Long-term multiscale analysis of temporal variability in the fish community in Terminos Lagoon

Abstract

The distribution of biological communities is structured at multiple spatiotemporal scales. The identification of trends and patterns in highly variable coastal ecosystems contributes to explaining the relative importance of the different scales. Herein, a temporally nested hierarchical analysis was applied to a fish community in order to determine the temporal variation in three time scales (month, season, and year) for four community attributes (species richness, abundance, biomass, and taxonomic distinctness) and two facets of species assemblages (species composition and abundance, and species composition and biomass). The analysis relied on data from four similar sets of samples belonging to a multidecadal series of Terminos Lagoon (1980, 1998, 2010, and 2016). In accordance with the hydrographic variability over time, the results revealed recurrent configurations of fish community characteristics, where the year (long term) and season (intermediate term) scales determined distribution trends and species composition patterns. In particular, trends emerged for the community attributes in the long term, whereas in the intermediate term, fluctuations were mostly recorded, which had higher values during the rainy and cold fronts seasons. Distribution patterns in both facets of species assemblages were consistent in the long and intermediate term, with the first one corresponding to an associated group of species for each year and the second one corresponding to a variable interaction with transparency and salinity according to the weather season. The present study highlights the fish adaptive response, which contributes to the ecological processes driving their temporal variability in Terminos Lagoon and is associated with hydrographic variability and estuarine condition shifts.