Rainfall and river networks prove accurate predictors of fish biodiversity

The figure at the top right represents average runoff (the amount of rainfall that ends up in rivers or streams) with the driest regions appearing in red and the wettest in blue. The middle figure is an abstraction of the Mississippi-Missouri river network. The figure in the foreground represents how many different species occupy different regions of the network, demonstrating a close correlation between the average runoff and the number of species. Areas with the fewest species are represented in red; the areas richest in the number of species are represented in blue.Image by Enrico Bertuzzo of École Polytechnique Fédérale de Lausanne (EPFL)