North Pennines Research Articles

Soil–plant interactions and the uptake of Pb at abandoned mining sites in the Rookhope catchment of the N. Pennines, UK — A Pb isotope study

This paper examines Pb concentrations and sources in soil, grass and heather from the Rookhope catchment in the North Pennines, UK, an area of historical Pb and Zn mining and smelting. Currently, the area has extensive livestock and sports shooting industries. Risk assessment, using the source-pathway-receptor paradigm, requires the quantification of source terms and an understanding of the many factors determining the concentration of Pb in plants. A paired soil and vegetation (grass and heather) geochemical survey was undertaken. Results showed no direct correlation between soil (total or EDTA extractable Pb) and vegetation Pb concentration. However, regression modelling based on the Free-Ion Activity Model (FIAM) suggested that the underlying mechanism determining grass Pb concentration across the catchment was largely through root uptake. Spatial patterns of 206/207Pb isotopes suggested greater aerosol deposition of Pb on high moorland and prevailing wind facing slopes. This was evident in the isotopic ratios of the heather plants. Pb isotope analysis showed that new growth heather tips typically had 206/207Pb values of ~1.14, whilst grass shoots typically had values ~1.16 and bulk soil and peat ~1.18. However, the 206/207Pb ratio in the top few cm of peat was ~1.16 suggesting that grass was accessing Pb from a historical/recent pool of Pb in soil/peat profiles and consisting of both Pennine ore Pb and long-range Pb deposition. Isotope Dilution assays on the peat showed a lability of between 40 and 60%. A simple source apportionment model applied to samples where the isotope ratios was not within the range of the local Pennine Pb, suggested that grass samples contained up to 31% of non-Pennine Pb. This suggests that the historical/recent reservoir of non-Pennine Pb accessed by roots continues to be a persistent contaminant source despite the principal petrol Pb source being phased out over a decade ago.

Cenozoic cooling and denudation in the North Pennines (northern England, UK) constrained by apatite fission-track analysis of cuttings from the Eastgate Borehole

The Cenozoic landscape development of Britain remains relatively poorly understood. On the one hand, ‘plumists’ have tried to explain the present-day topography as a consequence of effects of the Iceland mantle plume during the Palaeocene-Eocene British Tertiary Igneous Province (BTIP) magmatism, with little or no subsequent modification. On the other hand, abundant evidence exists from fluvial and marine terraces and superimposed karstic levels for significant vertical crustal motions during the Quaternary, which clearly has nothing to do with any mantle plume. To shed light on this issue, we present the first publication of data that constrain the Cenozoic thermal history of the North Pennine uplands of northern England, from apatite fission-track analysis of drill cuttings from the Eastgate Borehole in Weardale, in the western part of County Durham. Our results indicate ∼650m of regional denudation since the latest Oligocene/Early Miocene, plus the ∼400m of localized entrenchment that has created the modern Weardale valley. Before the latest Oligocene/Early Miocene, but following the BTIP magmatism, the crust in this region experienced significant cooling, mainly due to a decrease in the geothermal gradient from ∼55 to 61°Ckm−1 to the present 38°Ckm−1, along with ∼300±200m of denudation. Although significant BTIP magmatism occurred in northern England, it thus had only a limited net effect; the crust experienced dramatic heating, but cooled back to its original thermal state within, at most, a few tens of millions of years. We suggest that this rapid cooling effect resulted from westward flow of relatively cold material within the mobile lower-crustal layer, driven by the lateral pressure gradient induced by earlier heating effects and effects of surface processes. Whatever topography developed during the Palaeogene, as a direct result of these heating effects, underplating at the base of the crust, and the associated modest denudation, was presumably also short-lived; significant changes to the crustal thickness, and thus to the topography, can be envisaged as a consequence of subsequent lower-crustal flow.

