Richard E. Brazier’s research while affiliated with University of Exeter and other places

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Publications (195)


Images of the site before and after restoration with a conceptual diagram showing how rewetting has altered the hydrological connectivity of dendritic flow pathways across the site.
Shaded ribbons represent model 95% confidence limits for before and after restoration. General Additive Model (GAM) hydrographs with individual rainfall records presented as points (a) and individual event hydrographs presented as lines (b) with average event peaks shown as black crosses. General linear model fitted to the relationship between total hydrological event rainfall and peak event discharge (c).
Depth to water table (m) before and after restoration in (a), the peat pans and (b), the vegetated haggs. Ground level is indicated by the horizontal dashed line, this is offset by 0.2 m between the panels as the peat pans are stepped down relative to the surrounding haggs. Vertical lines reach the minimum and maximum, boxes stretch from the 5th to the 95th quantile, the horizontal bar indicates the median.
Maximum photosynthesis (a), ecosystem respiration (b) (µmol CO2 m⁻² s⁻¹) and alpha (c) from seasonal light response curves for different rewetting treatments in the vegetated haggs. Restoration occurred between the 2014 and 2015 measurements marked by the vertical line. Values are in Supplementary Information Table 1.
Measured mean (a) and estimated marginal mean (b) dark methane emissions (µmol CH4 m⁻² s⁻¹) for different rewetting treatments in vegetated haggs and sparsely vegetated peat pans. All measurements were taken following restoration. Letters denote statistically significant groups.

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Peatland restoration increases water storage and attenuates downstream stormflow but does not guarantee an immediate reversal of long-term ecohydrological degradation
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September 2023

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5 Citations

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Richard E. Brazier

Peatland restoration is experiencing a global upsurge as a tool to protect and provide various ecosystem services. As the range of peatland types being restored diversifies, do previous findings present overly optimistic restoration expectations? In an eroding and restored upland peatland we assessed short-term (0–4 year) effects of restoration on ecohydrological functions. Restoration significantly reduced discharge from the site, transforming peat pans into pools. These retained surface water over half the time and were deeper during wet periods than before. In the surrounding haggs water tables stabilised, as drawdown during dry conditions reduced, increasing the saturated peat thickness. Despite these changes, there were no effects on photosynthesis, ecosystem respiration or dissolved organic carbon loads leaving the site. Soil respiration did not decrease as water tables rose, but methane emissions were higher from rewet pools. Restoration has had a dramatic effect on hydrology, however, consequent changes in other ecosystem functions were not measured in the 4 years after restoration. Whilst restoration is crucial in halting the expansion of degraded peatland areas, it is vital that practitioners and policymakers advocating for restoration are realistic about the expected outcomes and timescales over which these outcomes may manifest.

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Eurasian beaver feeding on vegetation on the River Otter, England (Credit: R.E. Auster).
of key points in the cases for and against naming individual animals in reintroduction projects.
Should individual animals be given names in wildlife reintroductions?

June 2023

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214 Reads

Individual animals are often given names by humans. For example, names are attributed to domestic animals to acknowledge their closeness to people, some research studies use names to identify differences between individuals in a study group, or zoos often use names to tell stories that attract public or media attention. Publicly naming individual animals can provide opportunities in conservation, but there are also risks. In this perspective we exemplify such opportunities and risks in the context of wildlife reintroductions. We draw on examples and observations from our experience researching Eurasian beaver Castor fiber reintroduction in England, to encourage careful thinking before publicly attributing a name to an individual in reintroduction projects. Naming individuals in reintroduction can: be a low‐cost engagement tool; help people relate to unfamiliar reintroduced species; encourage local ownership of reintroduction projects; enable an effective tool for communicating information about the species and ways to coexist; or support creative or cultural expression. Yet naming individuals in reintroduction could: risk misrepresentation of natural species characteristics; make it challenging to normalise the sense that the reintroduced species is a wild animal; unintentionally imply that humans have ownership or power over the animal; cause distraction from establishing viable populations due to focus on the individual; or result in human investment in individual animals, which may have influence on reintroduction outcomes if that animal later comes to harm or dies (naturally or otherwise). Synthesis and Applications . We argue there is more to the act of naming individuals than may first appear. If considering doing so, we call for careful thought about whether it is appropriate and how to go about it. While we intentionally refrain from concluding whether ‘to name or not to name’, we call for careful, informative, message framing that takes advantage of the opportunities and is prepared for future circumstances, when naming of individuals does take place. Read the free Plain Language Summary for this article on the Journal blog.


