Geographic ranges of freshwater fishes: drainage network position and historical connectivity determine most of their size variation

Mr Juan D. Carvajal-Quintero1, Dr. Fabricio Villalobos1, Dr. Thierry Oberdorff2, Dr. Gaël Grenouillet2, Dr. Sébastien Brosse2, Dr. Céline Jezequel2, Dr. Bernard Hugueny2, Dr. Pablo A. Tedesco2

1Laboratorio de Macroecología Evolutiva, Red de Biología Evolutiva, Instituto de Ecología (INECOL), Xalapa, Mexico, 2UMR5174 EDB (Laboratoire Evolution et Diversité Biologique), CNRS, IRD, UPS, Université Paul Sabatier, Toulouse, France

Identifying the drivers of species’ geographic range size is crucial to understand the distribution of biodiversity and predict the response of species to the current global change. Despite being a fundamental aspect of biodiversity, the determinants of range size in freshwater fishes and the mechanistic explanations for its global-scale variation have not been investigated. Here, we determine for the first time the main drivers of the geographic range size variation in freshwater fishes at global and biogeographic scales, and identify the direct and indirect effects of these drivers on range size variation. We tested the most important hypotheses proposed to explain the variation of geographic range size using the largest dataset of freshwater fish geographic ranges assembled to date with 9075 species (i.e. 70% of all known freshwater species). We found that, unlike terrestrial species range sizes that are mainly determined by climate and topography, the position along the river network and the historical connectivity among river basins during low-sea-level periods are the main drivers of the geographic range size in freshwater fish species. Large-ranged fish species occurred in lowland areas of river drainage basins where hydrological connectivity is the highest and where historical connections among basins have occurred. Our results highlight the importance of current and historical hydrological connectivity in driving range size variation in freshwater species, and indicate that the accelerated rates in river fragmentation caused by the current hydropower expansion might strongly be affecting fish species distribution and the freshwater biodiversity.


Ph.D. student, Institute of Ecology (INECOL, México)

Juan is from Medellin, Colombia. He obtained his undergraduate degree in Biology from the Universidad de Antioquia, where he began to study and explore freshwater fish eight years ago. Today, as a Ph.D. student, he integrates ecology, evolution, and conservation to better understand freshwater ecosystems and produce better tools for their long-term management and preservation. His Ph.D. project has three primary objectives: 1) to determine the natural and human-induced factors that explain species’ range sizes at different spatial scales; 2)to assess the current and future vulnerability of freshwater fish species to major human-induced disturbances, such as climate and land use changes; and 3) to determine how changes in species range sizes, caused by different human disturbances, could influence spatial conservation priorities. Juan enjoys riding a bike and underwater sports.

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