CEH Wallingford

Benson, United Kingdom

CEH Wallingford

Benson, United Kingdom
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Liu L.,China Agricultural University | Xu Z.X.,Beijing Normal University | Reynard N.S.,CEH Wallingford | Hu C.W.,China Institute of Water Resources and Hydropower Research | Jones R.G.,UK Met Office
Journal of Flood Risk Management | Year: 2013

Changes in precipitation can be expected to have a major influence on the frequency and severity of flooding in the Taihu Basin. As part of an integrated assessment of flood risk in the Taihu Basin, this paper addresses the hydrological conditions and the potential impacts of climate change on Taihu Lake water levels. The hydrological system is simulated by using the distributed hydrological model VIC (Variable Infiltration Capacity), with future climate scenarios generated by the regional climate model PRECIS (Providing Regional Climates for Impacts Studies). The results indicate that maximum and mean flood water levels under the A2 and B2 scenarios for 2021-2050 will be higher than the levels during the baseline period (1961-1990), with larger increases under the B2 scenario than for the A2 scenario. The storm return periods leading to extreme water levels in the Taihu Lake in the future is projected to decrease significantly in comparison to the baseline period, implying the potential for the more frequent occurrence of major floods. These results indicate the importance of planning for future flood control in the Taihu Basin. © 2012 Blackwell Publishing Ltd and The Chartered Institution of Water and Environmental Management (CIWEM).

Nicholls J.A.,University of Edinburgh | Preuss S.,University of Edinburgh | Hayward A.,University of Edinburgh | Hayward A.,University of Oxford | And 7 more authors.
Molecular Ecology | Year: 2010

Little is known about the evolutionary history of most complex multi-trophic insect communities. Widespread species from different trophic levels might evolve in parallel, showing similar spatial patterns and either congruent temporal patterns (Contemporary Host-tracking) or later divergence in higher trophic levels (Delayed Host-tracking). Alternatively, host shifts by natural enemies among communities centred on different host resources could disrupt any common community phylogeographic pattern. We examined these alternative models using two Megastigmus parasitoid morphospecies associated with oak cynipid galls sampled throughout their Western Palaearctic distributions. Based on existing host cynipid data, a parallel evolution model predicts that eastern regions of the Western Palaearctic should contain ancestral populations with range expansions across Europe about 1.6 million years ago and deeper species-level divergence at both 8-9 and 4-5 million years ago. Sequence data from mitochondrial cytochrome b and multiple nuclear genes showed similar phylogenetic patterns and revealed cryptic genetic species within both morphospecies, indicating greater diversity in these communities than previously thought. Phylogeographic divergence was apparent in most cryptic species between relatively stable, diverse, putatively ancestral populations in Asia Minor and the Middle East, and genetically depauperate, rapidly expanding populations in Europe, paralleling patterns in host gallwasp species. Mitochondrial and nuclear data also suggested that Europe may have been colonized multiple times from eastern source populations since the late Miocene. Temporal patterns of lineage divergence were congruent within and across trophic levels, supporting the Contemporary Host-tracking Hypothesis for community evolution. © 2010 Blackwell Publishing Ltd.

Hancock S.,University of Swansea | Baxter R.,Durham University | Evans J.,CEH Wallingford | Huntley B.,Durham University
Remote Sensing of Environment | Year: 2013

This paper compares three global snow water equivalent (SWE) products, SSM/I (NSIDC), AMSR-E (NSIDC) and Globsnow (v1.0, ESA) to each other, snow covered area (SCA), ground measures of snow depth and meteorological data in an attempt to determine which might be most suitable for testing and developing land surface models. Particular attention is paid to which gives the most accurate peak accumulation, seasonal SWE changes and first and last dates of snow cover.SSM/I and AMSR-E are pure earth observation (EO) derived products whilst Globsnow is a combination of EO and ground data. The results suggest that the pure EO products can saturate in deeper snow (SWE>80-150. mm), can show spurious features during melt and can overestimate SWE due to strong thermal gradients and erroneous forest cover correction factors. Along with the comparison to ground data (only a single point) this suggests that Globsnow is the more accurate product for determining peak accumulation and seasonal SWE cycle.The snow start and end dates of the three SWE products were compared to an optically derived SCA (MOD10C1, taken as truth) and found to give large errors of snow start date (root mean square error of 20. + days, though SSM/I was correct on average). The snow end dates had lower errors (a bias of 1-6. days) although the spread was still on the order of three weeks.During the investigation, occasional abrupt changes in Globsnow were observed (in the v1.0 and v1.2 daily and v1.2 weekly products). These only occurred in around 1% of cases examined and seem to be spurious. Care should be taken to corrector avoid these jumps if using Globsnow to validate land surface models or in an assimilation scheme. © 2012 Elsevier Inc.

