peatlands may actually benefit from a warmer drier climate; productivity is often greater within drier hummock systems compared to wetter lawn/pool systems while warmer temperatures will also increase plant productivity. This may also lead to greater DOC formation and this may be governed by changes in the proportion of vascular plants vs. Sphagnum. Much of this is speculative and much more research is needed. Paleo-data, looking at past climate shifts, will be helpful here.

8.4. Knowledge gaps

8.4.1. The peatland carbon pool

While peat depth measurements are available for many of the major peat resources there are many areas in the centre, west and north-west of Scotland where we have had to rely on expert judgement to gauge peat depth. We have scant information on bulk density variation, both

29 across the country and changes with depth, with few values below 1 m. Similarly, we have a little knowledge of spatial variation in peat carbon content (%C). These aspects have been discussed in detail by Smith et al. (2009) and while further data has been gathered within the NSIS_2 resampling, it still remains inadequate.

8.4.2. Carbon dynamics in peatlands

There are few sites where a complete carbon budget has been attempted and hence it is difficult to generalise across the country. Usually these few studies have been linked to a particular catchment and so omit the changes at the macrotope-mesotope scale. There is a need to link carbon dynamics with the condition of the bog, whether it is diplotelmic or haplotelmic, or whether it could be considered “active” bog or not. As yet there is no peat ‘condition’ map that would cover the whole of Scotland. The term ‘condition’ needs to be clarified to mean more than just a site condition assessment, i.e. ideally encompassing likely C sequestering status. Carbon dynamics should be linked to vegetation and the macrotope– nanotope hierarchy but this whole area is poorly understood. Existing models of C turnover are limited by the lack of a vegetation component. Studies of methane flux within Scotland are few and existing data is based on a limited number of locations and peat types. The drivers of current DOC increase in peatland waters are still a topic of debate. SG published a report which suggests potential of EO (Earth Observation) to map erosion in organic soils and similar studies need to be evaluated for their potential in providing this type of information on condition.

8.4.3. Climate change

The precise consequences of climate change on peatlands are difficult to predict. Partly this arises from the lack of detailed future precipitation patterns at a local level due to the complexity and uncertainty in modelling precipitation dynamics. Contrary hypotheses on the impact of temperature increases suggest that long-term manipulation studies at a range of peatland sites would be very helpful. Impacts on vegetation and on microtope-nanotope architecture are not well understood. We need to have a better understanding of the impacts of drought on C sequestration and susceptibility to fire, as well as the impact of extreme rainfall events on peat instability and erosion. There are very few peatland sites so far that climate modelling has been applied to and the results have yet to be fully validated in terms of whether the forward projections are correct. Extrapolation to sites for which we have no gas exchange and/or peat accumulation rate data is a major difficulty because data are often needed to calibrate models. The interaction between climate change and other pressures on peatlands requires study, particularly on those already under hydrological stress. It is likely that under most scenarios for climate change there is likely to be a significant impact on the extent and condition of peatlands.

8.4.4. Forestry

While new forestry on peat is currently discouraged, there is a need to understand the carbon dynamics of existing forestry established on peat. What we know at present is based on very few sites and on forests that have yet to reach maturity. There is a poor understanding of what may happen in a second rotation, its impact on the whole carbon cycle, and how this may best be accomplished, or if forest removal and restoration is prescribed, then how to best implement this. Where forest drains are blocked, the resulting impacts on methane emissions are unknown. This is a key area where it would be beneficial to have a co-ordinated research effort.

8.4.5. Erosion

The causes of peatland erosion are not fully understood and the relative role of natural processes vs. anthropogenic factors is still under debate. There is a paucity of data on animal numbers and grazing pressure over time in areas of current erosion within Scotland. We do not know how effective different preservation, conservation or restoration practices might be or to what extent natural regeneration is an important process and how it might be encouraged. We

30 have a very poor understanding of the fate of eroded peat, whether it is deposited elsewhere in the catchment or finds itself in the ocean. Paleo-data input may to help understand some of the drivers of erosion. We do not have a current national estimate for the extent of peatland erosion and the SG is exploring the potential of EO to provide this scale of information in order to monitor trends (http://www.scotland.gov.uk/Publications/2009/11/06110108/0).

8.4.6. Burning/Grazing

Few studies have looked at the impact of muirburn and of wildfire on peatland ecosystems, especially in relation to the vegetation response, depth of burning, recovery times and impacts on the carbon cycle. Again, the investigation of paleo-data could be valuable in picking up past trends and impacts. The influence of fire on DOC release is poorly understood. Grazing impacts on peatland carbon dynamics, what are critical grazing levels and the link with erosion is little understood. There would be considerable benefit in collating information on relevant studies and identifying where resources may be required to address information gaps given the policy- relevance of this issue (MLURI is doing this for the SG just now).

8.4.7. Wind farms and hydro schemes

We have a limited understanding of the long-term impacts of energy generation schemes where these involve peat disturbance and monitoring of current installations would be useful. There is a particular problem with ‘floating roads’, whose long-term impact is unknown. The triggers of peat slides are poorly understood but very relevant to areas where large-scale peat works are implemented. The SG funded the development of a carbon calculator tool to try and estimate the impact of wind farm construction and operation on peatlands. More data is required to validate the assumptions made in this tool to improve confidence in the outputs. There is a need to validate correct use of tool in planning applications and for a body to take the lead on this in Scotland.

8.4.8. Peatland restoration

The impact of restoration practices on carbon cycling has not been studied in detail and it is not known how long it takes for a positive carbon balance to be achieved following restoration of the peatland vegetation in general. There are particular unknowns regarding methane release following the rewetting of formerly dry peatlands by drain blocking. The literature indicates mixed outcomes following restoration and here a co-ordinated programme of research would improve our understanding of the likely impacts of restoration.

8.5. Future research needs

What research is needed to improve our understanding of the likely response of soil carbon to land use and climate change scenarios and to monitor these changes?

The main immediate priorities for research were to improve our understanding of the impact of afforestation and forest removal on soil C cycling and GHG emissions, to monitor restoration efforts and to compile a peat condition map for Scotland. In the longer term, studies on the impacts of climate change were crucial. In short, these research priorities relate to the need for data collection and investment in field monitoring and experimentation. Modelers agree that data collection is essential for further model development.

31 References

Barber,K.E., 1981. Peat Stratigraphy and Climate Change: A palaeoecological test of the theory of cyclic peat bog vegetation. Ealkema, Rotterdam.

Chapman,S.J., Bell,J., Donnelly,D., Lilly,A., 2009. Carbon stocks in Scottish peatlands. Soil Use and Management 25, 105-112.

Ivanov,K.E., 1981. Water Movement in Mirelands. [English translation by A. Thompson and H.A.P. Ingram]. Academic Press, London.

Lilly,A., Towers,W., Malcolm,A., Paterson,E. 2004 Report on a workshop on the development of a Scottish Soils Knowledge and Information Base (SSKIB). Proceedings of a Workshop, Macaulay Institute, 22nd September 2004. http://www.macaulay.ac.uk/workshop/SSKIB/SSKIBWorkshop_Report.pdf

Lindsay,R. Peatlands and carbon: A critical synthesis. 2010. RSPB Scotland.

Smith,J.U., Chapman,S.J., Bell,J.S., Bellarby,J., Gottschalk,P., Hudson,G., Lilly,A., Smith,P., Towers,W. 2009. Developing a methodology to improve soil C stock estimates for Scotland and use of initial results from a resampling of the National Soil Inventory of Scotland to improve the ECOSSE model: Final Report. Edinburgh, Rural and Environment Research and Analysis Directorate of the Scottish Government, Science Policy and Co-ordination Division.

Smith,P., Smith,J., Flynn,H., Killham,K., Rangel-Castro,I., Foereid,B., Aitkenhead,M., Chapman,S., Towers,W., Bell,J., Lumsdon,D., Milne,R., Thomson,A., Simmons,I., Skiba,U., Reynolds,B., Evans,C., Frogbrook,Z., Bradley,I., Whitmore,A., Falloon,P. 2007. ECOSSE - Estimating carbon in organic soils sequestration and emissions. Edinburgh, Scottish Executive Environment and Rural Affairs Department.

The Scottish Soil Framework. 2009. Edinburgh, The Scottish Government.

Yallop,A.R., Clutterbuck,B., Thacker,J.I., 2009. Burning issues. The history and ecology of managed fire in the uplands. In: Bonn,A., Allott,T., Hubacek,K., Stewart,J. (Eds.), Drivers of Environmental change in Uplands. Routledge, Abingdon, pp. 171-185.

32

Appendices

Appendix 1. Questionnaire summary.ppt

Appendix 2. Workshop attendees.doc

Appendix 3. Peatbogs and carbon – key issues.doc

Appendix 4. Estimation of the peatland C stock.ppt

Appendix 5. ECOSSE 1 & 2 – Modelling developments.ppt

Appendix 6. Full list of priorities ranked by score.doc

33 QuestionnaireQuestionnaire SummarySummary

Rebekka Artz, Malcolm Coull, Willie Towers

with major contributions to this presentation by:

Dr. Janet Moxley (SEPA) Dr. Patricia Bruneau (SNH)

Expert workshop – The current state of knowledge & future evidence needs for the extent & condition of carbon stocks in Scottish peatlands; Aberdeen, 4-5 Nov 2009 Questionnaire setup

• An online survey was created on the Limeservice server that asked those responding to describe any field data they may hold (or are planning to gather) in relation to peatland extent, condition and C sequestration potential in relation to emission abatement.

• The survey was sent to 79 individuals from 38 institutions.

