Characterization and distribution of the endemic flora in Northern Italy

Floristic mapping advances the biogeographical knowledge by revealing patterns of biodiversity through a standardized grid-based survey of species’ occurrences. It consists of the systematic grid-based survey of species occurrence, aimed at producing distribution maps of vascular plants within a given territory. We compiled a dataset of 32,939 floristic records (field observations, herbarium specimens, and literature) referenced to the Central European Floristics Mapping standard, documenting the distribution of 447 endemic taxa across 3,612 grid cells (5' of longitude and 3' of latitude) in Northern Italy. This study aims to characterize the composition and distribution of Northern Italy’s endemic flora—encompassing the Alps and the northern Apennines, including Alpine-restricted taxa whose range extends beyond the Italian border), highlighting major geographical patterns and their functional and ecological attributes. We quantified endemic species richness, life-form and habitat preferences, and Landolt’s ecological indicator values. Endemism was spatially aggregated, with clear hotspots along the Alpine and Prealpine belts and species-poor, fragmented assemblages in the lowlands; regional floristic affinities mirrored shared substrates and elevation ranges. We also detected coherent ecological gradients, with a light/temperature axis opposing a moisture/nutrients axis, consistent with topographic and edaphic controls. Habitat use by endemics tended to be focused on open, primary substrates (e.g., rocky outcrops, grasslands, screes). Together, these results provide a complete overview of Northern Italy’s endemic flora, identify priority areas for conservation, and offer a reproducible baseline for land-use planning and climate-change monitoring.