Abstract
Scarification with bulldozers of forest floors dominated by Sasa bamboos was seen as a promotional treatment for natural regeneration. We experimentally examined postdispersal seed predation by small rodents on such a scarified forest floor in a conifer-hardwood mixed forest in northern Hokkaido, Japan, during the two years after the scarification. Seed predation of Picea glehnii MASTERS was significantly greater on Sasa bamboo floors than on scarified floors and their edges. The seed predation was also reduced with increasing distance from the edge up to 10 m on scarified floors. Four species of small rodents, Apodemus argenteus TEMMINCK, A. speciosus ainu THOMAS, Clethrionomys rufocanus bedfordiae THOMAS, and C. rutilus mikado THOMAS were live-trapped. The trappability of these rodents was significantly higher on the bamboo floor compared with the scarified floor. There was a significantly negative correlation between rodent trappability and the seed survival period at each location in all experiments. It is concluded that the low activity of small rodents caused a high seed survival rate on the scarified floor. The scarification of bamboo floors must be an effective treatment for natural regeneration because it prevents seed predation by small rodents.
