This data resource consists of two files: (a) 1x1 km resolution Average Accumulated Exceedance (AAE) data summarising the exceedances of acidity critical loads for eight habitats; (b) 1x1 km resolution AAE data summarising the exceedances of nutrient nitrogen critical loads for thirteen habitats. The data provide information on the amount of excess acid or nitrogen deposition above the critical load values set to protect acid- and nitrogen-sensitive habitats in the UK. The AAE has been calculated using UK 5x5 km Concentration Based Estimated Deposition (CBED) data for 2013-15 - https://doi.org/10.5285/fd8151e9-0ee2-4dfa-a254-470c9bb9bc1e . The data were generated under Defra-funded work to assess the potential areas of acid and nitrogen sensitive habitats at risk of adverse impacts from excess atmospheric acid and nitrogen deposition. Reducing the area and amount of critical load exceedance continues to be a driver of Government policy on reducing emissions of acidic and nitrogen-containing air pollutants (sulphur dioxide, nitrogen oxides and ammonia). Full details about this dataset can be found at https://doi.org/10.5285/e32745d2-fb56-4f91-a235-6b213a8b45cb

The data provide critical loads of acidity, and of nutrient nitrogen for the distributions of UK habitats sensitive to acidification and/or eutrophication. Critical loads have been calculated and applied to UK natural and semi-natural habitats sensitive to acidification and/or eutrophication (excess nitrogen as a nutrient). Critical loads data are available for these habitat types at 1x1 km resolution for the UK. In addition, acidity critical loads are available for 1752 selected freshwater sites throughout the UK. Critical loads are defined as the maximum pollutant load (of acid or nitrogen deposition) that a sensitive element of the environment (e.g., soils, vegetation) can tolerate without adverse harmful effects occurring, according to present knowledge. Habitat distributions are defined from a combination of CEH Land Cover Map 2000 and a number of ancillary data sets (e.g., species distributions, altitude, soils), used to further refine their distributions. It should be noted that the habitat distributions maps and areas provided here and used for UK critical loads research for Defra (a) only include areas where data exist for the calculation or derivation of critical loads; (b) may differ from other national habitat distribution maps or estimates of habitat areas. This may also result in a difference in the total habitat areas mapped for acidity and for nutrient nitrogen critical loads. The data have been generated under numerous Defra-funded contracts that brought together UK experts on the impacts of air pollution on UK habitats. The acidity critical loads data were last revised in 2004 and the nutrient nitrogen critical loads data were updated in 2011. The data are based on methods agreed at national and international meetings and workshops held under the UNECE Convention on Long-Range Transboundary Air Pollution (CLRTAP). Full details about this dataset can be found at https://doi.org/10.5285/299e2779-0787-46bb-9482-03ad474eae27

This dataset consists of fish species, fish length and fish weight from samples taken from small and medium catchments across Wales. Samples were collected in the summers and autumns of 2012 and 2013 using electrofishing. All the collected individuals were counted and recorded to represent the fish diversity and abundance of each sampling site and date. The main goal of this survey was to relate fish production with a gradient of aquatic biodiversity associated with different environmental settings (land-use intensify, recovery from acidification). Dr Isabelle Durance was responsible for organising the surveys, Dr Hugh Feeley was in charge of collecting, sorting and measuring the fish samples. The work was carried out under the Diversity in Upland Rivers for Ecosystem Service Sustainability (DURESS) project (Grant reference NERC NE/J014818/1). DURESS was a project funded by the Natural Environment Research Council (NERC) Biodiversity and Ecosystem Service Sustainability (BESS) programme. Full details about this dataset can be found at https://doi.org/10.5285/57f95ff8-e1b0-41b9-866a-feb231aecb67

These data are for macroinvertebrate taxonomy and abundance of Welsh upland rivers. The sampling sites were located in small and medium catchments across Wales. Sampling took place in either spring 2013 for sites in the Wye catchment or during 2012 for the other catchments. At each sampling point, 2-minute kick-samples were taken from river riffles to represent macroinvertebrate composition. Samples were preserved in industrial methylated spirit on site. Samples were then sorted and identified in the laboratory. The main goal of this survey was to characterise a gradient of aquatic biodiversity associated with different environmental settings for example land-use intensify and recovery from acidification. Dr Isabelle Durance was the responsible of organising the surveys, Dr Hugh Feeley was in charge of collecting, processing and sorting the invertebrate samples. Kath Layer was commissioned by Cardiff University for the identification. The work was carried out under Diversity in Upland Rivers for Ecosystem Service Sustainability (DURESS) project (Grant reference NERC NE/J014818/1). DURESS was a project funded by the Natural Environment Research Council (NERC) Biodiversity and Ecosystem Service Sustainability (BESS) programme. Full details about this dataset can be found at https://doi.org/10.5285/8f7b2269-73b1-449f-8590-e36c7c850913