Drewer J.,CEH Edinburgh | Finch J.W.,CEH Wallingford | Lloyd C.R.,CEH Wallingford | Baggs E.M.,University of Aberdeen | Skiba U.,CEH Edinburgh
GCB Bioenergy | Year: 2012

It is important to demonstrate that replacing fossil fuel with bioenergy crops can reduce the national greenhouse gas (GHG) footprint. We compared field emissions of nitrous oxide (N2O), methane (CH4) and soil respiration rates from the C4 grass Miscanthus × giganteus and willow (salix) with emissions from annual arable crops grown for food production. The study was carried out in NE England on adjacent fields of willow, Miscanthus, wheat (Triticum aetivum) and oilseed rape (Brassica napus). N2O, CH4 fluxes and soil respiration rates were measured monthly using static chambers from June 2008 to November 2010. Net ecosystem exchange (NEE) of carbon dioxide (CO2) was measured by eddy covariance on Miscanthus from May 2008 and on willow from October 2009 until November 2010. The N2O fluxes were significantly smaller from the bioenergy crops than that of the annual crops. Average fluxes were 8 and 32 μg m-2 h-1 N2O-N from wheat and oilseed rape, and 4 and 0.2 μg m-2 h-1 N2O-N from Miscanthus and willow, respectively. Soil CH4 fluxes were negligible for all crops and soil respiration rates were similar for all crops. NEE of CO2 was larger for Miscanthus (-770 g C m-2 h-1) than willow (-602 g C m-2 h-1) in the growing season of 2010. N2O emissions from Miscanthus and willow were lower than for the wheat and oilseed rape which is most likely a result of regular fertilizer application and tillage in the annual arable cropping systems. Application of 15N-labelled fertilizer to Miscanthus and oil seed rape resulted in a fertilizer-induced increase in N2O emission in both crops. Denitrification rates (N2O + N2) were similar for soil under Miscanthus and oilseed rape. Thus, perennial bioenergy crops only emit less GHGs than annual crops when they receive no or very low rates of N fertilizer. © 2011 Blackwell Publishing Ltd.

Collins A.L.,Rothamsted Research | Collins A.L.,University of Southampton | Murdoch N.,UK Environment Agency | Naden P.S.,CEH Wallingford
Environmental Science and Policy | Year: 2014

Diffuse water pollution represents a major environmental issue for the European Union. Attempts to provide a coordinated approach to the management of the freshwater environment require appropriate tools for macro-scale spatial analysis to deliver the evidence base for informing targeted decision making and interventions. In this context, this paper reports the development of a new national multiple pollutant (nutrients and sediment)source apportionment screening framework for England and Wales. SEPARATE (SEctor Pollutant AppoRtionment for the AquaTic Environment) includes emissions to the aquatic environment from both diffuse (agriculture, urban, river channel banks, atmospheric) and point (sewage treatment works (STWs), septic tanks, combined sewer overflows (CSOs), storm tanks) sources and summarises the source apportionment on the basis of Water Framework Directive cycle 2 waterbodies. National scale source proportions (with waterbody ranges) for total nitrogen (TN) were estimated to be in the order; agriculture (81%, 1-100%)>STWs (14%, 0-95%)>CSOs (1.5%, 0-73%)>direct atmospheric deposition (1.3%, 0-93%) >diffuse urban and storm tanks (both 1%, 0-80% and 0-93%) >septic tanks (0.2%, 0-30%) >river channel banks (~0%, 0-1%). The corresponding estimates for total phosphorus (TP) were; STWs (47%, 0-100%)>agriculture (31%, 0-100%)>CSOs (9%, 0-94%)>storm tanks (6%, 0-100%)>diffuse urban/septic tanks/river channel banks (all 2%, 0-100%, 0-70%, 0-71%)>direct atmospheric deposition (1%, 0-65%). For sediment, the estimates were in the order; agriculture (72%, 0-100%)>river channel banks (22%, 0-96%)>diffuse urban (5%, 0-100%)>STWs (1%, 0-91%). Without the inclusion of groundwater sources, agricultural contributions dominate water pollution by TN in 93% (130,384km2) of waterbodies across England Wales, compared to 58% (68,434km2) in the case of TP and 76% (104,434km2) for sediment. In combination, agricultural contributions of all three of these pollutants are dominant in 53% (63,030km2) of waterbodies. © 2014 Elsevier Ltd.

