From Inventories to Insights: Environmental Gradients Structuring Macro-Moths Assemblages Recorded in Nature Reserves

Inventorying biodiversity in reserves is a routine activity in conservation, yet for hyper-diverse insect groups such as macro-moths, general ecological patterns remain underexplored. We collated and analysed macro-moths (Lepidoptera) inventories from 292 nature reserves across the Czech Republic, encompassing 941 species. Inventories varied in surveying effort and methodology but collectively allowed examination of factors influencing moths' species richness, assemblages' composition and their associations with the species' traits. Species richness increased with elevational scope and was highest in reserves covering steppes and mesic grasslands. Geographic position of the reserves, altitude and elevational scope affected the moth assemblages' composition. Reserves at low altitudes hosted larger moths forming multiple generations and developing on forbs, whereas high-altitude reserves hosted species developing on shrubs and trees, forming fewer generations, overwintering in later stages and inhabiting broader habitat and altitude ranges. Regional biogeography also affected the assemblages, with Carpatho-Pannonian reserves supporting large-winged habitat-specialists, often overwintering in early developmental stages. Our results demonstrate that even heterogeneous data can reveal consistent patterns when interpreted through species' traits. These findings demonstrate the value of reserve inventories compiled by dedicated amateur lepidopterists for deciding on reserve management strategies and identifying key habitats for species of conservation concern.