South-east Northumberland Research Articles

Distributions of Species in theTegenaria atricaGroup (Araneae: Agelenidae) in North-East England: Chance, Contingency and Priority

Summary Tegenaria atrica is a species common in continental Europe and the Republic of Ireland but on the British mainland it has long been regarded as a relatively rare import that has failed to establish. The recent discovery of this species in some numbers and over several years in Burnopfield, County Durham, represented the first-reported, self-sustaining population. We show here that the species is widespread across a large swathe of country comprising parts of north County Durham, Tyne and Wear, and south-east Northumberland — an area of some 710 km2. Within a core range of approximately 400 km2, the other species in the Tegenaria atrica group, T. saeva and T. gigantea, tend to be uncommon or absent. The distributions of these three closely related species raise questions regarding the origins of the T. atrica population, the effect of chance and priority in initial establishment, and the role of possible competitive interactions between them. Although determining ecological processes from present p...

Ponds and the importance of their history: an audit of pond numbers, turnover and the relationship between the origins of ponds and their contemporary plant communities in south-east Northumberland, UK

An increasing focus of interest in ponds over the last two decades arose largely because of concerns at the loss of ponds in intensively developed landscapes. In the UK, pond numbers declined from approximately 800,000 in the nineteenth century to 200,000 by the 1980s. Since then pond numbers have started to increase. The focus on overall pond numbers overlooks the importance of the history and origins of different pond types. This study combines a detailed map based audit of pond numbers in south-east Northumberland, UK, recorded at seven time intervals since the mid-nineteenth century with a survey of contemporary plant communities in ponds with known and distinct histories to examine changes to numbers of ponds and communities associated with ponds with different origins. 222 ponds were recorded in the study area in the mid-nineteenth century, 257 in 2005/08. However, only 23 of the original ponds had survived with substantial losses and gains at all the map survey dates linked to changed land use from agriculture to coal mining then development of nature reserves and golf courses. Contemporary ponds on nature reserves, golf courses and subsidence ponds supported rather different plant communities to each other, with non-native invasives in golf and nature reserve sites, whilst individual reserves differed from one another perhaps due to intentional planting. Surviving old farm ponds were usually degraded. The results show that the history of ponds in a region can create an important cultural biodiversity which pond conservation strategies should incorporate.

The distribution of pond snail communities across a landscape: separating out the influence of spatial position from local habitat quality for ponds in south-east Northumberland, UK

Ponds support a rich biodiversity because the heterogeneity of individual ponds creates, at the landscape scale, a diversity of habitats for wildlife. The distribution of pond animals and plants will be influenced by both the local conditions within a pond and the spatial distribution of ponds across the landscape. Separating out the local from the spatial is difficult because the two are often linked. Pond snails are likely to be affected by both local conditions, e.g. water hardness, and spatial patterns, e.g. distance between ponds, but studies of snail communities struggle distinguishing between the two. In this study, communities of snails were recorded from 52 ponds in a biogeographically coherent landscape in north-east England. The distribution of snail communities was compared to local environments characterised by the macrophyte communities within each pond and to the spatial pattern of ponds throughout the landscape. Mantel tests were used to partial out the local versus the landscape respective influences. Snail communities became more similar in ponds that were closer together and in ponds with similar macrophyte communities as both the local and the landscape scale were important for this group of animals. Data were collected from several types of ponds, including those created on nature reserves specifically for wildlife, old field ponds (at least 150 years old) primarily created for watering livestock and subsidence ponds outside protected areas or amongst coastal dunes. No one pond type supported all the species. Larger, deeper ponds on nature reserves had the highest numbers of species within individual ponds but shallow, temporary sites on farm land supported a distinct temporary water fauna. The conservation of pond snails in this region requires a diversity of pond types rather than one idealised type and ponds scattered throughout the area at a variety of sites, not just concentrated on nature reserves.