Changes in water colour between 1986 and 2006 in the headwaters of the River Nidd, Yorkshire, UK: a critique of methodological approaches and measurement of burning management

The effect of moorland management on the release of dissolved organic carbon (DOC) from blanket peat is currently a topic of great interest in the UK. A recent paper by Chapman et al. (Biogeochemistry, doi:10.1007/s10533-010-9474-x, 2010) reports on changes in humic colour/DOC concentrations in surface waters draining 15 upland peat catchments in the North Pennines (UK) over two decades, and examines the possible underlying drivers of those changes. Chapman et al. identify significant variation in water colour between adjacent catchments and over time. One potential driver of changes in DOC is managed moorland burning, and Chapman et al. state that their study provides evidence that burning has no effect on colour in upland catchment drainage waters. This observation counters a recent series of papers showing strong links between new moorland burn management on blanket peat soils and colour/DOC in catchment drainage waters. We have reviewed the methodological approach and results presented by Chapman et al. that relate to the assessment of managed burning, and show significant errors in the data used in their analysis. This has resulted in conclusions being drawn about the role of managed burning in DOC release that are not supported by evidence.

Reply to discussion on ‘Hyper-permeable granite: lessons from test pumping in the Eastgate Geothermal Borehole, Weardale, UK’ by P.L. Younger and D.A.C. Manning

We are very grateful to F.W. Smith for his thoughtful consideration of the brief speculation we included in our paper about the origins of the permeable features encountered at 411 m depth in what is now known as the Eastgate No. 1 Borehole (Younger & Manning 2010). His remarks are very enlightening, and add significantly to the published record on the structural geology of the North Pennine Orefield. Dr Smith's comments actually penetrate a point of amicable difference between the two of us, with Younger being in favour of a predominantly structural interpretation, whereas Manning was more inclined to an explanation that also involved deep weathering. As it happens, further work undertaken at the site in 2010 has since shed further light on the matter, and would tend to support Dr Smith's suggestion that the empty voids found at 411 m depth in Eastgate No. 1 are essentially …

Landscapes of Belief: Non-Conformist Mission in the North Pennines

In addition to the well-known foreign missionary activities of eighteenth- and nineteenth-century churchmen, this same period saw campaigns of active proselytization within Britain. Whether couched in terms referring to “religious revival” or “home mission” it had the same aim as foreign mission activity, namely to effect religious change. This paper explores the way in which the religious changes associated with these campaigns affected the landscape of the lead-mining districts of the North Pennines in northern England. A repeating cycle of preaching first outdoors, then indoors and then in purpose-built structures can be recognized.

The extent and impact of shooting on black grouse Tetrao tetrix in northern England

AbstractIn northern England, 95% of black grouse Tetrao tetrix leks occur on the fringes of managed grouse moors. Recognising the threatened conservation status of black grouse in northern England, most grouse moors have refrained from deliberate shooting for more than a decade. Despite this, black grouse are unintentionally shot in mistake for red grouse Lagopus lagopus scoticus. We assessed the circumstances and frequency of shooting in northern England and its potential impact on population recovery from three independent sources, annual shooting returns as part of the Game and Wildlife Conservation Trust's (GWCT) National Gamebag Census (NGC), incidents of shooting reported independently to the North Pennines Black Grouse Recovery Project (NPBGRP) and losses of radio‐tagged black grouse to shooting. Moors contributing to the NGC between 1998 and 2008 reported 110 black grouse shot from 13 of 23 moors, averaging 1.2% of the estimated post‐breeding population. From 2001 to 2008, 152 black grouse from 28 moors were reported shot independently to the NPBGRP, equivalent to an annual 1.0% of the post‐breeding population. The majority appeared unintentional (78%), with females (68%) more frequently shot. Out of 244 radio‐tagged black grouse on 15 estates, four adult females were shot (1.6%). The voluntary restraint from harvesting black grouse in northern England appears effective, with incidents of shooting infrequent. Continued effort to minimise shooting incidents, particularly on the fringe of the range to encourage settlement of dispersing females, may contribute to increasing numbers and range.

