Brecon Beacons Research Articles

Speleogenetic evidence from Ogof Draenen for a pre‐Devensian glaciation in the Brecon Beacons, South Wales, UK

ABSTRACTThe British Isles have been affected by as many as 30 glaciations during the Quaternary. However, the evidence for pre‐Devensian glaciations in upland regions is scarce. Understanding the extent and timing of earlier upland glaciations is essential for modelling the long‐term evolution and sensitivity of the British Ice Sheet. Caves, being protected from surface erosion and weathering, can preserve evidence of earlier glaciations in the form of speleothem and sediment archives. The ∼70‐km‐long Ogof Draenen cave system in South Wales, UK, contains multiple cave levels related to changes in the surface topography and drainage during the past 0.5 Ma. The cave contains evidence of massive influxes of sediment that were sufficient to choke the cave and alter the underground drainage. Analysis of the cave sediments, passage morphology and geometry suggests the cave once acted as a subterranean glacial spill‐way before being overridden by ice. Speleothem U‐series data demonstrate that this sediment influx occurred before Marine Isotope State (MIS) 9, probably during the Anglian glaciation (MIS 12). Evidence from Ogof Draenen indicates the impact of subsequent glaciations on the landscape evolution of the region was minimal and that much of the surface topography dates from the Anglian. Copyright © 2014 British Geological Survey (NERC). Journal of Quaternary Science © 2014 John Wiley & Sons Ltd.

Long-term ecological study (palaeoecology) to chronicle habitat degradation and inform conservation ecology: an exemplar from the Brecon Beacons, South Wales

For ecosystems perceived as degraded, but for which the causal factors or timescales for the degradation are disputed or not known, long-term (palaeo-)ecological records may aid understanding and lead to more meaningful conservation approaches. To help ‘bridge the gap’ between (very) long-term ecology and contemporary ecology for practical application, there have been calls for working relationships to be established between palaeoecologists and conservation ecologists. One environment in which this has been attempted is blanket mire. Many blanket mires in Europe are degraded and contain few sphagna. In South Wales, almost all exhibit symptoms of degradation, with dominance by purple moor grass (Molinia caerulea) widespread. We used palaeoecological techniques on three peat profiles in the Brecon Beacons to investigate vegetation history of high-altitude blanket mire to help assess the relative contribution of various factors in mire degradation and to inform strategies for mire conservation and restoration management. We found that declines in sphagna preceded the rise to dominance of monocotyledons. Macrofossil records showed that although Molinia was already present on the Beacons before the start of the industrial revolution, its major rise to dominance in one profile was within the 20th Century, coincident with evidence for local fire. In another profile, it was out-competed by Eriophorum vaginatum after the start of the industrial revolution; there is circumstantial evidence to suggest that a reduction in burning contributed to the rise in E. vaginatum. Conservation management to reduce the current local dominance of both Eriophorum and Molinia is supported by the palaeoecological data, but severe erosion and hagging of peat will constrain practical methods for achieving this on the Beacons until the peat is stabilised. We suggest that palaeoecological techniques have wider applicability in conservation.

The last Welsh Ice Cap: Part 1 - Modelling its evolution, sensitivity and associated climate

A high-resolution, three-dimensional, thermomechanical ice-flow model is used to investigate the glaciodynamics of the Last Glacial Maximum Welsh Ice Cap – a large, independent ice centre of the British–Irish Ice Sheet. The model uses higher-order physics to solve longitudinal stresses, and is coupled to climate via a distributed, positive degree-day mass-balance scheme. A suite of model experiments driven by the GISP2 δ18O curve was initiated from a climatic optimum at 38.3 ka BP through to the Devensian/Holocene boundary to identify an icecap configuration compatible with available empirical evidence. An enhanced cooling from present of 11.85°C and strong precipitation suppression are required between 27.4 and 23.5 ka BP for the modelled icecap to attain well-established empirical limits, a scenario probably associated with Heinrich Event-2 and the potential collapse of thermohaline circulation in the North Atlantic. The experiments indicate ice-dispersal centres located in North and Mid Wales, the latter being essential for forcing ice southwards of the Brecon Beacons during the Last Glacial Maximum. Deglaciation of the Welsh Ice Cap was relatively rapid, occurring within one millennium. Dynamic stability is governed largely by the dominance and vigour with which fast-flowing outlet glaciers drain the icecap interior, which in turn are linked to variations in the climatic forcing. The distribution of permanently cold-based ice across the uplands and summits indicates the probable preservation of relict landscapes in these areas throughout the full glacial cycle.

