Western Britain Research Articles

Human genetic structure in Northwest France provides new insights into West European historical demography

The demographical history of France remains largely understudied despite its central role toward understanding modern population structure across Western Europe. Here, by exploring publicly available Europe-wide genotype datasets together with the genomes of 3234 present-day and six newly sequenced medieval individuals from Northern France, we found extensive fine-scale population structure across Brittany and the downstream Loire basin and increased population differentiation between the northern and southern sides of the river Loire, associated with higher proportions of steppe vs. Neolithic-related ancestry. We also found increased allele sharing between individuals from Western Brittany and those associated with the Bell Beaker complex. Our results emphasise the need for investigating local populations to better understand the distribution of rare (putatively deleterious) variants across space and the importance of common genetic legacy in understanding the sharing of disease-related alleles between Brittany and people from western Britain and Ireland.

Spatio-temporal clustering of extreme floods in Great Britain

ABSTRACT Quantifying the tendency of flood events to demonstrate clustering in time and space is crucial for flood risk assessments. We analyse the temporal (TC) and spatial (SC) coherence of floods in 554 catchments over Great Britain. TC was assessed using the dispersion-index and Conway-Maxwell-Poisson regression, with both methods applied to aggregation windows of 1–5 years. SC was investigated using the flood susceptibility index. Results show that i) most of the UK peak floods are overdispersed and ii) a positive relationship exists between winter mean North Atlantic Oscillation anomalies and the annual number of peak floods across western Britain. The susceptibility to widespread floods is higher for the southeast parts of Britain and for the Clyde-Forth valleys, and it increases with catchment permeability and with the influence of lakes/reservoirs. These findings are relevant to enhance existing flood hazard estimation methods and, in turn, will lead to more realistic flood risk quantification.

Variability in the summer movements, habitat use and thermal biology of two fish species in a temperate river

The ability of fish to cope with warm water temperatures in summer depends on factors including their thermal traits and the ability of individuals to access cool-water refugia. Knowledge is highly limited on the in situ responses of many fishes to elevated summer temperatures, including whether they express behavioural thermoregulation. The responses of two riverine species to summer water temperatures were tested here using the movement metrics, spatial habitat use and body temperatures of individual European barbel Barbus barbus (‘barbel’) and common bream Abramis brama (‘bream’) versus river temperatures. Acoustic biotelemetry was applied in the lower River Severn basin, western Britain, in summer 2021 (barbel) and 2022 (bream), where individuals could move across > 150 km of river, including a tributary of cooler water. Across all individuals, bream occupied 37 km of river length (mainstem only), with low inter-individual variability in their spatial habitat use, movements and body temperatures. In contrast, barbel occupied 62 km of river (main river/tributary), with relatively high inter-individual variability in spatial habitat use, movements and body temperatures, with higher variation in body temperatures as river temperatures increased (maximum mean daily temperature difference between individuals on the same day: 4.2 °C). Although warmer individuals generally moved more, their activity was greatest at relatively low temperatures and higher flows, and neither species revealed any evidence of behavioural thermoregulation during elevated temperatures. Enabling phenotypically diverse fish populations to express their natural behaviours and thermal preferences in summer water temperatures thus requires maintaining their free-ranging in thermally heterogenous habitats.

Movements and habitat use of native and invasive piscivorous fishes in a temperate and channelized lowland river

AbstractLowland temperate rivers provide important habitats for piscivorous fishes, but with their year-round spatial and temporal habitat use is often poorly understood, including their use of off-channel habitats. Here, the movements and habitat use of the piscivorous native Northern pike Esox lucius and invasive pikeperch Sander lucioperca were investigated using acoustic telemetry in the highly regulated (through impoundment) lower River Severn, Western England over a 12-month period, where off-channel habitat availability was limited to a single boat marina. The movements of both species varied with season and temperature, with both species moving greater distances in spring. Increasing water temperatures up to 15 °C resulted in a higher frequency of movements of both species, but movements then decreased at temperatures higher than this. Northern pike detections in the river increased in periods of lower river discharge and warmer temperatures, with the off-channel refuge providing an important habitat all year round (78% of detections occurred there). While 63% of pikeperch detections also occurred in the marina, 89% of these detections occurred between December and April. These results thus emphasise the importance of this limited off-channel habitat as potential spawning locations for invasive pikeperch and foraging areas for native Northern pike.