• 53 responses were received, of which 32 were complete. These 53 responses included some duplicated information (several groups working on the same site) and were collated into 31 unique site responses. Data workup

• Due to large differences in spatial cover of the various datasets we received information for, the results are presented using a split for major, nation-wide (Scotland), surveys and smaller surveys (individual or < 10 sites)

• All other smaller or individual responses were collated by attributes according to the main purpose of data collection Major surveys

• 1940/1950’s Peat surveys

• National Soils Inventory of Scotland, phase 1 1978-1988 (NSIS-1, MLURI)

• National Soils Inventory of Scotland, resampling 2007-2009 (NSIS-2, MLURI)

• Site Conditions Monitoring (SNH)

• Loch and River TOC monitoring (SEPA)

• BioSoil (Forest Research) Early Peat surveys

• The 1:250 000 scale digitized soil map of Scotland contains 1328 peat polygons ranging in size from 1.25 ha to 53989.3 ha

• 6 peat types were mapped

Unit Peat Type 3 Basin Peat (>0.5m) 4 Undifferentiated Blanket Peat (>0.5m) 603 Eroded Basin Peat (>0.5m) 604 Deep Blanket Peat (>1m) 605 Eroded Deep Blanket Peat (>1m) 606 Eroded Undifferentiated Blanket Peat (>0.5m) 1940’s and 1950’s Scottish peat surveys • Peatland database compiled by Sally Ward (circa 1991) – transect data

• Department of Agriculture and Fisheries for Scotland reports - Scottish Peat (1962), 2nd report of the Scottish Peat Committee and Scottish Peat Surveys Vols 1-4 (1964-1968)

• Reports held at The Macaulay Institute by the Scottish Peat Committee (SPC) and International Survey Committee (ISC), Soil Survey of Scotland memoirs

• Peat Survey field notebooks (Macaulay Institute) - depths from sometimes from >300 recordings • Peat Survey maps • Commercial extraction surveys • Forestry Commission site survey reports Red sites – extensive depth data Scottish peat surveys

Weighted mean peat depth in peat map units • Sites with known depth data (278 of Peat Type Mean depth (m) the 1328 peat polygons) were entered in a spreadsheet containing bog Undifferentiated Blanket Peat 1.3 name, NGR, average depth and

Undifferentiated Eroded Blanket Peat 1.3 source of data.

Deep Blanket Peat 2.3 • Using GIS, these bogs were Eroded Deep Blanket Peat 1.7 matched using the NGR, with peat Basin Peat 2.9 polygons on the 1:250 000 scale soil Eroded Basin Peat 2.7 map

NSIS 1

• Within the 5 km grid NSIS 1 dataset, there are 1591 sites on deep peat or peaty organo-mineral soils

• The database associated vegetation information as per classification by Robertson (1984)

• Extracting sites with vegetation classes likely to relate to typical peatland vegetation reduces the dataset to 1176 sites

• There are a further 137 sites with tree plantations, 4 sites with unidentified vegetation and 274 sites that are cultivated or have atypical (grassland) vegetation. NSIS 1 – attributes

Profile name: Grid reference: SYMBOL LABNO Surveyor: DEPTH SYMBOL COLOUR LOSS ON IGNITION Sample date: MOTTLES CALCIUM Altitude: TEX TURE MAGNESIUM Slope description: Ap STRUCTURE SODIUM Aspect & bearing: MOIST POTASSIUM Rocks and boulders: CONSISTENCE HYDROGEN Vegetation: ROOTS SUM Flushing: Bs STONES SATN BOUNDARY pH Site drainage: CARBON Soil drainage: NITROGEN Erosion: OM Association/ Series: C TOTAL P Parent material: ACETIC P Major soil subgroup: TOP DEPTH Rock type: BOTTOM DEPTH SAND Climate: SILT Land Capability Agriculture CLAY Base of pit: Bulk samples: NSIS 1

• Within the 10 km grid NSIS 1 dataset, there are 403 sites on deep peat or peaty organo-mineral soils

• Extracting sites with vegetation classes likely to relate to typical peatland vegetation reduces the dataset to 301 sites

• There are a further 29 sites with tree plantations, 1 site with unidentified vegetation and 72 sites that are cultivated or have atypical (grassland) vegetation. NSIS 2 – attributes Profile name: LABNO SYMBOL Grid reference: SYMBOL DEPTH COLOUR Surveyor: LOSS ON IGNITION MOTTLES Sample date: CALCIUM TEX TURE Altitude: MAGNESIUM STRUCTURE MOIST Slope description: SODIUM CONSISTENCE Aspect & bearing: POTASSIUM ROOTS Rocks and boulders: HYDROGEN STONES Vegetation: SUM BOUNDARY Flushing: Ap SATN Site drainage: pH Plus: Soil drainage: CARBON NITROGEN additional mottling; Erosion: max rooting depth; Association/ Series: Bs OM Parent material: TOTAL P Σ% stone; Major soil subgroup: ACETIC P Rock type: TOP DEPTH Climate: BOTTOM DEPTH Land Capability Agriculture SAND Base of pit: C SILT Bulk samples: CLAY Plus: bulk density; SMRC/LLWR; aggregate stability; N Mineralisation (UK-SIC indicator); Microbial Plus: GPS NGR; biomass and slope length; community structure by PLFA; Total DNA by erosion type and area affected pico-green assay; Community composition by minus: LCA molecular fingerprinting (M-TRFLP); XRD, FTIR, NIR; wax markers. NSIS 2

• Within the 20 km grid NSIS 2 dataset, there are 104 sites on deep peat or peaty organo-mineral soils

• The database associated vegetation information as per classification by Robertson (1984)

• Extracting sites with vegetation classes likely to relate to typical peatland vegetation reduces the dataset to 78 sites

• There are a further 9 sites with tree plantations and 17 sites that are cultivated or have atypical (grassland) vegetation. SEPA monitoring sites

• 219 Loch sites have around 5 years data

•58 river sites have < 10 years TOC data (but < 30 y). Remaining 432 river sites have 2 -3 years data

• Water quality (DOC/TOC/particulate organic carbon)

• Supporting water quality data (e.g pH, conductivity, nutrients, water temp, suspended solids) and flow data for most of the river TOC

• Flow data can be modelled from adjacent catchments if there is no flow gauge at the TOC sampling point

• Management history is various. SEPA do not have detailed information of this for all catchments monitored (may for some sites e.g ECN/AWMN or areas of specific concern) SEPA monitoring sites CSM sites

• The site condition monitoring dataset held by SNH recorded information collected during phase 1 and 2 of the Common Standards Monitoring (CSM) for Special Areas of Conservation (SAC), Special Protection Areas (SPA), Ramsar sites and Sites of Special Scientific Interest (SSSI).

•The conditions of interest features for which the protected site has been notified or designated is monitored.

•Each interest feature will have one or more measurable attributes that will be assessed against targets, thus provide a pass or fail result.

•Additional information may also be recorded as narrative relating observed changes in the condition of the interest features to the reasons for such changes.

•SNH provided data for peatland CSM sites: 259 upland habitats (includes blanket bog), 237 lowland wetlands, 30 lowland dry heath sites, 7 bog woodland sites and 19 Quaternary of Scotland features Forest Research BioSoil sites

• Specific baseline monitoring of forest soils

• 12 Scottish BioSoil sites on peat

• includes data on biomass C, soil parameters (includes e.g. bulk density, particle size, organic C, total N, elemental analysis)

Soil sampled at 0 -10 cm, 10 - 20 cm, 20 -40 cm and 40 - 80 cm (also incl. mineral horizons) Smaller surveys – collated data from survey responses

1) GHG exchange sites

Site Type Since Frequency Measurement Group Other Auchencorth Eddy 2002 Continuous NEE CEH covariance 2006 (+ biweekly N2O, CH4 Chamber sporadic based 1995/06) Forsinard Eddy April 2008 Continuous NEE CEH covariance For 2 years Chamber ? CO2, CH4 UoE based

Flanders Chamber March 2008 Biweekly/monthly N2O, CH4, FR Moss based (EC CO2, DOC in future) 13 Whim Moss Chamber 2006 Intermittent until CO2, CH4 CEH, C based 2008, then UoE pulse monthly chase label (UoA, MLURI)

Middlemuir Chamber 2003-2005 Approx monthly CO2, CH4 MLURI Moss based

Ellergower Chamber 1990’s variable CH4, CO2, Clymo Moss based (discontinuous) DOC et al., CEH Deepsyke Chamber 4 years 6 x annually GHG fluxes CEH Head based

Glensaugh Chamber 1 year (2004- 6 x annually N2O, CH4, CEH based 5) CO2

Ullapool Chamber 1 year (2004- 6 x annually N2O, CH4, CEH based 5) CO2

Loch More Chamber May-June 60 measurements CH4 CEH based 1994

Smaller surveys – collated data from survey responses

2) Sites with data for aquatic fluxes

Site Since Frequency Measurement Group Auchencorth 2006 weekly Aquatic C CEH (sporadic export from 2002) Forsinard June 1-3 x C and trace ERI/St 2007/April annually/biweekly elements Andrews/CEH 2008 Flanders March 2008 Biweekly/monthly DOC FR Moss Whitelee 2006 15 min (DOC 6 pH, cond, temp UoG hourly over 24 hour (DOC, POC, period for 14 DIC) months) plus spot samples Girnock April 2004 15 min (DOC 6 pH, cond, temp UoG hourly over 24 hour (DOC, POC, period for 14 DIC) months) plus spot samples Glen Dye July 2003 15 min (DOC 6 pH, cond, temp UoG hourly over 24 hour (DOC, POC, period for 14 DIC) months) plus spot samples Trossachs * 1988-1991, intervals during DOC UoS, UoA, 2003-2007 storm events FRS Ochils * 1981,1983, intervals during DOC UoS 2003-2006 storm events Braes of recent intervals during DOC UoS Doune storm events (windfarm) *

Also microcosm data from: Loch Coire nan Arr,Allt a'Mharcaidh, Dargall Lane and others * Not located on map, NGR/XY co-ordinate data pending Smaller surveys – collated data from survey responses

