AUTHOR=Sutton Lauren , Mueter Franz J. , Bluhm Bodil A. , Iken Katrin 

TITLE=Environmental Filtering Influences Functional Community Assembly of Epibenthic Communities

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 8 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.736917

DOI=10.3389/fmars.2021.736917

ISSN=2296-7745

ABSTRACT=Community assembly theory states that species assemble non-randomly as a result of dispersal limitation, biotic interactions, and environmental filtering. Strong environmental filtering likely leads to local assemblages that are similar in their functional trait composition (high trait convergence) while functional trait composition will be less similar (high trait divergence) under more benign environmental filters. We used two Arctic shelves as case studies to examine the relationship between functional community assembly and environmental filtering using the geographically close but functionally and environmentally dissimilar shelf epibenthic communities on the Chukchi and Beaufort Sea shelves. Environmental drivers were compared to functional trait composition and to trait convergence within each shelf. Functional composition in the Chukchi Sea was more strongly correlated with environmental gradients compared to the Beaufort Sea, with 45% and 21% of the total functional variance explained in the two seas, respectively. In the Chukchi Sea, epibenthic functional composition, particularly fragility, larval development, and several behavioral traits (i.e., feeding habit, living habit, movement), was most strongly related to sediment grain size, temperature, salinity, and depth. In the Beaufort Sea, epibenthic functional composition, particularly of behavioral traits, was related to depth and sediment grain size. The stronger environmental filter in the Chukchi Sea confirmed the hypothesized relationship with higher trait convergence. Strong environmental filtering generally provides a challenge for biota and can be a barrier for invading species, a growing concern for the Chukchi Sea shelf communities under warming conditions. Weaker environmental filtering, such as on the Beaufort Sea shelf, generally leads to communities that are more structured by biotic interactions, and possibly representing niche complementarity from intermediate disturbance levels. We provide evidence that environmental filtering can structure functional community composition, providing a baseline of how community function could be affected by stresses such as changes in environmental conditions or increased anthropogenic disturbance.