A new chronology for the Welsh hillfort of Dinas Powys

Excavated by Leslie Alcock in the 1950s, the inland promontory fort of Dinas Powys is widely cited as a type site for elite settlements of post-Roman western Britain. Alcock's interpretation and dating of the main defences as a Norman-period castle were effectively disproven in the 1990s, but the excavator's original chronology continues to be cited. Here, the authors present a revised chronology, integrating new radiocarbon dates and stratigraphic analysis to re-evaluate the history of occupation. The new phasing redates the main defences to the early medieval period, which aligns with the site's notable early medieval assemblage. The findings contribute to understanding of post-Roman western Britain and the (re)occupation of late antique hilltop sites more generally.

Abrupt drought termination in the British–Irish Isles driven by high atmospheric vapour transport

During protracted dry spells, there is considerable interest from water managers, media and the public in when and how drought termination (DT) will occur. Robust answers to these questions require better understanding of the hydroclimatic drivers of DT than currently available. Integrated vapour transport (IVT) has been found to drive DT in Western North America, but evidence elsewhere is lacking. To evaluate this association for the British–Irish Isles, event coincidence analysis is applied to 354 catchments in the UK and Ireland over the period 1900–2010 using ERA-20C reanalysis IVT data and 7589 DT events extracted from reconstructed river flow series. Linkages are identified for 53% of all DT events across all catchments. Associations are particularly strong for catchments in western and southern regions and in autumn and winter. In Western Scotland, 80% of autumn DTs are preceded by high IVT, whilst in Southern England more than two thirds of winter DTs follow high IVT episodes. High IVT and DT are most strongly associated in less permeable, wetter upland catchments of Western Britain, reflecting their maritime setting and orographic enhancement of prevailing south-westerly high IVT episodes. Although high IVT remains an important drought-terminating mechanism further east, it less frequently results in DT. Furthermore, the highest rates of DT occur with increasing IVT intensity, and the vast majority of the most abrupt DTs only occur following top decile IVT and under strongly positive North Atlantic Oscillation (NAO) conditions. Since IVT and NAO forecasts may be more skilful than those for rainfall which underpin current forecasting systems, incorporating these findings into such systems has potential to underpin enhanced forecasting of DTs. This could help to mitigate impacts of abrupt recoveries from drought including water quality issues and managing compound drought–flood hazards concurrently.

Adam Smith revisited: the relationship between the English woollen manufacture and the availability of coal before the use of steam power

AbstractThe timing of textile de-industrialisation in eastern, southern, and western England and the concomitant shift of the woollen manufacture to the West Riding of Yorkshire is examined in temporal detail. The study shows that the manufacture was moving to settlements with cheap coal, low cost of living and running water as early as the sixteenth century. These settlements became key woollen manufacture centres and remained so until the nineteenth century. The industry was located on the West Riding of Yorkshire coal field long before the industrial revolution and the demand for coal to generate steam power.

Seismicity of Ireland, and why it is so low: How the thickness of the lithosphere controls intraplate seismicity

