Universal beta-diversity-functioning relationships are neither observed nor expected

Widespread evidence shows that local species richness (a-diversity) loss hampers the biomass production and stability of ecosystems. (3-Diversity, namely the varia-tion of species compositions among different ecological communities, represents another important biodiversity component, but studies on how it drives ecosystem functioning show mixed results. We argue that to better understand the importance of (3-diversity we need to consider it across contexts. We focus on three scenarios that cause gradients in (3-diversity: changes in (i) abiotic heterogeneity, (ii) habitat isolation, and (iii) species pool richness. We show that across these scenarios we should not expect universally positive relationships between (3-diversity, production, and ecosystem stability. Nevertheless, predictable relationships between (3-diversity and ecosystem functioning do exist in specific contexts, and can reconcile seemingly contrasting empirical relationships.

Automated summary

Widespread evidence suggests that the loss of local species richness (a-diversity) hampers biomass production and ecosystem stability. However, studies on the impact of 3-diversity (variation in species compositions among ecological communities) on ecosystem functioning have produced mixed results. To better understand the importance of 3-diversity, it is necessary to consider it in different contexts. By examining three scenarios that create gradients in 3-diversity, namely changes in abiotic heterogeneity, habitat isolation, and species pool richness, it is demonstrated that there are not universally positive relationships between 3-diversity, production, and ecosystem stability. Nevertheless, predictable relationships exist in specific contexts, which can reconcile seemingly contrasting empirical relationships.