Gnawing damage by rodents to the seedlings of Fagus crenata and Quercus mongolica var. grosseserrata in a temperate Sasa grassland‐deciduous forest series in southwestern Japan

The effects of dwarf bamboo, Sasa , cover on the initial morrality of hardwood seedlings were investigated by transplanting 1‐year‐old beech ( Fagus crenata ) and current‐year oak ( Quercus mongolica var. grosseserrata ) seedling to three different stands; old‐growth beech and secondary oak forests with Sasa undergrowth, and a Sasa grassland in a grassland‐forest series near the top of Mt Jippo, southwestern Japan. The most frequent cause of seedling morrality was gnawing of the stems by rodents. In the beech forest, the gnawing was more likely to occur under Sasa cover, suggesting that it provides a good habitat for rodents on the beech forest floor. The Sasa under growth may thus play an imporrant role in regeneration of beech forest. In the oak floor, mortality of both species was low and only a little gnawing occurred during a year. However, no natural oak seedling were found in the forest even after a mast year. This may be because most of the acorns disappeated before establishment. The early‐stage demography of hardwood seedling as oak may thus play an imporrant role in regeneration of oak forest. In the Sasa grassland where the seed supply is small, almost all of the seedlings died fromo gnawing regardless of the presence of Sasa cover. These factors prevent the recruitment of a sizable seedling bank. Rodents may thus play an imporrant role in maintenance of the Sasa grassland.