Climate change will decrease the range of a keystone fish species in La Plata River Basin, South America

Climate change threatens freshwater fish by severely modifying water quality and hydrological dynamics, hence altering the species distribution. We assessed the climate change effects on the geographical distribution of Salminus brasiliensis , a keystone species of economic interest in the La Plata River basin. Using ecological niche models, we estimated the species range in the present time and assessed the range shift phenomena through climatically suitable areas in the future. We also quantified the predictive uncertainty from niche models, atmosphere–ocean general circulation models, and carbon emission scenarios. Our predictions indicated a great range contraction of S. brasiliensis in the future. The south-central portion of the basin should retain the climate refuge function for the species at 2050. Nonetheless, the segregation of this climate refuge in two smaller parts was predicted at the end of the century. Our study also revealed that the greatest source of uncertainty in forecasts of species range shifts arises from using alternative niche algorithms in modeling process. Our results contribute to more effective measures for conservation of S. brasiliensis , thus helping to ensure the ecosystem processes and socioeconomic activities in the basin dependent on this species.