There has been a surge of research into the role that different aspects of biodiversity have to play in sustaining ecosystem function and structure. However, past research has most often focused on how species richness influences biomass in primary producer communities in experimental settings. To help address these gaps, our work aims to explore similar questions with alternative diversity measures, species groups, and methodology. Using in situ community composition data, we ask how different aspects of taxonomic, functional, and phylogenetic metrics of diversity are correlated to fish biomass within eelgrass meadows in northern British Columbia, Canada. Using the same functional diversity metrics, we question whether a variety of trait values, as measured by the diversity indices or a dominance of trait values, as measured by the community weighted average trait values, lead to communities with higher biomass. Finally, we ask which life history traits and feeding strategies influence a species’ dominance within our eelgrass communities.
Results/Conclusions
Our results show how different aspects of biodiversity can give conflicting answers to the question of how biodiversity influences ecosystem function. We found that measures of richness that ignored abundance demonstrated no relationship with biomass while those than incorporate it, i.e. measures of diversity, showed a negative relationship. Congruently, it was the community average trait values, not the diversity values that best predicted biomass in our communities. These results suggest that it is the dominance of a few species rather than the presence of many, which drives the biomass or “function” of this ecosystem. In studying the traits of these dominant species, we found that traits related to prey location and uptake were the best predictors of a species’ dominance within a community. Against expectations, the different aspects of biodiversity, traditional, functional, and phylogenetic metrics showed similar relationships and comparable predictive power when predicting fish community biomass. While such findings are community and function specific, they suggest that simple taxonomic measures of biodiversity can be adequate for answering questions related to ecosystem function. By researching a community in a real world ecosystem, this work provides better understanding of natural diversity-function relationships as well as insights into their underpinnings.