Thursday, August 15, 2019: 9:50 AM
M109/110, Kentucky International Convention Center
Melissa R. Kardish, Evolution and Ecology, UC Davis, Davis, CA, Zostera Experimental Network Partners, Smithsonian Institution, Washington, DC, J. Emmett Duffy, Tennenbaum Marine Observatory Network, Smithsonian Institution, Washington, DC, Kevin Hovel, Coastal and Marine Institute, San Diego State University, San Diego, CA, Jonathan A. Eisen, Evolution and Ecology, University of California, Davis, Davis, CA, Pamela L. Reynolds, Department of Ecology and Evolution, University of California Davis, Davis, CA and John J. Stachowicz, Department of Evolution and Ecology, University of California, Davis, Davis, CA
Background/Question/Methods: The study of the assembly of communities is often restricted to studying particular guilds independently. Separate studies within the same physical environment might consider the assembly of plant communities, the animals that use those plants as food and habitat, and the microbes associated with those plants. This approach neglects the role that trophic interactions and habitat associations among groups can play in influencing community composition, and misses identifying the potential common drivers of community organization that apply across taxa and levels of biological organization. We simultaneously consider patterns of similarity in environmental conditions, plant genetics, epifaunal invertebrates, and plant-associated bacteria among 50 seagrass beds dominated by eelgrass,
Zostera marina. Sampling was conducted across the Northern Hemisphere in 2014 by the Zostera Experimental Network, a worldwide group of scientists coordinating efforts to study large-scale biogeographic patterns in eelgrass. We calculated similarity matrices among sites for each of these variables using distance metrics appropriate to each variable and then assessed how each predicted community similarity in invertebrate species composition using multiple matrix regression.
Results/Conclusions: The similarities of the epifaunal invertebrate community were correlated with the similarities of plant genetics and root-associated microbial communities. We suspect that plant genetic distance strongly correlates with invertebrate communities because it serves as a good proxy of connectivity among sites. Notably, effects of environmental and habitat similarity were weak or non-significant predictors. This suggests that dispersal and connectivity, rather than local habitat characteristics, are prominent drivers of invertebrate community assembly. Surprisingly, root microbial community similarity was also a significant and substantial predictor of invertebrate community similarity. This suggests either a partnership of the plant and root microbes mediating an unmeasured plant trait affecting the invertebrate community or that the root microbial community is indicative of an unmeasured environmental parameter that directly or indirectly affects invertebrate community structure. We aim to further disentangle this potential relationship between root microbial and invertebrate community distances by identifying the microbial community members driving this correlation, which may allow better understanding of the factors driving differences in invertebrate communities mediated by plants. Simultaneously considering similarities in multiple community components revealed unexpected correlations that suggest some common drivers of biological patterns across levels and potential interactions that would have gone unappreciated without this approach.