3) Peat depth and/or spatial soil C surveys

Talla (BGS) Forsinard (RSPB, MLURI (ongoing) Dun Moss (UoD) Silver Flowe (Brishie) (UoD) Strathy Bog (Meala) (UoD) Duich Moss (UoD) Shetland (UoD) Bankhead Moss (UoD) Red Moss of Balerno Fannyside Muir (UoD) Laxford Bridge (UoD) Sligachan (Caiplach) (UoD) Coladoir Bog (UoD) Blar na Caillich Buidhe (UoD) Red Moss of Netherley (Peter Hulme, SNH) Moine Mhor (UoD) Claish Moss (UoD) Smaller surveys – collated data from survey responses

4) Hydrological surveys

Talla (ongoing, BGS) Red Moss of Netherley (Hulme/SNH) Dun Moss (UoD) Silver Flowe (Brishie) (UoD) Strathy Bog (Meala) (UoD) Duich Moss (UoD) Shetland (UoD) Kirkconnell Flow (UoD) Bankhead Moss (UoD) Forsinard (CEH, ERI) Threepwood Moss (SWT) Flanders Moss (UoD, SNH, SWT) Fannyside Muir (UoD) Smaller surveys – collated data from survey responses

5) Patterning and hydromorphology

Ellergower Moss (Clymo et al) Forsinard (ongoing, ERI) Dun Moss (UoD) Silver Flowe (Craigeazle) (UoD) Silver Flowe (Brishie) Strathy Bog (Meala) (UoD) Duich Moss (UoD) Kirkconnell Flow (UoD) Bankhead Moss (UoD) Laxford Bridge (UoD) Sligachan (Caiplach) (UoD) Coladoir Bog (UoD) Blar na Caillich Buidhe (UoD) Moine Mhor (UoD) Claish Moss (UoD) Flanders Moss (UoD, SNH, SWT) Red Moss of Balerno (UoD) Fannyside Muir (UoD) Red Moss of Netherley (Hulme, SNH) Smaller surveys – collated data from survey responses 6) Vegetation/condition monitoring

Ellergower Moss (Clymo et al) Methven Moss SSSI/SAC (UoD) Fealar Estate (MLURI) Forsinard (ERI) Corrour Estate (MLURI) Munsary (UoEL) South Loch Tay DMG ((MLURI) Threepwood Moss (SWT) Gairloch DMG (MLURI) Laxford Bridge (UoD) Angus Glens DMG (MLURI) Sligachan (Caiplach) (UoD) Northern DMG (MLURI) Coladoir Bog (UoD) West Sutherland DMG (MLURI) Blar na Caillich Buidhe (UoD) East Sutherland DMG (MLURI) Moine Mhor (UoD) North Ross DMG (MLURI) Claish Moss (UoD) South Ross DMG (MLURI) Flanders Moss (UoD, SNH, SWT) Mid West Assoc DMG (MLURI) Red Moss of Balerno (UoD) East Loch Ericht DMG (MLURI) Red Moss of Netherley (Hulme, Dun Moss (UoD) SNH) Silver Flowe (Brishie) (UoD) Silver Flowe (Craigeazle) (UoD) some data on many others Strathy Bog (Meala) (UoD) (SWT condition monitoring) Duich Moss (UoD) Shetland (UoD) Kirkconnell Flow (UoD) Bankhead Moss (UoD) Rannoch Moor Smaller surveys – collated data from survey responses

7) Sites with manipulations

Site Experimental Measures Groups contrasts Flanders Moss Drained/Un-drained GHG & aquatic fluxes FR Forsinard Tree removal Various, including GHG fluxes CEH, ERI, Uo chronosequence & & aquatic export, vegetation StA, MLURI Grip blocking surveys Whim Moss N deposition GHG fluxes incl. N2O, (13C CEH (MLURI) (wet/dry) pulse label tracing) Forsinard Grazing GHG fluxes (chamber based) UoE & vegetation surveys

Potentially relevant data outwith Scotland

• Countryside Survey (England & Wales) – long term monitoring of soil quality (since 1978)

• Moorhouse NNR (since 1960s) – long term monitoring of GHG fluxes, aquatic discharge, LiDar peat depth mapping, long term vegetation data, long term hydrological data

• Roudsea Wood & Mosses NNR/SSSI – EU Elevated CO2 project (mid 1990s)

• Lake Vyrnwy – long term monitoring of GHG fluxes, includes CH4 ebullition studies

• various sites in Sweden & Finland – C stock & dynamics, long term monitoring of GHG fluxes

• South Pennines , Greenleighton, Cronkley, Hard Hill, Keighley Moor, Green Withens, Bleaklow, Goyt Valley- varying sampling frequency for soil C, some for GHG fluxes & aquatic export, vegetation monitoring (many used for model validation) Contributors to the survey

• Alan Gray (Centre for Ecology and Hydrology) • Mike Billett (Centre for Ecology and Hydrology) • Allan Lilly (MLURI) • Neil Cowie (RSPB) • Allan Robertson (IPS) • Norrie Russell (RSPB) • Andrew Nolan (MLURI) • Olivia Bragg (University of Dundee) • David Hopkins (SCRI) • Pete Smith (University of Aberdeen) • Dicky Clymo • Rebekka Artz (MLURI) • Joanna Clark (Bangor University) • Russell Lawley (British Geological Survey) • Yit Arn Teh (University of St Andrews) • Sarah Crowe (Environmental Research Institute) • Elena Vanguelova (Forest Research) • Sirwan Yamulki (Forest Research) • Fred Worrall (University of Durham) • Susan Waldron (University of Glasgow) • Helaina Black (MLURI) • Ute Skiba (Centre for Ecology and Hydrology) • Ian Grieve (University of Stirling) • Willie Towers (MLURI) • Janet Moxley (SEPA) • Johan Schutten (SEPA) • Anonymous contributors • Julia Drewer (Centre for Ecology and Hydrology) • Kerry Dinsmore (Centre for Ecology and Hydrology) • Lucy Sheppard (Centre for Ecology and Hydrology) • Mark Reed (University of Aberdeen) • Martin Evans (University of Manchester) Appendix 2. Workshop attendees

SURNAME FIRST NAME INSTITUTION Artz Rebekka MLURI Bailey Sallie FC Bain Clifton SWT Bonn Aletta Moors for the Future Bragg Olivia University of Dundee Bruneau Patricia SNH Chapman Steve MLURI Clark Joanna University of Bangor Coupar Andrew SNH Cowie Neil RSPB Crowe Sarah University of the Highlands & Islands Dinsmore Kerry CEH Edinburgh Dobbie Karen SEPA Lilly Allan MLURI Lindsay Richard University of East London Puri Geeta SG Russell Norrie RSPB Smith Jo University of Aberdeen Smith Pete University of Aberdeen Vanguelova Elena Forest Research, Alice Holt Worral Fred University of Durham

Peatbogs and carbon : key issues Richard Lindsay Head of Environmental Research group University of East London [email protected]

1. Size of the peat-carbon resource

1.1 Challenges

1.1.1 Mapping of the extent of peat varies considerably in both nature and quality across, between, and within England, Scotland, Wales, Northern Ireland and the UK. 1.1.2 Mapping of peat thickness is based on a relatively small number of field samples, though evidence indicates that thickness can vary substantially over distances of 10-50 m. 1.1.3 Estimates of carbon density (bulk density) are based on a relatively small number of field observations which are mainly taken from the uppermost 1 m of the peat profile, although evidence indicates that bulk density can vary substantially through a complete peat profile. 1.1.4 UK soil-carbon and land-use database only holds data for peat thicknesses of 1 m. 1.1.5 The ecological condition of the peat bog resource is poorly recorded in terms of macrotope–nanotope hierarchy, and in terms of diplotelmic, haplotelmic and “active” bog.

1.2 Actions

1.2.1 Identify, critically evaluate, collate, and then disseminate, field data which already exist (ECOSSE 2 has already done this to some extent for Scotland). 1.2.2 Discuss with BGS a revision of BGS drift maps (peat >1 m) as part of an integrated, cross-sectoral, and standardised UK peat-mapping programme. 1.2.3 Discuss with Soil Surveys the mapping of areas >1 m and <1 m deep in concert with BGS. 1.2.4 Discuss with CEH and CMS the linking of vegetation mapping with soil/drift mapping as part of integrated peat-mapping programme. 1.2.5 Develop extensive programme of peat-thickness measurements as part of integrated peat-mapping programme. 1.2.6 Incorporate macrotope-nanotope classification into integrated peat-mapping programme. 1.2.7 Incorporate diplotelmic and haplotelmic mapping, and “active” bog, within integrated peat-mapping programme. 1.2.8 Generate more fine-scale mapping of bulk density across a range of differing sites using transect methods of Shotbolt et al. (1998), down full depth of peat thickness, to determine bulk-density characteristics across a range of conditions. 1.2.9 Investigate bulk density in relation to microtope-nanotope features both within the present surface and within the peat archive, relating this to the Barber (1981) phasic model of microtope-nanotope adjustment to varying climate/hydrological conditions. 1.2.10 Investigate relationship between bulk density and ecological condition of peat bog systems, particularly in relation to ‘inverted’ Clymo model with high BD at surface and lower BD at depth. 1.2.11 Investigate reliability of relationship identified by Päiväinen (1969) and Clymo (1983) between bulk density and von Post values for possible use of von Post scale as a convenient field-proxy for bulk density. 1.2.12 Expand UK soil-carbon land-use database to incorporate values for peat >1 m thickness. 1.2.13 More widespread measurements of peat bog biomass carbon both in terms of vascular plants and bryophyte (particularly Sphagnum) cover.