Optical reflectance across spatial scales—an intercomparison of transect-based hyperspectral, drone, and satellite reflectance data for dry season rangeland

June 2023

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240 Reads

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3 Citations

Drone-based multispectral sensing is a valuable tool for dryland spatial ecology, yet there has been limited investigation of the reproducibility of measurements from drone-mounted multispectral camera array systems or the intercomparison between drone-derived measurements, field spectroscopy, and satellite data. Using radiometrically calibrated data from two multispectral drone sensors (MicaSense RedEdge (MRE) and Parrot Sequoia (PS)) co-located with a transect of hyperspectral measurements (tramway) in the Chihuahuan desert (New Mexico, USA), we found a high degree of correspondence within individual drone data sets, but that reflectance measurements and vegetation indices varied between field, drone, and satellite sensors. In comparison to field spectra, MRE had a negative bias, while PS had a positive bias. In comparison to Sentinel-2, PS showed the best agreement, while MRE had a negative bias for all bands. A variogram analysis of NDVI showed that ecological pattern information was lost at grains coarser than 1.8 m, indicating that drone-based multispectral sensors provide information at an appropriate spatial grain to capture the heterogeneity and spectral variability of this dryland ecosystem in a dry season state. Investigators using similar workflows should understand the need to account for biases between sensors. Modelling spatial and spectral upscaling between drone and satellite data remains an important research priority.


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

May 2023

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248 Reads

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6 Citations

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 <2 m spatial resolution offer a means of doing so within UK settings. The high cost of LiDAR prohibits use for regular monitoring of THaW change, but space-borne sensors such as Sentinel-1 Synthetic Aperture Radar (SAR at ca. 10 m resolution) can potentially meet this need once baseline distributions are established. We address two aims in this manuscript-(1) to rapidly quantify THaW across UK landscapes using LiDAR data and (2) to monitor canopy change intra- and inter-annually using SAR data. We show that workflows applied to airborne LiDAR data can deliver THaW baselines at 2 m resolution, with positional accuracy of >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.


Figure 1. Summary maps showing location of beaver (top) and water vole (bottom) recorded field survey signs in the year beavers were released into the site (2016) and the most recent post-beaver survey year. Insert map shows location of study site in Southwest England. The main river network bordering the site is mapped based upon the OS Open Rivers Network © Ordnance Survey Limited 2021 with the direction of flow indicated by the blue arrow in the top left map.
Figure 2. Water vole field sign numbers for each survey year.
Figure 3. Overlay between water vole signs with beaver impacted areas (derived from beaver feeding sign surveys) and ponded surface water between the year beavers were released into the site (2016) and the most recent survey year (2021). Buffered layers used to represent GPS uncertainty. The main river network bordering the site is mapped based upon the OS Open Rivers Network © Ordnance Survey Limited 2021 with the direction of flow indicated by the blue arrow in the left map.
Figure 4. Examples of 2021 water vole field signs recorded in beaver created wetland areas. Background image is a drone orthomosaic of the site whilst signs represent examples of recorded water vole field sign locations recorded with GPS and buffered to account for spatial uncertainty.
Positive coexistence of water voles and beaver: water vole expansion in a beaver engineered wetland

May 2023

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406 Reads

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1 Citation

Mammal Communications

Water voles (Arvicola amphibius) are critically endangered in Great Britain and there is a pressing need for successful conservation strategies. Meanwhile, another semi-aquatic rodent, the Eurasian beaver (Castor fiber) is being restored to much of its native range including Great Britain. Beavers are known as ecosystem engineers and keystone species, creating wetland habitats. As part of the River Otter Beaver Trial in SouthWest England, free-living beavers were reintroduced in a location where water vole were present and being surveyed. Here, we present survey data showing the expansion of water vole into newly beaver engineered wetland areas. We propose that complex beaver wetlands may benefit water vole populations by creating new habitat and providing refuge from predation, warranting further investigation as a nature recovery option.