SUMMARY Ireland and neighbouring Britain share much of their tectonic history and are both far from active plate boundaries at present. Their seismicity shows surprising lateral variations, with very few earthquakes in Ireland but many low-to-moderate ones in the adjacent western Britain. Understanding the cause of these variations is important for our understanding of the basic mechanisms of the intraplate seismicity distributions and for regional hazard assessment. The distribution of microseismicity within Ireland and its underlying causes have been uncertain due to the sparsity of the data sampling of the island, until recently. Here, we use the data from numerous recently deployed seismic stations in Ireland and map its seismicity in greater detail than previously. The majority of detectable seismic events are quarry and mine blasts. These can be discriminated from tectonic events using a combination of the waveform data, event origin times, and the epicentres’ proximity to quarries and mines, catalogued or identified from the satellite imagery. Our new map of natural seismicity shows many more events than known previously but confirms that the earthquakes are concentrated primarily in the northernmost part of the island, with fewer events along its southern coast and very few deeper inland. Comparing the seismicity with the recently published surface wave tomography of Ireland and Britain, we observe a strong correspondence between seismicity and the phase velocities at periods sampling the lithospheric thickness. Ireland has relatively thick, cold and, by inference, mechanically strong lithosphere and has very few earthquakes. Most Irish earthquakes are in the north of the island, the one place where its lithosphere is thinner, warmer and, thus, weaker. Western Britain also has relatively thin lithosphere and numerous earthquakes. By contrast, southeastern England and, probably, eastern Scotland have thicker lithosphere and, also, few earthquakes. The distribution of earthquakes in Ireland and Britain is, thus, controlled primarily by the thickness and mechanical strength of the lithosphere. The thicker, colder, stronger lithosphere undergoes less deformation and features fewer earthquakes than thinner, weaker lithosphere that deforms more easily. Ireland and Britain are tectonically stable and the variations in the lithospheric thickness variations across them are estimated to be in a 75–110 km range. Our results thus indicate that moderate variations in the lithospheric thickness within stable continental interiors can exert substantial control on the distributions of seismicity and seismic hazard—in Ireland, Britain and elsewhere around the world.

‘A hard rain's a‐gonna fall’: torrential rain, flash floods and desert lakes in the Late Triassic Arden Sandstone of Central England

The Arden Sandstone Formation of central and western England is a thin but conspicuous arenaceous unit within the Late Triassic Mercia Mudstone Group. Sedimentological and palaeontological data point to lacustrine depositional conditions, in contrast to the red desert mudstones above and below which were deposited as continental dryland desert floodplains. The Arden Sandstone records deposits of the lake margins and may be the high stand lateral equivalent of the halite and gypsum deposits which formed in the lake centre. The Carnian age of the Arden Sandstone potentially links it to the Carnian Pluvial Episode, marking the coalescence, spread and freshening of the formerly saline desert lakes, and deposition of sandy, fluvial and lacustrine deposits, during the wetter climate that prevailed for at least a million years.

A multidisciplinary investigation of Storms Ciara and Dennis, February 2020

High magnitude storms have periodically impacted the communities of Western Britain and this storm threat is predicted to increase with climate change. Understanding the factors that contribute to storm catastrophe is essential to mitigate the effects of future storms. This multidisciplinary study collectively analyses meteorological, tidal gauge and newspaper data from Storms Ciara and Dennis in February 2020 to assess the environmental, social and political impacts and causes of the catastrophe in Western Britain. The analysis shows that although the storm period comprising Ciara and Dennis was a meteorological climate anomaly and short-term local authority and community responses were effective, shortcomings in governmental policies likely enhanced storm impacts. The study findings suggest that substantive changes to UK government coastal and fluvial management policies and the wider long-term climate change strategy are required to address climate change risk and reduce community storm vulnerability in Western Britain. The key roles of the media in enhancing public hazard preparedness and raising awareness of the impacts of climate change catastrophes and the wider climate crisis are exhibited. A multidisciplinary mixed methods analysis combining quantitative meteorological and tidal data, qualitative newspaper data and peer-reviewed research is shown to identify the likely cause of catastrophe and can inform future climate change vulnerability mitigation.

Pleistocene environments, climate, and human activity in Britain during Marine Isotope Stage 7: insights from Oak Tree Fields, Cerney Wick, Gloucestershire

