Connectivity of River Floodplains - The Case of Ibera Wetlands after 10,000 Years of Isolation from Parana River

Abstract

“Esteros del Ibera” is one of the most outstanding wetlands in South America, by its size (12,300 km2 ) and biodiversity, the largest recorded at this latitude. Owing to this, it is recognized as a Ramsar Wetland of International Importance and as a National Park in Argentina. Esteros del Ibera is an “open-air laboratory” since its landscape was created by the lateral migration of the Parana River, leaving a vast paleo-alluvial fan from Argentina to Paraguay. Here, we compare the species richness in the landscapes of Ibera with that in the equivalent landscapes of the active course of Parana River in order to understand the causes of change in diversity patterns over the past 10,000 years. We found that the loss of connectivity with the pulse regime of Parana River led to an increase in specific complexity of Ibera biota. This likely resulted from the combination of a limited change in water quality, the belonging to the vast Amazon biogeographical domain, the natural niche amplitude of wetland species, and the self-designing capacity of the Ibera ecosystem.