Functional evenness and community-weighted mean traits have strong correlation with macrophyte community productivity

Biodiversity is declining globally at a rapid rate nowadays as a result of a variety of global changes, and estimating how biodiversity loss affects ecosystem process (e.g., productivity) is critical. However, little is known about the relationship of macrophyte community productivity to trait-based biodiversity nor the comparative strength of trait-based biodiversity relative to species diversity in relation to productivity. Here, we investigated how multifaceted biodiversity indices were related with macrophyte community productivity using the data collected from a survey of 78 macrophyte plots in Liangzi lake, a shallow freshwater lake in China. We found that functional evenness and community-weighted mean traits had close association with community productivity, while species diversity, functional richness and divergence, and functional group richness were not significantly correlated with productivity. The connection between characteristics of dominant species and community productivity depended on the given trait. The significant correlation between community-level photosynthetic traits (Fv/Fm and chlorophyll content) and productivity revealed the importance of taking photosynthetic traits into account when exploring the mechanism behind the biodiversity-productivity relationship. Moreover, our results showed the redundancy and complementarity of the biodiversity indices in predicting community productivity. Overall, our results suggested that both mass ratio hypothesis and niche complementarity hypothesis can operate on community productivity.

Automated summary

Biodiversity is declining rapidly globally, and the relationship between macrophyte community productivity and trait-based biodiversity has been explored. The study found that functional evenness and community-weighted mean traits were closely associated with community productivity, while species diversity and other biodiversity indices showed no significant correlation.