Exploring the drivers of the distribution of species abundances across the geographic range in freshwater fishes.

Mr Juan D. Carvajal-Quintero¹, Dr. Fabricio Villalobos¹, Dr. Thierry Oberdorff², Dr. Gaël Grenouillet², Dr. Céline Jezequel², 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

Understanding the distribution of species abundances across their geographic ranges lies in the heart of macroecology, biogeography, and population ecology. Currently, two main hypotheses have been proposed to explain the unequal distribution of abundance across species ranges, the abundance-center and abundance-suitability hypotheses. The first hypothesis states that species are most abundant in the center of their geographic distribution, whereas the latter claims that favorable environments will support higher species abundances. However, these hypotheses have yielded mixed support, with some studies finding strong support, while others showing no evidence. Among the most important reasons explaining these mixed findings are the difficulties in gathering datasets at a large geographical scale with standardized sampling protocols. Furthermore, previous studies have ignored the multiple potential responses of species abundance to other factors like species interactions, dispersal limitations, and resource availability. Here, we used extensive and standardized monitoring data (1992-2015) for freshwater fish assemblages throughout France to assess the drivers of species abundance across the geographic range of 32 species. We tested multiple hypotheses proposed to explain the variation of local abundance in a community. We hypothesize that the distribution of species abundance across geographic ranges not only depends on the distance to the center of the range itself or to an optimal niche within that range, but also on other factors related to dispersal capacity and limitations, and on factors that restrict the co-occurrences such as species interactions or resource availability.

Biography:

Ph.D. student, Institute de Ecología (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.