ABSTRACTInvestigations at Oak Tree Fields, Cerney Wick, Gloucestershire, in western England have revealed a sequence of fluvial deposits dating from Marine Oxygen Isotope Stage (MIS) 7 to 5. At the base of the sequence, a series of gravel and sand facies were deposited, initially as part of a meandering river. Reductions in flow energy of the latter and avulsion led to the development of short‐lived channels and episodic backwater environments, the deposits of which are recorded as Facies Associations 1–3. Poorly sorted, probably colluvial deposits formed beyond the limit of the channel (Facies Association 4). Mollusca, Coleoptera, plant macrofossils, pollen and vertebrates recovered from the channel facies indicate broadly similar climatic conditions throughout accretion. Temperature ranges derived from mutual climatic range analysis of the Coleoptera almost completely overlap with those of Cerney Wick at the present day, albeit that winters may have been cooler when the channel was active. Further, the floral and faunal data suggest that the meandering river flowed through an open grassland environment, the latter heavily grazed by large vertebrates, most notably mammoth. Most of the botanical and faunal remains, together with four optically stimulated luminescence (OSL) age estimates ranging from 225 ± 23 to 187 ± 19 ka, suggest correlation of the channel deposits with MIS 7. The basal deposits (Facies Association 1) yielded the majority of vertebrate remains and all the lithic artefacts, most of which seem likely to have travelled only a short distance. Although only a few artefacts were recovered, they add to the relatively limited evidence of human activity from the upper Thames. The channel deposits are overlain by sheet gravels (Facies Association 5) which are attributed to the Northmoor Member of the Upper Thames Formation. These were likely to have been deposited as bedload in a braided stream environment, while two OSL age estimates of 129 ± 14 and 112 ± 11 ka suggest accumulation during MIS 5.

Plague, Climate and Faith in Early Medieval Western Britain: Investigating Narratives of Change

RECENTLY COMPILED DATASETS for hillforts and corn-drying kilns in the west of Britain, when subject to chronological analysis using Kernel Density Estimation (KDE), show a sharp and lasting fall-off in activity in the later 6th and 7th centuries. This paper investigates this through the regional and broader evidence for three major paradigms of change at this time: the Justinianic Plague, climate change, and the growth of Christianity, the last manifested in transfers of land to churches and in an ascetism which affected assembly practices. The resultant analysis provides archaeologically derived insights into social changes of this period, and raises questions about the applicability of dominant narratives framed in other regions.

Burning Matters: The Rise and Fall of an Early-Medieval Fortified Centre. A New Chronology for Clatchard Craig

ONE OF THE MOST SIGNIFICANT DEVELOPMENTS in early-medieval northern Britain was the re-emergence of fortified enclosures and settlements. As in western England and Wales, the fort rather than the hall formed the most prominent material manifestation of power of an elite and their client group. While fortified sites dominate our knowledge of the form that central places of power and governance took in the early-medieval period in northern Britain, our historical sources reveal little about the character, longevity and lifespan of many of these important nodes of power, and archaeological investigation has also tended to be limited. Hence only a handful of forts in northern Britain provide well-dated and investigated sequences for what are critical sites for understanding the character of post-Roman society in the north. As part of the Leverhulme Trust-funded Comparative Kingship project, a suite of new radiocarbon dates was produced using archived material from excavations at the now-destroyed early-medieval hillfort of Clatchard Craig in Fife, eastern Scotland (NGR NO 2435 1780); one of the most complex early-medieval forts yet identified in northern Britain. Some 35 years ago, Joanna Close-Brooks oversaw the publication of a report on the hillfort based on excavations which had occurred more than two decades earlier in response to the quarrying of this multivallate hillfort. 5 Due to the imprecision and scarcity of radiocarbon dating, a broad 6th to 8th + century ad chronology for the defences and occupation of the interior was obtained. With higher precision AMS dates and a new Bayesian model, a much tighter sequence of dating has been produced suggesting the development and destruction of the monumentally enclosed phase of the site centred on a much shorter period in the 7th century ad. The new chronology for the site, which suggests the fort was constructed and destroyed within a few generations at most, has important implications for the role of fortifications, and the character of warfare in early-medieval society. The burning of the fort suggests a catastrophic and rapid end to a site that is likely to have been constructed by the Pictish elite. The fort may have been a victim of the tumultuous and pivotal events of the latter half of the 7th century when southern Pictland came under Northumbrian control before being wrested back into Pictish overkingship in the aftermath of the Battle of Nechtanesmere of ad 685.