Carbon budgets of an upland blanket bog managed by prescribed fire

This study presents the carbon budget of a blanket bog, North Pennines, UK, subject to grazing and prescribed burning for vegetation management. The budget considers both fluvial and gaseous carbon fluxes and the following uptake and release pathways: dissolved organic carbon, particulate organic carbon, excess dissolved CO2, release of methane (CH4), net ecosystem respiration of CO2, and uptake of CO2 through primary productivity. Measurements of CH4 were not directly measured as part of this study but were estimated from hydroclimatic variables measured within the study. The results show that, if management combinations were extrapolated across the catchment, then over a 3 year period, the catchment would be a net source of carbon of between 62 and 206 gC m−2 yr−1. The action of both burning and grazing was to significantly decrease the magnitude of the carbon source relative to unburnt controls. Over the study period burnt sites were a mean source of approximately 117.8 gC m−2 yr−1 compared to unburnt sites with a mean source of 156.7 gC m−2 yr−1. Even when including the loss of carbon during the vegetation combustion, there are conditions under which the long‐term loss of carbon is less than if no burning had occurred. If total combustion of vegetation occurs, provided burning occurs at cycles longer than 32 years, then less carbon is predicted to be lost than in a no‐burn scenario.

The North Pennine batholith (Weardale Granite) of northern England: new data on its age and form

SUMMARY A three-dimensional gravity model of the North Pennine batholith is interpreted to show that it comprises five contiguous steep-sided plutons. The North Pennine batholith was previously referred to as the Weardale Granite, but this term is now restricted to the largest, most central pluton, which was proved by the Rookhope Borehole in 1961. The surrounding plutons are the Tynehead and Scordale plutons in the west, and the Rowlands Gill and Cornsay plutons in the east. A new U–Pb zircon age of 399.3±0.7 Ma demonstrates an unequivocal Early Devonian (Emsian) age of emplacement for the Weardale Pluton. The similarity of the forms of the four unsampled plutons to the body beneath Rookhope, and to other Devonian granites in northern England, strongly suggests that they are also of Devonian age. Seismic reflection evidence supports a contrast between relatively deep-seated Devonian granites and tabular Ordovician granites in northern England. The most conspicuous magnetic anomalies over the North Pennine batholith are associated with the Early Permian Great Whin Sill, but there is also evidence of magnetized basement rocks or denser magnetic intrusive phases on the flanks of the non-magnetic, low density plutons. A long-wavelength magnetic low can be explained in part by the granite puncturing a deep magnetic basement, although the demagnetized zone may extend beneath the batholith. A spatial correlation between the vein systems in the Northern Pennine Orefield and the form of the batholith suggests that the granite masses played a significant role in focussing mineralizing fluids into the overlying Carboniferous rocks. The highest temperature mineralization occurs over the Weardale and Tynehead plutons, where there is also the clearest evidence for the channelling of mineralizing fluids through the batholith. The other plutons are generally associated with a lower intensity of mineralization, which occurs on their flanks rather than above their roofs. The Rookhope and Tynehead areas may therefore mark the location of convective ‘chimneys’ which were important in focussing the fluid circulation responsible for the mineralization. The coincidence of the ‘chimney’ zones with the minimum of the long wavelength magnetic low suggests that the hydrothermal system may also have played a role in modifying crustal magnetization.

Land management as a factor controlling dissolved organic carbon release from upland peat soils 2: Changes in DOC productivity over four decades

