Site indices, as a relative measure of the actual population size, 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 actual 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 accurate indices of abundance cannot currently be 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 are calculated for almost 1,500 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 in 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. Although the Centre for Ecology & Hydrology (CEH) and Butterfly Conservation (BC) are responsible for the calculation and interpretation of site indices, the collection of the data used in its creation is ultimately reliant on a large volunteer community. The UKBMS is run by Butterfly Conservation (BC), the Centre for Ecology & Hydrology (CEH) and the British Trust for Ornithology (BTO), in partnership with the Joint Nature Conservation Committee (JNCC), and supported and steered by Forestry Commission (FC), Natural England(NE), Natural Resources Wales (NRW), Northern Ireland Environment Agency (NIEA), and Scottish Natural Heritage (SNH). The UKBMS is indebted to all volunteers who contribute data to the scheme. Full details about this dataset can be found at https://doi.org/10.5285/378f0f77-1842-4789-ba15-6fbdf7d02299

Plant-pollinator interactions database derived from biological recording data, unpublished experimental data and published interactions in books and papers. The database covers all recorded interactions for bees, hoverflies and butterflies in mainland GB. Interactions were inferred from biological recording metadata by algorithmically screening for text matching a valid scientific or vernacular plant name (or a widely used synonym or abbreviation of either), followed by manual data cleaning. These data were compiled for the construction of multiple potential plant-pollinator networks in combination with plant and pollinator occurrence data. Full details about this dataset can be found at https://doi.org/10.5285/6d8d5cb5-bd54-4da7-903a-15bd4bbd531b

Here, we present a comprehensive traits database for the butterflies and macro-moths of Great Britain and Ireland. The database covers 968 species in 21 families. Ecological traits fall into four main categories: life cycle ecology and phenology, host plant specificity and characteristics, breeding habitat, and morphological characteristics. The database also contains data regarding species distribution, conservation status, and temporal trends for abundance and occupancy. This database can be used for a wide array of purposes including further fundamental research on species and community responses to environmental change, conservation and management studies, and evolutionary biology. Full details about this dataset can be found at https://doi.org/10.5285/33a66d6a-dd9b-4a19-9026-cf1ffb969cdb

This dataset contains information about moth caterpillar abundance at sites lit by streetlights (LED; high pressure sodium and low-pressure sodium) and unlit control sites. Caterpillars were sampled at 26 matched pairs of lit and unlit sites between 2018 and 2020 as part of a study of the effects of street lighting on the early life stages of moths. Full details about this dataset can be found at https://doi.org/10.5285/4d3f4c8a-5605-4990-8ca1-42f8ddf63698

Counts of caterpillars arising from a short-term experiment that installed lighting rigs in previously unlit areas to test for a change in nocturnal feeding behaviour. Caterpillars were counted from lit and control transects at two locations in Oxfordshire during January and February 2019. Lighting rigs were installed during the afternoon and switched on one hour before sunset. To give the nocturnal caterpillars time to become active, sampling occurred between 60 and 120 minutes after sunset. On a sampling night, all transects were sampled within a 5–10-minute period. Full details about this dataset can be found at https://doi.org/10.5285/7e7ce7c1-aa16-484f-86b1-90c5b088a64c

This dataset consists of behaviour and distribution data of Lepidoptera from chalk grassland fragments at the Stonehenge World Heritage Site in Wiltshire, UK, in 2011. The landscape consists of small fragments of ancient chalk grassland on slopes and groups of burial mounds (barrows) which have retained many of the characteristic chalk grassland plant and butterfly species. Surveys were located at four of these chalk grassland fragments. At each chalk grassland fragment, four 20 m long survey boundaries, were set up on boundaries with adjacent land cover of either arable land or new grassland re-creation sown in the years 2009 or 2010. Control surveys were also carried out in areas of continuous habitat within the chalk grassland fragment and in the adjoining land cover type. Surveys of Lepidoptera behaviour were carried out from May to July between 10am and 4pm and effort was taken to survey the same site at different times of the day in order to minimise the effect of survey time on behaviour. Standing at the chalk grassland fragment edge the flight path of individual Lepidoptera was tracked in the survey area for up to three minutes. Measures of vegetation characteristics and nectar flower availability were recorded for each plot. Vegetation characteristics were measured as vegetation height and density and the percentage cover of bare ground and dead vegetation. Nectar resources were measured in terms of the number and percentage coverage of flowering units, the total number of nectar flowering units and of relevant families (Dipsacaceae, Fabaceae and Asteraceae). The data were collected as part of a PhD project funded by the Natural Environment Research Council and the National Trust. Full details about this dataset can be found at https://doi.org/10.5285/61561232-3307-470a-b8dc-a923b25e1641