Figure 1. Visualization of the three stages in the Species-specific Management Group process.
Learning to Live with Reintroduced Species: Beaver Management Groups are an Adaptive Process

March 2023

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114 Reads

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7 Citations

Restoration Ecology

In anthropogenic landscapes, wildlife reintroductions are likely to result in interactions between people and reintroduced species. People living in the vicinity may have little familiarity with the reintroduced species or associated management, so will need to learn to live with the species in a new state of ‘Renewed Coexistence’. In England, Eurasian beavers (Castor fiber) are being reintroduced and UK Government agencies are currently considering their national approach to reintroduction and management. Early indications are this will include requirement for ‘Beaver Management Groups’ (BMGs) to engage with local stakeholders. This policy paper reports on qualitative research that captured lessons from the governance of two existing BMGs in Devon (south‐west England), drawing on prior study (Auster et al. 2022c) and new interview data. Through the analysis, we identified that BMGs are not a fixed structure, but an adaptive process. This consists of three stages (Formation, Functioning, and Future?), influenced by resource availability and national policy direction. We argue that, where they are used, species‐specific Management Groups could provide a ‘front line’ for the integration of reintroduced species into modern landscapes, but their role or remit could be scaled back over time and integrated into existing structures or partnerships to reduce pressure on limited resources, as knowledge of reintroduced species (such as beaver) grows and its presence becomes ‘normalised’. There must be sufficient flexibility in forthcoming policy to minimise constraint on the adaptive nature of BMGs and similar groups for other reintroduced species, if they are to facilitate a sustainable coexistence. This article is protected by copyright. All rights reserved.


Testing a novel sonar‐based approach for measuring water depth and monitoring sediment storage in beaver ponds

November 2022

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81 Reads

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3 Citations

River Research and Applications

Widely available ‘fish‐finder’ echo‐sounding devices are beginning to be used in bathymetric studies to estimate geomorphic change. To date, however, there have been no applications in shallow and complex wetlands, where changes in sediment storage are notoriously dynamic in time and difficult to describe accurately in space. Therefore, in this study, we tested the performance of an ‘off‐the‐shelf’ fish‐finder for mapping bathymetry in a shallow beaver pond. We tested fish‐finder sonar depth readings against a traditional‐sounding lead‐line method across 21 paired Sampling Points with a minimum depth of 0.31 m and a mean of 0.65 m. Spatial accuracy of the unit was also tested against a differentially corrected Global Navigation Satellite System (GNSS) receiver. Measured depths to pond bottom from the fish‐finder were on average within 5%, although significantly 0.015 m (SD = 0.034) less than those obtained by the lead‐line method. Spatial accuracy, however, varied greatly compared to the corrected GNSS receiver readings, with a mean discrepancy of 2.7 m (SD = 1.5) but up to 6.2 m. Given the close match of depth readings between the two methods, we conclude that sonar is a suitable, cost‐effective, and less‐intrusive method than existing techniques, even in moderately vegetated shallow waterbodies. Methods do need to be adopted to account for poor spatial precision with ‘off‐the‐shelf’ fish‐finder models, but this can be rectified with survey design or using a secondary GNSS. Application of this technology will allow rapid one‐off surveys or repeated monitoring of depth, bedform and sediment accumulation in otherwise hard‐to‐access or disturbance‐sensitive wetlands, such as beaver ponds and water treatment or flow attenuation wetlands.


