Estimated the habitat suitability of the endangered algal species “Thorea okadae” in Yasumuro River of Hyogo Prefecture, Japan

Abstract

In this case study, to manage the appropriate discharge regime and stream channel, we estimated the habitat suitability of endangered algal species Thorea okadae in Yasumuro River at Hyogo prefecture. Firstly, we invetigated the distribution of Thorea okadae and physical environmental characteristics as four hydraulic parameters, solar radiation and surface water temperature. We analyzed the correspondence between algal occurrence and the environmental parameters by statistical test. Secondly, we predicted the potential distribution of the algae using ecological niche modeling which is based on logistic regression analysis and bootstrap resampling method. Finally, we estimated the total area of suitable micro-habitat on each discharge by application of the model. Our result indicated that the peak of the area in discharge is at 0.95 m³/s, which is slightly higher than regular discharge level, therefore.