Spatial and seasonal drivers of fish fauna in estuaries from the Brazilian semiarid coast: Taxonomic and functional perspectives

Abstract

Estuaries are spatiotemporally dynamic environments that structure biological communities in a complex manner. We investigated how the taxonomic and functional structures of the fish fauna in estuaries along the Brazilian semiarid coast (BSC) vary between estuarine zones and seasons. Standardized collection methods sampled fish in five estuaries of the BSC. Each species was categorized by trophic guild and estuarine use guild, and fish–estuary association score (FEAS). Non-metric multidimensional scaling (nMDS) analyzed species and trophic guild compositions according to zone and season. PERMANOVA tested differences among groups. Similarity percentage (SIMPER) analysis and the relative preference index (RPi) identified the species and trophic guilds that contributed most to group distinction (lower zone versus upper zone, and dry season versus rainy season). In total, 113 fish species were recorded. The most representative estuarine use guilds were marine migrants and estuarine. Among the nine trophic guilds, the most representative were detritivores, omnivores, opportunists, macrocarnivores, and zoobenthivores. Taxonomic (species composition) and functional (trophic guilds) approaches revealed both spatial and temporal differences. The functional approach using FEAS detected spatial variation of small magnitude and indicated temporal homogeneity. Thus, there is substantial taxonomic and functional heterogeneity considering approaches from species, estuarine use guilds, and trophic guilds.