Johnson A.C.,CEH Wallingford | Yoshitani J.,Japan National Institute for Land and Infrastructure Management | Tanaka H.,Environmental Quality Management | Suzuki Y.,Public Works Research Institute
Environmental Science and Technology | Year: 2011

The predicted aquatic estrogen concentrations for the whole of England and Japan were determined and compared using population and flow data. The overall value for English surface waters was 0. 9 ng/L estradiol equivalents (EEQ) compared to 0. 1 ng/L overall for Japan. Available dilution of sewage effluent was considered to be more important than contraceptive pill usage in this relative risk. A national survey of Japanese rivers using the yeast estrogen assay (YES) gave a median value of 0. 27 ng/L EEQ which, while higher than that predicted, confirmed an overall low endocrine disruption risk. Using local population and flow data for 27 separate catchments, the predicted EEQ and measured EEQ (YES) values compared well, confirming the national picture that endocrine disruption would not be a widespread phenomena in Japan. Simple predictions based on population and flow can give an appropriate "ball park" value for catchments and even nations for concentrations of polar organic contaminants which have a majority human origin. © 2011 American Chemical Society.

Fagan K.C.,CEH Monks Wood | Pywell R.F.,CEH Monks Wood | Bullock J.M.,CEH Wallingford | Marrs R.H.,University of Liverpool
Restoration Ecology | Year: 2010

Assessments of restoration are usually made through vegetation community surveys, leaving much of the ecosystem underexamined. Invertebrates, and ants in particular, are good candidates for restoration evaluation because they are sensitive to environmental change and are particularly important in ecosystem functioning. The considerable resources currently employed in restoring calcareous grassland on ex-arable land mean that it is important to gather as much information as possible on how ecosystems change through restoration. We compared ant communities from 40 ex-arable sites where some form of restoration work had been implemented between 2 and 60 years previously, with 40 paired reference sites of good quality calcareous grassland with no history of improvement or cultivation. A total of 11 ant species were found, but only two of these were found to be significantly different in abundance between restoration and reference sites: Myrmica sabuleti was more likely to be present in reference sites, whereas Lasius niger was more likely to be found in restoration sites. Myrmica sabuleti abundance was significantly positively correlated with age of restoration sites. The potential number of ant species found in temperate grasslands is small, limiting the information their assemblages can provide about ecosystem change. However, M. sabuleti is a good indicator species for calcareous grassland restoration success and, alongside information from the plant community, could increase the confidence with which restoration success is judged. We found the survey to be quick and simple to carry out and recommend its use. © 2008 Society for Ecological Restoration International.

Jones J.I.,Queen Mary, University of London | Collins A.L.,Soils Crops and Water | Collins A.L.,University of Southampton | Naden P.S.,CEH Wallingford | Sear D.A.,University of Southampton
River Research and Applications | Year: 2012

