David Luscombe

Mr. David Luscombe


Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 September 2015 in Journal of Environmental Management
Verified
Journal Article
Open access
EGE. Grand-Clement
E. Grand-Clement
KAK. Anderson
K. Anderson
DSD. Smith
D. Smith
MAM. Angus
M. Angus
DLDavid Luscombe
David Luscombe
RBR.E. Brazier
R.E. Brazier
Globally, 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.

1 September 2014 in Science of The Total Environment
Verified
Journal Article
Open access
EGE. Grand-Clement
E. Grand-Clement
DLDavid Luscombe
David Luscombe
KAK. Anderson
K. Anderson
NGN. Gatis
N. Gatis
PBP. Benaud
P. Benaud
RBR.E. Brazier
R.E. Brazier
Losses 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.

25 June 2014 in Ecohydrology
Verified
Journal Article
Closed access
PDF file
DLDavid Luscombe
David Luscombe
KAKaren Anderson
Karen Anderson
NGNaomi Gatis
Naomi Gatis
AWAndrew Wetherelt
Andrew Wetherelt
EGEmilie Grand‐Clement
Emilie Grand‐Clement
RBRichard E. Brazier
Richard E. Brazier

8 July 2014 in Hydrological Processes
Verified
Journal Article
Closed access
PDF file
DLDavid Luscombe
David Luscombe
KAKaren Anderson
Karen Anderson
NGNaomi Gatis
Naomi Gatis
EGEmilie Grand‐Clement
Emilie Grand‐Clement
RBRichard E. Brazier
Richard E. Brazier

25 May 2023 in Ecology and Evolution
Verified
Journal Article
Open access
DLDavid Luscombe
David Luscombe
NGNaomi Gatis
Naomi Gatis
KAKaren Anderson
Karen Anderson
DCDonna Carless
Donna Carless
RBRichard E. Brazier
Richard E. Brazier
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.

23 February 2019 in Wetlands Ecology and Management
Verified
Journal Article
Open access
PDF file
NGNaomi Gatis
Naomi Gatis
PBPia Benaud
Pia Benaud
JAJosie Ashe
Josie Ashe
DLDavid Luscombe
David Luscombe
EGEmilie Grand-Clement
Emilie Grand-Clement
RBRichard E. Brazier
Richard E. Brazier
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.