Lithofacies control on the formation of deformation bands: An example from the Sherwood Sandstone Group (Induan–Anisian, Lower Triassic) in western England

Lithofacies control on the formation of deformation bands: An example from the Sherwood Sandstone Group (Induan–Anisian, Lower Triassic) in western England

Individual movement variation in upstream‐migrating sea lamprey Petromyzon marinus in a highly fragmented river

Abstract Anthropogenic reductions in riverine connectivity can severely impede the migrations of anadromous species. In fragmented rivers, successful migrations depend on the ability of migrants to negotiate barriers or locate alternative passage routes. However, individual variation in the specific aspects of movement that determine migration success in fragmented rivers, is poorly characterised. Here, individual variation was investigated in the spawning migrations of 56 adult sea lamprey Petromyzon marinus, an anadromous, semelparous species that does not show fidelity to natal rivers. The variability and consequences of two key aspects of fish migration within fragmented rivers were tested: passage time (total time taken to pass a barrier) and retreats (exploratory downstream movements after unsuccessful passage attempts). These were tested using acoustic telemetry in the highly fragmented River Severn catchment, western England, U.K. Distinct unimodal, bimodal, and multimodal patterns of variation in passage times were displayed across the different barriers, potentially related to the physical characteristics of the barrier and prevailing river discharge conditions when the barriers were first approached, but were not related to lamprey body sizes. At the first three barriers encountered by upstream‐migrating sea lamprey in the study, between 30% and 46% of individuals made retreat movements, and between 5% and 100% of retreating individuals were able to locate alternative tributaries. Retreating individuals were highly variable in their distance and frequency of retreats; overall, retreat movements comprised 11% (lower‐upper quartiles 0%–52%, range 0%–76%) of the total distance moved before reaching spawning areas. Time‐to‐event analysis indicated that retreat rates reduced as river discharge increased. There was no evidence indicating that individual variation in passage time, or presence of retreat movements at barriers, influenced the subsequent upstream migration speed or final upstream extent of lampreys. While predictability in rank arrival timing was high within three unobstructed reaches, this predictability was disrupted at barriers due to individual variation in passage times. Anthropogenic barriers thus can both disrupt and reveal individual variation in the migration dynamics of anadromous species. Substantial variability in retreat behaviours can be displayed by anadromous species facing delays at barriers, with these behaviours also associated with environmental conditions and the availability of alternative migration routes. Individual variation in exploration and passage time of migrants strongly influence their eventual spawning distribution.

Adverse Trends in Myocardial Infarction Incidence and Hospitalisation in Women Aged <55 years in Australia

There is accumulating evidence from jurisdictions including Western Australia (WA), England and Norway, that the incidence of myocardial infarction (MI) is increasing in younger women. This study examines temporal trends in the incidence of MI in 20–54 year-olds from three Australian states.

Rethinking Wat’s Dyke: A Monument’s Flow in a Hydraulic Frontier Zone

Britain’s second-longest early medieval monument – Wat’s Dyke – was a component of an early medieval hydraulic frontier zone rather than primarily serving as a symbol of power, a fixed territorial border or a military stop-line. Wat’s Dyke was not only created to monitor and control mobility over land, but specifically did so through its careful and strategic placement by linking, blocking and overlooking a range of watercourses and wetlands. By creating simplified comparative topographical maps of the key fluvial intersections and interactions of Wat’s Dyke for the first time, this article shows how the monument should not be understood as a discrete human-made entity, but as part of a landscape of flow over land and water, manipulating and managing anthropogenic and natural elements. Understanding Wat’s Dyke as part of a hydraulic frontier zone not only enhances appreciation of its integrated military, territorial, socio-economic and ideological functionality and significance, most likely the construction of the middle Anglo-Saxon kingdom of Mercia, it also theorises Wat’s Dyke as built to constitute and maintain control both across and along its line, and operating on multiple scales. Wat’s Dyke was built to manage localised, middle-range as well as long-distance mobilities via land and water through western Britain and beyond.

