Determining the effects of peatland restoration on carbon dioxide exchange and potential for climate change mitigation

Over the last millennium peatlands have accumulated significant carbon stores. Drainage for agricultural use has been widespread and has altered the functioning of these mires: shifting them towards carbon release. Recently, in recognition of the range of ecosystem services derived from these landscapes peatland restoration projects have been initiated. Carbon storage is often cited amongst the aims of these projects, especially since the inclusion of rewetting wetlands in the Kyoto Protocol. However, little is known about the effects of ditch blocking on CO2 fluxes, particularly in Molinia caerulea dominated peatlands, a species common on degraded peatlands which tolerates a range of water table depths. This thesis aims firstly to quantify CO2 fluxes from a drained Molinia caerulea dominated blanket bog and to improve understanding of the temporal and spatial controls on these fluxes and secondly, to quantify the immediate effects of ditch blocking. Closed chamber measurements of net ecosystem exchange and partitioned below-ground respiration from control-restored paired sites were collected over the growing seasons immediately pre- (2012) and post-restoration (2013/2014). These flux data were coupled with remotely sensed data quantifying vegetation phenology and structure with a fine resolution (daily/cm) over large extents (annual/catchment). Although temporal variation in water table depth was not related to CO2 fluxes, the seasonal average related to vegetation composition suggesting raising water tables may promote a change in vegetation composition within these species-poor ecosystems. The distribution of water table depths, vegetation composition and CO2 fluxes did not vary with proximity to drainage ditches despite their prominence. An empirical model suggests in a drained state these peatlands are CO2 sources, indicating carbon previously accumulated is gradually being lost. Data suggest restoration does not always significantly affect water tables and consequently CO2 fluxes in the short-term. Where shallower water tables were maintained during dry conditions photosynthesis decreased and heterotrophic respiration increased: enhancing carbon release. Research undertaken during atypical weather has been unable to determine if restoration will be able to raise water tables sufficiently to protect the existing peat store and promote the vegetation change required to reinstate CO2 sequestration in the longer-term.University of ExeterSouth West Wate

New approaches to the restoration of shallow marginal peatlands

ArticleGlobally, the historic and recent exploitation of peatlands through management practices such as agricultural reclamation, peat harvesting or forestry, have caused extensive damage to these ecosystems. Their value is now increasingly recognised, and restoration and rehabilitation programmes are underway to improve some of the ecosystem services provided by peatlands: blocking drainage ditches in deep peat has been shown to improve the storage of water, decrease carbon losses in the long-term, and improve biodiversity. However, whilst the restoration process has benefitted from experience and technical advice gained from restoration of deep peatlands, shallow peatlands have received less attention in the literature, despite being extensive in both uplands and lowlands. Using the experience gained from the restoration of the shallow peatlands of Exmoor National Park (UK), and two test catchments in particular, this paper provides technical guidance which can be applied to the restoration of other shallow peatlands worldwide. Experience showed that integrating knowledge of the historical environment at the planning stage of restoration was essential, as it enabled the effective mitigation of any threat to archaeological features and sites. The use of bales, commonly employed in other upland ecosystems, was found to be problematic. Instead, ‘leaky dams’ or wood and peat combination dams were used, which are both more efficient at reducing and diverting the flow, and longer lasting than bale dams. Finally, an average restoration cost (£306 ha-1) for Exmoor, below the median national value across the whole of the UK, demonstrates the cost-effectiveness of these techniques. However, local differences in peat depth and ditch characteristics (i.e. length, depth and width) between sites affect both the feasibility and the cost of restoration. Overall, the restoration of shallow peatlands is shown to be technically viable; this paper provides a template for such process over analogous landscapes.South West WaterUniversity of ExeterTechnology Strategy BoardNERCKnowledge Transfer Partnership programm

Rapid, repeatable landscape‐scale mapping of tree, hedgerow, and woodland habitats (THaW), using airborne LiDAR and spaceborne SAR data