These data consist of stream water chemistry for selected Welsh upland rivers. The sampling sites were located in sixty one small and medium catchments. Catchments were chosen from the Welsh Acid Water Surveys (WAWS) program (41 sites) and the Wye catchment (20 sites). Results for pH, alkalinity, conductivity and major cation and anion measurements are presented for the WAWS catchments. Results for pH, alkalinity, conductivity and major anion measurements are presented for the Wye catchment. Samples from the Wye catchment were collected in May 2012. Samples from the WAWS catchments were taken during the summer and autumn of 2012 and spring and summer of 2013. The data were collected to characterise water chemistry variation along a gradient of aquatic biodiversity associated with different environmental settings for example land-use intensify and recovery from acidification. Dr Isabelle Durance was responsible for organising the surveys, Dr Hugh Feeley was in charge of collecting and preserving the water samples. Analysis of the water samples was carried out at the Forest Research Laboratories. The work was carried out under Diversity in Upland Rivers for Ecosystem Service Sustainability (DURESS) project (Grant reference NERC NE/J014818/1). DURESS was a project funded by the Natural Environment Research Council (NERC) Biodiversity and Ecosystem Service Sustainability (BESS) programme. Full details about this dataset can be found at https://doi.org/10.5285/d329ca18-c3d8-49f0-b2fd-5243d76dc650

These data are macroinvertebrate composition and abundance in eight Welsh upland rivers with contrasting land-use, moorland and exotic conifer, in response to riparian deciduous leaf addition. Eight sampling reaches were chosen at two sites, Llyn Brianne (4 reaches) and Plynlimon (4 reaches). The experiment consisted of adding deciduous leaves to half of the reaches whilst the other half were maintained as control (no addition). Nylon mesh bags containing deciduous leaves were fixed in both experimental and control reaches to estimate leaf decomposition rates. The macroinvertebrate composition of the nylon mesh bags was surveyed in January 2013 and again in March 2013 in each sampling reach. The main goal of this survey was to examine how aquatic biodiversity responds to leaf addition in moorland and conifer forested rivers. Dr Isabelle Durance was responsible for organising the surveys, Dr Hugh Feeley, Dr Dan Perkins and Marian Pye were in charge of collecting, processing and sorting the invertebrate samples. The work was carried out under Diversity in Upland Rivers for Ecosystem Service Sustainability (DURESS) project (Grant reference NERC NE/J014818/1). DURESS was a project funded by the Natural Environment Research Council (NERC) Biodiversity and Ecosystem Service Sustainability (BESS) programme Full details about this dataset can be found at https://doi.org/10.5285/3e6a9ffd-59f2-48ea-840b-1582dc6c1e3d

Stream water chemistry data from the UK Environmental Change Network (ECN) terrestrial sites. Variables measured include pH, conductivity, alkalinity, aluminium, calcium, chloride, ammonium, nitrate nitrogen, phosphate phosphorous, potassium, sulphate sulphur, sodium, total nitrogen and total dissolved phosphorous. The data are collected by dip samples at ECN's terrestrial sites (where there is a stream present) using a standard protocol. They represent continuous weekly records from 1992 to 2015. The sites at which these data are collected are: Cairngorms, Glensaugh, Moor House - Upper Teesdale, North Wyke, Rothamsted, Sourhope, Wytham and Y Wyddfa (Snowdon). ECN is the UK's long-term environmental monitoring programme. It is a multi-agency programme sponsored by a consortium of fourteen government departments and agencies. These organisations contribute to the programme through funding either site monitoring and/or network co-ordination activities. These organisations are: Agri-Food and Biosciences Institute, Biotechnology and Biological Sciences Research Council, Cyfoeth Naturiol Cymru - Natural Resources Wales, Defence Science & Technology Laboratory, Department for Environment, Food and Rural Affairs, Environment Agency, Forestry Commission, Llywodraeth Cymru - Welsh Government, Natural England, Natural Environment Research Council, Northern Ireland Environment Agency, Scottish Environment Protection Agency, Scottish Government and Scottish Natural Heritage. Full details about this dataset can be found at https://doi.org/10.5285/fd7ca5ef-460a-463c-ad2b-5ad48bb4e22e

