The role of Japanese macaques (Macaca fuscata) as endozoochorous seed dispersers on Kinkazan Island, northern Japan

Abstract

a b s t r a c tWe studied the characteristics of seeds within faeces, an important aspect of endozoochorous seed dispersal, in Japanese macaques Macaca fuscata inhabiting Kinkazan Island, northern Japan. We intermittently collected faecal samples from 1999 to 2009 (N = 1294) and examined the rate of seed occurrence, species/life-form composition, number of seeds, and their intact rate. Seeds were found within faecal samples during every month, but their characteristics changed monthly: the rate of seed occurrence and the number of plant species within faecal samples were greater in summer and fall, and the intact rate and number of intact seeds observed within single faecal samples were also higher during these seasons than spring and winter. These results suggest that Japanese macaques on Kinkazan act as seed dispersers in summer and fall and that they disperse intact seeds into wider areas within the forest through defecation. During the study period, we observed seeds from a total of 35 plant species from 22 families in our samples. In addition to those of woody plants, we also observed seeds from as many as 12 herbaceous plants, for which sympatric sika deer (Cervus nippon) have historically been considered the sole seed dispersal agents. The intact rate of seeds was significantly negatively correlated with the seeds' mean cubic diameter, and this relationship was strengthened for non-fleshy fruits. We also conducted regional comparisons of the characteristics of defecated seeds in order to address whether regional variations in the diet of the macaques affect their efficacy as seed dispersers, both in terms of quantity and quality. Macaques living in the natural habitats of Kinkazan and Yakushima dispersed more seeds of tall tree species than do macaques inhabiting the human-altered areas of in Shimokita and Kashima. The number of plant species represented within single faecal samples also varied geographically, being greater in Yakushima. This pattern likely resulted from Yakushima's warm temperate climate, as the other three study sites occur in the cool temperate region. Our results suggest that the composition of seeds dispersed by Japanese macaques is not rigid, but is determined instead by the vegetation found in a given habitat.

Neglected seed dispersers: endozoochory by Javan lutungs (Trachypithecus auratus) in Indonesia

“…We calculated the number of dispersal events ( DE ), defined as the number of fecal samples containing seeds for each month or for each plant species (Tsuji et al . ).…”

Endozoochorous seed dispersal by Japanese macaques (Macaca fuscata): Effects of temporal variation in ranging and seed characteristics on seed shadows

“…Japanese macaques primarily feed on fleshy fruits and nuts throughout their range, especially in fall (September-November; reviewed in Tsuji, 2010, Tsuji et al, 2015, and defecate and spit out seeds of 12-35 plant species [Otani & Shibata, 2000;Tsuji, 2011Tsuji, , 2014Tsuji et al, 2011] inside forests. Further, ingestion by macaques enhanced germination for seeds of several plant species [Otani & Shibata, 2000], although many seeds were masticated before ingestion [Otani, 2004;Tsuji et al, 2010b].…”

Relationships Between the Fruiting Phenology of Prunus jamasakura and Timing of Visits by Mammals - Estimation of the Feeding Period Using Camera Traps

“…In Japan, seed dispersal by Japanese macaque (Macaca fuscata) has been studied intensively among the mammals and shows macaques are important seed dispersers (e.g., Otani, 2003Otani, , 2004Tsuji et al, 2011a). However, the importance of carnivorous mammals in seed dispersal is poorly documented in Japan (e.g., Otani, 2002).…”

“…Basic data on the number of seeds per fecal sample, which serves as an index of the quantitative effectiveness of seed dispersal (Schupp, 1993), as well as basic information on the physical damage to seeds that pass through a mammal's gastrointestinal tract, which is an index of qualitative effectiveness of seed disperal, are known in Japan for carnivores (Koike et al, 2008b) and macaques (Tsuji et al, 2011a). Koike et al, (2008b) studied five carnivores in the Okutama Mountains (Asiatic black bear (Ursus thibetanus), Japanese marten (Martes melampus), Japanese badger (Meles meles), red fox (Vulpes vulpes), and raccoon dog (Nyctereutes procyonoides)) and recovered seeds from 17 plant species, representing about 50% of the fleshy-fruited plants occurring in the same study forest, from the carnivore fecal samples.…”

“…These findings suggest all five carnivores can act as seed dispersers for some fleshy-fruited plants in cool-temperate deciduous forests. On the Kinkazan Island in northern Japan, Tsuji et al, (2011a) suggest macaque acts as s seed dispersers in summer and fall. The percentage of intact seeds found in macaques fecal samples was significantly negatively correlated with the seed's mean diameter, and this relationship was strengthened for non-fleshy fruits.…”