2. Carbon dynamics of the peat resource

2.1 Challenges

2.1.1 Carbon dynamics not sufficiently linked to nature of the bog system in terms of macrotope-nanotope classification and associated vegetation. 2.1.2 Carbon sequestration within vegetation not yet clearly linked to carbon transfer from acrotelm to catotelm into long-term storage. 2.1.3 Acrotelm dynamics, with respect to microtopes-nanotopes and carbon fluxes, not yet sufficiently well understood to model carbon pathways of e.g. methane with confidence. 2.1.4 Relationship between vegetation and carbon pathways poorly documented and understood. 2.1.5 Source of DOC, and its relationship with land use, still the subject of considerable debate. 2.1.6 “Active bog” increasingly (though incorrectly) conflated with ‘carbon storage’. 2.1.7 Mass-balance studies use catchment rather than macrotope-mesotope as descriptive unit, thereby studying partial sites. 2.1.8 Mass-balance studies do not allow for use of carbon within re-shaping of acrotelm rather than as part of long-term carbon sequestration, generally being of too short a duration to identify such processes.

2.2 Actions

2.2.1 Studies to provide clearer understanding of the part played by microtope- nanotope complex in peat accumulation. 2.2.2 Studies into ‘residence time’ of carbon within the acrotelm, prior to transfer to catotelm. 2.2.3 Investigations into the contribution to catotelm peat made by vascular plants (aerial parts, leaf bases, roots) compared with Sphagnum. 2.2.4 Carbon-flux studies in future more tightly defined in terms of the microtope- nanotope-vegetation complexes being studied. 2.2.5 More detailed studies of microtope-nanotope response to change, and the consequences of this for carbon sequestered by acrotelm. 2.2.6 Relationship between methane, condition of the bog, microtopes-nanotopes, and vegetation (vascular plants and Sphagnum) requires more detailed study. 2.2.7 Dynamics of catotelm methane merit detailed study in relation to methane formation, methane release, and possible role in peat hydraulic conductivity. 2.2.8 Dynamics of acrotelm methane merit detailed study in relation to methane formation, methane release and oxidation processes in the acrotelm. 2.2.9 Measurements of DOC age, to help determine its likely origins, along with recognition that DOC consists of potentially many fractions, possibly derived from differing sources and with differing ages. 2.2.10 Detailed studies of ARCA and ARDA, and clear guidance in relation to “active bog” versus ‘peat accumulation’.

3. Peat bog drainage

3.1 Challenges

3.1.1 Lack of evidence for relationship between drainage, subsidence and oxidative wastage. 3.1.2 Measurements of water-table draw-down usually taken in relation to bog surface rather than fixed datum, and consequently water table appears to change little while changes expressed as subsidence are not recorded. 3.1.3 Small-scale changes (of 4-5 cm) to acrotelm hydrology and ‘removal of surface water’ by drainage are not recognised as being significant. 3.1.4 Concerns that re-wetting drains releases significant quantities of methane.

3.2 Actions

3.2.1 Studies required to measure relative rates of subsidence and oxidation in drained peat bog systems. 3.2.2 Maintenance of detailed drainage/forestry study established by Anderson et al. (2000) at Bad á Cheo, Caithness, but more similar studies required. 3.2.3 Inclusion of detailed macrotope-nanotope-vegetation information, and palaeo- archive analysis, within the study established by Anderson et al. (2000) to relate measured ground and water-table changes to key features of the enclosed and surrounding bog system. 3.2.4 Extensive palaeo-archive survey of peat bogs subject to drainage, to determine the extent to which the recent peat archive displays microtope- nanotope-vegetation changes coincident with drainage operations. 3.2.5 Further development of Holden’s ‘topographic index’ model in relation to drainage impacts. 3.2.6 Further studies into relationship between DOC and drainage, but associated with detailed records of microtope-nanotope-vegetation features within study site, noting particularly biomass of differing vegetation stands. 3.2.7 Further studies into ditch-blocking and DOC and methane, associated particularly with detailed vegetation recording to link DOC flows and methane emissions to vegetation type.

4. Windfarms

4.1 Challenges

4.1.1 Lack of appropriate eco-hydrological studies associated with the impacts of ‘floating roads’ despite their widespread construction in recent years. 4.1.2 Lack of appropriate engineering tools to assess peatslide risk. 4.1.3 Need for appropriate parameters within, and input values to, Nyak et al. (2008) windfarm calculator.

4.2 Actions

4.2.1 Establish detailed eco-hydrological studies of ‘floating roads’ in a variety of conditions and peat bog systems. 4.2.2 Further studies into engineering properties of peat soils. 4.2.3 Inputs from scientific community to parameters and input values for windfarm calculator model.

5. Forestry

5.1 Challenges

5.1.1 Cannell et al. (1993) develop a carbon-balance model for trees on peat, and identify that equilibrium models indicate a net carbon gain if oxidation of the peat is 50-100 g C m-2 yr-1, but a net carbon loss if oxidation results in >100 g C m-2 yr-1. Clearly it is of considerable value to have data for the actual scale of oxidative losses but very few such data have so far been obtained. 5.1.2 A significant number of investigations into forestry impacts on peat have been undertaken at a single site – Bad á Cheo, Caithness – whereas a wide range of blanket mire conditions have been subject to afforestation 5.1.3 Almost all studies of forestry on peat involve forests which have yet to reach maturity, and consequently the effects which trees close to maturity may have on the peat have not yet been observed. 5.1.4 Concerns have been expressed that felling and re-wetting forested ground may release significant carbon dioxide and methane.

5.2 Actions

5.2.1 Establish studies on a wider range of sites to investigate the effects of afforestation on peat under differing conditions. 5.2.2 Maintain the study at Bad á Cheo established by Anderson et al. (2000) but add gas-flux measurements, microtope-nanotope-vegetation studies, and palaeo-ecological studies of the recent peat archive. 5.2.3 Develop further appropriate figures for peat-bog biomass to be used within peat-forest carbon estimates. 5.2.4 Further develop the decomposition model assembled by Colls and modified by Lindsay to apportion more appropriately decomposition levels of woody tissue within surface layers, acrotelm and catotelm. 5.2.5 Investigate the pattern of vegetation colonisation across felled timber, particularly in terms of Sphagnum growth, and link this with measurements of methane flux.

6. Hydro schemes

6.1 Challenges

6.1.1 GHG release from flooded vegetation and peat, with high levels of GHG maintained for a considerable period following flooding. 6.1.2 GHG release from peat material washed into reservoir from surrounding catchment. 6.1.3 Reduced reservoir storage capacity resulting from allochthanous peat brought in from catchment, though lack of reservoir profiles makes calculations of storage-capacity loss difficult. 6.1.4 Potential for methyl mercury to be formed and released from flooded peat soils.

7. Climate change

7.1 Challenges

7.1.1 Climate models vary, but some indicate that bogs in the lowlands, and some areas of blanket bog, may have dryer, warmer summers but wetter winters, with possible negative effects on the bog water-balance. 7.1.2 Damaged bogs are already drier than they should naturally be, and thus may be even more strongly affected by predicted climate change. 7.1.3 Increased storminess and heavy rainfall, combined with extended dry spells, may give rise to instances of instability and slope failure, particularly where the peat has already been influenced by human action. 7.1.4 Longer warm, dry periods of weather are likely to predispose peat bogs to fires, caused either by human action or by lightning during intense convective storms. 7.1.5 It can be assumed that warmer conditions and elevated levels of CO2 will give rise to more vigorous plant growth. On the (yet to be fully-proven) assumption that the majority of DOC released from bogs is derived from relatively young vascular-plant litter, it can be assumed that warmer (and particularly drier) conditions will encourage more vigorous growth of both vascular plants and Sphagnum, but the increased biomass of vascular plants may result in increased levels of DOC release. Currently, no regular measurements of blanket mire plant biomass are taken, not even on ECN (Environmental Change Network) sites. 7.1.6 On the (yet to be fully-proven) assumption that the majority of DOC released from bogs is derived from relatively young vascular-plant litter, it can also be assumed that warmer (and particularly drier) conditions will encourage more vigorous growth of vascular plants in damaged blanket mire systems lacking good Sphagnum cover, particularly those which are haplotelmic, and thereby lead to even greater increases in levels of DOC release. 7.1.7 Raised bogs in the lowlands are already under considerable hydrological stress, generally because the surrounding lagg fen has been drained. Warmer, drier conditions are likely to intensify this hydrological stress substantially.

7.2 Actions

7.2.1 Given that bogs with a functioning microtopography, vegetation and acrotelm have demonstrably survived through warm dry climate periods in the past by altering the composition of the living vegetation, it would be reasonable to suggest that a programme designed to restore such functioning bog systems extensively might mean that the peat bog resource was better able to respond to climate changes than it is at present. 7.2.2 A better understanding is required of the processes and mechanisms which lead to slope-failure in blanket mires, linked closely to an assessment of the condition of the habitat. 7.2.3 An assessment of peatslide risk across the UK blanket mire resource, as is currently being undertaken in the Republic of Ireland, would help to identify areas potentially and particularly at risk under changing climate conditions, particularly if linked to models of potential storminess and intense rainfall events.. 7.2.4 An assessment of potential fire risk across the UK blanket mire resource, particularly if linked to models of potential soil water-deficit and drought periods, could assist in identifying areas potentially most at risk from fire damage. 7.2.5 Further investigations are required into the source of DOC, based on age and chemical composition (and recognising that ‘DOC’ is a broad term embracing a wide range of carbon-based compounds). In particular, further investigations are required into the relationship between rising DOC and declining atmospheric pollution, DOC and vascular-plant litter, and DOC and Sphagnum. 7.2.6 Regular, repeated measurements of above- and below-ground plant biomass should be obtained for both vascular plants and non-vascular plants, from at least the ECN sites, but ideally from a larger network of sites. 7.2.7 In the lowlands, water-management schemes could be drawn up for ground associated with raised bogs in order to provide them with the necessary natural hydrological resilience to respond to warmer and drier conditions.

