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Regular reassessment of extinction risk is critical to prioritise conservation action during the current period of rapid, anthropogenic biodiversity change.Butterflies are a flagship group for insect monitoring and conservation, as they are highly visible, well studied and exhibit rapid responses to environmental change. Here, we use systematic population monitoring data from the UK Butterfly Monitoring Scheme and citizen‐science derived occurrence records to provide an updated assessment of extinction risk in Great Britain (GB) by applying current International Union for Conservation of Nature (IUCN) criteria to 62 butterfly species.The resulting regional Red List categorises four species as Regionally Extinct, 24 (41% of the remaining, extant species) as threatened (8 Endangered and 16 Vulnerable), 5 (9%) as Near Threatened and 29 (50%) as Least Concern. Recent reduction in population size (Criterion A) based on smoothed, long‐term time series of abundance and occurrence data, was responsible for most of the threatened or Near Threatened categorisations.While the status of some species improved, likely due to conservation efforts, the revised Red List demonstrates an ongoing deterioration in the status of GB butterflies, with a 26% increase in threatened species since the previous assessment.A greater proportion of butterflies was classed as threatened than for most other GB taxa. While this may stem from greater data availability for butterflies than most other groups (thus allowing tests of extinction risk against more criteria), it highlights the need to reinvigorate conservation efforts for these charismatic insects. [ABSTRACT FROM AUTHOR]

The description of how biological information is compiled over time is essential to detect temporal biases in biodiversity data that could directly influence the utility, comparability, and reliability of ecological and biogeographical studies.We explore trends in species recording over time using one of the most spatially and temporally comprehensive country‐level databases for any group of insects in the world – the database of butterfly occurrences from Great Britain.Firstly, we used two crucial milestones (the year in which the taxonomic inventory is complete, i.e., when the last species was recorded, the year in which all species are recorded together for the first time) to delimit three main phases in the process of biodiversity recording (taxonomic, faunistic and exhaustive phases). Secondly, we aimed to quantify how far species features (attractiveness and detectability) influence the process of recording through time.During the first stage of biodiversity compilation, when the main aim is to complete the taxonomic inventory (taxonomic period), entomologists tend to record attractive species more frequently. However, once the inventory is complete, particularly in the period during which more spatially and temporally comprehensive information about species distribution is amassed (the exhaustive period), the recording pattern clearly changes to more detectable species.Common, highly detectable species are undersampled in the first phase of biodiversity data compilation and oversampled in the final stages. Awareness of such temporal patterns in recording is necessary in order to correctly interpret and address bias in insect biodiversity trends. [ABSTRACT FROM AUTHOR]

The night‐time environment is increasingly being lit, often by broad‐spectrum lighting, and there is growing evidence that artificial light at night (ALAN) has consequences for ecosystems, potentially contributing to declines in insect populations.Moths are species‐rich, sensitive to ALAN, and have undergone declines in Europe, making them the ideal group for investigating the impacts of light pollution on nocturnal insects more broadly. Here, we take a life cycle approach to review the impacts of ALAN on moths, drawing on a range of disciplines including ecology, physiology, and applied entomology.We find evidence of diverse impacts across most life stages and key behaviours. Many studies have examined flight‐to‐light behaviour in adults and our meta‐analysis found that mercury vapour, metal halide, and compact fluorescent bulbs induce this more than LED and sodium lamps. However, we found that ALAN can also disrupt reproduction, larval development, and pupal diapause, with likely negative impacts on individual fitness, and that moths can be indirectly affected via hostplants and predators. These findings indicate that ALAN could also affect day‐flying insects through impacts on earlier life stages.Overall, we found strong evidence for effects of artificial light on moth behaviour and physiology, but little rigorous, direct evidence that this scales up to impacts on populations. Crucially, there is a need to determine the potential contribution of ALAN to insect declines, relative to other drivers of change. In the meantime, we recommend precautionary strategies to mitigate possible negative effects of ALAN on insect populations. [ABSTRACT FROM AUTHOR]

Abstract: Abundance data are the foundation for many ecological and conservation projects, but are only available for a few taxonomic groups. In contrast, distribution records (georeferenced presence records) are more widely available. Here we examine whether year‐to‐year changes in numbers of distribution records, collated over a large spatial scale, can provide a measure of species' population variability, and hence act as a metric of abundance changes. We used 33 British butterfly species to test this possibility, using distribution and abundance data (transect counts) from 1976 to 2012. Comparing across species, we found a strong correlation between mean year‐to‐year changes in total number of distribution records and mean year‐to‐year changes in abundance (N = 33 species; r2 = 0.66). This suggests that annual distribution data can be used to identify species with low versus high population variability. For individual species, there was considerable variation in the strength of relationships between year‐to‐year changes in total number of distribution records and abundance. Between‐year changes in abundance can be identified from distribution records most accurately for species whose populations are most variable (i.e. have high annual variation in numbers of records). We conclude that year‐to‐year changes in distribution records can indicate overall population variability within a taxon, and are a reasonable proxy for year‐to‐year changes in abundance for some types of species. This finding opens up more opportunities to inform ecological and conservation studies about population variability, based on the wealth of citizen science distribution records that are available for other taxa. [ABSTRACT FROM AUTHOR]

. 1. Population declines among insects are inadequately quantified, yet of vital importance to national and global biodiversity assessments and have significant implications for ecosystem services. 2. Substantial declines in abundance and distribution have been reported recently within a species-rich insect taxon, macro-moths, in Great Britain and other European countries. These declines are of concern because moths are important primary consumers and prey items for a wide range of other taxa, as well as contributing to ecosystem services such as pollination. 3. I summarise these declines and review potential drivers of change. Direct evidence for causes of moth declines is extremely limited, but correlative studies and extrapolation from closely related taxa suggest that habitat degradation (particularly because of agricultural intensification and changing silviculture) and climate change are likely to be major drivers. There is currently little evidence of negative population-level effects on moths caused by chemical or light pollution, non-native species or direct exploitation. 4. I make suggestions for future research with a focus on quantifying impacts of land management practices, light pollution and climate change on moth population dynamics and developing evidence-based measures that can be incorporated into agri-environment schemes and other policy initiatives to help reverse the widespread decline of moths in Great Britain and beyond. [ABSTRACT FROM AUTHOR]

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