Increasing DOC concentrations in surface waters have been observed across parts of Europe and North America over the past few decades. Most proposed explanations for these widespread trends invoke climate change or reductions in sulphate deposition. However, these factors do not seem apposite to explain either the fine-scale (within kilometres) or regional-scale spatial variation in DOC concentrations observed across the UK. We have reconstructed DOC concentrations and land use for one North Pennine and five South Pennine catchments (UK), located in three discrete areas, over the last four decades. Rainfall, temperature and sulphate deposition data, where available, were also collated and the potential influence of these factors on surface water DOC concentrations was assessed. Four of the six catchments examined showed highly significant ( p < 0.001) increases (53–92%) in humic coloured DOC (hDOC) concentrations in drainage waters over the period 1990–2005. Changes in temperature and sulphate deposition may explain 20–30% of this trend in these four catchments. However, the rapid expansion of new moorland burn on blanket peat can explain a far greater degree (> 80%) of the change in hDOC. Far smaller increases in hDOC (10–18%) were identified for the two remaining catchments. These two sites experienced similar changes in sulphur deposition and temperature to those that had seen largest increases in DOC, but contained little or no moorland burn management on blanket peat. This study shows that regional-scale factors undoubtedly underlie some of the recent observed increases in drainage humic coloured DOC. However, changes in land management, in this case the extensive use of fire management on blanket peat, are a far more important driver of increased hDOC release from upland catchments in some parts of the UK. It suggests that the recent rapid increase in the use of burning on blanket peat moorland has implications for ecosystem services and carbon budgets.

Valuing complex environmental goods: landscape and biodiversity in the North Pennines

SUMMARYHuman activities may have detrimental effects on biodiversity, and appropriate economic valuation of biodiversity can provide additional motivation to protect it. To date, there are no estimates of visitor values for landscape and wildlife changes in the North Pennines (UK) and very few studies have explored competing influences of landscape and biodiversity in public preferences. Contingent valuation estimates of visitor values for the North Pennines landscape and biodiversity, as expressed in voluntary contributions, were used to assess the importance of different factors in influencing these valuations. Policy-linked scenarios were developed, each representing the outcome of a particular policy direction such as grouse-moor specific subsidies, back-to-nature subsidies, or a ban or decline in red grouse shooting. The influence of management information provision was tested and economic values were elicited for a number of alternatives. Landscape and biodiversity were both found to be important in preference formation. In particular, respondents highly valued a mosaic landscape with increases in blanket bog and the associated increases in rare and threatened birds and mammals. Notably, significant negative valuations were obtained for some of the scenarios presented. Provision of land use information did not significantly influence visitors' valuations, a surprising result given the controversial nature of one of the primary land uses, namely red grouse shooting.

Synoptic monitoring as an approach to discriminating between point and diffuse source contributions to zinc loads in mining impacted catchments

One of the global legacies of industrialisation is the environmental impacts of historic mineral exploitation. Recent national initiatives to manage the impacts on ground and surface waters have driven the need to develop better techniques for assessing understanding of the catchment-scale distribution and characterisation of the relative contribution of point and diffuse contaminant sources. The benefits of a detailed, multidisciplinary investigation are highlighted through a case study focused on the Rookhope Burn, a tributary of the River Wear, which falls within a significantly mine impacted area of the North Pennines Orefield, UK. Zinc (Zn) has been identified as the contaminant of concern within this catchment, which is judged by the Environment Agency to be at risk of failing to achieve good water quality status in the context of the Water Framework Directive. The results of synoptic flow monitoring and sampling for chemical determinations of major and trace elements have been used to calculate mass balances of instream and inflow chemical loads in the Rookhope Burn. Despite a dominant impact on the water quality from a mine outburst (especially Zn [1.45 to 2.42 mg/l], Fe [2.18 to 3.97 mg/l], Mn [3.69 to 6.77 mg/l], F [3.99 to 4.80 mg/l] and SO(4) [178 to 299 mg/l]), mass balance calculations combined with geological mapping have facilitated the identification of significant, previously unknown, subsurface contributions of Zn contaminated groundwater (with Zn concentrations in excess of 0.4 to 0.9 mg/l and 0.18 to 0.36 mg/l) to the Burn. The subsurface contributions exhibit spatial correspondence to mine workings with associated mineral veins and adits, or to points of suspected karst groundwater resurgence. These findings reiterate the challenges posed in decision making with respect to remediation, in this case in the context of the management of significant subsurface contributions.

