航空写真・地形・流況データを用いた裸地砂州への植生の侵入・定着過程に関する研究

抄録

The expansion of riparian vegetation is the problem in river engineering and ecology, and many researchers have studied the vegetation dynamics in river. Previous research has mainly dealt with vegetation growth and destruction, but the initial step of vegetation expansion—germination (Immigration) and survival (Establishment) of seedling—is also important. In fact, there was wider bare area in 1970s in many rivers than at present in Japan, thus the analysis of aerial photographs, geomorphology and flow regime in 1970s might suggest the Immigration and Establishment process. The time of Establishment is determined by the analysis of aerial photograph, and spatial distribution of plant establishment area is discussed with the result of analysis of geomorphology and flow regime.

The results of this study suggested that the seedling immigration area mainly depends upon submergence during winter, and the simulation of bed material mobility during annual maximum flood suggested that the seedling immigration area and the area in where bed material can move during flood determine the plant establishment area.