Environmental and seasonal filtering of taxonomic, functional and phylogenetic diversity patterns of mountain butterflies in a prime butterfly area, <scp>Greece</scp>

Abstract Combining taxonomic, functional and phylogenetic diversity facets offers a more complete view of biodiversity, yet their fine‐scale drivers for mountainous insect communities remain poorly understood. We investigated butterfly communities in mountain grasslands and forest clearings in two roadless and protected mountains of Pindus Mt. range in Greece (Smolikas and Tymfi, 1240–1950 m), by seasonally surveying 22 transects (300 × 5 m) and 66 microhabitat plots (5 × 5 m) in 2022. Multifaceted diversity was quantified from species data, 11 functional traits and a phylogenetic tree, and related to herb/grass height, flowerhead abundance, elevation and slope using generalized linear models. We recorded 83 species, including species of conservation concern (35%); mountain grasslands and forest clearings seemed to support comparable taxonomic, functional and phylogenetic diversity but differed in species composition, highlighting their complementary conservation value. Herb/grass height and flowerhead abundance declined from spring to late summer, while the Community Temperature Index and functional dispersion increased, indicating a shift toward warmer‐adapted and more functionally heterogeneous communities under reduced resource availability. Herb/grass height and flowerhead abundance emerged as the main positive predictors of multifaceted diversity, whereas elevation reduced abundance, functional richness and phylogenetic diversity; the trait‐based model revealed non‐random links between habitat structure and species traits, particularly for temperature affinity, oligophagy, range size and flight period. Our results could inform sustainable grazing in Mediterranean mountain landscapes and contribute to the implementation of the Nature Restoration Regulation.