This dataset provides the details of all sites on which butterflies have been monitored as part of the UK Butterfly Monitoring Scheme (UKBMS). This includes all standard UKBMS transect sites, Wider Countryside Butterfly Survey (WCBS) sites and targeted species survey sites (timed counts, single-species transects, larval web and egg counts). Data includes the location within the UK, the length and number of sections for the butterfly transect on each site and the number of years each transect has been monitored. The location of some sites are sensitive and are excluded from this dataset. Users requiring access to the complete dataset, including sensitive site location data, can submit a request via the UKBMS website. The UKBMS started in 1976 with fewer than 50 sites. Since then the number of sites monitored each year has increased to several thousand. There are new sites each year and a small number where the transect is no longer surveyed. Details of this are provided in the site dataset in the form of the first and last year in which each site was surveyed. The majority of site data is provided by recorders at the time a transect is created. Site data are crucial in order to determine where extra recording effort is required and to investigate where butterfly populations are changing most and thus where conservation should be targeted, including across different habitat types. The UK Butterfly Monitoring Scheme is organized and funded by Butterfly Conservation (BC), the UK Centre for Ecology & Hydrology (UKCEH), the British Trust for Ornithology (BTO), and the Joint Nature Conservation Committee (JNCC). The UKBMS is indebted to all volunteers who contribute data to the scheme. This work was supported by the Natural Environment Research Council award number NE/R016429/1 as part of the UK-SCAPE programme delivering National Capability. Full details about this dataset can be found at https://doi.org/10.5285/d7256b49-f2e3-4ae7-907d-af729610c768

This dataset comprises individual site indices for UK butterfly species calculated from data from the UK Butterfly Monitoring Scheme (UKBMS). Site indices are a relative rather than an absolute measure of the size of a population, and have been shown to relate closely to other, more intensive, measures of population size such as mark, release, recapture (MRR) methods. The site index can be thought of as a relative measure of the population size, being a more or less constant proportion of the number of butterflies present. The proportion seen is likely to vary according to species; some butterfly species are more conspicuous and thus more easily detected, whereas others are much less easy to see. Site indices are only calculated at sites with sufficient monitoring visits throughout the season, or for targeted reduced effort surveys (timed observations, larval web counts and egg counts) where counts are generally obtained as close to the peak of the flight period as possible and are subsequently adjusted for the time of year and size of the site (area of suitable habitat type for a given species). Wider Countryside Butterfly Survey (WCBS) sites are thus excluded because they are based on very few visits from which indices of abundance are not calculated. For transect sites, a statistical model (a General Additive Model, 'GAM') is used to impute missing values and to calculate a site index. Each year most transect sites (over 90%) produce an index for at least one species and in recent years site indices have been calculated for over 2,000 sites across the UK. Site indices are subsequently collated to contribute to the overall 'Collated Index' for each species, which are relative measures of the abundance of each species across a geographical area, for example, across the whole UK or at country level for England, Scotland, Wales or Northern Ireland. Individual site indices are important in informing conservation management as not all sites show the same patterns for each species and likely reflect a combination of local climate and habitat management at the site. The UK Butterfly Monitoring Scheme is organized and funded by Butterfly Conservation (BC), the UK Centre for Ecology & Hydrology (UKCEH), the British Trust for Ornithology (BTO), and the Joint Nature Conservation Committee (JNCC). The UKBMS is indebted to all volunteers who contribute data to the scheme. This work was supported by the Natural Environment Research Council award number NE/R016429/1 as part of the UK-SCAPE programme delivering National Capability. Full details about this dataset can be found at https://doi.org/10.5285/53a1c705-4437-48bb-9bcd-b68977f8edd9

HadEX3 is a land-surface dataset of climate extremes indices available on a 1.875 x 1.25 longitude-latitude grid. These 29 indices have been developed by the World Meteorological Organization (WMO) Expert Team on Climate Change Detection and Indices (ETCCDI). Daily precipitation, as well as maximum and minimum temperature observations, are used to calculate these indices at each station. The daily data, as well as indices, have been supplied, quality controlled and combined to make a gridded set of NetCDF files covering 1901-2018 (inclusive). Spatial coverage is determined by the number of stations present at each time point as well as the spatial correlation structure between the stations for each index. The spatial coverage is lowest at the beginning of the dataset, rising until around 1960 where it plateaus, and then declines slightly after 2010. All indices are available as annual quantities, with a subset also available on a monthly basis. A number of the indices use a reference period to determine thresholds. For these, we provide two versions, one set using 1961-1990 and another using the more recent 1981-2010 (these reference periods have been indicated in the file name as either 'ref-6190' or 'ref-8110').