Granite and Grit: A Walker’s Guide to the Geology of British MountainsGranite and Grit: A Walker’s Guide to the Geology of British Mountains by TurnbullRonald. 2011. Frances Lincoln Ltd, London. 208 pp. ISBN 978-0-7112-3180-1, £16.99 (pbk).

Contents 1. The Crunch of Continents - Various earth-shattering events of the last two billion years: Scotland crashes into England the UK drifts north through tropics the nudge from Africa the opening of the Atlantic. 2. The Work of Ice - Glaciers carved the shapes as we see them today 3. Gneiss Times - The Lewisian Gneiss, in the Outer Hebrides and Wester Ross landscape of knock and lochan a moment in the Malverns 4. The Monsters of Torridon - Sandstone lands of Wester Ross buried landscapes the origin of our oxygen 5. Quartz and Quartzite - Beinn Eighe and the Grey Corries the Moine Thrust 6. Squashed Stones: Slate to Schist - Metamorphism, rocks cooked and crushed shale to slate to schist the Mountains of Moine and the Dalradian schist 7. Greywacke and the Ruggednessof Rhinog - How ocean-bottom sludge became the rock of the Rhinogs 8. Shales and Underwater Mud - More ocean sludge in the Howgills, Isle of Man, mid-Wales and the Southern Uplands the life and times of the graptolite Charles Lapworth in Dobbs Linn 9. All-Terrain Lakeland - Volcanoes and slate, grey shale and granite four different sorts of country but only one Lakeland 10. Red-Hot Flying Avalanche: Ignimbrites in Snowdonia - Various cataclysms above Llyn Idwal 11. Walking the Fault Faults, and a walk along one in particularm the Rossett Gill Fault of Lakeland 12. Andesite and Rhyolite - More volcanoes, at Ben Nevis and Glen Coe collapsing cauldrons 13. Granite Lands - Cairngorms, Dartmoor, Arran, Mourne, Galloway - very different but all of them a bit grim the cause of tors 14. Stone Arriving Sideways: Dolerite Intrusions - The Whin Sill in the north Pennines, Arthur's Seat in Edinburgh and God vs Mr James Hutton 15. The Sands of Time - The Old Red Sandstone of the Brecon Beacons the New Red Sandstone fails to make mountains 16. Mountain Limstone, Millstone Grit - Yorkshire and the Peak District lime to grit to shale: the Yoredale Series 17. The Black Magic of Gabbro - The Tertiary Volcanic Province the Black Cuillin of Skye 18. Basalt Lands and the Opening of the Atlantic - The Death of Gaia Lakeland Lavas, black rocks of Snowdonia, and the Quiraing on Skye a round-up of the red-hot rocks 19. A Two Hundred Million Year Walk Over Dufton Pike - Brekaing the Law of Superposition behind Dufton Pike, with a visit to the Great Whin Sill Conclusion - My country, your country, further reading and more things to see Reading about Rocks Glossary Index Index of Places Acknowledgements

Memories from a Theatre of War

Where is the site of the “Persians”? Can we (re-)locate Aeschylus’ play, earliest remaining tragedy of Western Civilization, literally, in front of the palace of Susa, at the tomb of king Dareios (who reappears as ghost)? Or do we have to locate it rather historically in the theatre of Dionysos in Athens, the place where the tragedy was performed first, in order to let Greek spectators imagine the despair of their defeated enemies? Since this play, like all tragedies, may be performed at any theatre in the world today, what could be its relation to a particular site? In August 2011, Mike Pearson, former co-director of Brith Gof, has staged a new version of the “Persians” in an extraordinary setting: In the Welsh national park Brecon Beacons, there is a military training ground with a “German Village”. The scene was the so-called “Social Skills House”, an open, half-cut concrete building designed for the presentation of in-house military action, in front of a grand stand for army audiences. This unique theatre of war was at the same time a theatre of memory (constructed during the Cold War, anticipating a battlefield in the “Fulda-Gap”; later on transformed into a “Balkan”-village), and a theatre of site specific experience (in a landscape almost untouched for many decades, inhabited only by sheep). A brief analysis of the performance examines how Mike Pearson and his collaborators developed paradigmatic relations between site and play, memory and simulation, technology and experience.

