The question how biodiversity affects ecological stability has long interested ecologists. Many theoretical and experimental studies have reported positive relationships between biodiversity and ecosystem stability, yet whether biodiversity is of critical importance in maintaining ecosystem stability in the face of accelerated global environmental change remains controversial. In nature, environmental factors other than diversity may have strong effects on ecosystem productivity and stability, which may potentially overwhelm the effect of diversity. We asked the question if species diversity would still have detectable effect on the temporal stability of natural communities after accounting for environmental covariates. We intended to answer this question with a meta-analysis of previous empirical studies that quantified the effect of species richness on temporal stability of community productivity, while controlling for common environmental covariates (e.g., soil nutrients).
Results/Conclusions
Meta-analysis across all studies showed an overall positive relationship between species richness and temporal stability at both the community and population level. There was no significant difference in effect sizes between observational and experimental studies. Yet, the effect of diversity differed between terrestrial and aquatic studies, as well as between single-trophic and multitrophic studies. Temporal stability showed a general trend of increase as diversity increased in aquatic studies and multitrophic communities, but the positive association was not as pronounced in terrestrial studies and single-trophic level studies. More importantly, our analyses showed that species richness promoted temporal stability of community productivity; however, the positive diversity-stability relationship was not statistically significant when environmental covariates were controlled for. The results from this study provide a more comprehensive understanding of diversity-stability relationships and help improve ecosystem predictability in a world of greater environmental variability.