HadEX3 is a land-surface dataset of climate extremes indices available on a 1.875 x 1.25 longitude-latitude grid. These 29 indices have been developed by the World Meteorological Organization (WMO) Expert Team on Climate Change Detection and Indices (ETCCDI). Daily precipitation, as well as maximum and minimum temperature observations, are used to calculate these indices at each station. The daily data, as well as indices, have been supplied, quality controlled and combined to make a gridded set of NetCDF files covering 1901-2018 (inclusive). Spatial coverage is determined by the number of stations present at each time point as well as the spatial correlation structure between the stations for each index. The spatial coverage is lowest at the beginning of the dataset, rising until around 1960 where it plateaus, and then declines slightly after 2010. All indices are available as annual quantities, with a subset also available on a monthly basis. A number of the indices use a reference period to determine thresholds. For these, we provide two versions, one set using 1961-1990 and another using the more recent 1981-2010 (these reference periods have been indicated in the file name as either 'ref-6190' or 'ref-8110'). In September 2020, a user identified some issues in the DTR and TN90p (61-90) indices. These were found to have arisen from erroneous values in a few stations which were not picked up by any quality control checks. These stations were noted on the bad list and these two indices re-run, hence v3.0.1.

HadEX3 is a land-surface dataset of climate extremes indices available on a 1.875 x 1.25 longitude-latitude grid. These 29 indices have been developed by the World Meteorological Organization (WMO) Expert Team on Climate Change Detection and Indices (ETCCDI). Daily precipitation, as well as maximum and minimum temperature observations, are used to calculate these indices at each station. The daily data, as well as indices, have been supplied, quality controlled and combined to make a gridded set of NetCDF files covering 1901-2018 (inclusive). Spatial coverage is determined by the number of stations present at each time point as well as the spatial correlation structure between the stations for each index. The spatial coverage is lowest at the beginning of the dataset, rising until around 1960 where it plateaus, and then declines slightly after 2010. All indices are available as annual quantities, with a subset also available on a monthly basis. A number of the indices use a reference period to determine thresholds. For these, we provide two versions, one set using 1961-1990 and another using the more recent 1981-2010 (these reference periods have been indicated in the file name as either 'ref-6190' or 'ref-8110'). Version 3.0.2 was added due to a correction to the land-sea mask used. More details can be found in the HadEX3 blog under 'Details/Docs' tab.

HadEX3 is a land-surface dataset of climate extremes indices available on a 1.875 x 1.25 longitude-latitude grid covering 1901-2018. These 29 indices have been developed by the World Meteorological Organization (WMO) Expert Team on Climate Change Detection and Indices (ETCCDI). Indices are available on an annual, and for some a monthly, basis. Some indices use a reference period to calculate thresholds, and for these, we provide versions using 1961-90 and 1981-2010. The indices are available in NetCDF files, with one index per file and separate files for annual and monthly values, as well as the different reference periods if appropriate. The codes used to create the dataset are available online, and a wide number of analysis plots are on the dataset homepage. For a detailed description of the methods behind the dataset, please see the paper in Details/Docs.

HadEX3 is a land-surface dataset of climate extremes indices available on a 1.875 x 1.25 longitude-latitude grid. These 29 indices have been developed by the World Meteorological Organization (WMO) Expert Team on Climate Change Detection and Indices (ETCCDI). Daily precipitation, as well as maximum and minimum temperature observations, are used to calculate these indices at each station. The daily data, as well as indices, have been supplied, quality controlled and combined to make a gridded set of NetCDF files covering 1901-2018 (inclusive). Spatial coverage is determined by the number of stations present at each time point as well as the spatial correlation structure between the stations for each index. The spatial coverage is lowest at the beginning of the dataset, rising until around 1960 where it plateaus, and then declines slightly after 2010. All indices are available as annual quantities, with a subset also available on a monthly basis. A number of the indices use a reference period to determine thresholds. For these, we provide two versions, one set using 1961-1990 and another using the more recent 1981-2010 (these reference periods have been indicated in the file name as either 'ref-6190' or 'ref-8110'). Version 3.0.3 was added due to an error in how the Rx1day and Rx5day data were being handled for one of the West African data sources. More details can be found in the HadEX3 blog under 'Details/Docs' tab.