Cannibals in the Brecon Beacons: Torchwood, Place and Television Horror

Cannibals in the Brecon Beacons: <i>Torchwood</i>, Place and Television Horror

Impacts of pollution and climate change on ombrotrophic Sphagnum species in the UK: analysis of uncertainties in two empirical niche models

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 45:163-176 (2010) - DOI: https://doi.org/10.3354/cr00969 Impacts of pollution and climate change on ombrotrophic Sphagnum species in the UK: analysis of uncertainties in two empirical niche models S. M. Smart1,*, P. A. Henrys1, W. A. Scott1, J. R. Hall2, C. D. Evans2, A. Crowe1, E. C. Rowe2, U. Dragosits3, T. Page4, J. D. Whyatt4, A. Sowerby2, J. M. Clark5,6,7 1NERC Centre for Ecology and Hydrology, Library Avenue, Bailrigg, Lancaster LA1 4AP, UK 2NERC Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK 3NERC Centre for Ecology and Hydrology, Bush estate, Penicuik, Midlothian EH26 0QB, UK 4Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster LA1 4AP, UK 5Wolfson Carbon Capture Laboratory, School of Biological Sciences, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK 6Grantham Institute for Climate Change Fellow, and Environmental Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK 7Present address: Walker Institute for Climate Systems Research and Soils Research Centre, Geography and Environmental Science, School of Human and Environmental Sciences, University of Reading, Whiteknights Reading RG6 6DW, UK *Email: ssma@ceh.ac.uk ABSTRACT: A significant challenge in the prediction of climate change impacts on ecosystems and biodiversity is quantifying the sources of uncertainty that emerge within and between different models. Statistical species niche models have grown in popularity, yet no single best technique has been identified reflecting differing performance in different situations. Our aim was to quantify uncertainties associated with the application of 2 complimentary modelling techniques. Generalised linear mixed models (GLMM) and generalised additive mixed models (GAMM) were used to model the realised niche of ombrotrophic Sphagnum species in British peatlands. These models were then used to predict changes in Sphagnum cover between 2020 and 2050 based on projections of climate change and atmospheric deposition of nitrogen and sulphur. Over 90% of the variation in the GLMM predictions was due to niche model parameter uncertainty, dropping to 14% for the GAMM. After having covaried out other factors, average variation in predicted values of Sphagnum cover across UK peatlands was the next largest source of variation (8% for the GLMM and 86% for the GAMM). The better performance of the GAMM needs to be weighed against its tendency to overfit the training data. While our niche models are only a first approximation, we used them to undertake a preliminary evaluation of the relative importance of climate change and nitrogen and sulphur deposition and the geographic locations of the largest expected changes in Sphagnum cover. Predicted changes in cover were all small (generally <1% in an average 4 m2 unit area) but also highly uncertain. Peatlands expected to be most affected by climate change in combination with atmospheric pollution were Dartmoor, Brecon Beacons and the western Lake District. KEY WORDS: Nitrogen · Sulphur · Generalised linear model · Generalised additive model · Uncertainty · Large scale · Peatlands · UKCP09 · UKCIP02 Supplementary material PreviousNextCite this article as: Smart SM, Henrys PA, Scott WA, Hall JR and others (2010) Impacts of pollution and climate change on ombrotrophic Sphagnum species in the UK: analysis of uncertainties in two empirical niche models. Clim Res 45:163-176. https://doi.org/10.3354/cr00969 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 45. Online publication date: December 30, 2010 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2010 Inter-Research.