8. Commercial peat extraction

8.1 Challenges

8.1.1 Evidence suggests that the major carbon-cost of commercial peat extraction is the oxidation of the extracted peat (71% according to calculations in Canada). Remarkably, the rate of oxidative loss from exposed, extracted peat under differing environmental conditions is rather poorly documented. 8.1.2 The limited number of studies looking at the GHG balance of peat bogs in Britain (or indeed across most of Europe) means that it is difficult to put any measurements of GHG flux obtained from cut-over bogs into any wider context. 8.1.3 Incubation measurements of GHG-flux potential should be treated with caution because this potential may not be realised in the field. 8.1.4 Although particulate losses of peat in water systems is well documented for Finland, measurements for extraction sites in Britain are more limited, while aerial losses of particulate carbon have been little-studied. 8.1.5 Commercial peat extraction sites which are now subject to restoration management tend to consist either of old-style ‘baulk and hollow’ cuttings, or extensive milled peat fields, or sometimes both. On the basis of relatively limited experimental evidence, the GHG-flux experience for these two types of extraction appears to differ substantially, with milled-peat surfaces more easily demonstrating carbon gains following restoration management. However, the evidence-base for this is very limited.

8.2 Actions

8.2.1 Studies of peat-oxidation rates under differing conditions are urgently required. 8.2.2 Further GHG-flux studies are needed from both uncut and commercially- extracted peat bogs. 8.2.3 More widespread studies of POC loss, both water-borne and airborne, are required within the British context. 8.2.4 Estimates for the extent of ‘baulk and hollow’ cuttings, and milled peat fields, should be made across Britain to determine the potential extent of these two starting-points in the restoration process. 8.2.5 A survey and analysis of existing bog regeneration, whether managed or spontaneous, within abandoned commercial workings should be undertaken in order to assess the sequence of recovery processes demonstrated on such sites, and combined with GHG-flux, biodiversity, water quality and DOC measurements. 8.2.6 Detailed studies, incorporating GHG-flux, biodiversity, water quality and DOC, and building on the best of the restoration techniques described from Britain, Ireland, continental Europe, and Canada in particular, should be established on both abandoned ‘baulk and hollow’ and milled peat fields.

9. Burning

9.1 Challenges

9.1.1 Burning is certainly the longest-established, as well as arguably the most widespread, impact on blanket mires, demonstrably having occurred as far back as Mesolithic times in many peat cores. These ancient fires may be natural or may be anthropogenic, but the more recent fire record is generally attributable to human action. Despite this long association, the relationship between fire, ecological condition, hydrology and recovery processes remains poorly documented for blanket mires. 9.1.2 Evidence suggests that anthropogenic fires have increased substantially in the last 200 years, and indeed have increased even more dramatically in the last 20 years. The implications of this on ecological condition, hydrology and recovery processes in blanket mires have yet to be adequately described and explored. 9.1.3 Fire tends to favour vascular-plant cover at the expense of Sphagnum cover, with heather being encouraged in the east of Britain while in the west and north, species such as deer grass and purple moor grass are encouraged. The majority of research into fire and vegetation dynamics has tended to focus on the relationship between fire and heather and/or grassland management, rather than the relationship between fire and Sphagnum cover. 9.1.4 The timescales of recovery in blanket mire environments are poorly documented, but the little evidence which does exist for peatbog systems in both lowland and upland environments suggests that recovery times are substantially under-estimated, particularly in the harsher blanket mire environment. 9.1.4 Confusing and conflicting messages have been emerging recently about the effect of fire on the carbon store of, and DOC-release from, blanket bogs. This confusion appears to result mainly because the areas under investigation are not adequately described in terms of their ecological character and ecological condition. 9.1.5 If climate models are correct in predicting warmer, drier conditions for at least some parts of the blanket mire resource in future, fire is likely to feature as an even more significant element in blanket mire dynamics in these parts.

9.2 Actions

9.2.1 Detailed palaeo-archival studies are required of fire events and the record of vegetation dynamics following fire, across the range of available time-spans, and in a range of geographical areas, from the Mesolithic Period to the present day. 9.2.2 Work in the Pennines and Peak District looking at fire frequency in recent years should be extended to other parts of Britain to obtain a wider picture of modern fire frequency. 9.2.3 Studies of burning, whether in terms of fire frequency or in terms of carbon balance, should include detailed descriptions of the ecological character and ecological condition of the bog system, including in particular details of the Sphagnum cover, its species composition, and the microtopography of the bog surfaces involved. 9.2.4 Recovery times to original ecological condition following fire should be investigated, particularly in a range of blanket mire environments. 9.2.5 The relationship between deep peat and heather cover should be examined with a view to determining likely long-term trajectories for the ecological character of areas under differing burning regimes and changing climatic conditions. 9.2.6 Future GHG-flux and DOC studies in blanket mire habitats should ensure that detailed descriptions are obtained of the ecological character and ecological condition of the bog system, including in particular details of the Sphagnum cover, its species composition, and the microtopography of the bog surfaces involved. 9.2.7 The age of the carbon involved in both GHG-flux and DOC studies should be determined in an attempt to identify whether these losses are from the carbon store or from recent plant litter and root systems.

10. Erosion, burning and grazing

10.1 Challenges

10.1.1 The initiating causes of blanket mire erosion are still not known, although a number of theories have been put forward over the years. It is thus not known whether erosion is a natural part of blanket mire dynamics: an end- point of a natural process or cycle, or a process initiated by human-induced processes. It is therefore not clear whether erosion is a sign that action is needed or certain actions be curtailed, or whether the erosion process should be allowed to follow its natural course much as coastal erosion is now being accepted as the price of living on an island. 10.1.2 Evidence suggests that significant erosion has occurred at a number of times in the past though always within the time-span when Britain was populated, and that erosion in more recent times has been particularly marked, but precisely what initiated these erosion events has not been clearly identified. 10.1.3 Although several theories have been proposed to explain the onset of erosion, the only directly-observed cause has been burning; all other explanations have been inferred or have been proposed as potential mechanisms based on the available evidence. Fire is thus the only demonstrable initiator of erosion but the weight of opinion appears nevertheless to favour natural processes or the impact of grazing as the initiating agent. 10.1.4 The relationship between fire-age, ecosystem-recovery times and presence and extent of erosion has not been adequately investigated, perhaps leading to unwarranted assumptions about the lack of a relationship between ‘recent’ fire-evidence in the peat archive and the present eroded state. 10.1.5 While trampling by red deer and even cattle may be a cause of peatland erosion, sheep have been more usually identified as a possible cause of erosion, but there has been insufficient analysis of the relationship between the introduction of sheep to Britain and the observed pattern of erosion present in the palaeo-archive of, for example, lakes in blanket mire catchments. 10.1.6 The inter-relationship between recorded grazing levels, fire events (either documented or visible in the recent palaeo-archive), recovery times from burning, and the initiation of erosion (rather than simply the intensification of existing erosion), have yet to be adequately investigated. 10.1.7 The relationship between burning, grazing and erosion in other parts of the world where blanket mire can be found has not yet been subject to any systematic investigation, although Spain possesses grazed blanket mire which shows little sign of erosion, and Tierra del Fuego has blanket mire which is neither burnt nor grazed and shows no evidence of erosion.

10.2 Actions

10.2.1 More widespread and more detailed studies of lake sediments within peatland catchments should be carried out, in particular investigating the timing of erosion events, the presence of charcoal, and accompanied by associated palaeo-archival investigation of the blanket peat in the catchment to correlate patterns of burning, recovery times identifiable from the succeeding vegetation archive, and evidence of erosion, between lake and catchment. 10.2.2 Detailed studies based on palaeo-archival work and documented evidence of recent fires in a number of geographical areas and climatic conditions should be undertaken to determine evidence for recovery rates following fire events under differing conditions. 10.2.3 Peat cores taken in a grid across sections of blanket mire could be analysed in detail for their palaeo-archival record of erosion and recovery, looking in particular for evidence of earlier erosion events and subsequent recovery and infilling of gullies. Such work would involve detailed 3-D palaeo-archival analysis combined with carbon-dating of the various profiles in order to determine obvious age-discontinuities. 10.2.4 Detailed work is required into the relationship between the introduction of sheep to Britain and the observed pattern of erosion present in the palaeo- archive of, for example, lakes in blanket mire catchments. 10.2.5 The inter-relationship between recorded grazing levels, fire events (either documented or visible in the recent palaeo-archive), recovery times from burning, and the initiation of erosion (rather than simply the intensification of existing erosion), should be investigated. 10.2.6 The relationship between burning, grazing and erosion in other parts of the world where blanket mire can be found should be the subject of a systematic investigation.

