A New Approach to Estimating Potential Reduction in Fish Species Richness in a Global Hydrological Model

Thursday, 18 December 2014
Shinjiro Kanae1, Sayaka Yoshikawa1, Sujan Koirala2, Yukiko Hirabayashi3, Aki Yanagawa1, Yuuichi Iwasaki1, Chihiro Yoshimura1 and Pengzhe Sui1, (1)Tokyo Institute of Technology, Tokyo, Japan, (2)University of Tokyo, Tokyo, Japan, (3)The University of Tokyo, Tokyo, Japan
Two statistical methods to link flow regimes to fish species richness (FSR) on a global scale will be introduced: a conventional one based on a linear relationship between FSR and mean river discharge and the other one, a newly proposed one, based on a multi-linear relationship between FSR and several ecologically relevant flow indices. These two methods were connected with a set of global hydrological simulations so that the differences in model outputs due to the potential impact of climate-change-induced flow alterations were calculated. The new method showed very different responses from the conventional one. Differences are apparent in arid regions and in snow regions. Although it is not the purpose of this study to show which prediction is better, it can be said that taking plural ecologically relevant flow indices into account in global modeling would lead to different results in terms of estimating changes in fish species richness.