Regional lead isotope study of a polluted river catchment: River Wear, Northern England, UK

High precision, lead isotope analyses of archived stream sediments from the River Wear catchment, northeast England (1986–88), provide evidence for three main sources of anthropogenic lead pollution; lead mining, industrial lead emissions and leaded petrol. In the upper catchment, pollution is totally controlled and dominated by large lead discharges from historic mining centres in the North Pennine Orefield ( 208Pb/ 206Pb, 207Pb/ 206Pb ratios range from 2.0744–2.0954 and 0.8413–0.8554 respectively). In the lower catchment, co-extensive with the Durham Coalfield and areas of high population density, pollution levels are lower and regionally more uniform. Isotope ratios are systematically higher than in the upper catchment ( 208Pb/ 206Pb, 207Pb/ 206Pb ratios range from 2.0856–2.1397 and 0.8554–0.8896 respectively) and far exceed values determined for the geogenic regional background. Here, the pollution is characterised by the atmospheric deposition of industrial lead and petrol lead. Lead derived from the combustion of coal, although present, is masked by the other two sources. Recent sediments from the main channel of the River Wear are isotopically indistinguishable from older, low order stream sediments of the North Pennine Orefield, indicating that contamination of the river by lead mining waste (up to several 1000 mg/kg Pb at some locations) continues to pose an environmental problem; a pattern that can be traced all the way to the tidal reach. Using within-catchment isotope variation and sediment lead concentrations, estimates can be made of the discharges from discrete mines or groups of mines to the overall level of lead pollution in the River Wear. As well as providing information pertinent to source apportionment and on-going catchment remediation measures, the database is a valuable resource for epidemiologists concerned with the health risks posed by environmental lead.

Historic and contemporary sediment transfer in an upland Pennine catchment, UK

AbstractA sediment budget for an upland catchment–reservoir system at Burnhope Reservoir, North Pennines, UK has been developed. This provides a framework for quantifying historic and contemporary sediment yields and drainage basin response to disturbance from climate change and human activities in the recent past. Bathymetric survey, core sampling, 137Cs dating and aerial photographs have been used to assess sediment accumulation in the reservoir. The average reservoir sedimentation rate is 1·24 cm yr−1 (annual sediment yield 33·3 t km−2 yr−1 ± 10%, trap efficiency 92%). Mean annual reservoir sedimentation over the 67 year period has been estimated at 592 t ± 10%. Inputs of suspended sediment from direct catchwater streams account for 54% of sediment supply to the budget (best estimate yield of 318 t yr−1 ± 129%), while those from actively eroding reservoir shorelines contribute 328 t yr−1 ± 92%. Sediment yield estimates from stream monitoring and reservoir sedimentation are an order of magnitude lower than those reported from South Pennine reservoirs of comparable drainage basin area. Analysis of historical rainfall series for the catchment shows fluctuations in winter and summer rainfall patterns over the past 62 years. From 1976 to 1998 there has been a diverging trend between winter and summer rainfall, with a large increase in winter and a gradual decrease in summer totals. Periods of maximum variation occur during the summer drought events of the late 1970s, early 1980s and mid‐1990s. Analysis of the particle size of core sediments highlights abrupt increases in sand‐sized particles in the top 20 cm of the core. Based on the 137Cs chronology, these layers were deposited from the late 1970s onwards and relate to these diverging rainfall records and rapidly fluctuating reservoir levels. This provides evidence of potential sediment reworking within the reservoir by rapid water‐level rise after drought. Copyright © 2008 John Wiley &amp; Sons, Ltd.

