Dr. Jon Bennett (University of Saskatchewan, Canada)
Plant diversity is expected to have positive effects on primary productivity, in part by promoting more beneficial soil microbial communities. Although many studies support this idea, there are also others that suggest that the belowground benefits of plant diversity are likely to be more nuanced. In my group, we have found both positive and negative soil-mediated effects of plant diversity on productivity, potentially due to matching between plant and microbial species. More detailed analysis suggests that the composition of multiple soil microbial groups may influence plant productivity by both changing the average response to soil microbes as well as the variation in these responses among plant species. Interestingly, we find beneficial effects of plant diversity in both natural and anthropogenic grasslands, but these effects appear to be driven by shifts in microbial composition, rather than any change in microbial diversity.