Watch out for aurorae

From Alastair McBeath The articles on the aurorae in A&G at the start of this year made interesting reading for those of us with a long-time interest in the aurora, and observing it from the UK. My own first auroral sightings from Britain were made by chance in 1978, at the geographic latitude I still observe from, about halfway up the British Isles, around 55°N in south-east Northumberland. In the 28 full years since, 104 visible displays have come my way, with anything from zero to 14 nights of aurorae per calendar year, 102 of those since I first started making regular checks of the sky every clearer night, in 1982. Consequently, I was surprised by some of Jim Wild’s pessimistic comments (Wild 2006) regarding the supposedly poor prospects for UK auroral observers generally. My site is pretty average both for overnight weather, and its location within the UK. Yes, observers further north than me do see significantly more aurorae than I do, but with a long-term annual mean of 3.7 nights of aurorae here, this seems rather better than Wild’s comment would suggest, that “on average we can expect to see visible aurorae over the UK a couple of times per year”. In 2005, I spotted definite displays on five nights, but I achieved this with no technological prompting. As experience from Britain has demonstrated repeatedly over the decades, strong geomagnetic or radio auroral signals frequently do not translate into visible aurorae, nor do visible aurorae always give strong instrumental signatures. As an example to compare with Wild’s, the 21/22 January 2005 auroral event was at its very best for the entire night visually for me between 19.00 and 19.30 UT. At its strongest, at 19.19 h, the auroral light was casting shadows, and the display’s southern edge passed through the zenith. Between 19.20 h and 19.26 h, the southern edge was within 60° of the southern horizon, so the display covered two-thirds of the sky. As Jim Wild showed, geomagnetically, there was at the time only a moderate chance of UK activity as recorded by his AuroraWatch system. After 19.30 h, the aurora remained confined to my northern sky for the rest of the night through to 02.20 h, when clouds halted observing. There were a few brighter interludes, notably around 22.15 h very briefly, and more sustainedly from 22.25 h to 22.50 h (at 22.35 h the display reached the zenith again momentarily). This coincided with the AuroraWatch’s strongest response for the whole of 21 January, though visually the display was far less impressive than it had been soon after 19.00 h. By 23.00 h, only a feeble glow within 30° of my northern horizon remained, growing weaker and lower as the night continued, yet the Aurora Watch geomagnetic response was only marginally lower from 23.00–00.00 h than it had been from 19.00–20.00 h. While geomagnetic observations of the aurora are valuable in their own right, I would not recommend anyone should rely on them solely who genuinely wanted to observe the visible aurora. The best method for seeing auroral displays remains to check the northern sky regularly after dark, knowing what to look out for, and what that northern sky should look like under different conditions with no aurora present. There does seem to be a general lack of awareness of just how much detailed visual and photographic auroral observing and recording has been, and continues to be, carried out in the British Isles, especially since the International Geophysical Year in 1957–58, from the Society’s recent journals (witness also Harrison’s historical aurora comments from 1771–1805 [2005], who seemed to struggle to find suitable recent comparison data from the Stroud area, though there is no shortage). Consequently, it seems sensible to mention here that further observing advice for prospective UK aurora-watchers, and details of auroral events from recent decades, are available from the Aurora Sections of the Society for Popular Astronomy (www. popastro.com) and the British Astronomical Association (baaaurora.fsnet.co.uk). Alastair McBeath, Morpeth, Northumberland. meteor@popastro.com

Reply: denudation rates in southeast Northumberland since the Devensian glaciation

Undoubtedly the coastal till plateau of Northumberland was deeply incised by rivers crossing from the ice-covered uplands inland, and no doubt locally modified by subglacial drainage before the ice wasted back. Two approaches were used to allow for this in the measurement of the contribution of postglacial subaerial erosion to the shape of the contemporary landscape, and thus in the calculation of mean rates of erosion. If, despite these adjustments, the average depth of erosion has been overestimated, the error can be little more than 15 per cent. Copyright © 1998 John Wiley & Sons, Ltd.

Discussion: denudation rates in southeast Northumberland since the Devensian glaciation

Discussion: denudation rates in southeast Northumberland since the Devensian glaciation

Discussion: denudation rates in southeast Northumberland since the Devensian glaciation

Discussion: denudation rates in southeast Northumberland since the Devensian glaciation

Reply: denudation rates in southeast Northumberland since the Devensian glaciation

Reply: denudation rates in southeast Northumberland since the Devensian glaciation

Decomposition of river water nitrate time-series — comparing agricultural and urban signals

This article explores the combined effects of agricultural and urban influences on the time-series of the nitrate concentration in river water. The temporal and spatial variation of the river water signal for nitrate are examined using time-series analysis. The catchment chosen for this study was the River Wansbeck in south-east Northumberland where a distinct agricultural to urban gradient exists down the catchment. The time-series were obtained from the network of Environment Agency monitoring stations on the river. Twelve such stations provided monthly data stretching, in one case, as far back as 1973. The time-series from parts of the catchment dominated by agricultural land use showed a clear annual cycle which was lost downstream as larger settlements begin to appear on the banks of the river. The time-series, taken at the tidal limit, showed an asymmetric annual cycle that was not seen higher up the catchment, a pattern which could not be linked directly to the influence of sewage works discharging into the lower sections of the river. This study was not able to account adequately for the variation in the nitrate concentration of the river as it enters its estuary. Two new approaches are suggested to solve this problem.

Factors Influencing General Practitioners' Referral Decisions

This paper presents some findings from a small scale qualitative study of referral decision making conducted in south-east Northumberland in 1988-89. The study was prompted by an interest in variability in referral rates and the view that existing studies had not attempted to understand referral from the perspective of those involved in making the decisions. Our findings suggest that such understandings are crucial in the analysis of referral decisions and in any policy making initiatives designed to influence the pattern of referring.

