The ZEN of seagrass ecology: Biodiversity, environment, and eelgrass ecosystem functioning on a planetary scale

Background/Question/Methods

Ecosystem processes are mediated by interactions between resource supply, consumer pressure, and community composition, with the balance shifting along environmental gradients. A frontier in basic and applied ecology is understanding how these multifarious processes interact, and organizing the complexity into predictive models. One promising way forward is the comparative-experimental approach, integrating standardized experiments with observational data. In the Zostera Experimental Network (ZEN, www.zenscience.org) collaborators across 15 partner sites study the ecology of communities associated with eelgrass (Zostera marina), the most widespread marine plant and foundation of important but threatened coastal ecosystems throughout the northern hemisphere. In 2011, parallel field experiments factorially added nutrients and excluded crustacean mesograzers for four weeks, and measured community and ecosystem responses. 

Results/Conclusions

Hierarchical mixed models documented unprecedented strong correlations of biodiversity, both eelgrass genotypic diversity and grazer species richness, with plant and grazer biomass and production even across global gradients in environmental factors. These results largely corroborate controlled, small-scale biodiversity experiments and suggest that impacts of biodiversity loss on ecosystems will be of comparable magnitude to those of other global change factors.