Spatial and temporal investigation of Echinococcus granulosus coproantigen prevalence in farm dogs in South Powys, Wales

The prevalence of canine echinococcosis appears to have been increasing in mid/south Wales in recent years – raising the concern of a potential resurgence in transmission to humans. A campaign was therefore conducted in 2008 in order to provide dogs in South Powys with anthelmintics, estimate the coproantigen prevalence amongst these dogs, and evaluate potential risk factors for coproantigen positivity. The coproantigen prevalence identified in these dogs (n=577) was 10.6% (95% confidence interval 7.6–13.5%), with 20.6% (15.6–25.7%) of farms (n=247) containing at least one coproantigen-positive dog. Further spatial investigation identified considerable spatial heterogeneity amongst the farms, with an increased coproantigen prevalence in the regions of Brecknockshire and the Brecon Beacons National Park. Within these areas, there was strong evidence of an increase in coproantigen prevalence, compared to that found in a study conducted in 2002. Finally, a mixed effects logistic regression model identified increased roaming behaviour and decreased dog weight as being associated with increased odds of coproantigen positivity, whereas pet dogs on some farms had similar odds of infection to working dogs. Further surveillance efforts in South Powys are required and should also include the northern areas of Gwent and Glamorgan.

Spider Diversity of an Upland Calcareous Grassland Habitat in the Brecon Beacons National Park, UK

Spider Diversity of an Upland Calcareous Grassland Habitat in the Brecon Beacons National Park, UK

Setting free the spirit of English in the Brecon Beacons: The value of learning outside the classroom

In this paper, I draw on interviews with two colleagues, student comments and my own experiences of leading and developing a two day residential course for A Level English Language students at the beginning of Year 12 to explore the role that out‐of‐school learning can have in ‘setting free the spirit of English’. I argue that not only is it possible to use creative and imaginative approaches to learning in English within the constraints of the curriculum but also that these approaches are valuable experiences which can underpin and enhance pupils’ learning.

Monitoring fragile upland landscapes: The application of airborne lidar

This paper investigates the potential of airborne lidar for recording and monitoring erosion levels in environmentally fragile upland landscapes, using an area of the Brecon Beacons National Park as a case study. Upland areas contain a rich variety of natural and cultural resources that are increasingly endangered through factors such as insensitive land-use practices, improvements in recreational access and climate change. Airborne lidar provides a highly detailed record of microtopography, in this example at a resolution of 0.5 m with a vertical accuracy of c.0.15 m and the ability to differentiate elevation changes to within 1-2 cm. The technique therefore allows the rapid and cost-effective recording of the nature and extent of erosion at a landscape scale, with the results of this analysis recording over 46 kilometres of path erosion within a 3.8 km 2 area. The technique also provides the ability to highlight particular areas of risk, such as extensive braided erosion around path intersections and damage to protected SSSI habitats, providing a snapshot record of erosion at a particular point in time and an invaluable source of information for conservationists and policy-makers.

Reply to comments by Shakesby and Matthews “Comments on Jansson, K.N. and Glasser, N.F. (2008) Modification of peripheral mountain ranges by former ice sheets: The Brecon Beacons, southern UK,” Geomorphology 97, 178–189

Reply to comments by Shakesby and Matthews Comments on Jansson, KN and Glasser, NF (2008) Modification of peripheral mountain ranges by former ice sheets: The Brecon Beacons, southern UK. Geomorphology 97, 178-189

Comments on Jansson, K.N. and Glasser, N.F. (2008) “Modification of peripheral mountain ranges by former ice sheets: The Brecon Beacons, southern UK,” Geomorphology 97, 178–189