ABH secretion in Northumberland, England.

The frequency of ABH non-secretory (29.2%) in a sample of 1,752 school-children resident in Northumberland is very similar to those reported in neighbouring populations. Allocation of individuals among four regions of Northumberland on the basis of residence and birthplace revealed no overall heterogeneity. However, those born in the south-east region exhibited a significantly (p less than 0.05) higher frequency of non-secretors than those born elsewhere. This suggests that ABH secretion can be added to the list of polymorphisms including ABO, Hp phenylthiocarbamide tasting and skin colour that distinguish the population of south-east Northumberland from the rest of the county.

Pollution injury in south east Northumberland: The analysis of field data using canonical correlation analysis

Detailed investigations of the relationship between plant growth and environmental factors were carried out at 12 sites in order to trace the cause of marginal necrosis observed in field grown plants of Pisum sativum L. The analysis of the results indicates that the observed injury was due to sulphur dioxide. Analysis further showed that about one-quarter of the total variation in plant performance was attributable to microclimatic differences between the sites. Canonical correlation analysis was a powerful tool in the analysis of the multivariate field data, proving to be more powerful than conventional methods of analysis based on bivariate correlation and regression.

Haptoglobin distribution in north-east England.

SummaryIn north-east England local differences in the frequency of haptoglobin types support the biological distinction of the population of south-east Northumberland from the remainder of the county.

An investigation of the aquifer potential of the Fell Sandstone of Northumberland

Summary The results of this preliminary investigation indicate that the Fell Sandstone is the best aquifer in Northumberland, and that the groundwater potential is largely undeveloped. The formation has an outcrop of 118 square miles (305 km 2 ), of which 65 square miles (168 km 2 ) are drift free. The attractive qualities of the sandstone are the friable, granular nature, the good sorting and the commonly occurring fissures and joints. The storage capacity of the formation is of the order of 10 12 Imperial gallons (4·55 × 10 12 litres). Analysis of precipitation data and water balance calculations suggest an average recharge of between 40 and 70 mgd, (182 × 10 6 l/d–319 × 10 6 1/d). Determinations of porosity and laboratory permeability give mean values of 13·8 percent and 6·4gpd/ft 2 , (314 1/d/m 2 ) respectively; the transmissibility could be considerably greater than the mean value of 5300 gpd/ft (7900 1/d/m) calculated by pumping the existing boreholes. The results of chemical analyses show that the water quality is good. There seems little doubt that further water supplies required for commercial development on Tweedside and in south-east Northumberland could be developed from the Fell Sandstone aquifer. Proposals for the economic development and future study of the aquifer are outlined.

SUBMARINE SLUMPING AND SLIDING IN THE LOWER MAGNESIAN LIMESTONE OF NORTHUMBERLAND AND DURHAM

Summary The effects of submarine slumping and sliding which occurred in north-east Durham and south-east Northumberland in early and late Lower Magnesian Limestone times are described and discussed. The earlier slumps affected a thin group of beds some three to seven metres above the Marl Slate and gave rise to disturbed beds and turbidites extending, perhaps discontinuously, from near Sunderland to the River Tees. The later episode, which is perhaps more correctly described as a slide, occurred at the end of Lower Magnesian Limestone times and is thought to have removed as much as twenty five metres of this formation from parts of an area of perhaps two hundred square kilometres, mainly north of Sunderland. It is suggested that sliding on this scale is most likely to have been initiated by an earthquake shock.

REDDENED BEDS IN THE COAL MEASURES BENEATH THE PERMIAN OF DURHAM AND SOUTH NORTHUMBERLAND

Summary A zone of reddening of Coal Measures sediments averaging 25 ft. thick underlies the sub-Permian surface in Durham and south-east Northumberland. It is present irrespective of stratigraphical horizon. The fact that the basal Permian sands and the Permian limestones which rest on the surface are nowhere reddened is regarded as conclusive evidence that the reddening of the Coal Measures strata took place before the commencement of Permian sedimentation in the area. Petrographical study indicates that it is due to oxidation of pyrite and chalybite in situ and to introduction of red iron oxide along joints and in the pore-spaces of sandstones. It is suggested that hot-humid uplands during the Coal Measures-Zechstein interval became covered with thick red soils, perhaps in part protected by rain forests. Erosion of these soils from remaining high areas in late Zechstein, Bunter and Keuper times may have contributed towards “Red Bed” sediments.

I.—The Magnesian Limestone of Durham

The Divisions of the Limestone—The Thrusting in South-East Northumberland and North-East Durham—The Breccias.

The geology of North-East Durham and South-East Northumberland

The geology of North-East Durham and South-East Northumberland