A new comprehensive trait database of European and Maghreb butterflies, Papilionoidea

Trait-based analyses explaining the different responses of species and communities to environmental changes are increasing in frequency. European butterflies are an indicator group that responds rapidly to environmental changes with extensive citizen science contributions to documenting changes of abundance and distribution. Species traits have been used to explain long- and short-term responses to climate, land-use and vegetation changes. Studies are often characterised by limited trait sets being used, with risks that the relative roles of different traits are not fully explored. Butterfly trait information is dispersed amongst various sources and descriptions sometimes differ between sources. We have therefore drawn together multiple information sets to provide a comprehensive trait database covering 542 taxa and 25 traits described by 217 variables and sub-states of the butterflies of Europe and Maghreb (northwest Africa) which should serve for improved trait-based ecological, conservation-related, phylogeographic and evolutionary studies of this group of insects. We provide this data in two forms; the basic data and as processed continuous and multinomial data, to enhance its potential usage

New approaches to understanding functional traits and butterfly responses to environmental changes in Europe

The geographic distributions and abundances of the butterfly fauna of Europe are changing and these changes are not uniform across these species. Trait-based approaches are being used to explain these responses to environmental change over a range of temporal and spatial scales. These have generally focused on a limited subset of life-history traits, estimated mobility and biotope occupancy data, and not focused on functional traits related to resource use by all life-history stages, despite evidence that this may be a useful approach. The analyses presented here explore how well functional resource-based traits of the European butterfly fauna explain the responses of butterflies to environmental changes over different temporal scales. A trait database for the 507 European butterflies has been constructed, encompassing 241 traits describing resource use, behaviour and life history and the variation in these traits for all life-history stages. For the UK butterfly fauna, different trait sources were compared to examine discontinuity in trait information. Single sources of information differ in their explanatory power of species occurrences and responses to environmental changes. A multivariate analysis of resource based and life-history traits encompassing their variability, without biotope occupancy produces an informative ecological classification. The most important traits which explain occurrence and abundance changes are identified. Using Cluster and Principal Component analyses a functional classification of European butterflies with four distinct groups of species, associated with distinct broad biotopes, is identified. These differ in measures of conservation concern. A group of small arboreal species may be especially vulnerable to environmental change. These could be used as indicators of changes in the status of species in structurally complex biotopes. Using traits, climate data and genetic divergence data the link between traits and lineage divergence of a sample of the European butterflies over a glacial-interglacial cycle scale was examined. Traits underlying mobility contribute to population structuring observed between putative glacial refugia and explain this better than past climate and landscape resistance alone. Comprehensive resource-based and behavioural traits can thus be used to expand on our knowledge of the ecological responses of butterflies to environmental change across both ecological and evolutionary timescales