Jansson and Glasser (Jansson, K.N., Glasser, N.F., 2008. Modification of peripheral mountain ranges by former ice sheets: the Brecon Beacons, southern UK. Geomorphology 97, 178–189.) have recently provided unconventional interpretations of selected glacial erosional and depositional landforms in the Brecon Beacons, UK, based on remotely sensed imagery. These new interpretations contradict well-established and reliable evidence for the origins and ages of certain glacial landforms of this upland area and elsewhere. They suggest that during a post-Last Glacial Maximum (LGM) ice-sheet event ice flowed up supposed, essentially “fluvial” valleys producing “glacial lineations” and depositing marginal moraines at the valley heads and on cirque floors. We argue that their interpretations of some key landforms are incorrect and that they have ignored much of the previous dating and field geomorphological evidence. Sedimentary and morphological evidence (e.g., lack of erratic content; convex planform with respect to the headwall; relatively large height range of moraines; and close association with headwall extent, height, and steepness) all indicate that higher level cirque-floor and valley-head moraines in the Brecon Beacons (> c. 400 m) were formed by cirque glaciers. Available dating evidence indicates a Younger Dryas age. We demonstrate that the supposed “fluvial” valleys, comprising trough heads with steep headwalls, have more nearly parabolic than V-shaped cross profiles indicating substantial glacial modification. Field evidence shows that proposed key exemplar post-LGM glacial lineations are in fact debris flow deposits. We conclude that whilst the adoption of a macroscale approach can shed new light on large-scale, ice-sheet movements, this approach should not be undertaken without consideration of the associated field evidence.

Modelling topoclimatic controls on palaeoglaciers: implications for inferring palaeoclimate from geomorphic evidence

Evidence of small glaciers is often used to infer past atmospheric climate through calculation of steady-state ELAs. However, if topographic niches such as shading or windblown-snow augmented mass-balance then ELAs cannot reflect regional climate and determining the significance of these topoclimates is therefore important. The Brecon Beacons, South Wales, contains upland glacial landforms dating to the Younger Dryas (11,000–10,000 yr BP) when local climate was at the threshold for glaciation. This case study categorises topoclimate using three-dimensional modelling of topography and reconstructed palaeoglaciers from two sites containing mapped moraines whose orientation suggest complex patterns of deglaciation. Ablation season solar radiation is modelled over multiple ice-surfaces as shade from surrounding topography and intensity from ice-surface incidence angle. Snowblow and avalanching potential models are also used and the significance of all topoclimate variables assessed against a mass-balance deficit calculated for each glacier given palaeoclimate models for the region. Results demonstrate that both glaciers were likely to be heavily reliant on topoclimate and that previous studies underestimate the significance of solar radiation. Modelled over multiple ice-surfaces reflecting patterns of recession, results indicate that the distribution of topoclimate variables predicts the style of deglaciation at both sites, possibly explaining the complexity of glacial evidence in this environment.

Finding the Lost Children of Craig-y-nos

Craig-y-nos Castle (meaning ‘Rock of the Night’) lays claim to be the most haunted castle in Wales. Perched on the edge of the Brecon Beacons National Park, it was the estate of Adelina Patti, the world famous opera singer, from 1878 until her death in 1919. Within the castle grounds, Patti built an ornate theatre where she sang for audiences of up to 150 guests including British and European Royalty. The Patti Theatre is now a Grade 1 listed opera house and headquarters of the Opera School Wales. On Patti’s death, her third husband, Baron Rolf Cederstrom, sold the estate to the King Edward VII Welsh National Memorial Association, established in 1910, to combat tuberculosis in Wales. As the Adelina Patti Hospital, it served for 40 years as a sanatorium for children and young women, at a time when the incidence and death rate of TB in the industrial areas of south Wales were higher than anywhere else in Britain. TB claimed the lives of 12 young men and 17 young women a year in every Welsh community of 6000 people.

Complex relationships between younger dryas glacial, periglacial and paraglacial landforms, Brecon Beacons, South Wales

The Brecon Beacons represent the most southerly area subject to marginal glaciation during the Younger Dryas/Loch Lomond Stadial in the British Isles and the interpretation of upland landforms in this area therefore has particular palaeo-environmental significance. This study reports geomorphological evidence within two trough-heads in the central Brecon Beacons previously thought to reflect Younger Dryas glaciation. A complex suite of landforms is identified at both sites, reflecting a range of environmental processes dating from throughout the Lateglacial period. Possible Younger Dryas terminal and recessional moraines are identified at each site, consisting of passively and actively transported debris, which have subsequently undergone considerable paraglacial modification. A number of other non-glacial landforms and sediments are identified, including a protalus/pronival rampart. The initial interpretations are tested using a glaciological approach of reconstructing former glacier dynamics, and suggests that some of the terminal moraines observed reflect mountain glaciation prior to the Younger Dryas, and may demonstrate final stages of retreat from the Last Glacial Maximum (LGM). A morphostratigraphic sequence for both sites is reconstructed, reflecting landscape evolution in a range of environments from final LGM deglaciation through to Holocene landscape stability. It is concluded that associations of such landforms may be common in marginal areas of former glaciation, and that interpretations of former niche/cirque glaciation should be supported by the reconstruction of probable mass-balance, glacier dynamics and palaeoclimatic implications to improve on geomorphological speculation.

