Invariant scaling relationship between functional dissimilarity and co‐occurrence in fish assemblages of the Patos Lagoon estuary (Brazil): environmental filtering consistently overshadows competitive exclusion

Abstract

Determining how assembly rules (e.g. limiting similarity, environmental filtering and neutrality) shape community structure along environmental gradients and across spatial scales is still controversial. The study of functional relationships between coexisting species may help to disentangle among these assembly rules. Here, we compared pairwise functional dissimilarities between fish species to their corresponding pairwise co-occurrences. Fish assemblages (n  835) were sampled monthly in Patos-Mirim system (Brazil) using both bottom trawling and beach seining. Species occurrences were recorded and functional traits related to locomotion and food acquisition were measured on several individuals from each species. The region studied was divided in two areas corresponding to each side of a floodgate located in São Gonçalo Channel: a freshwater channel up the floodgate and, down the floodgate, the Patos Lagoon estuary. The relationship between functional dissimilarity and co-occurrence between species pairs was assessed using quantile regressions for each month and at different spatial scales. Overall, quantile regression coefficients between functional dissimilarities (either based on locomotion types or feeding habits) and co-occurrence values were negative, suggesting that co-occurrence increases with functional redundancy regardless of spatial scale. Our results support the assumption that environmental filters have more influence than biotic interactions on the structure of fish assemblages even locally.

Influence of limnological zones on the spatial distribution of fish assemblages in three Brazilian reservoirs

“…The combination of spatial gradients and biological interactions can influence the distribution of different species with different ecological requirements and adaptability to one or more habitats (Gido et al, 2002;Field et al, 2009;Mouchet et al, 2013). The Três Marias riverine zone had greater total abundance of fishes than its lacustrine zone, which has been reported in other reservoir studies (Britto and Carvalho, 2006;Juza et al, 2009 (Fernando and Holčík, 1991;Sanches et al, 2014).…”

Co-occurrence patterns of fish species in two aquatic habitats of the Arauca River floodplain, Venezuela

“…Undoubtedly, the assembly of fish communities has been intensely studied through different approaches that include the modeling of species abundances (Strange et al 1992), the effect of environmental filters (Mouillot et al 2007, Mouchet et al 2013, Pease et al 2015, trophic eco-morphology (Adlte and Winemiller 1996, Sampaio et al 2013, Blasina et al 2016, the elements of meta-community structure (Fernandes et al 2013, Erős et al 2016), among others. These studies have contributed to the understanding of the influence of environmental factors, landscape, the evolutionary history of the species and biotic interactions in the organization of communities.…”

Fish functional groups in a tropical wetland of the Yucatan Peninsula, Mexico

“…Studies of functional groups in fish communities have shown highly congruent patterns of habitat use, assemblage structure and functional redundancy at global biogeographic (Bellwood et al, 2002), regional (Aguilar-Medrano & Calderon-Aguilera, 2015), and local scales (Hoeinghaus et al, 2007;Teresa & Casatti, 2012;Bordignon et al, 2015). A useful tool to understand the ecological function of fish consists in the analysis of functional traits by means of an ecomorphological approach (Mason et al, 2007;Mouillot et al, 2006;Villéger et al, 2010;Mouchet et al, 2013). Two key functions have been recognized: locomotion and food acquisition.…”