R A Lindsay London 1 November 2009

Workshop on current status and future needs to determine C stocks

Estimation of the C stock held within the organic soils of Scotland

Based on work by S. J. Chapman, J. Bell, D. Donnelly, G. Hudson and A. Lilly

The Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK. Basin peat Blanket peat Moraine field Slope Moraine Total carbon stock =

area ¯ depth ¯ bulk density ¯ %C

But uncertainties exist in each

Area

• Area error not easy to define

Polygon error Grid count error Area (km2) Area (km2) Mean S.E. PEAT MAP UNITS Mean S.E. Basin Peat 673 6 Basin peat 666 22 Eroded Basin Peat 8 1 Blanket peat 6994 708 Blanket Peat 3711 24 Peat Map unit total 7660 808 Deep Blanket Peat 1679 16 Eroded Deep Blanket Peat 309 7 Eroded Blanket Peat 1259 14 PEAT WITHIN OTHER MAP UNITS cf Basin peat 681 km2 Blanket peat 6958 km2 Basin Peat 54 8 Semi-confined Peat 5423 360 Blanket Peat 4155 261 TOTAL 17269 Depth - Survey kit

Depthing Rods

Russian (or Macaulay) Sampler Depth - Archived records

Field notebooks Published material

FC site reports Soil Survey memoirs Depth

Peat depth (m) means ± standard errors (number of values)

Peat Type Weighted Average Depth Basin peat (>0.5 m) 2.87 ± 0.09 (360) Undifferentiated blanket peat (>0.5 m) 1.34 ± 0.10 (652) Eroded basin peat (>0.5 m) 2.72 ± 0.39 (4) Deep blanket peat (>1 m) 2.30 ± 0.15 (166) Eroded deep blanket peat (>1 m) 1.70 ± 0.04 (30) Eroded undifferentiated blanket peat (>0.5 m) 1.32 ± 0.08 (116) Peat in other map units Blanket peat 1.12 ± 0.07 (48) Basin peat 2.87 ± 0.34 (8) Semi-confined peat 1.28 ± 0.09 (71)

Dry Bulk density

• Relatively easy to measure • Few values • Limited distribution Bulk density (g cm-3) means ± standard errors (number of values)

Depth (m) 0–0.3 0.3–1 > 1

Basin peat 0.136 ± 0.022 (12) 0.114 ± 0.017 (17) 0.092 ± 0.004 (16)

Blanket peat 0.134 ± 0.009 (17) 0.123 ± 0.004 (34) 0.143 ± 0.010 (8) Dry bulk density samples

•Red Moss (Netherley) and Middlemuir bogs as part of the project

•Peat samples collected as part of other projects

•Peat samples from the NSIS_2 phases 1 and 2.

•Samples taken from Glensaugh as part of the ECOSSE1 project (Smith et al., 2007b). (Averaged to avoid bias) Proportion of carbon

• Fairly well defined (Scottish Soils Database)

Carbon contents (%) means ± standard errors (number of values)

Depth (m) – IPCC layers 0–0.3 0.3–1 > 1 Basin peat 51.1 ± 1.0 (25) 48.6 ± 1.1 (43) 60.8 ± 3.4 (2) Blanket peat 50.6 ± 1.8 (21) 52.9 ± 0.7 (49) 54.6 ± 3.2 (7) Eroded deep blanket peat 50.1 ± 3.5 (10) 57.1 ± 0.4 (8) 54.2 ± 1.2 (2) Eroded blanket peat 53.0 ± 0.9 (40) 55.2 ± 1.0 (33) 54.0 ± 3.2 (9) Relative uncertainties

Estimation of errors

% Error in Parameter No. samples Location estimates

Country-wide but some areas under- Depth ~6000 7.2 represented Country-wide but mainly near surface % C 240 3.4 (0 – 1 m) Country-wide but weighted towards NE Bulk density 104 Scotland and few deep samples 8.3 (>2 m) 1455 Area Country-wide 4.5 polygons

mean SE as %age of mean Carbon stock

Estimated carbon stocks (MtC) within Scotland for organic soils (means ± SE) Soil type C Stock C Stock Total C (<100 cm (>100 cm Stock depth) depth)

Blanket peat 737 ± 19 355 ± 46 1091 ± 50

Basin peat 44 ± 4 77 ± 6 120 ± 8

Semi-confined peat 323 ± 39 85 ± 28 408 ± 49

Total peat 1104 ± 44 516 ± 55 1620 ± 70

Validation via NSIS

• National Soils Inventory for Scotland (NSIS_1) • Select points where peat occurs • Total peatland C stock (to 100 cm) 1166 Mt C • Compares with 1104 Mt C derived from QM soil map Conclusions

Peatland C stock is 56% of total soil C stock

We believe we have a better estimate but – Little data from some areas of Scotland – Need better estimates of proportions within map units – Need more bulk density values – More measurement of peat depths • more measurements from within non-peat map units Power analysis

Precision Number • Number of samples to obtain a degree of 95% 99% precision in depth • Mean depth 2.28 m, mean variance 1.93 ± 20 % 38 65 • Confidence 95% or 99% ± 10 % 145 250 • Assumes variance in unknown areas is same ± 5 % 573 989 as in known Thanks to:

Ann Malcolm and Margaret McKeen for help with the GIS work, to Jackie Potts for statistical help, and to Zoё Frogbrook (CEH Bangor) for supplying some peat data.

Funding from the Scottish Government and the National Assembly for Wales is gratefully acknowledged. ECOSSE –Model developments Estimating Carbon in Organic Soils – Sequestration and Emissions Model development team: Jo Smith, Pia Gottschalk, Jessica Bellarby, Dali Nayak, Mark Richards, Jagadeesh Yeluripurti, Matt Aitkenhead, Martin Wattenbach, Helen Flynn, Pete Smith

Rural and Environment Research and Analysis Directorate (RERAD) Thanks to rest of project team!

Ken Killham1, Ignacio Rangel1, Ute Skiba2, Ivan Simmons2, Amanda Thomson2, Deena Mobbs2, Ronnie Milne2, Steve Chapman3, Willie Towers3, Allan Lilley3, John Bell3, Gordon Hudson3, David Lumsdon3, Brian Reynolds4, Chris Evans4, Zoë Frogbrook4, Ian Bradley5, Marianne McHugh5, Andy Whitmore6, Pete Falloon6

1 School of Biological Sciences, University of Aberdeen 2 Centre for Ecology and Hydrology (Edinburgh) 3 Macaulay Institute 4 Centre for Ecology and Hydrology (Bangor) 5 National Soils Resources Institute, University of Cranfield 6 Rothamsted Research Static models are widely used for greenhouse gas inventories Change in Soil Organic Carbon due to Land Use Change Results from CEH Inventory Approach

Calculations by D.Mobbs & A.Thomson, CEH.

Maps by M. Wattenbach, UoA …but static models do not simulate dynamic processes - robust but not applicable to new conditions

Climate Change

Changing N Changes in

Deposition CO2 conc. Dynamic models simulate processes – can be used to simulate new conditions

Arable Grassland … but 0-30cm 0-30cm previous models did not work for highly organic soils

Yellow –model works Blue -not run Red - model does not work Calculations with RothC by P.Falloon, Roth.Res. Objectives of ECOSSE model 1. Simulate new conditions & future changes → Dynamic → Process-based 2. Simulate highly organic & mineral soils → Anaerobic conditions → Layering to depth → Effect of pH → Losses of dissolved organic matter → Methane emissions → Changing microbial efficiency → Physical protection of SOM 3. Function at a range of scales → National – policy relevant → Field - evaluation → Functional model – SOM described as pools PoolPool modelsmodels

Assumption: SOM in each pool is uniform and acts in the same way

RR1 RR2 RR3 RR4 …… RRn

enzymes RR1 pp1RR1 ++ pp2RR2 ++ pp3RR3 ++ …… COCO2

Assumption: Rate dependent on concentration of R1 only -d[R ] -d[R1] which integrates to… = k1[R1] [R1]t = [R1]0 exp(-k1tt) abc) dt RateConcentration Rateconstant of ConcentrationConcentration RateEnvironmental constantTime

decompositionof R1 of R1 at timeof tR1 at start rate modifiers PoolPool modelsmodels

RothC (Jenkinson & Rayner, 1977)

DPM Decomposable plant material DPM:RPMDPM:RPM isis setset byby landland useuse typetype RPM Resistant plant material DPM:RPM Arable / Improved grassland 1.44 Unimproved grassland / Scrub 0.67 Deciduous / Tropical woodland 0.25 PoolPool ModelsModels

CO2 CO2 RothC Pools defined by (Jenkinson, 1977) - Rate constant (k) - Biomass:Humus = 0.85

- CO2 / (BIO + HUM) DPM BIO Active organicBIO matter from % clay k = 10 yr-1 k = 0.66 yr-1

RPM HUM StabilisedHUM organic matter k = 0.3 yr-1 k = 0.02 yr-1 Size of pools defines Inert organic matter IOM activity of SOM What is the initial size of the SOM pools?

Initialisation of soil C and N pools

Equilibrium Run Measured Actual Default Soil C Plant = Plant X Inputs Inputs Simulated Soil C

Equilibrium Run

C in DPM, RPM, BIO & HUM Full Simulation ECOSSE model structure

INPUTS CH4 CO2 NPP CO2 CH4 LU Type

Soil RPM DPM level

Methane Meth. Carbon Oxidation Oxid. Component BIO Decomposition HUM IOM of Organic Water Soils Model level

Derived from Water re T Texture u ex Module st t Module RothC (Jenkinson INPUTS oi ur INPUTS M e & Rayner, 1977) Max.Water T Soil T e Decomposition level e m Parameters m n n p M Drivers e e Rain,PET p e le g g o e r u y y r a d x d a t x u o t u O l O e u r M r e INPUTS e Acidity Air Temp DOC Acidity Module ECOSSE model structure

N2O NH3 INPUTS NPP, LU Type & N2 Plant N

Soil RPM DPM level NH + Nitrogen 4 Component Decomposition BIO HUM IOM of Organic Water - NO3 Soils Model level re T u ex st t Derived from Water oi ur Texture M e INPUTS Module T Module SUNDIAL e m Decomposition Max.Water n (Bradbury et al, T p e e Drivers e g level r m y n INPUTS 1993; Smith et a M x e p t le Rain,PET g o e u u Soil al, 1996) O y d r r d a e x u o t Parameters l O e u Acidity M r INPUTS e Leached Air Temp DON Nitrate N Acidity Module Evaluation of ECOSSE 1. Traditional evaluation against detailed field data • Detailed information • Does not include all soils, land uses and climates • More detail than available at national scale 2. Evaluation against national soils inventory data • Information at same detail as in national simulations • Good coverage of all soils, land uses and climates 3. Comparison to national GHG inventory estimates • Ground truth against robust estimates • Not a true evaluation Evaluation against field scale data (traditional model evaluation) Input Data

