Plant community evenness responds to spatial plant-soil feedback heterogeneity primarily through the diversity of soil conditioning

1.Plant-soil feedback (PSF) has been identified as a key driver of local plant diversity and evenness in competitive communities. However, while it has been shown that spatial PSF heterogeneity can alter plant performance and competitive interactions, there is no proof of principle that spatial PSF heterogeneity enhances community diversity.

2.Using a grassland model system we separated two aspects of spatial heterogeneity: the number of species conditioning the soil and spatial distribution of the PSFs.

3.Our data show that PSFs promoted a higher plant evenness when the soil was conditioned by multiple species (mixed-conditioned), then when the soil was conditioned by a single species (mono-conditioned). On mono-conditioned soils, heterospecifics typically outperformed the focal species. In addition, there was a trend for increasing community evenness from uniform, via fine-grained to coarse-grained mixed-conditioned soils, but this was not significant.

4.On mixed-conditioned ...