North Atlantic air pressure and temperature conditions associated with heavy rainfall in Great Britain

AbstractSevere flooding in the United Kingdom is often linked to the occurrence of heavy rainfall events, which can be characterized by the synoptic scale meteorological conditions over the North Atlantic region. Seasonal heavy rainfall events (summer and winter 1‐day maxima) were extracted from 125 locations across Great Britain over the period 1950–2017. For each event, anomaly sea‐level pressure and 2 m air temperature conditions across the North Atlantic sector were extracted. In contrast to earlier studies, these two datasets were combined and clustered to identify how the pressure and temperature conditions co‐vary within each half‐year to produce heavy rainfall events. Distinctly different spatial patterns were found for four classes in summer and for three classes in winter. For all classes there is a negative sea‐level pressure anomaly centred over or near the British Isles. However, whereas in summer the low pressures are associated with either predominantly cold or warm anomalies over most of the North Atlantic, in winter two phases of a smaller‐scale four‐pole temperature pattern emerges. Nevertheless, for one of the winter classes the cold anomaly over the northwest Atlantic is so deep, persistent and widespread that, unusually for the winter season, a significant relationship between the class's frequency of occurrence and the Atlantic Multidecadal Oscillation (AMO) index is found (r = −.39). Further, for both seasons heavy rainfall occurs when the AMO and the North Atlantic Oscillation (NAO) are in opposing phases. Particularly, positive NAO and negative AMO result in heavy rainfall in western Britain. Two classes in each season are consistent with positive and negative phases of the NAO, and the two non‐NAO summer classes are associated with a northward extension of the subtropical high pressure and heavy rainfall in the southeast. The association between heavy rainfall and large‐scale circulation and temperature drivers can find application in, for example, weather generators.

Current status of the rare British endemic Gentianella amarella subsp. occidentalis, Dune Gentian (Gentianaceae)

Gentianella amarella subsp. occidentalis, Dune Gentian, is a rare annual of dune slacks endemic to Western Britain. Its current status was compared to historic records. A maximum of 2250 plants were found in ten subpopulations in four sites in 2019-2020. It was not refound in three sites and 15 subpopulations. It is assessed as IUCN threat category ‘Endangered’. Its primary vegetation type is SD14d Salix repens - Campylium stellatum dune slack Festuca rubra subcommunity, within which it favours short, open structure on dry, low nutrient soils. Conservation requires managing and creating its niche in the dune slacks.

Impact of minimum unit pricing on alcohol purchases in Scotland and Wales: controlled interrupted time series analyses

As a policy option to reduce consumption of alcohol and the harm it does, on May 1, 2018, Scotland introduced a minimum price of 50 British pence (p) per unit of alcohol (8 g) sold; Wales followed suit on March 2, 2020, with the same minimum unit price (MUP). We analysed household purchase data based on bar codes to assess the impact of these policy options in the medium term for Scotland and in the immediate term for Wales. For these location-controlled, interrupted time series regression analyses, the data source was Kantar WorldPanel's household shopping panel, which, at the time of our analysis, included 35 242 British households providing detailed information on 1·24 million separate alcohol purchases in 2015-18 and the first half of 2020. With no data exclusions, we analysed the impact of introducing MUP in Scotland, using purchases in northern England as control, and in Wales, using western England as control. The studied changes associated with MUP were price paid per gram of alcohol purchased, grams of alcohol purchased, and amount of money spent on alcohol. In Scotland, price increases and purchase decreases following the introduction of MUP in 2018 were maintained during the first half of 2020. The difference between Scotland and northern England in 2020 was a price increase of 0·741 p per gram (95% CI 0·724-0·759), a 7·6% increase, and a purchase decrease of 7·063 g per adult per household per day that an alcohol purchase was made (6·656-7·470), a 7·7% decrease. In Wales, the introduction of MUP led to similar results. The difference between Wales and western England was a price increase 0·841 of 0·841 p per gram (0·732-0·951), an 8·2% increase, and a purchase decrease of 7·052 g per adult per household per day that an alcohol purchase was made (6·463-7·640), an 8·6% decrease. For both Scotland and Wales, reductions in overall purchases of alcohol were largely restricted to households that bought the most alcohol. The introduction of MUP was not associated with an increased expenditure on alcohol by households that generally bought small amounts of alcohol and, in particular, those with low incomes. The changes were not affected by the introduction of COVID-19 confinement in the UK on March 26, 2020. The evidence base supporting the positive, targeted impact of MUP is strengthened by the comparable results for Scotland and Wales. The short-term impact of MUP in Scotland during 2018 is maintained during the first half of 2020. MUP is an effective alcohol policy option to reduce off-trade purchases of alcohol and should be widely considered. None.