This dataset provides data on the timing of butterfly flight periods for each UK butterfly species across all monitored sites in the UK Butterfly Monitoring Scheme (UKBMS). Annual data from over 2,500 sites are presented relating to the timing (first appearance, last appearance, date of peak abundance and mean flight date) and the duration (total number of days, standard deviation around the mean flight date) of the flight period for all UK butterfly species from 1976 to the year in the name of this dataset. Phenology change is a widely used measure of the biological impacts of climate change because of the close relationship between temperature and the timing of biological events. This dataset provides an invaluable tool for assessing the impacts of climate change both spatially and temporally. The UK Butterfly Monitoring Scheme is organized and funded by Butterfly Conservation (BC), the UK Centre for Ecology & Hydrology (UKCEH), the British Trust for Ornithology (BTO), and the Joint Nature Conservation Committee (JNCC). The UKBMS is indebted to all volunteers who contribute data to the scheme. This work was supported by the Natural Environment Research Council award number NE/R016429/1 as part of the UK-SCAPE programme delivering National Capability. Full details about this dataset can be found at https://doi.org/10.5285/b9d237fc-5a79-4449-bcee-34c52d87608f

Collated indices are a relative measure of butterfly abundance across sites monitored as part of the UK Butterfly Monitoring Scheme. Data from all survey sites (standard UKBMS transects, Wider Countryside Survey transects and targeted species surveys such as timed, larval web and egg counts) are used in the calculation of these indices. The statistics are presented as log10 values. These values are centred round an arbitrary value of 2 as a mean for the time series in order to help show which years are below or above average. Collated indices are calculated annually for each individual butterfly species that has been recorded on five or more sites in that year. Indices are calculated at UK level and at individual country level for England, Scotland, Wales and Northern Ireland where sufficient data are available. Based on this criterion, collated indices have been calculated for the entire time series from 1976 (UK, England and Wales), 1979 (Scotland) and 2004 (Northern Ireland) to the current year for the majority of species, but for some rarer species this has not been possible in some years, particular those in the first part of the time series. Collated indices are calculated using a log-linear model incorporating individual site indices from all monitored sites across the UK or country for a given species in a given year. The number of sites for each species ranges from 5 to several hundred or more and fluctuates from year to year. By 2010 almost 2,000 sites were monitored in total across the UK, with this number rising to more than 3,000 over the next decade. Collated indices are calculated so that we can determine how butterfly populations are changing over time across the UK. This data can be used, for example, to determine where to target conservation efforts and more generally the condition of the UK countryside. Butterflies are recognised as important indicators of biodiversity and environmental change, for example in UK and country Biodiversity Indicators, and have been used in numerous studies of the impacts of climate and habitat change on biodiversity. The UK Butterfly Monitoring Scheme is organized and funded by Butterfly Conservation (BC), the UK Centre for Ecology & Hydrology (UKCEH), the British Trust for Ornithology (BTO), and the Joint Nature Conservation Committee (JNCC). The UKBMS is indebted to all volunteers who contribute data to the scheme. This work was supported by the Natural Environment Research Council award number NE/R016429/1 as part of the UK-SCAPE programme delivering National Capability. Full details about this dataset can be found at https://doi.org/10.5285/a70d8b0b-0ef5-484e-8195-42bcfd818229

This dataset provides the details of all sites on which butterflies have been monitored as part of the UK Butterfly Monitoring Scheme (UKBMS). This includes all standard UKBMS transect sites, Wider Countryside Butterfly Survey (WCBS) sites and targeted species survey sites (timed counts, single-species transects, larval web and egg counts). Data includes the location within the UK, the length and number of sections for the butterfly transect on each site and the number of years each transect has been monitored. The location of some sites are sensitive and are excluded from this dataset. Users requiring access to the complete dataset, including sensitive site location data, can submit a request via the UKBMS website. The UKBMS started in 1976 with fewer than 50 sites. Since then the number of sites monitored each year has increased to several thousand. There are new sites each year and a small number where the transect is no longer surveyed. Details of this are provided in the site dataset in the form of the first and last year in which each site was surveyed. The majority of site data is provided by recorders at the time a transect is created. Site data are crucial in order to determine where extra recording effort is required and to investigate where butterfly populations are changing most and thus where conservation should be targeted, including across different habitat types. The UK Butterfly Monitoring Scheme is organized and funded by Butterfly Conservation (BC), the UK Centre for Ecology & Hydrology (UKCEH), the British Trust for Ornithology (BTO), and the Joint Nature Conservation Committee (JNCC). The UKBMS is indebted to all volunteers who contribute data to the scheme. This work was supported by the Natural Environment Research Council award number NE/R016429/1 as part of the UK-SCAPE programme delivering National Capability. Full details about this dataset can be found at https://doi.org/10.5285/226979d4-6d81-4f5b-9bb7-4a430caa7f51