Evapotranspiration Rainfall Air temperature Land use / crop type

Water table Carbon contents depth Soil pH Texture Evaluation against field scale data (traditional model evaluation) Evaluated against... Gaseous emissions -Carbon dioxide -Nitrous oxide -Methane

Leaching losses Leaching losses Stock changes -Nitrate -Total C -Dissolved organic C -Nitrate -Dissolved organic N -Ammonium Evaluation against field scale data (traditional model evaluation)

Conclusions

• General agreement with field data Annual C and N fluxes Total C and N stocks • Some disagreement Timing of gaseous emissions and leaching events • Evaluations and improvements continue for different soil and plant types Evaluation of ECOSSE 1. Traditional evaluation against detailed field data • Detailed information • Does not include all soils, land uses and climates • More detail than available at national scale 2. Evaluation against national soils inventory data • Information at same detail as in national simulations • Good coverage of all soils, land uses and climates 3. Comparison to national GHG inventory estimates • Ground truth against robust estimates • Not a true evaluation Evaluation against data from national soils inventory Data availability • Soils data – NSIS 1 (Initialisation of SOM pools) – NSIS 2 (Evaluation of simulation of change in soil carbon)

• Land use and land use change –Exact dates unknown – Assumed land use change after 15 years

• Weather – Long term average weather data from period 1961-1990 – Actual monthly data up to 2005 Evaluation against data from national soils inventory Simulation of soil carbon

NSIS2 Sampling

) 1000000 -1 R2 = 0.94 800000

600000

400000

200000

Simulated Carbon 0-100cm (kg C ha 0 0 200000 400000 600000 800000 1000000 Measured Carbon 0-100cm (kg C ha-1) Evaluation against data from national soils inventory Simulation of soil carbon Association Lack of Coincidence Land Use R2 P-value RMSE (%) Arable 0.91 < 0.001 21 Grassland 0.93 < 0.001 39 Forestry 0.97 < 0.001 19 Natural 0.94 < 0.001 15 Overall 0.94 < 0.001 20 Evaluation against data from national soils inventory Simulation of changes in soil carbon

25 1:1 Line 20 Association 2 15 R 0.25 10 R2 5 (excluding sites with 0.80

0 CI95% > 40%) -100 -50 0 50 100 -5 Lack of 11% -10 coincidence (exp.error = -15 53%) Simulated Change Carbonin 0-100cm (%) RMS -20 Bias -25 -4% ArableMeasured -> Grass Change in CarbonGrass 0-100cm -> Arable (%) E Natural -> Forestry Evaluation against data from national soils inventory Conclusions • Simulation of change in carbon is within experimental error at all sites with land use change • Average error in the simulation of carbon change is 11% • Bias in simulation of carbon change is -4% • Uncertainty in simulation of carbon change (to be used in the national simulations) is 11% • Further evaluations against next phase of NSIS2 needed Evaluation of ECOSSE 1. Traditional evaluation against detailed field data • Detailed information • Does not include all soils, land uses and climates • More detail than available at national scale 2. Evaluation against national soils inventory data • Information at same detail as in national simulations • Good coverage of all soils, land uses and climates 3. Comparison to national GHG inventory estimates • Ground truth against robust estimates • Not a true evaluation Data used to run the model New data on soils 1km2 Carbon stocks greater than 1 metre depth

Quantified and mapped for the first time in ECOSSE Data used to run the model New data on land use change 20km2

NCMS (National Countryside Monitoring Scheme)

MLC (Monitoring Landscape Change)

Spatial scale: Counties (1971) Spatial scale: LA groupings Time periods: 1947-1969, 1969-1980 Time periods: 1947-1973, 1973-1988

Courtesy of Amanda Thomson, CEH Comparison of ECOSSE with CEH national GHG inventory

Scotland 20 2000-2009 10

-1 0 0 10 20 -50 -40 -30 -20 -10 -10 (10yrs) -2

R² = 0.93 -20

-30 (kt C (20km) C (kt

-40 1:1 Line ECOSSE simulationECOSSE of change in soil C -50 CEH estimates of change in soil C (kt C (20km)-2 (10yrs)-1 Comparison of ECOSSE with CEH national GHG inventory

Scotland 2000-2009 to arable to grassland to forestry to semi-natural -1 arable arable arable arable grassland grassland grassland grassland forestry forestry forestry forestry semi-nat semi-nat semi-nat semi-nat 20 (10yrs) -2 10 Gain in soil C 0

-10

-20 Loss of soil C

-30

Change in soil C (kt C (20km) -40

-50

ECOSSE CEH

MeasuredSoil disturbance steady state C contents of soil under grassland and semi-natural land use Comparison of ECOSSE with CEH national GHG inventory Total change in soil carbon due to all land use changes from 1950-2009. Soil changes from 2000-2009 CEH Inventory ECOSSE simulation (a) (b) (c)

Simulated changes in soil carbon (kt C 20km-2 (10 years)-1) Comparison of ECOSSE with CEH national GHG inventory Change in soil carbon due to land use change grassland to arable from 1950-2009. Soil changes from 2000-2009 CEH Inventory ECOSSE simulation (b) (a) (c)

Simulated changes in soil carbon (kt C 20km-2 (10 years)-1) Comparison of ECOSSE with CEH national GHG inventory Change in soil carbon due to land use change grassland to arable from 1950-2009. Soil changes from 2000-2009 CEH Inventory ECOSSE simulation (a) (b) (c) (a)

Simulated changes in soil carbon (kt C 20km-2 (10 years)-1) Comparison of ECOSSE with CEH national GHG inventory Conclusions

• High correlation between ECOSSE simulations and CEH estimates of change in soil C • Correspondence between magnitude and sign of changes in soil C for different land uses • Distribution of estimated emissions across the country differs in detail, especially for highly organic soils Policy relevant questions

1. What are C losses from Scottish soils? 2. On which soil types do C losses occur? 3. What changes in land use are most likely to reduce C losses? What are the carbon losses from Scottish Soils?

CEH Inventory ECOSSE (kt / year) (kt / year) 1990-1999 -913 -822 (-732 to -912)

2000-2009 -878 -810 (-721 to -899) On which 0.0 -20000.0 soil types -40000.0 Organic soils -60000.0 Mineral soils do carbon -80000.0 All soils -100000.0

-120000.0 Total change since 1950 in

losses C stocks across Scotland (kt) 50-59 60-69 70-79 80-89 90-99 00-09 occur? Decade

90.0 80.0 70.0 60.0 50.0 Organic soils 40.0 Mineral soils 30.0 20.0 10.0

Proportion of total C losses (%) losses total C ofProportion 0.0 50-59 60-69 70-79 80-89 90-99 00-09 Decade What land use changes are most likely to reduce carbon losses ?

to arable to grassland to forestry to semi-natural arable arable arable arable semi-nat semi-nat semi-nat semi-nat grassland grassland grassland grassland forestry forestry forestry forestry 100%

50% Gain in soil C 0%

-50% Loss of soil C

-100% Potential to change C emissions (%) emissions C change to Potential -150% 1.What Decrease land usegrassland changes to arearable most to likely 28%to reduce of current carbon rate losses ?

to arable to grassland to forestry to semi-natural arable arable arable arable semi-nat semi-nat semi-nat semi-nat grassland grassland grassland grassland forestry forestry forestry forestry 100%

50% Gain in soil C 0%

-50% Loss of soil C

-100% Potential to change C emissions (%) emissions C change to Potential -150% 1. Decrease grassland to arable to 28% of current rate No mitigation Mitigation applied

(a) (b)

Simulated changes in soil carbon (kt C 20km-2 (10 years)-1) 2. Stop conversion of semi-natural land to arable or grassland and a. increase grassland to semi-natural by 125%

to arable to grassland to forestry to semi-natural arable arable arable arable semi-nat semi-nat semi-nat semi-nat grassland grassland grassland grassland forestry forestry forestry forestry 100%

50% Gain in soil C 0%

-50% Loss of soil C

-100% Potential to change C emissions (%) emissions C change to Potential -150% 2a. Stop conversion of semi-natural land to arable or grassland and increase grassland to semi-natural by 125%

No mitigation Mitigation applied (a) (b)

Simulated changes in soil carbon (kt C 20km-2 (10 years)-1) 2. Stop conversion of semi-natural land to arable or grassland andand b.a. increaseincrease grasslandarable toto semi-naturalgrassland by by63% 125%

to arable to grassland to forestry to semi-natural arable arable arable arable semi-nat semi-nat semi-nat semi-nat grassland grassland grassland grassland forestry forestry forestry forestry 100%

50% Gain in soil C 0%

-50% Loss of soil C

-100% Potential to change C emissions (%) emissions C change to Potential -150% 2b. Stop conversion of semi-natural land to arable or grassland and increase arable to grassland by 63%

No mitigation Mitigation applied (a) (b) (a) (b)

Simulated changes in soil carbon (kt C 20km-2 (10 years)-1) 2. Stop conversion of semi-natural land to arable or grassland and b.c. decreaseincrease arablegrassland to grasslandto arable byto 77%63%

to arable to grassland to forestry to semi-natural arable arable arable arable semi-nat semi-nat semi-nat semi-nat grassland grassland grassland grassland forestry forestry forestry forestry 100%

50% Gain in soil C 0%

-50% Loss of soil C

-100% Potential to change C emissions (%) emissions C change to Potential -150% 2c. Stop conversion of semi-natural land to arable or grassland decrease grassland to arable to 77% of current rate

No mitigation Mitigation applied (a) (b)

(a) (b)

Simulated changes in soil carbon (kt C 20km-2 (10 years)-1) What about increasing net conversion of semi-natural to forestry?

to arable to grassland to forestry to semi-natural arable arable arable arable semi-nat semi-nat semi-nat semi-nat grassland grassland grassland grassland forestry forestry forestry forestry 100%

50% Gain in soil C 0%

-50% Loss of soil C

-100% Potential to change C emissions (%) emissions C change to Potential -150% What about increasing net conversion of semi-natural to forestry?