Collated indices are a relative measure of butterfly abundance across monitored sites in the UK, calculated from data collected by the UK Butterfly Monitoring Scheme (UKBMS). Collated indices are calculated annually for each individual butterfly species that has been recorded on five or more sites in that year. Based on this criterion collated indices have been calculated for the entire UKBMS time series from 1976 to the current year for the majority of species. For some rarer species the time series starts in a later year due to lack of data. Collated indices are calculated using a statistical model that accounts for missing data. The number of sites for each species ranges from 5 to several hundred and varies from year to year. Since 2008 more than 1,000 sites have been monitored across the UK each year. 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 to measure the condition of the UK countryside. Butterflies are recognised as important indicators of biodiversity and environmental change (e.g. as official UK Biodiversity Indicators), and have been used in numerous research studies to understand the impacts of changes in climate and the extent and condition of habitats. 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 dataset is updated annually and a more recent version of the UKBMS collated indices is available. Full details about this dataset can be found at https://doi.org/10.5285/ace3c3ef-df89-40b9-ba8b-106997fd6d9c

This dataset provides linear trends, over varying time periods, for the UK Butterfly Monitoring Scheme (UKBMS) Collated Indices of individual butterfly species across the UK. The main statistical values derived from a linear regression (slope, standard error, P-value) are presented for the entire time series for each species (1976 to 2011), for the last 20 years, and for the last decade. In addition a trend class, based on slope direction and its significance, and a percentage change for that time period are provided to describe the statistical trends. These trend data are provided for 59 UK butterfly species. Trends across different time series allow us to determine the long and short-term trends for individual species. This is enables us to focus conservation and research and also to assess species responses to conservation already in place. The Centre for Ecology & Hydrology (CEH) and Butterfly Conservation (BC) are responsible for the calculation and interpretation of this trend datasets. The collection of the underlying UKBMS data is reliant on a large volunteer community. The UK Butterfly Monitoring Scheme is funded by a consortium of organisations led by the Joint Nature Conservation Committee (JNCC). This dataset is updated annually and a more recent version of the UKBMS species trends (2012) is now available. Full details about this dataset can be found at https://doi.org/10.5285/cad2af6c-0c97-414c-8d5f-992741b283cf

This dataset consists of behaviour and distribution data of Lepidoptera at the Stonehenge World Heritage Site in Wiltshire, UK, between 2010-2011. A long term landscape scale grassland restoration and re-creation project has been underway at the site since 2000. 200m long transects were located in the centre of different grassland re-creation fields of different ages, arable land, chalk grassland fragments on slopes and on ancient burial mounds, and semi-improved pasture. Transects were surveyed on three occasions spread across the field season (June to September), and throughout the day and were selected ad-hoc for survey in order to minimise the effect that the time of year and day would have on results. During the survey, the transect was walked at a slow, steady pace allowing five minutes for each 20m section of transect and the number and species of Lepidoptera present 5m either side and ahead were recorded. If Lepidoptera were observed feeding, then the nectar plant species was also recorded. Habitat quality, defined in terms of vegetation characteristics and nectar resources, was quantified throughout each transect by sampling quadrats in each 20m segment of the transect. Vegetation characteristics were measured as vegetation height and density and the percentage cover of bare ground and dead vegetation. Nectar resources were measured in terms of the number and percentage coverage of flowering units, the total number of nectar flowering units and of relevant families (Dipsacaceae, Fabaceae and Asteraceae). The data were collected as part of a PhD project funded by the Natural Environment Research Council and the National Trust. Full details about this dataset can be found at https://doi.org/10.5285/a384bdfb-0bf2-4c3e-80ab-e171f38d503d

Collated indices are a relative measure of butterfly abundance across monitored sites in the UK, calculated from data collected by the UK Butterfly Monitoring Scheme (UKBMS). Collated indices are calculated annually for each individual butterfly species that has been recorded on five or more sites in that year. Based on this criterion collated indices have been calculated for the entire UKBMS time series from 1976 to the current year for the majority of species. For some rarer species the time series starts in a later year due to lack of data. Collated indices are calculated using a statistical model that accounts for missing data. The number of sites for each species ranges from 5 to several hundred and varies from year to year. Since 2008 more than 1,000 sites have been monitored across the UK each year. 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 to measure the condition of the UK countryside. Butterflies are recognised as important indicators of biodiversity and environmental change (e.g. as official UK Biodiversity Indicators), and have been used in numerous research studies to understand the impacts of changes in climate and the extent and condition of habitats. Although the UK Centre for Ecology & Hydrology (UKCEH) and Butterfly Conservation (BC) are responsible for the calculation and interpretation of the Collated indices, the collection of the data used in their creation is ultimately reliant on a large volunteer community. The UKBMS is funded by a consortium of organisations led by the Joint Nature Conservation Committee (JNCC). This dataset is updated annually and more recent versions of the UKBMS collated indices are available. Full details about this dataset can be found at https://doi.org/10.5285/7949cc99-76c4-4a3e-8c33-41a35b8b7777