Key publications
Glendell M, Macshane G, Farrow L, Quinton J, Anderson K, Evans M, Benaud P, Rawlins B, Morgan D, Jones L, et al (In Press). Testing the utility of structure from motion photogrammetry reconstructions using small unmanned aerial vehicles and ground photography to estimate the extent of upland soil erosion. Earth Surface Processes and Landforms
Gatis N, Benaud P, Ashe J, Luscombe D, Grand-Clement E, Hartley I, Anderson K, Brazier R (2019). ASSESSING THE IMPACT OF PEAT EROSION ON GROWING SEASON CO2 FLUXES BY COMPARING EROSIONAL PEAT PANS AND SURROUNDING VEGETATED HAGGS.
Wetlands Ecology and Management, 1-19.
Abstract:
ASSESSING THE IMPACT OF PEAT EROSION ON GROWING SEASON CO2 FLUXES BY COMPARING EROSIONAL PEAT PANS AND SURROUNDING VEGETATED HAGGS
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
Abstract.
Fawcett D, Blanco-Sacristán J, Benaud P (2019). Two decades of digital photogrammetry: Revisiting Chandler’s 1999 paper on “Effective application of automated digital photogrammetry for geomorphological research” – a synthesis.
Progress in Physical Geography,
43(2), 299-312.
Abstract:
Two decades of digital photogrammetry: Revisiting Chandler’s 1999 paper on “Effective application of automated digital photogrammetry for geomorphological research” – a synthesis
Digital photogrammetry has experienced rapid development regarding the technology involved and its ease of use over the past two decades. We revisit the work of Jim Chandler who in 1999 published a technical communication seeking to familiarise novice users of photogrammetric methods with important theoretical concepts and practical considerations. In doing so, we assess considerations such as camera calibration and the need for photo-control and check points, as they apply to modern software and workflows, in particular for structure-from-motion (SfM) photogrammetry. We also highlight the implications of lightweight drones being the new platform of choice for many photogrammetry-based studies in the geosciences. Finally, we present three examples based on our own work, showing the opportunities that SfM photogrammetry offers at different scales and systems: at the micro-scale for monitoring geomorphological change, and at the meso-scale for hydrological modelling and the reconstruction of vegetation canopies. Our examples showcase developments and applications of photogrammetry which go beyond what was considered feasible 20 years ago and indicate future directions that applications may take. Nevertheless, we demonstrate that, in-line with Chandler’s recommendations, the pre-calibration of consumer-grade cameras, instead of relying entirely on self-calibration by software, can yield palpable benefits in micro-scale applications and that measurements of sufficient control points are still central to generating reproducible, high-accuracy products. With the unprecedented ease of use and wide areas of application, scientists applying photogrammetric methods would do well to remember basic considerations and seek methods for the validation of generated products.
Abstract.
Publications by year
In Press
Glendell M, Macshane G, Farrow L, Quinton J, Anderson K, Evans M, Benaud P, Rawlins B, Morgan D, Jones L, et al (In Press). Testing the utility of structure from motion photogrammetry reconstructions using small unmanned aerial vehicles and ground photography to estimate the extent of upland soil erosion. Earth Surface Processes and Landforms
2020
Gatis N, Luscombe D, Benaud P, Ashe J, Grand-Clement E, Anderson K, Hartley I, Brazier R (2020). Gatis et al (2020) DATASET for Drain blocking has limited short-term effects on greenhouse gas fluxes in a Molinia caerulea dominated shallow peatland Ecological Engineering.
Benaud P, Anderson K, Evans M, Farrow L, Glendell M, James MR, Quine TA, Quinton JN, Rawlins B, Jane Rickson R, et al (2020). National-scale geodata describe widespread accelerated soil erosion.
Geoderma,
371Abstract:
National-scale geodata describe widespread accelerated soil erosion
Accelerated soil erosion can result in substantial declines in soil fertility and has devastating environmental impacts. Consequently, understanding if rates of soil erosion are acceptable is of local and global importance. Herein we use empirical soil erosion observations collated into an open access geodatabase to identify the extent to which existing data and methodological approaches can be used to develop an empirically-derived understanding of soil erosion in the UK (by way of an example). The findings indicate that whilst mean erosion rates in the UK are low, relative to the rest of Europe for example, 16% of observations on arable land were greater than the supposedly tolerable rate of 1 t ha−1 yr−1 and maximum erosion rates were as high as 91.7 t ha−1 yr−1. However, the analysis highlights a skew in existing studies towards locations with a known erosion likelihood and methods that are biased towards single erosion pathways, rather than an all-inclusive study of erosion rates and processes. Accordingly, we suggest that future soil erosion research and policy must address these issues if an accurate assessment of soil erosion rates at the national-scale are to be established. The interactive geodatabase published alongside this paper offers a platform for the simultaneous development of soil erosion research, formulation of effective policy and better protection of soil resources.
