Aridity drives phylogenetic diversity and species richness patterns of nitrogen‐fixing plants in North America

Aim Nitrogen (N)-fixing plants are an important component of global plant communities, but the drivers N-fixing diversity, especially in temperate regions, remain underexplored. Here, we examined broad-scale patterns and non-fixing phylogenetic diversity (PD) species richness (SR) across a wide portion North America, focusing on relationships with soil N aridity. We also tested whether exotic species, without symbiosis, have fewer abiotic limitations compared native species. Location USA Puerto Rico. Time period Current. Major taxa studied Vascular plants, groups (orders Fabales, Fagales, Rosales Cucurbitales). Methods subset National Ecological Observatory Network (NEON) plot data from all sites along two axes (N fixing–non-N fixing native–exotic), calculating plot-level SR, PD mean pairwise distance (MPD). then used linear mixed models to investigate between values key measurements, aridity, temperature fire frequency. Results Aridity was sole predictor proportional fixers. The SR fixers still decreased marginally arid whereas N-fixer MPD increased indicative unique lineages driest conditions, contrast non-N both low-N soils. did not affect fixers, unlike other groups, showed lower increasingly high-N soils, suggesting filtering, contrary what found for Main conclusions Our results suggest that it is nitrogen, or any nutrient, has strongest effect relative success communities. Rather, aridity driver, at least line empirical biomes understanding fixation as mechanism avoid water loss.