Novel approach to zinc removal from circum-neutral mine waters using pelletised recovered hydrous ferric oxide

Data are presented which evaluate the performance of a pilot-scale treatment system using pelletised hydrous ferric oxide (HFO; a waste stream from coal mine water treatment) as a high surface area sorbent for removing zinc (Zn) from a metal mine water discharge in the North Pennines Orefield, UK. Over a 10-month period the system removed Zn at mean area- and volume-adjusted removal rates of 3.7 and 8.1 g m −3 day −1, respectively, with a mean treatment efficiency of 32% at a low mean residence time of 49 min. There were seasonal effects in Zn removal owing to establishment and dieback of algae in the treatment tank. This led to increased Zn uptake in early summer months followed by slight Zn release upon algae senescence. In addition to these biosorptive processes, the principal sinks for Zn appear to be (1) sorption onto the HFO surface, and (2) precipitation with calcite-dominated secondary minerals. The latter were formed as a product of dissolution of portlandite in the cement binder and calcium recarbonation. Further optimisation of the HFO pelletisation process holds the possibility for providing a low-cost, low footprint treatment option for metal rich mine waters, in addition to a valuable after-use for recovered HFO from coal mine water treatment facilities.

Current status and recent trends in numbers and distribution of Black Grouse Tetrao tetrix in northern England

Capsule Surveys of Black Grouse in northern England in 1998, 2002 and 2006 show population recovery in the form of increases in both numbers and range. Aims To quantify the population size and range of Black Grouse in northern England. Methods Male black grouse attending leks were surveyed in 1998, 2002 and 2006. These results were put in context with a longer-term trend in northern England, using annual counts from a non-random sample of leks in the North Pennines between 1989 and 2006. Results Numbers of males increased from 773 in 1998 to 1029 in 2006. Range increased from 74 occupied 5-km grid squares in 1998 to 93 in 2006. Conclusion The English Black Grouse population is increasing in both numbers and range, but has become fragmented into two subpopulations, one in North Northumberland, the other in the North Pennines.

Reconstructions of the Late Devensian (Dimlington Stadial) British-Irish Ice Sheet: the role of the upper Tees drumlin field, north Pennines, England

SUMMARY It has long been known that the upland areas of the Pennines, northern England, were a local ice source during the Late Devensian (Dimlington Stadial) glaciation of Britain. However, there has been little detailed work on their significance for ice sheet reconstructions. The presence of drumlins at high elevations within the northern Pennines is reported from the upper reaches of the Tees valley and Harwood Beck. Geomorphological mapping has identified 134 drumlins occurring up to an elevation of 662 m OD in association with superimposed drumlins and drift tails. These landforms, particularly the presence of superimposed forms, enable the reconstruction of two ice flow events associated with a local ice centre that formed during the Late Devensian glaciation in northern England. The earlier flow event was directed straight down the upper Tees valley from a limited source area on the high ground to the east of Cross Fell. The later event indicates a flow direction more transverse to the valley, from a more extensive source area that had migrated and expanded westwards across the high plateau of Cross Fell and southwards towards Dufton Fell. The presence of drumlins at this high altitude indicates sufficient ice thickness to allow basal deformation and suggests that drumlin upper elevation defines a thermal regime above which the plateau ice field was cold based and frozen to the bed. This requires the area to be completely covered by ice. This study demonstrates the importance of these upland areas in detailed reconstructions of a multi-domed, British-Irish Ice Sheet (BIIS).

Predicting the future carbon budget of an upland peat catchment

Using data from a single upland peat catchment (North Pennines, UK), this study combines descriptions of the uptake of carbon by primary productivity and input from both wet and dry deposition with descriptions of carbon release pathways: soil CO2 respiration, CH4 flux, particulate organic carbon (POC), dissolved organic carbon (DOC), and excess dissolved CO2. Each pathway is projected 10 years into the future based upon extrapolated changes in rainfall and temperature. The study shows that the catchment is presently a net source of carbon and that over a period of 10 years the catchment goes from a net source of 11.2 to 20.9 gC/m2/year. The probability that the catchment is a net sink of carbon decreases from 35 to 26% over the study period, i.e. upland peats are predicted to become an increasing source of carbon. With respect to carbon gases (CO2 + CH4), the catchment remains a net sink but this decreases from 15.9 to 11.2 gC/m2/year, given current trends the catchment will become a net source of carbon gases by 2034. For most pathways the predicted increases or decreases are in line with increasing temperature predicted for the area, but DOC flux shows a larger percentage increase because of additional production caused by the increased frequency of severe droughts within the catchment. If this result is extended across the UK uplands, peats would be a net source of between 0.26 and 0.45 Mt C/year, but with respect to carbon gases alone the catchment is net sink of between 0.35 and 0.23 Mt C/year.

