Seed dispersal and predation of fleshy-fruited plants by Japanese macaques in the cool temperate zone of northern Japan.

Abstract

Japanese macaques, Macaca fuscata, play an important role in dispersing seeds of fleshy-fruited plants in the warm temperate forest of Yakushima Island, southern Japan (Yumoto et al. 1998; Otani and Shibata 2000). Various plant species with fleshy fruits are also found in the cool temperate zone of northern Japan (Nakanishi 1996). The frugivorous diet of the macaque in fall, which was recorded by direct observations of foraging behavior {e.g. Nakayama et al. 1999), implies that the macaques act as a seed disperser in the cool temperate zone even at the northern limit of their range. In order to evaluate a species* role as a seed disperser, it is necessary, initially, to examine which plant species and how many seeds they disperse successfully. There have been, however, no qualitative or quantitative studies of seed dispersal by the macaques in the northern part of their range. In this study, therefore, fecal analysis was conducted to identify seed species and abundance. The size of seeds dispersed was also examined, as seed size is an important factor influencing the seed treatment by macaques (Corlett and Lucas 1990; Otani and Shibata 2000).