Mapping landscape-scale peatland degradation using airborne lidar and multispectral data

This is the final version. Available on open access from Springer via the DOI in this recordContext An increased interest in the restoration of peatlands for delivering multiple benefits requires a greater understanding of the extent and location of natural and artificial features that contribute to degradation. Objectives We assessed the utility of multiple, fine-grained remote sensing datasets for mapping peatland features and associated degraded areas at a landscape-scale. Specifically, we developed an integrated approach to identify and quantify multiple types of peatland degradation including: anthropogenic drainage ditches and peat cuttings; erosional gullies and bare peat areas. Methods Airborne LiDAR, CASI and aerial image datasets of the South West UK, were combined to identify features within Dartmoor National Park peatland area that contribute to degradation. These features were digitised and quantified using ArcGIS before appropriate buffers were applied to estimate the wider ecohydrologically affected area. Results Using fine-scale, large-extent remotely sensed data, combined with aerial imagery enabled key features within the wider expanse of peatland to be successfully identified and mapped at a resolution appropriate to future targeted restoration. Combining multiple datasets increased our understanding of spatial distribution and connectivity within the landscape. An area of 29 km2 or 9.2% of the Dartmoor peatland area was identified as significantly and directly ecohydrologically degraded. Conclusions Using a combination of fine-grained remotely sensed datasets has advantages over traditional ground survey methods for identification and mapping of anthropogenic and natural erosion features at a landscape scale. The method is accurate, robust and cost-effective particularly given the remote locations and large extent of these landscapes, facilitating effective and targeted restoration planning, management and monitoring.Dartmoor National Park AuthorityDartmoor Peatland PartnershipDuchy of CornwallEnvironment AgencyForestry CommissionMinistry of DefenceNatural EnglandSouth West partnership for Environmental and Economic Prosperity (SWEEP)South West WaterNatural Environment Research Council (NERC

Assessing the impact of peat erosion on growing season CO2 fluxes by comparing erosional peat pans and surrounding vegetated haggs (article)

This is the author accepted manuscript. The final version is available from International Mire Conservation Group and International Peat Society via the DOI in this record.The research data supporting this publication are openly available from the University of Exeter's institutional repository at: https://doi.org/10.24378/exe.1143.Peatlands are recognised as an important but vulnerable ecological resource. Understanding the effects of existing damage, in this case erosion, enables more informed land management decisions to be made. Over the growing seasons of 2013 and 2014 photosynthesis and ecosystem respiration were measured using closed chamber techniques within vegetated haggs and erosional peat pans in Dartmoor National Park, southwest England. Below-ground total and heterotrophic respiration were measured and autotrophic respiration estimated from the vegetated haggs. The mean water table was significantly higher in the peat pans than in the vegetated haggs; because of this, and the switching from submerged to dry peat, there were differences in vegetation composition, photosynthesis and ecosystem respiration. In the peat pans photosynthetic CO2 uptake and ecosystem respiration were greater than in the vegetated haggs and strongly dependent on the depth to water table (r2>0.78, p<0.001). Whilst in the vegetated haggs, photosynthesis and ecosystem respiration had the strongest relationships with normalised difference vegetation index (NDVI) (r2=0.82, p<0.001) and soil temperature at 15 cm depth (r2=0.77, p=0.001). Autotrophic and total below-ground respiration in the vegetated haggs varied with soil temperature; heterotrophic respiration increased as water tables fell. An empirically derived net ecosystem model estimated that over the two growing seasons both the vegetated haggs (29 and 20 gC m 2; 95 % confidence intervals of -570 to 762 and -873 to 1105 gC m-2) and the peat pans (7 and 8 gC m 2; 95 % confidence intervals of -147 to 465 and -136 to 436 gC m 2) were most likely net CO2 sources. This study suggests that not only the visibly degraded bare peat pans but also the surrounding vegetated haggs are losing carbon to the atmosphere, particularly during warmer and drier conditions, highlighting a need for ecohydrological restoration.MomentaSouth West Water (SWW)Dartmoor National Park Authorit

Drain blocking has limited short-term effects on greenhouse gas fluxes in a Molinia caerulea dominated shallow peatland (article)