The interplay between erosion and deposition are fundamental characteristics of river basins. These processes result in the delivery, retention and conveyance of sediment through river systems. Although the delivery of sediment to rivers is a natural phenomenon, in recent years there has been increasing concern about the enhancement of sediment loadings as a result of anthropogenic activities. The presence of macrophytes in river channels tends to increase the retention of fine sediment leading to changes in bed composition. However, a complex relationship exists between macrophytes and fine sediment: macrophytes affect the conveyance of fine sediment and are, in turn, affected by the sediment loading. This review deals with these two reciprocal effects and, in particular, summarizes the available evidence base on the impact of fine sediment on macrophytes. Increased inputs of fine sediment appear to have both direct and indirect impacts on the macrophyte community, altering light availability, and the structure and quality of the river bed. The nature of these impacts depends largely on the rate of deposition and the nature of the material deposited. Changes in macrophyte community composition may ensue where the depositing material is more nutrient rich than the natural river bed. Many of the changes in macrophyte flora that occur with increased fine sediment inputs are likely to closely parallel those that occur with increased dissolved nutrient availability. If attempts to manage nutrient inputs to rivers are to achieve their goals, it is critical that fine sediment-associated nutrient dynamics and transfers are considered. © 2011 John Wiley & Sons, Ltd.

Krampis K.,J. Craig Venter Institute | Booth T.,CEH Wallingford | Chapman B.,Harvard University | Tiwari B.,CLC Bio | And 3 more authors.
BMC Bioinformatics | Year: 2012

Background: A steep drop in the cost of next-generation sequencing during recent years has made the technology affordable to the majority of researchers, but downstream bioinformatic analysis still poses a resource bottleneck for smaller laboratories and institutes that do not have access to substantial computational resources. Sequencing instruments are typically bundled with only the minimal processing and storage capacity required for data capture during sequencing runs. Given the scale of sequence datasets, scientific value cannot be obtained from acquiring a sequencer unless it is accompanied by an equal investment in informatics infrastructure.Results: Cloud BioLinux is a publicly accessible Virtual Machine (VM) that enables scientists to quickly provision on-demand infrastructures for high-performance bioinformatics computing using cloud platforms. Users have instant access to a range of pre-configured command line and graphical software applications, including a full-featured desktop interface, documentation and over 135 bioinformatics packages for applications including sequence alignment, clustering, assembly, display, editing, and phylogeny. Each tool's functionality is fully described in the documentation directly accessible from the graphical interface of the VM. Besides the Amazon EC2 cloud, we have started instances of Cloud BioLinux on a private Eucalyptus cloud installed at the J. Craig Venter Institute, and demonstrated access to the bioinformatic tools interface through a remote connection to EC2 instances from a local desktop computer. Documentation for using Cloud BioLinux on EC2 is available from our project website, while a Eucalyptus cloud image and VirtualBox Appliance is also publicly available for download and use by researchers with access to private clouds.Conclusions: Cloud BioLinux provides a platform for developing bioinformatics infrastructures on the cloud. An automated and configurable process builds Virtual Machines, allowing the development of highly customized versions from a shared code base. This shared community toolkit enables application specific analysis platforms on the cloud by minimizing the effort required to prepare and maintain them. © 2012 Krampis et al; licensee BioMed Central Ltd.

Thomas J.A.,University of Oxford | Simcox D.J.,CEH Wallingford | Hovestadt T.,University of Oxford | Hovestadt T.,CNRS Mechanical Adaptation and Evolution
Journal of Insect Conservation | Year: 2011

Few results of research aimed at solving questions arising from butterfly conservation are rigorously tested by manipulating populations and habitats in the field. Some factors common to successful conservation projects are analysed. In most non-migratory species, population density may vary by up to two orders of magnitude between sites or over time, and is primarily determined by the extent to which a subset of each species' foodplant (or ant host) exists in the optimum growth-form or micro-habitat preferred by its larvae. Successful conservation projects have identified the optimum subset of each species' larval resource before managing sites to increase its representation. In contrast, short-term fluctuations around a site's carrying capacity or equilibrium level are mainly attributable to variation in weather, and are generally two orders of magnitude smaller than that attributable to larval habitat quality. There is little evidence that changing the abundance of adult resources, apart from shelter, influences population size or trends. The main constraint of the adult stage is the inability of many species to track the generation of new habitat patches that arise across modern landscapes. Within-patch larval habitat quality is again critical at the meta-population scale, explaining slightly more examples of patch occupancy than site isolation. This is because the higher density populations supported by optimum habitat are less likely to go extinct, and immigrants to new high-quality patches have a higher probability of founding new populations. Such patches may also generate up to a hundred times more emigrants per hectare than low-quality source patches. © 2010 Springer Science+Business Media B.V.

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