Belowground traits, rare species, and environmental stress regulate the biodiversity-ecosystem function relationship

The dataset represents data used in the publication "Belowground traits, rare species, and environmental stress regulate the biodiversity-ecosystem function relationship". ABSTRACT(1) Understanding the relationship between biodiversity and ecosystem functioning (BEF) is crucial to predicting the consequences of ongoing global biodiversity loss. However, what drives BEF relationships in natural ecosystems under globally changing conditions remains poorly understood.(2) To address this knowledge gap, we applied a trait-based approach to data from coastal dune plant communities distributed along a natural environmental stress gradient. Specifically, we compared the relative importance of belowground and aboveground traits in predicting productivity, decomposition, water regulation, carbon stock, and nutrient pools, and tested how these BEF relationships were modulated by environmental stress and the presence of rare species that are typically excluded from experimental systems.(3) Belowground traits were just as important as aboveground traits in driving ecosystem functioning. Moreover, despite having low abundances, rare species positively influenced ecosystem multifunctionality. However, most biodiversity effects became weaker as environmental stress increased.(4) Our study shows that to understand variation in ecosystem functioning we must consider belowground traits as much as aboveground ones. Moreover, it highlights the importance of conserving rare species for maintaining ecosystem multifunctionality. However, our findings also suggest that rapid global change could dampen the positive effects of diversity on ecosystem functioning.