Habitat and land-use intensity shape moth community structure across temperate forest and grassland.

Land-use change and intensification are major drivers of biodiversity loss, yet their effects on diversity have usually been studied within a single habitat type or land-use category, limiting our understanding of cross-habitat patterns. Moths, a species-rich taxon worldwide, represent a significant portion of the biodiversity in both temperate forests and grasslands, functioning as pollinators and herbivores. While increasing land-use intensity (LUI) in both habitats is expected to negatively impact moth assemblages, the strength of this effect remains uncertain. Moreover, land-use intensification interacts with broader environmental factors, such as weather conditions and the spread of artificial light at night (ALAN), but their combined effects on moth community diversity and turnover across habitats remain poorly understood. We sampled moth communities across 150 grassland and 150 forest plots along land-use gradients in Germany. We quantified plot- and landscape-scale LUI and tested the role of plant diversity, temperature and precipitation during the night of sampling and the preceding season, and ALAN in shaping moth diversity (standardized by coverage) along Hill numbers. Forests supported significantly higher moth abundance, biomass and diversity than grasslands, with habitat type being the main driver of moth community composition. LUI at the plot scale had contrasting effects on moth abundance, increasing it in forests but reducing it in grasslands. Impacts of LUI were more pronounced at the landscape level, reducing moth diversity particularly in areas dominated by grasslands. Plant diversity and temperature were key determinants for moth communities, increasing alpha diversity across diversity metrics, that is Hill numbers. ALAN had no significant influence on moth abundance or biomass but significantly decreased Simpson diversity. Beta diversity increased with geographic distance, habitat change and LUI but decreased with weather differences among plots. Our results highlight the interplay between LUI, habitat type and abiotic factors in shaping moth communities across large spatial scales. Effective conservation strategies should consider maintaining habitat heterogeneity and promoting plant diversity, particularly in temperate habitats exposed to high land-use intensification.