Leaf size doesn’t matter: environment shapes eelgrass biodiversity more than a foundation species’ traits.
|Acceptance Date||2022-01 IN PRESS|
|Author(s)||Muller Alexandre1, Dubois Stanislas1, Boye Aurelien1, 3, Becheler Ronan1, Droual Gabin1, Chevalier Mathieu1, Pasquier Marine1, Roudaut Loïg1, Fournier Jérôme2, Auby Isabelle3, Nunes Flavia1|
|Affiliation(s)||1 : IFREMER Centre de Bretagne, DYNECO, Laboratoires d’Ecologie Benthique Côtière, 29280 Plouzané, France
2 : CNRS, Centre d'Écologie et des Sciences de la Conservation (CESCO), Station de Biologie marine MNH, 29182 Concarneau, France
3 : IFREMER, Laboratoire Environnement Ressources d’Arcachon, 33120, Arcachon, France
|Source||Submitted to Ecology and Evolution (Authorea, Inc.) In Press|
|Note||This is a preprint and has not been peer reviewed. Data may be preliminary.|
Aim: Understand the ecological processes that shape community composition in eelgrass meadows along the coast of France at local and regional scales. Location: Northeastern Atlantic. Methods: Combining taxonomic and trait-based approaches with structural equation modeling, we explored the mechanisms governing community assembly in five meadows located over a distance of 800 km along the French coast in the Northeast Atlantic. We assessed the spatial variability of eelgrass-associated invertebrate communities as affected by environmental parameters or morphological traits of the eelgrass and linked these mechanisms to their impacts at local and regional scales through analyses of the taxonomic and functional α and β diversities. We then quantified the direct and indirect effects of environmental factors on macrofaunal structure and composition. Results: Eelgrass meadows locally favored higher species abundance, diversity, and functional traits present in the community relative to nearby bare sediments. At the regional scale, eelgrass diversity was comparable between sites, with high species turnover observed among them, and each site being characterized by different species and different sets of traits. These differences were due in part to morphological traits of the meadows, but the explanatory variables that best explained the differences among the meadows were environmental conditions, including temperature, current velocity, and Δ water level. Main conclusions: Meadows appear to harbor subsets of species from the regional species pool, rather than harboring eelgrass-specific assemblages. The processes that maintain seagrass diversity appear to reflect a seascape-scale meta-community composed of many habitats connected by source-sink dynamics. Given that eelgrass enhances the diversity and abundance of species found in neighboring habitats, conservation programs should consider ecosystem-level protection spanning multiple habitats, including eelgrass, in order to maximize the protection of biodiversity.