Data from: Species richness and the temporal stability of biomass production: a new analysis of recent biodiversity experiments

The relationship between biological diversity and ecological stability has
fascinated ecologists for decades. Determining the generality of this
relationship, and discovering the mechanisms that underlie it, are vitally
important for ecosystem management. Here, we investigate how species
richness affects the temporal stability of biomass production by
re-analyzing 27 recent biodiversity experiments conducted with primary
producers. We find that, in grasslands, increasing species richness
stabilizes whole-community biomass but destabilizes the dynamics of
constituent populations. Community biomass is stabilized because species
richness impacts mean biomass more strongly than its variance. In algal
communities, species richness has a minimal effect on community stability
because richness affects the mean and variance of biomass nearly equally.
Using a new measure of synchrony among species, we find that for both
grasslands and algae, temporal correlations in species biomass are lower
when species are grown together in polyculture than when grown alone in
monoculture. These results suggest that interspecific interactions tend to
stabilize community biomass in diverse communities. Contrary to prevailing
theory, we found no evidence that species' responses to environmental
variation in monoculture predicted the strength of diversity's
stabilizing effect. Together, these results deepen our understanding of
when and why increasing species richness stabilizes community biomass.