Exploring the dynamics of flow attenuation at a beaver dam sequence

October 2022

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147 Reads

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4 Citations

Hydrological Processes

Beavers influence hydrology by constructing woody dams. Using a Before After Control Impact experimental design, we quantified the effects of a beaver dam sequence on the flow regime of a stream in SW England and consider the mechanisms that underpin flow attenuation in beaver wetlands. Rainfall‐driven hydrological events were extracted between 2009 and 2020, for the impacted (n=612) and control (n=634) catchments, capturing events seven years before and three years after beaver occupancy, at the impacted site. General additive models were used to describe average hydrograph geometry across all events. After beaver occupancy, Lag times increased by 55.9% in the impacted site and declined by 17.5% in the control catchment. Flow duration curve analysis showed a larger reduction in frequency of high flows, following beaver dam construction, with declines of Q5 exceedance levels of 33% for the impacted catchment and 15% for the control catchment. Using event total rainfall to predict peak flow, five generalised linear models were fitted to test the hypothesis that beaver dams attenuate flow, to a greater degree, with larger storm magnitude. The best performing model showed, with high confidence, that beaver dams attenuated peak flows, with increasing magnitude, up to between 0.5‐2.5 m3 s‐1 for the 94th percentile of event total rainfall; but attenuation beyond the 97th percentile cannot be confidently detected. Increasing flow attenuation, with event magnitude, is attributed to transient floodplain storage in low gradient/profile floodplain valleys that results from an increase in active area of the floodplain. These findings support the assertion that beaver dams attenuate flows. However, with long‐term datasets of extreme hydrological events lacking, it is challenging to predict the effect of beaver dams during extreme events with high precision. Beaver dams will have spatially variable impacts on hydrological processes, requiring further investigation to quantify responses to dams across differing landscapes and scales. This article is protected by copyright. All rights reserved.


Beaver Management Groups: Capturing lessons from the River Otter Beaver Trial and River Tamar Catchment (NECR434)

September 2022

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276 Reads

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1 Citation

This Natural England commissioned report is a social science case study of how beaver management groups are forming around the unofficial beaver populations. It draws on findings from a previous, peer-reviewed study that captured the experiences of stakeholders involved in governing the River Otter Beaver Trial (ROBT) (Renewed Coexistence: Learning from Steering Group Stakeholders on a Beaver Reintroduction Project in England, 2022), and explores the applicability of those findings to the River Tamar. The findings of the report can be applied to other settings and inform the development of other Beaver Management Groups. The findings were that Beaver Management Groups can be adaptive structures that evolve in reflection of changing circumstances and new learning. Rather than being a fixed governance structure therefore, Beaver Management Groups themselves are a process, that seeks to facilitate renewed coexistence between humans and beavers in catchment settings. Three key stages to in the beaver management group process were identified: ‘Formation’, ‘Functioning’, and ‘Future?’. It also considers the external factors at play at each stage of the process.


Citations (87)


... Water Table Depth (WTD) can fall dramatically during drought periods. Rewetting through blocking erosion gullies or drainage ditches has, however, been shown to stabilise WTD, particularly by reducing drops in water levels during dry months (Gatis et al., 2023;Wilson et al., 2010). Wilson et al. (2010) found that WTD in rewetted peatland never fell below approx. ...

Reference:

Climate change impacts on blanket peatland in Great Britain
Peatland restoration increases water storage and attenuates downstream stormflow but does not guarantee an immediate reversal of long-term ecohydrological degradation

... The high spatial resolution available with drones provides an effective support to achieve more accurate analysis than satellite data (Slade et al., 2023). Excellent results can also be achieved with free downloadable image processing software (Hung et al., 2019), but these require a large amount of data. ...

Optical reflectance across spatial scales—an intercomparison of transect-based hyperspectral, drone, and satellite reflectance data for dry season rangeland

... This finding underscores a concerning oversight in present estimations of tree distribution, as it disregards smaller or less connected tree, hedgerow, and woodland habitats (THaW) canopies. These neglected habitats constitute a substantial portion of overall THaW habitat coverage, landscape carbon storage capacities, and ecological interconnectedness [121]; and so should be identified, understood, and analyzed. The automatic extraction of hedgerows from remotely sensed images has gained attention in recent years. ...

