Thermophilisation drives multi-scale declines in carabid species richness in temperate forests over 25 years

This dataset comprises long-term resurvey data on carabid beetle communities collected from 54 temperate forest plots in Belgium. The original sampling took place in 1997 using standardized pitfall trapping methods and was repeated in 2023 following the same protocol, enabling direct comparisons over a 25-year interval. Each plot was selected to represent relatively undisturbed forest conditions, spanning gradients in microclimate and landscape context. The dataset includes species-level abundance data, thermal affinity classifications, and site-level environmental metadata and a site-by-species matrix showing the number of individuals of each species found in each plot. It supports analyses of climate-driven thermophilisation, species turnover, and biodiversity change across spatial scales. This resource is especially valuable for understanding temporal shifts in community composition and trait-based responses to global change.