Cross-site synthesis project finds new mechanism for grazing effects on plant species diversity

To paraphrase the abstract:

Herbivores alter plant species richness but the magnitude and direction of these effects vary widely across ecosystems. Previous theory predicted that herbivores enhance species richness at high productivity sites but have the opposite effect at low productivity sites. We synthesized data from 252 herbivore exclusion studies, spanning a large range in site productivity, to test the hypothesis that herbivores change the competitive environment which determines how species richness responds to herbivory regardless of site productivity. We found that herbivore-induced changes in dominance, independent of site productivity, is the best predictor of herbivore effects on species richness in grasslands and savannahs. Given that most herbaceous ecosystems are dominated by one or a few species, altering the competitive environment via herbivores or by similar means (perhaps mowing) may be an effective strategy for conserving biodiversity in grasslands and savannahs globally. Read more at: