HABITAT EVALUATION MODEL FOR GENUS UCA IN SHIKOKU ISLAND

Abstract

The purpose of this study is to use HEP (Habitat Evaluation Procedure) for studying rare species on tidal flats and to evaluate the value of tidal flats themselves. In this study, based on the results both of field observations and numerical simulations, SI (Suitability Index) curves for each mud property and physical factors such as friction velocity were plotted. Then, HSI (Habitat Suitability Index) for each tidal flat was calculated by multiplying each SI curves score and comparing the HSI value among the tidal flats. The following results were obtained: 1) The Yoshino River mouth, which is the largest habitat of genus Uca in Shikoku Lsland, had the highest SI score. 2) The suitability of habitation for other kinds of tidal-living crabs may be estimated as the Yoshino River also had the highest score. Using this method, the value of tidal flats could be discussed indirectly, that is, as the HSI score becomes larger, the necessity of tidal flats becomes great.