[THIS DATASET HAS BEEN WITHDRAWN]. Stream water chemistry data from the UK Environmental Change Network (ECN) terrestrial sites. Variables measured include pH, conductivity, alkalinity, aluminium, calcium, chloride, ammonium, nitrate nitrogen, phosphate phosphorous, potassium, sulphate sulphur, sodium, total nitrogen and total dissolved phosphorous. The data are collected by dip samples at ECN's terrestrial sites (where there is a stream present) using a standard protocol. They represent continuous weekly records from 1992 to 2012. The sites at which these data are collected are: Cairngorms, Glensaugh, Moor House-Upper Teesdale, North Wyke, Rothamsted, Sourhope, Wytham and Y Wyddfa (Snowdon). ECN is the UK's long-term environmental monitoring programme. It is a multi-agency programme sponsored by a consortium of fourteen government departments and agencies. These organisations contribute to the programme through funding either site monitoring and/or network co-ordination activities. These organisations are: Agri-Food and Biosciences Institute, Biotechnology and Biological Sciences Research Council, Cyfoeth Naturiol Cymru - Natural Resources Wales, Defence Science & Technology Laboratory, Department for Environment, Food and Rural Affairs, Environment Agency, Forestry Commission, Llywodraeth Cymru - Welsh Government, Natural England, Natural Environment Research Council, Northern Ireland Environment Agency, Scottish Environment Protection Agency, Scottish Government and Scottish Natural Heritage. Full details about this dataset can be found at https://doi.org/10.5285/5a715fd9-aefa-40cc-bbb6-56984b6db554

Soil solution data from the UK Environmental Change Network (ECN) terrestrial sites. Variables measured include pH, conductivity, alkalinity, aluminium, calcium, chloride, ammonium, nitrate nitrogen, phosphate phosphorous, potassium, sulphate sulphur, sodium, total nitrogen and total dissolved phosphorous. These data are collected by suction samplers at all of ECN's terrestrial sites using a standard protocol. They represent continuous fortnightly records from 1992 to 2015. ECN is the UK's long-term environmental monitoring programme. It is a multi-agency programme sponsored by a consortium of fourteen government departments and agencies. These organisations contribute to the programme through funding either site monitoring and/or network co-ordination activities. These organisations are: Agri-Food and Biosciences Institute, Biotechnology and Biological Sciences Research Council, Cyfoeth Naturiol Cymru - Natural Resources Wales, Defence Science & Technology Laboratory, Department for Environment, Food and Rural Affairs, Environment Agency, Forestry Commission, Llywodraeth Cymru - Welsh Government, Natural England, Natural Environment Research Council, Northern Ireland Environment Agency, Scottish Environment Protection Agency, Scottish Government and Scottish Natural Heritage. Full details about this dataset can be found at https://doi.org/10.5285/b330d395-68f2-47f1-8d59-3291dc02923b

[THIS DATASET HAS BEEN WITHDRAWN]. Soil solution data from the UK Environmental Change Network (ECN) terrestrial sites. Variables measured include pH, conductivity, alkalinity, aluminium, calcium, chloride, ammonium, nitrate nitrogen, phosphate phosphorous, potassium, sulphate sulphur, sodium, total nitrogen and total dissolved phosphorous. These data are collected by suction samplers at all of ECN's terrestrial sites using a standard protocol. They represent continuous fortnightly records from 1992 to 2012. ECN is the UK's long-term environmental monitoring programme. It is a multi-agency programme sponsored by a consortium of fourteen government departments and agencies. These organisations contribute to the programme through funding either site monitoring and/or network co-ordination activities. These organisations are: Agri-Food and Biosciences Institute, Biotechnology and Biological Sciences Research Council, Cyfoeth Naturiol Cymru - Natural Resources Wales, Defence Science & Technology Laboratory, Department for Environment, Food and Rural Affairs, Environment Agency, Forestry Commission, Llywodraeth Cymru - Welsh Government, Natural England, Natural Environment Research Council, Northern Ireland Environment Agency, Scottish Environment Protection Agency, Scottish Government and Scottish Natural Heritage. Full details about this dataset can be found at https://doi.org/10.5285/456c24dd-0fe8-46c0-8ba5-855c001bc05f