The ongoing biodiversity loss has led to the increasing concern that it may impact the functioning of ecosystems, including their stability. Both early conceptual ideas and recent theory suggest a positive relationship between biodiversity and temporal stability of aggregated community properties. While quite a number of empirical studies, particularly experiments that directly manipulated species diversity, support this hypothesis, exceptions are not uncommon. This raises the question of whether there is a general positive diversity-stability relationship. Previous meta-analytic studies have investigated this question, but they suffer from relatively low sample size. Furthermore, these studies have not examined mechanisms underlying the effect of diversity on community temporal stability or compared the effect of diversity to that of environmental covariates.
We conducted an updated, comprehensive meta-analysis of empirical studies of the relationship between species diversity and temporal stability of aggregated community properties (primarily total community biomass). These data also allowed us to answer the question of whether asynchrony among population dynamics of different species, perceived as an important stabilizing mechanism, increases with diversity and contributes to positive diversity-stability relationships, as well as the question of whether species diversity matters for stability after accounting for the roles of abiotic environmental factors that potentially influence stability.
Results/Conclusions
Our meta-analyses showed that community temporal stability generally increased as species diversity increased, regardless of investigation venues, habitat types, and trophic complexity of the study system. Our analyses also revealed that increasing diversity had a positive effect on species asynchrony, which contributed to increased community temporal stability. The positive effect of species diversity on community stability persisted even after accounting for influences of abiotic environmental variables. We conclude that there is compelling evidence for a consistently positive relationship between species diversity and community-level temporal stability, emphasizing the need to conserve biodiversity for more reliable ecosystem products and services.