This is the final version. Available on open access from Elsevier via the DOI in this recordThe dataset associated with this article is available in ORE at https://doi.org/10.24378/exe.2723Drained peatlands dominated by purple moor grass (Molinia caerulea) are widespread in the UK and Western Europe. Although substantial carbon stores may be present in these peatlands, in this degraded state they are not currently acting as carbon sinks. Therefore, M.caerulea dominated peatlands have been identified as potential sites for ecohydrological restoration to tackle the current climate emergency. However, at present little is known about whether ditch blocking can raise water tables and promote the recovery of bog plant species, and the subsequent effects on carbon sequestration in these peatlands. To investigate the potential for restoration, we measured changes in water table depth, vegetation composition, photosynthesis at 1000 μmol Photons m−2 s−1 (PG1000), ecosystem respiration (REco) and partitioned below-ground respiration in two M.caerulea dominated peatlands in which drainage ditches had been blocked located in Exmoor National Park, southwest England. Measurements were made in two headwater catchments at ⅛, ¼ and ½ of the distance between adjacent drainage ditches at four control-restored paired sites, during the growing seasons pre- (2012) and post- (2014, 2016 & 2018) restoration. Restoration had a small but significant (p = 0.009) effect on water table depths however, this did not result in a significant change in vegetation composition (p > 0.350). Ecosystem respiration increased in both the control and restored locations following restoration however, this increase was significantly smaller (p = 0.010) at the restored locations, possibly due to a similarly reduced increase in photosynthesis, although this change was not significant (p = 0.116). Below-ground respiration showed no significant changes following restoration. This research illustrates how degraded these shallow peatlands are, and raises concerns that ditch blocking alone may not bring about the high and stable water tables required to perturb the existing Molinia caerulea-dominated ecosystem and substantially alter the carbon balance. Additional restoration measures may be required.South West Water (SWW)University of ExeterTechnology Strategy Board CouncilNatural Environment Research Council (NERC

Mapping upland peat depth using airborne radiometric and lidar survey data

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.A method to estimate peat depth and extent is vital for accurate estimation of carbon stocks and to facilitate appropriate peatland management. Current methods for direct measurement (e.g. ground penetrating radar, probing) are labour intensive making them unfeasible for capturing spatial information at landscape extents. Attempts to model peat depths using remotely sensed data such as elevation and slope have shown promise but assume a functional relationship between current conditions and gradually accrued peat depth. Herein we combine LiDAR-derived metrics known to influence peat accumulation (elevation, slope, topographic wetness index (TWI)) with passive gamma-ray spectrometric survey data, shown to correlate with peat occurrence to develop a novel peat depth model for Dartmoor. Total air absorbed dose rates of Thorium, Uranium and Potassium were calculated, referred to as radiometric dose. Relationships between peat depth, radiometric dose, elevation, slope and TWI were trained using 1334 peat depth measurements, a further 445 measurements were used for testing. All variables showed significant relationships with peat depth. Linear stepwise regression of natural log-transformed variables indicated that a radiometric dose and slope model had an r2 = 0.72/0.73 and RMSE 0.31/0.31 m for training/testing respectively. This model estimated an area of 158 ±101 km2 of peaty soil >0.4 m deep across the study area. Much of this area (60 km2) is overlain by grassland and therefore may have been missed if vegetation cover was used to map peat extent. Using published bulk density and carbon content values we estimated 13.1 Mt C (8.1-21.9 Mt C) are stored in the peaty soils within the study area. This is an increase on previous estimates due to greater modelled peat depth. The combined use of airborne gamma-ray spectrometric survey and LiDAR data provide a novel, practical and repeatable means to estimate peat depth with no a priori knowledge, at an appropriate resolution (10 m) and extent (406 km2) to facilitate management of entire peatland complexes.The authors would like to thank the anonymous reviewers for the thorough reviews, their suggestions improved this paper. This work was supported by South West Water [SK06855], Dartmoor National Park Authority [SK07279] and the South West Partnership for Environmental and Economic Prosperity (SWEEP). SWEEP was funded by the Natural Environment Research Council (NE/P011217/1)

A review of planting principles to identify the right place for the right tree for ‘net zero plus’ woodlands: Applying a place‐based natural capital framework for sustainable, efficient and equitable (SEE) decisions