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

... As significant anthropogenically driven wetland habitat loss persists across the beaver's native range, the higher biodiversity within beaver wetlands is generally considered a positive effect (Law et al. 2017). Several freshwater threatened and endangered species benefit from beaver-created habitat as well, including steelhead (Oncorhynchus mykiss) (Bouwes et al. 2016), Oregon spotted frogs (Rana pretiosa) (Rowe et al. 2024), Columbia spotted frogs (Rana luteiventris) (Arkle & Pilliod 2015), and water voles (Arvicola amphibius) (Puttock et al. 2023). ...

Positive coexistence of water voles and beaver: water vole expansion in a beaver engineered wetland

Mammal Communications

... A review of the literature on applying SfM in geosciences can be found in some publications 1,2,[11][12][13] . In the case of geomorphology, there is also a wide range of applications in studies, e.g. of river valleys and channel systems [14][15][16][17][18][19][20][21] , coasts [22][23][24][25][26][27][28][29][30] , weathering and slope processes [31][32][33][34] , soil erosion [35][36][37] , glacial and periglacial relief 13,[38][39][40][41] , volcanic relief 42 , the role of macrofauna in the transformation of mudflat relief 43 , fault zone transformation and channel development 44 , the transformation of anthropogenic relief 45 . ...

Structure-from-Motion Photogrammetry and Rare Earth Oxides can quantify diffuse and convergent soil loss and source apportionment
  • Citing Article
  • May 2023

International Soil and Water Conservation Research

... Chalk streams are a UK government priority habitat for restoration (Environment Agency 2021) and mitigation measures are therefore required to improve chalk stream status. The reintroduction of the Eurasian beaver (Castor fiber) is currently being proposed more broadly by catchment conservation groups as a potential river restoration solution (Auster et al. 2020(Auster et al. , 2023. ...

Learning to Live with Reintroduced Species: Beaver Management Groups are an Adaptive Process

Restoration Ecology

... Sonar systems (sound navigation and ranging) are an RS technology that can be used to measure the water depth (only for rather shallow water, with ICESat up to approx. 12 m in turbid Baltic Sea water) and volume by sending sound pulses into the water and recording the time it takes for them to return [103]. Furthermore, optical RS technology such as Word View, Sentinel-2 MSI or Landsat 8/9 OLI can be used for quantifying the water level, especially in the case of lakes and reservoirs [104]. ...

Testing a novel sonar‐based approach for measuring water depth and monitoring sediment storage in beaver ponds
  • Citing Article
  • November 2022

River Research and Applications

... The reduction of peak discharge by online and offline storage areas is effective and notable in both fieldwork and modeling results (Table S1). However, the location of offline storage features is the most important factor, which depends on the soil type, number, and spatial distribution of these features in the catchment (Bezak et al. 2021;Fennell et al. 2022;Graham et al. 2022;Metcalfe et al. 2017aMetcalfe et al. , 2017bMetcalfe et al. 2018;Nicholson et al. 2020). In contrast, impacts due to land-cover changes have more uncertainty. ...

Exploring the dynamics of flow attenuation at a beaver dam sequence

Hydrological Processes

... Such solutions can work as well or better than traditional infrastructure while also providing habitat or shelter for a diverse array of organisms. Typical examples involve creating floodable land (usually on former floodplains) by working with farmers or by creating bypasses around cities for flood waters (Opperman et al. 2017 ), promoting upland reforestation and decompacting soil, using natural materials such as logs to create permeable barriers that can reduce flow velocities and provide habitat (Deane et al. 2021 ), and reintroducing beaver ( Castor spp.) in the northern hemisphere (Auster et al. 2022 ). ...

Reference:

Flood ecology
Beaver Management Groups: Capturing lessons from the River Otter Beaver Trial and River Tamar Catchment (NECR434)

... Earlier DOC export estimates have mostly been based on weekly or bi-weekly grab samples leading to a large uncertainty in export numbers, especially in small catchments (Schleppi et al., 2006a;Schleppi et al., 2006b). By using novel 50 techniques, high-frequency measurements over long periods lead to better estimates of DOC export (Ritson et al., 2022). ...

High frequency UV–Vis sensors estimate error in riverine dissolved organic carbon load estimates from grab sampling