The scientists studied plant diversity in grasslands in Italy to see if changes in biodiversity are different at various sites. They looked at two types of communities in each location and measured different plant traits. They found that the types of plants present varied between sites, and the functions of the plants also differed locally. They discovered that when new plant species replaced existing ones, taxonomic diversity changed, while functional diversity changed when both new and existing plants played a role in shaping the community. This shows that small-scale differences in grassland biodiversity depend on the specific site, impacting both the types of plants present and the functions they perform.