Abstract
In order to evaluate the role of Apodemus mice in invasion of Pasania edulis Makino into a plantation of Japanese cedar, Cryptomeria japonica D. Don, we studied the primary dispersal of acorns from parent trees, secondary dispersal of acorns by mice, and seedling establishment in the plantation and adjacent evergreen broad-leaved forest at the Kagoshima University Forest from April 2003 to January 2005. By primary dispersal, acorns were dispersed on average 2.4 m from the crown edge of the parent trees, and the maximum distance of invasion into the plantation by primary dispersal was 4.4 m from the border of the forests of two types. Of the 200 magnet-attached acorns we placed in the broad-leaved forest in autumn of 2003 and 2004, mice transported 66 and 58 acorns, respectively, into the plantation. The maximum distance from the border to cache site in the plantation was 34.5 m in 2003 and 18.5 m in 2004. Six acorns cached in 2003 remained intact until the next spring. In the plantation, the density of seedlings decreased with the distance from the border, but within 10 m of the border, the density did not differ significantly from that in the broad-leaved forest. From these results, we concluded that wood mice contribute to the invasion of P. edulis into the plantation as an important seed disperser.
