Fish composition and species richness in eastern South American coastal lagoons: additional support for the freshwater ecoregions of the world

Abstract

The relationships between fish composition, connectivity and morphometry of 103 lagoons in nine freshwater ecoregions (FEOW) between 2·83° S and 37·64° S were evaluated in order to detect possible congruence between the gradient of species richness and similarities of assemblage composition. Most lagoons included in the study were <2 km(2) , with a maximum of 3975 km(2) in surface area. Combined surface area of all lagoons included in the study was 5411 km(2) . Number of species varied locally from one to 76. A multiple regression revealed that latitude, attributes of morphometry and connectivity, and sampling effort explained a large amount of variability in species richness. Lagoon area was a good predictor of species richness except in low latitude ecoregions, where lagoons are typically small-sized and not affected by marine immigrants, and where non-native fish species accounted for a significant portion of species richness. Relationships between species and area in small-sized lagoons (<2 km(2) ) is highly similar to the expected number in each ecoregion, with systems located between 18·27° S and 30·15° S attaining higher levels of species richness. Similarities in species composition within the primary, secondary and peripheral or marine divisions revealed strong continental biogeographic patterns only for species less tolerant or intolerant to salinity. Further support for the FEOW scheme in the eastern border of South America is therefore provided, and now includes ecotonal systems inhabited simultaneously by freshwater and marine species of fishes.

Influences of the area, shape and connectivity of coastal lakes on the taxonomic and functional diversity of fish communities in Southern Brazil

“…The relationship between species richness and area has been established for a long time in ecology, particularly for freshwater ecosystems (Drakou et al 2009, Petry et al 2016). However, lake area was not the best predictor of taxonomic fish diversity in the Tramandaí River Basin.…”

“…Coastal lakes are spatially and temporally dynamic ecosystems containing a substantial quantity of biodiversity (Esteves et al 2008, Petry et al 2016. Even though in these systems many factors influence biological communities, most previous studies have focused on the importance of water quality in determining alpha diversity.…”

“…From a regional perspective, the local climate (temperature, precipitation and wind patterns) is the main driver of water quality and nutrient availability, which influence taxonomic diversity (Heino et al 2007, Caliman et al 2010. Besides these regional factors, local biotic interactions and anthropogenic disturbances can modify taxonomic diversity (Esteves et al 2008, Petry et al 2016. Additionally, landscape characteristics (position, morphometry and connectivity) of the lakes may also determine community structure in lakes, although their use is very recent (Quinlan et al 2003).…”

“…The mechanisms that influence fish community diversity in lakes are mainly associated with the complexity of the area and the shoreline habitat (Tonn and Magnuson 1982, Eadie and Keast 2011, Petry et al 2016, which are positively associated with primary productivity (Dodson et al 2000), habitat heterogeneity (Dodson et al 2009, Scheffer et al 2006) and availability of refuges from large predators (Jennings et al 1999). Particularly in coastal lakes, the salinity regimen is an important factor for fish communities at local and regional scales, in view of the changes it produces in species composition (Jones and West 2005, Pérez-Ruzafa et al 2007, Camara et al 2018.…”

Long-Term Spatiotemporal Variation in the Juvenile Fish Assemblage of the Tramandaí River Estuary (29°S) and Adjacent Coast in Southern Brazil

“…Globally, estuaries, and coastal areas are environments with high biological productivity, and are considered important nursery areas for juvenile of many coastal fish species, including those of economic interest (Beck et al, 2001; Barletta et al, 2010). Estuaries potentially provide connectivity between marine and freshwater environments (Guimarães et al, 2014;Petry et al, 2016) and several species develop dependency on them. The natural variation of the estuarine environment and anthropogenic effects influence the dynamics of fish populations over time (Barletta et al, 2010;Martins et al, 2015).…”