Predicted changes in the distribution of Ostracoda (Crustacea) from river basins in the southern cone of South America, under two climate change scenarios

While many studies predict changes in the distribution of individual species as a result of climate change, few studies have assessed such changes at the community level for aquatic invertebrates. We used ostracods (bivalved micro-crustaceans) to assess the effects of climate change on regional species richness, (re-) distribution and community composition across the river basins of the Southern Cone of South America. Using a range of niche-based models, we present projections of changes in diversity components in the light of two scenarios on increased carbon emissions: the moderate-optimistic (RCP 4.5) and the pessimistic (RCP 8.5) scenarios from four climate models on 2050 and 2080 scenarios. Future projections show increase in the number of (mapped) cells with a richness up to five species as compared to present-day situations. La Plata basin (LPLA) presents the highest species loss, mainly in the Paraguay and Parana rivers, while the species gain occurred mainly in the La Puna Region, North Chile-Pacific Coast and southern LPLA basins. Global change might impact ostracod communities even on a medium term (2050). Despite losses of local species in all future scenarios, a small portion of the LPLA was identified as a potential future climatic refugia for ostracod communities, while the distribution area in Patagonia was predicted to be extremely small for some ostracods at the southernmost parts of South Argentina-South Atlantic Coast and South Chile-Pacific Coast basins in both futures. These results indicate that non-model organisms can also contribute greatly to formulate evidence-based management plans for aquatic ecosystems under climate change scenarios