The effect of niche filtering on plant species abundance in temperate grassland communities

1. Niche filtering predicts that abundant species in communities have similar traits that are suitable for the environment. However, niche filtering can operate on distinct axes of trait variation in response to different ecological conditions. Here, we use a trait-based approach to infer niche filtering processes and (1) test if abundant and rare species in grassland communities are differently positioned along distinct axes of trait variation, (2) determine if these trait variation axes, as well as phylogenetic and functional similarities, drive species relative abundance (aboveground cover) within communities, and (3) explore if these relationships vary across grassland types and macro-climatic gradients. 2. We analysed species abundance in a set of ~2,000 vegetation plots from temperate grasslands in Central Europe as a function of species position along three axes of trait variation: the ‘Plant Size Spectrum’ (PSS), the ‘Leaf Economics Spectrum’ (LES), and the ‘Lifespan/Clonalit...