Abstract In the UK, tree, hedgerow, and woodland (THaW) habitats are key havens for biodiversity and support many related ecosystem services. The UK is entering a period of agricultural policy realignment with respect to natural capital and climate change, meaning that now is a critical time to evaluate the distribution, resilience, and dynamics of THaW habitats. The fine‐grained nature of habitats like hedgerows necessitates mapping of these features at relatively fine spatial resolution—and freely available public archives of airborne laser scanning (LiDAR) data at 90%. It was also possible to combine LiDAR mapping data and Sentinel‐1 SAR data to rapidly track canopy change through time (i.e., every 3 months) using, cloud‐based processing via Google Earth Engine. The resultant toolkit is also provided as an open‐access web app. The results highlight that whilst nearly 90% of the tallest trees (above 15 m) are captured within the National Forest Inventory (NFI) database only 50% of THaW with a canopy height range of 3–15 m are recorded. Current estimates of tree distribution neglect these finer‐grained features (i.e., smaller or less contiguous THaW canopies), which we argue will account for a significant proportion of landscape THaW cover

Using airborne thermal imaging data to measure near-surface hydrology in upland ecosystems

This is the accepted version of the following article: Luscombe D. J., Anderson K., Gatis N., Grand-Clement E., and Brazier R. E. (2015), Using airborne thermal imaging data to measure near-surface hydrology in upland ecosystems, Hydrol. Process., 29; pages 1656–1668, which has been published in final form at http://dx.doi.org/10.1002/hyp.10285Upland ecosystems are recognized for their importance in providing valuable ecosystem services including water storage, water supply and flood attenuation alongside carbon storage and biodiversity. The UK contains 10-15% of the global resource of upland blanket peatlands, the hydrology and ecology of which are highly sensitive to external anthropogenic and climatic forcing. In particular, drainage of these landscapes for agricultural intensification and peat extraction has resulted in often unquantified damage to the peatland hydrology, and little is understood about the spatially distributed impacts of these practices on near-surface wetness. This paper develops new techniques to extract spatial data describing the near-surface wetness and hydrological behaviour of drained blanket peatlands using airborne thermal imaging data and airborne Light Detection and Ranging (LiDAR) data. The relative thermal emissivity (E{open}r) of the ground surface is mapped and used as a proxy for near-surface wetness. The results show how moorland drainage and land surface structure have an impact on airborne measurements of thermal emissivity. Specifically, we show that information on land surface structure derived from LiDAR can help normalize signals in thermal emissivity data to improve description of hydrological condition across a test catchment in Exmoor, UK. An in situ field hydrological survey was used to validate these findings. We discuss how such data could be used to describe the spatially distributed nature of near-surface water resources, to optimize catchment management schemes and to deliver improved understanding of the drivers of hydrological change in analogous ecosystems.South West Water Ltd.University of Exete

Project planning practices based on ERP projects in SMEs

Journal ArticleResearch Support, Non-U.S. Gov't© 2014 Published by Elsevier B.V.This is the author's version of a work accepted for publication by Elsevier. A definitive version was published in Science of The Total Environment Volume 493, 15 September 2014, Pages 961–973. doi:10.1016/j.scitotenv.2014.06.091Losses of dissolved organic carbon (DOC) from drained peatlands are of concern, due to the effects this has on the delivery of ecosystem services, and especially on the long-term store of carbon and the provision of drinking water. Most studies have looked at the effect of drainage in deep peat; comparatively, little is known about the behaviour of shallow, climatically marginal peatlands. This study examines water quality (DOC, Abs(400), pH, E4/E6 and C/C) during rainfall events from such environments in the south west UK, in order to both quantify DOC losses, and understand their potential for restoration. Water samples were taken over a 19 month period from a range of drains within two different experimental catchments in Exmoor National Park; data were analysed on an event basis. DOC concentrations ranging between 4 and 21 mg L(-1) are substantially lower than measurements in deep peat, but remain problematic for the water treatment process. Dryness plays a critical role in controlling DOC concentrations and water quality, as observed through spatial and seasonal differences. Long-term changes in depth to water table (30 days before the event) are likely to impact on DOC production, whereas discharge becomes the main control over DOC transport at the time scale of the rainfall/runoff event. The role of temperature during events is attributed to an increase in the diffusion of DOC, and therefore its transport. Humification ratios (E4/E6) consistently below 5 indicate a predominance of complex humic acids, but increased decomposition during warmer summer months leads to a comparatively higher losses of fulvic acids. This work represents a significant contribution to the scientific understanding of the behaviour and functioning of shallow damaged peatlands in climatically marginal locations. The findings also provide a sound baseline knowledge to support research into the effects of landscape restoration in the future

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

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