Ecology and conservation of an endangered willow, Salix hukaoana

Abstract

Several riverine willow (Salix) species are known to occur in the floodplains of rivers in Japan. These willow species are characterized by their unique life-history features, as well as by the conditions of the habitats they occupy, e.g., soil texture and moisture, light conditions, and so on. These willow species often constitute typical riparian forests over open floodplains, representing important elements at the early stages of ecological succession (Ishikawa 1983, Ishikawa 1988; Niiyama 1987; Yoshikawa & Fukushima 1999). These Salix species have obviously adapted to changing riparian habitats, such as flooding caused by snow melting and typhoons with heavy rainfalls, since they can maintain their populations in such extremely changing environments. (Niiyama 2002).