This is the final version. Available from Wiley via the DOI in this record. DATA AVAILABILITY STATEMENT: This is a review paper and has no original data to archive.We outline the principles of the natural capital approach to decision making and apply these to the contemporary challenge of very significantly expanding woodlands as contribution to attaining net zero emissions of greenhouse gases. Drawing on the case of the UK, we argue that a single focus upon carbon storage alone is likely to overlook the other ‘net zero plus’ benefits which woodlands can deliver. A review of the literature considers the wide variety of potential benefits which woodlands can provide, together with costs such as foregone alternative land uses. We argue that decision making must consider all of these potential benefits and costs for the right locations to be planted with the right trees. The paper closes by reviewing the decision support systems necessary to incorporate this information into policy and decision making. Read the free Plain Language Summary for this article on the Journal blog.Biotechnology and Biological Sciences Research CouncilTuring-HSBC-ONS Economic Data Science Awar

An operational land cover and land cover change toolbox processing open-source data with open source software (dataset)

Land cover and land cover change maps (2017-2021) with associated accuracy assessments for Dartmoor National Park (10m2 resolution)Natural Environment Research Council (NERC

Evaluating MODIS vegetation products using digital images for quantifying local peatland CO2 gas fluxes

ArticleIn peatlands plant growth and senescence affect annual ecosystem carbon dioxide (CO2) exchange, and CO2 fluxes show considerable inter-annual variability. Phenology is a fundamental indicator of ecosystem carbon dynamics and can be measured from remote sensing systems, but the extent to which satellite products provide useful proxies of peatland vegetation phenology is not well known. Using MODIS vegetation products coupled with field observations of phenology from a basic camera system and coupled with measurements of Gross Primary Productivity (GPP) measured using a closed chamber method, we sought to establish the extent to which satellite observations capture phenological processes at a UK peatland site. Daily, true-colour digital images were captured with a time-lapse camera (Brinno TLC100) between 23-Apr-2013 and 29-Oct-2013 and converted to a Green Red Vegetation Index (GRVI). These were compared with a range of MODIS vegetation products at various spatial resolutions. We found vegetation products with finer spatial resolution (0.90). The camera-GRVI (P=0.005, r=0.98) and MODIS-GRVI (P=0.041, r=0.89), products showed the strongest significant correlations with gross primary productivity measured using static chambers in the field. This work demonstrates that freely available MODIS data captured up to 92 % of the daily variation in phenology over an upland peatland. This approach shows great potential for capturing ecosystem carbon dynamics which underpin carbon trading schemes, a budding funding source for peatland restoration projects.The authors would like to thank the Exmoor Mires Project for their help with site access. This research received financial support from South West Water, The University of Exeter (SK05284) and the Knowledge Transfer Partnership programme (KTP 8099). This KTP was funded by the Technology Strategy Board and the Natural Environment Research Council

Drain blocking has limited short-term effects on greenhouse gas fluxes in a Molinia caerulea dominated shallow peatland (dataset)

Data collected and analysed in the production of the manuscript Gatis et al (2020) Drain blocking has limited short-term effects on greenhouse gas fluxes in a Molinia caerulea dominated shallow peatland Ecological Engineering. It includes net ecosystem exchange, methane, below-ground soil respiration and vegetation composition data for a pre-post, control-restored paired experiment of a restored drained Molinia caerulea dominated peatland. Requires Microsoft Excel to open.The article associated with this dataset is available in ORE at http://hdl.handle.net/10871/123252This is the dataset used for the Gatis et al. (2020) article "Drain blocking has limited short-term effects on greenhouse gas fluxes in a Molinia caerulea dominated shallow peatland" published in Ecological Engineering.South West Water (SWW)South West Water (SWW)University of ExeterTechnology Strategy BoardNatural Environment Research Council (NERC

Peatland restoration increases water storage and attenuates downstream stormflow but does not guarantee an immediate reversal of long-term ecohydrological degradation (dataset and analysis code)

Before and after peatland restoration data - Water table depths, stage, discharge, water quality (DOC, absorption at 254nm, 400nm, 465nm, pH), CO2 fluxes, CH4 fluxes, soil temperature. All data saved as csv files. Code used for data analysis provided in R.South West WaterSouth West Water (SWW)South West Water (SWW)South West Water (SWW)MomentaSouth West Water (SWW