Limited evidence for spatial resource partitioning across temperate grassland biodiversity experiments

Locally, plant species richness supports many ecosystem functions. Yet, the mechanisms driving these often-positive biodiversity–ecosystem functioning relationships are not well understood. Spatial resource partitioning across vertical resource gradients is one of the main hypothesized causes for enhanced ecosystem functioning in more biodiverse grasslands. Spatial resource partitioning occurs if species differ in where they acquire resources and can happen both above- and belowground. However, studies investigating spatial resource partitioning in grasslands provide inconsistent evidence.
We present the results of a meta-analysis of 21 datasets from experimental species-richness gradients in grasslands. We test the hypothesis that increasing spatial resource partitioning along vertical resource gradients enhances ecosystem functioning in diverse grassland plant communities above- and belowground. To test this hypothesis, we asked three questions: 1. Does species richness enhance bioma...