Carvajal-Quintero J. auteur aut IRD Villalobos F. auteur aut IRD Oberdorff Thierry auteur aut IRD Grenouillet G. auteur aut IRD Brosse S. auteur aut IRD Hugueny Bernard auteur aut IRD Jézéquel Céline auteur aut IRD Tedesco Pablo auteur aut IRD text journalArticle eng text/pdf born digital access Identifying the drivers and processes that determine globally the geographic range size of species is crucial to understanding the geographic distribution of biodiversity and further predicting the response of species to current global changes. However, these drivers and processes are still poorly understood, and no ecological explanation has emerged yet as preponderant in explaining the extent of species' geographical range. Here, we identify the main drivers of the geographic range size variation in freshwater fishes at global and biogeographic scales and determine how these drivers affect range size both directly and indirectly. We tested the main hypotheses already proposed to explain range size variation, using geographic ranges of 8,147 strictly freshwater fish species (i.e., 63% of all known species). We found that, contrary to terrestrial organisms, for which climate and topography seem preponderant in determining species' range size, the geographic range sizes of freshwater fishes are mostly explained by the species' position within the river network, and by the historical connection among river basins during Quaternary low-sealevel periods. Large-ranged fish species inhabit preferentially lowland areas of river basins, where hydrological connectivity is the highest, and also are found in river basins that were historically connected. The disproportionately high explanatory power of these two drivers suggests that connectivity is the key component of riverine fish geographic range sizes, independent of any other potential driver, and indicates that the accelerated rates in river fragmentation might strongly affect fish species distribution and freshwater biodiversity. specialized freshwater fishes species distribution global scale connectivity river networks 036 034 116 27 13434-13439 2019 0027-8424 https://www.documentation.ird.fr/hor/fdi:010076190 10.1073/pnas.1902484116 0027-8424 [F B010076190] https://www.documentation.ird.fr/hor/fdi:010076190 https://www.documentation.ird.fr/intranet/publi/2019/07/010076190.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2019-08-05 2025-02-24 fdi:010076190 fre