Renewable energy in remote communities

This research has demonstrated that even in a small urbanised country like Britain, communities can still be remote. The paper analyses the nature of remote settlements and suggests that beyond the rural idyll, there are deprived communities. In order to obtain real data, a study area in the North Pennines was selected. The types of remote communities were evident throughout the study area and one of each type was selected for further study. It became clear that villages with an industrial base had most potential, due to high energy demand, vulnerability and community involvement. A village with a high measure of multiple deprivation and suffering from fuel poverty was chosen for a more detailed investigation. Energy demand profiles were developed and candidate technologies nominated. The latter were tested by filters that assessed fitness for application, robustness and autonomy. The most appropriate combinations of technologies were proposed. The residents and their community representatives were involved in the process and recognised the benefits of the proposals to themselves and others.

An experimental assessment of the potential effects of human disturbance on Black Grouse Tetrao tetrix in the North Pennines, England

In the United Kingdom, Black Grouse Tetrao tetrix have declined in range and abundance during the 20th century. In England at present, birds are largely found only on the margins of managed grouse moors in the north, where more than 80% of birds are confined to the North Pennines Area of Outstanding Natural Beauty. The Black Grouse is one of a group of species potentially at risk from increased human recreational disturbance owing to their threatened status and their use of habitats to which a statutory right of human recreational access has recently been granted. To assess the likely impact of increased disturbance to Black Grouse, 77 were caught and radiotagged between 2002 and 2004, and each was randomly assigned to one of three experimental disturbance categories: no disturbance (low), fortnightly disturbance (moderate) or twice weekly disturbance (high). Birds that were disturbed more regularly flushed at greater distances, especially in spring and winter when birds exposed to high disturbance flushed at 32% greater distances than those in moderate disturbance treatments. There were no differences in fecundity (clutch size, hatching success, breeding success) or survival between disturbance treatments. Winter survival was 78% and summer survival 92%. There was no age‐related difference in survival. The disturbance regimes imposed had no discernible impact upon Black Grouse population dynamics. However, in the absence of appropriate data to indicate likely changes in patterns and levels of human recreation resulting from open access, we cannot be sure whether the levels we applied will be representative in the future. Should actual disturbance levels be higher than those we used in this study, we list visitor management options that may help reduce any conflict that arises.

Modelling the impact of drainage and drain-blocking on dissolved organic carbon release from peatlands

It has been hypothesized that the trend in increasing DOC concentration in rivers draining from peat catchments is enhanced by drainage of the peat. It follows that blocking of drainage ditches could stabilise or decrease concentrations of DOC in stream water flowing from peat catchments. This study develops a model for the flux of DOC from a peat catchment in the North Pennines, UK. This model is used to predict the future DOC flux for an undrained and a drained catchment and for one where the drains were blocked. The model predicted that: i. For a pristine catchment the DOC concentration will continue to rise at an average rate of 3% per year; ii. Drained catchments export more DOC and increases are of the order of 15–33% over a 10-year period depending upon the drain-spacing; iii. When drainage is blocked improvements in DOC export are predicted but the magnitude of the decrease is critically dependent upon the drain-spacing and for the larger drain-spacings no decrease may be observed. Over time, the improvements in DOC export are shown to lessen as formerly drained catchments revert to behaviour like that of a pristine catchment. Since pristine catchments are predicted to continue to lose DOC at an increasing rate the blocking of peat drains can only be considered as a medium term strategy for mediating the problem.