POTENTIAL DISTRIBUTION OF WILLOWS IN WESTERN JAPAN - TOWARD SUITABLE MANAGEMENT OF FORESTATION IN RIVERS-

Abstract

 In recent years, forestation of rivers has become one of major problems in river management. In this study, we predicted potential habitat of willows, one of the major factors of forestation, by using vegetation map created by the Biodiversity Center of Japan, GIS, and maximum entropy modeling (Maxent). The base map for setting managerial objective and analyzing the factor of forestation was created by using potential distribution map and actual distribution data for willows. The results of Maxent show that the area under the curve (AUC) exceeded 0.7 and the sensitivity based on the vegetation map of the River Environment Database exceeded 0.9 in all cases. Thus, these results provided adequate accuracy that can explain the potential habitat of willows. In addition, in the case of the Saba River, density of the weir was higher in the area of actual than in the area of potential willow habitat.