IT-V net: the ITalian Intraspecific Trait Variability network

Plants, as sessile organisms, experience environmental variation across spatial and temporal scales, producing phenotypic differences among and within populations (intraspecific trait variability, ITV). At the global scale, ITV can contribute up to 31% of total plant trait variation within communities, depending on the trait–habitat combination. Yet, particularly at local to regional extents where ITV may be most influential, we still lack consistent, plot-level datasets that quantify the magnitude and structure of ITV across many ecosystems. We present ITV-net (ITalian Intraspecific Trait Variability Network), launched in 2021 as a national collaborative platform that harmonises georeferenced vegetation plots with field-measured, individual-level plant traits. By coupling replicated trait measurements with community context (relative abundances of co-occurring species) and plot descriptors, ITV-net enables analyses of within-species trait distributions in real assemblages rather than relying on species-mean values. The first data call compiled >8,000 individual measurements for two key leaf traits (Leaf Area and Specific Leaf Area) covering >700 species across 1,043 plots distributed throughout Italy. We describe the network’s rationale, sampling principles, data-standardisation workflow and first results. Finally, we outline next steps to broaden trait coverage and expand participation beyond Italy, positioning ITV-net as a transferable framework for coordinated ITV research. In the context of accelerating global change, such coordinated, plot-level ITV data are essential for understanding and forecasting communities’ functional responses in situ.