Effects of an artificial and annual opening of a natural sandbar on the fish community in a coastal lagoon system: a case study in Lagoa do Peixe floodplains, southern Brazil

Abstract

Two hypotheses were tested: that the artificial sandbar opening decreases the richness, diversity and abundance of fishes and alters the fish composition in floodplain ponds; that the salinity variations influence fish richness, diversity, abundance, as well as composition. Results suggest that artificial sandbar openings did not reduce the richness or diversity of freshwater fishes in southern Brazil floodplain ponds. Nevertheless, this process causes an increase in salinity, which determines significant differences in species composition between natural and managed areas. In this sense, the artificial sandbar opening must be considered with caution, since the area of study is one of the most important conservation units in wetland systems of southern Brazil.