Not included due to method used to generate soil survey data for forestry Mitigation options

1. Decrease grassland to arable to 28% of current rate

2. Stop conversion of semi-natural land to arable or grassland and a. increase grassland to semi-natural by 125% b. increase arable to grassland by 63% c. decrease grassland to arable to 77% of current rate Conclusions 1. Field scale evaluation shows good agreement between ECOSSE and measured soil C and N stocks and annual fluxes 2. Evaluation against soil C from national soils inventory suggests uncertainty of 11% in the national simulations 3. Comparison to CEH estimates of GHG emissions shows good agreement across land uses 4. National simulations can be used to assess the impact of climate change and potential mitigation options. Acknowledgements

Rural and Environment Research and Analysis Directorate (RERAD)

European Union, Framework 7 Appendix 6. Full list of priorities for peatland research ranked by score.

Sections 1 and 2 give issues of immediate priority while sections 3 and 4 give issues that will become important in the medium term (5 – 10 years). Sections 1 and 3 give rankings based on scores for all 28 places, while sections 2 and 4 give rankings based on scores for the top 6 places only.

1. Immediate priority (sum of all 28)

Number Title Sum of all 28 21 Impact of afforestation / deforestation on soil C / net GHG emissions 412 1 Monitoring of restoration (including control on-site, success criteria) 396 10 Compile a Peat condition map for Scotland (including habitat condition, soil C stock, hydrological condition etc) 382 23 Compilation of Standard methodologies for peat and hydrology surveys (including remote sensing) 326 20 Collation of existing data (needs collaboration of researchers and funders) 306 14 Measurements of/ understanding methane production/oxidation in the context of full GHG budgets 302 2 Long term studies on impacts of climate change 294 5 Data on depth of drying / burning effects 283 4 Gather evidence on changes in vegetation due to muirburn 281 22 Information on forest soils and forest management (e.g. Impact of stump removal / brash removal) 280 13 Land use change effects on organo-mineral soils 278 6 Model development: to include feedbacks (e.g. vegetation succession) 271 18 Critical review of management techniques for restoration (e.g. Worrall et al – in press) for Scottish scenario 265 28 Peat depth & spatial variability - specifically bulk density measurements 265 12 Gain survey data from undersampled areas of Scotland 264 7 Model evaluation using more detailed studies on eco-hydrology and GHG / C balance 263 3 Fate of plant and peat C after incineration 254 8 Understanding tradeoffs between GHG emissions and other ecosystem services such as energy production 238 15 Changes in hydrology due to impact of renewable energy schemes 237 17 Define Timescales of carbon budgeting for restoration 234 27 Peat depth & spatial variability - specifically %C measurements 227 16 Changes associated with different types of access tracks constructed on peatlands (and other infrastructure) 206 25 Critical grazing levels 191 19 Combine socio-economic analysis of timing of restoration (cost/benefits of restoring) 182 24 Bioenergy / SRF / SRC (what are the pressures/ opportunities; policy drivers) 179 11 Define proportions of peats in map units that may be small so get missed (complex topography) 174 26 Understanding Nitrous oxide production in the context of full GHG budgets 153 9 Grazing - Dependence on plant communities 127 2. Immediate priority (scores based on rankings 1-6)

Number Title Sum of top 6 21 Impact of afforestation / deforestation on soil C / net GHG emissions 309 1 Monitoring of restoration (including control on-site, success criteria) 279 10 Compile a Peat condition map for Scotland (including habitat condition, soil C stock, hydrological condition etc) 268 20 Collation of existing data (needs collaboration of researchers and funders) 210 23 Compilation of Standard methodologies for peat and hydrology surveys (including remote sensing) 181 22 Information on forest soils and forest management (e.g. Impact of stump removal / brash removal) 149 13 Land use change effects on organo-mineral soils 133 2 Long term studies on impacts of climate change 131 12 Gain survey data from undersampled areas of Scotland 128 14 Measurements of/ understanding methane production/oxidation in the context of full GHG budgets 120 6 Model development: to include feedbacks (e.g. vegetation succession) 118 28 Peat depth & spatial variability - specifically bulk density measurements 78 4 Gather evidence on changes in vegetation due to muirburn 74 8 Understanding tradeoffs between GHG emissions and other ecosystem services such as energy production 74 7 Model evaluation using more detailed studies on eco-hydrology and GHG / C balance 52 25 Critical grazing levels 52 27 Peat depth & spatial variability - specifically %C measurements 52 3 Fate of plant and peat C after incineration 51 5 Data on depth of drying / burning effects 50 17 Define Timescales of carbon budgeting for restoration 50 18 Critical review of management techniques for restoration (e.g. Worrall et al – in press) for Scottish scenario 50 24 Bioenergy / SRF / SRC (what are the pressures/ opportunities; policy drivers) 50 19 Combine socio-economic analysis of timing of restoration (cost/benefits of restoring) 48 16 Changes associated with different types of access tracks constructed on peatlands (and other infrastructure) 47 9 Grazing - Dependence on plant communities 0 11 Define proportions of peats in map units that may be small so get missed (complex topography) 0 15 Changes in hydrology due to impact of renewable energy schemes 0 26 Understanding Nitrous oxide production in the context of full GHG budgets 0 3. Medium term priority rank (5-10 yrs) based on all rankings

Number Title Sum of all 28 2 Long term studies on impacts of climate change 444 21 Impact of afforestation / deforestation on soil C / net GHG emissions 345 10 Compile a Peat condition map for Scotland (including habitat condition, soil C stock, hydrological condition etc) 339 1 Monitoring of restoration (including control on-site, success criteria) 308 6 Model development: to include feedbacks (e.g. vegetation succession) 265 22 Information on forest soils and forest management (e.g. Impact of stump removal / brash removal) 261 12 Gain survey data from undersampled areas of Scotland 257 8 Understanding tradeoffs between GHG emissions and other ecosystem services such as energy production 253 14 Measurements of/ understanding methane production/oxidation in the context of full GHG budgets 247 13 Land use change effects on organo-mineral soils 242 23 Compilation of Standard methodologies for peat and hydrology surveys (including remote sensing) 242 7 Model evaluation using more detailed studies on eco-hydrology and GHG / C balance 240 17 Define Timescales of carbon budgeting for restoration 238 20 Collation of existing data (needs collaboration of researchers and funders) 224 28 Peat depth & spatial variability - specifically bulk density measurements 208 4 Gather evidence on changes in vegetation due to muirburn 203 27 Peat depth & spatial variability - specifically %C measurements 201 26 Understanding Nitrous oxide production in the context of full GHG budgets 185 5 Data on depth of drying / burning effects 183 15 Changes in hydrology due to impact of renewable energy schemes 177 18 Critical review of management techniques for restoration (e.g. Worrall et al – in press) for Scottish scenario 172 11 Define proportions of peats in map units that may be small so get missed (complex topography) 170 25 Critical grazing levels 162 16 Changes associated with different types of access tracks constructed on peatlands (and other infrastructure) 161 3 Fate of plant and peat C after incineration 160 24 Bioenergy / SRF / SRC (what are the pressures/ opportunities; policy drivers) 153 19 Combine socio-economic analysis of timing of restoration (cost/benefits of restoring) 148 9 Grazing - Dependence on plant communities 105 4. Medium term priority rank (5-10 yrs) based on top 6 rankings

Number Title Sum of top 6 2 Long term studies on impacts of climate change 369 10 Compile a Peat condition map for Scotland (including habitat condition, soil C stock, hydrological condition etc) 270 21 Impact of afforestation / deforestation on soil C / net GHG emissions 227 1 Monitoring of restoration (including control on-site, success criteria) 202 23 Compilation of Standard methodologies for peat and hydrology surveys (including remote sensing) 154 12 Gain survey data from undersampled areas of Scotland 153 14 Measurements of/ understanding methane production/oxidation in the context of full GHG budgets 125 22 Information on forest soils and forest management (e.g. Impact of stump removal / brash removal) 121 8 Understanding tradeoffs between GHG emissions and other ecosystem services such as energy production 107 20 Collation of existing data (needs collaboration of researchers and funders) 102 7 Model evaluation using more detailed studies on eco-hydrology and GHG / C balance 101 28 Peat depth & spatial variability - specifically bulk density measurements 81 13 Land use change effects on organo-mineral soils 79 6 Model development: to include feedbacks (e.g. vegetation succession) 78 27 Peat depth & spatial variability - specifically %C measurements 74 26 Understanding Nitrous oxide production in the context of full GHG budgets 72 19 Combine socio-economic analysis of timing of restoration (cost/benefits of restoring) 71 17 Define Timescales of carbon budgeting for restoration 50 11 Define proportions of peats in map units that may be small so get missed (complex topography) 49 15 Changes in hydrology due to impact of renewable energy schemes 46 4 Gather evidence on changes in vegetation due to muirburn 25 24 Bioenergy / SRF / SRC (what are the pressures/ opportunities; policy drivers) 25 16 Changes associated with different types of access tracks constructed on peatlands (and other infrastructure) 24 18 Critical review of management techniques for restoration (e.g. Worrall et al – in press) for Scottish scenario 24 25 Critical grazing levels 24 3 Fate of plant and peat C after incineration 0 5 Data on depth of drying / burning effects 0 9 Grazing - Dependence on plant communities 0

© Crown copyright 2010

ISBN: 978-0-7559-7822-9

Scottish Government St Andrew’s House Edinburgh EH1 3DG

Produced for the Scottish Government by RR Donnelley B63691

Published by the Scottish Government, February 2010

www.scotland.gov.uk