Testing the water

Recently, a team of Year-12 students from Ysgol Tre-Gib (a bilingual 11-18 school in South Wales, participated in an Engineering Education Scheme Wales project with Brecon Beacons Natural Waters. In this article, their teacher describes how they enjoyed their taste of real engineering.

Modification of peripheral mountain ranges by former ice sheets: The Brecon Beacons, Southern UK

The Brecon Beacons in southern Wales is a large upland area (900 km 2) close to the periphery of the former British–Irish Ice Sheet. The geomorphology of the Brecon Beacons highlands and surrounding areas was mapped using satellite imagery and a digital elevation model (DEM). A fragmentary pattern of glacial lineations is inferred to represent ice build-up in the mountains. A more coherent set of glacial lineations formed by southward ice flow across the area from the Welsh Ice Cap represents recession from the Last Glacial Maximum (LGM). During this phase the Brecon Beacons acted as an obstacle, deflecting the ice around higher terrain. Most of the higher terrain in the Brecon Beacons therefore appears to have escaped significant glacial erosion during both phases of ice-flow due to cold-based ice or low basal ice velocities beneath a local ice cap. Landforms previously interpreted as cirques in fact have v-shaped profiles and lack evidence of major over-deepening. They are interpreted to have been formed primarily by processes other than glacial erosion. The overall impact of glaciation in the Brecon Beacons appears to be limited primarily to the time when the area was over-run by the Welsh Ice Cap and the influence of local glaciation has been minimal. This study has two main implications for landscape evolution in mountain ranges that lie at the periphery of former ice sheets. First, due to the presence of cold-based ice or low basal ice velocities beneath a local ice cap it may be possible to find fragmentary traces of pre-LGM ice flow. Second, the pattern of glacial lineations in and around the Brecon Beacons indicates that peripheral mountain ranges may have deflected ice flow at the LGM, resulting in low basal ice flow velocities and possible frozen-bed conditions over higher terrain which consequently resulted in ineffective glacial erosion within the mountains themselves.

A Neolithic Wetland Site at Abercynafon, Talybont, South Wales

This paper presents the results of an integrated archaeological and palaeoecological investigation following the discovery of waterlogged worked-wood in a small boggy hollow on the southern edge of the Brecon Beacons in south Wales. Analysis of the pollen, radiocarbon and dendrochronological evidence suggests the main phase of activity at the site involved local clearance of the primary oak forest in the early 3rd millennium BC. Later activity at the site is indicated by dates in the mid 1st millennium AD along with two pewter bowls of known Roman form. A tree-ring chronology spans the period 3098–2730BC. Neolithic woodworking techniques are examined from what was for the most part debris from the processing of large trees. Possible parallels for the site are discussed and suggestions made for its use.

Arthropod trackways from the Early Devonian of South Wales: a functional analysis of producers and their behaviour

Abundant arthropod trackways, assigned to Diplichnites gouldi, are described from the Lower Old Red Sandstone (Early Devonian; Lochkovian) of Pant-y-Maes quarry, Brecon Beacons, South Wales. The trackways are preserved on bedding planes of finely laminated planar and rippled siltstones. The sedimentology of the succession indicates that these units represent bar top and marginal deposits in a braided fluvial setting. Two trackway types are recognized (Type A and B); comparisons with contemporaneous myriapodous producers favour kampecarid and eoarthropleurid myriapods, respectively. Functional analysis of the trackways indicates that the producers were not using the most efficient, stable, walking techniques, but instead utilized in-phase ‘swimming stroke’-like gaits. Together with their occurrence on rippled surfaces, and lateral displacement of some trackways (attributed to currents), this indicates that they were produced sub-aqueously.