Abstract.
2019
Gatis N, Benaud P, Ashe J, Luscombe D, Grand-Clement E, Hartley I, Anderson K, Brazier R (2019). ASSESSING THE IMPACT OF PEAT EROSION ON GROWING SEASON CO2 FLUXES BY COMPARING EROSIONAL PEAT PANS AND SURROUNDING VEGETATED HAGGS.
Wetlands Ecology and Management, 1-19.
Abstract:
ASSESSING THE IMPACT OF PEAT EROSION ON GROWING SEASON CO2 FLUXES BY COMPARING EROSIONAL PEAT PANS AND SURROUNDING VEGETATED HAGGS
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
Abstract.
Gatis NL, Benaud P, Ashe J, Luscombe D, Grand-Clement E, Hartley I, Anderson K, Brazier R (2019). Assessing the impact of peat erosion on growing season CO2 fluxes by comparing erosional peat pans and surrounding vegetated haggs (dataset).
Fawcett D, Blanco-Sacristán J, Benaud P (2019). Two decades of digital photogrammetry: Revisiting Chandler’s 1999 paper on “Effective application of automated digital photogrammetry for geomorphological research” – a synthesis.
Progress in Physical Geography,
43(2), 299-312.
Abstract:
Two decades of digital photogrammetry: Revisiting Chandler’s 1999 paper on “Effective application of automated digital photogrammetry for geomorphological research” – a synthesis
Digital photogrammetry has experienced rapid development regarding the technology involved and its ease of use over the past two decades. We revisit the work of Jim Chandler who in 1999 published a technical communication seeking to familiarise novice users of photogrammetric methods with important theoretical concepts and practical considerations. In doing so, we assess considerations such as camera calibration and the need for photo-control and check points, as they apply to modern software and workflows, in particular for structure-from-motion (SfM) photogrammetry. We also highlight the implications of lightweight drones being the new platform of choice for many photogrammetry-based studies in the geosciences. Finally, we present three examples based on our own work, showing the opportunities that SfM photogrammetry offers at different scales and systems: at the micro-scale for monitoring geomorphological change, and at the meso-scale for hydrological modelling and the reconstruction of vegetation canopies. Our examples showcase developments and applications of photogrammetry which go beyond what was considered feasible 20 years ago and indicate future directions that applications may take. Nevertheless, we demonstrate that, in-line with Chandler’s recommendations, the pre-calibration of consumer-grade cameras, instead of relying entirely on self-calibration by software, can yield palpable benefits in micro-scale applications and that measurements of sufficient control points are still central to generating reproducible, high-accuracy products. With the unprecedented ease of use and wide areas of application, scientists applying photogrammetric methods would do well to remember basic considerations and seek methods for the validation of generated products.
Abstract.
2016
Luscombe DJ, Anderson K, Grand-Clement E, Gatis N, Ashe J, Benaud P, Smith D, Brazier RE (2016). How does drainage alter the hydrology of shallow degraded peatlands across multiple spatial scales?.
Journal of Hydrology,
541, 1329-1339.
Abstract:
How does drainage alter the hydrology of shallow degraded peatlands across multiple spatial scales?
Shallow, degraded peatlands differ in both their structure and function from deeper, peatland ecosystems. Previous work has shown that shallow, drained peatlands demonstrate rapid storm runoff that is only minimally controlled by antecedent hydrological conditions. However, such peatlands are also known to exhibit significant variation in ecohydrological organisation and structure across different spatial scales. In addition, predictions of hydrological response using spatially distributed numerical models of rainfall-runoff may be flawed unless they are evaluated with datasets describing the spatial variability of hydrological responses. This paper evaluates to what extent, flow generation and water storage within shallow, degraded peatland catchments may be controlled by the spatial attributes of the contributing area of the peatland, the drainage ditch size, morphology and geometry. Results from an experiment conducted over multiple spatial scales and multi-annual timescales highlights that subtle variations in the local slope and topography account for the long-term spatial patterns of water table depth. Neither the local scale of the drainage feature or the topographic contributing area is shown to be a definitive predictor of runoff in the studied catchments. Results also highlight the importance of using spatially distributed observations to ensure that estimates of water storage and runoff are representative of the fine scale spatial variability that occurs in such damaged and shallow peatlands.
Abstract.
2014
Grand-Clement E, Luscombe DJ, Anderson K, Gatis N, Benaud P, Brazier RE (2014). Antecedent conditions control carbon loss and downstream water quality from shallow, damaged peatlands.
Science of the Total Environment,
493, 961-973.
Abstract:
Antecedent conditions control carbon loss and downstream water quality from shallow, damaged peatlands
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, Abs400, 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 19month 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 21mgL-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 (30days 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.
Abstract.
