Dispersal and effects of ingestion by mammals on the germination of Hovenia dulcis seeds with edible peduncles

Abstract

To determine seed dispersal agents of Hovenia dulcis, which does not produce pulp-coated seeds but does produce seeds with edible peduncles, we counted the number of animals recorded by camera traps under the canopy of H.dulcis trees in Yamagata prefecture, northern Japan. In addition, we counted the number of H.dulcis seeds contained in fecal samples. Japanese macaque (Macaca fuscata) was recorded most frequent by camera traps in all animal species. H.dulcis seeds were found in all fecal samples of the Masked palm civet (Paguma larvata) and Raccoon dog (Nyctereutes procyonoides) collected. The results suggest that these animals are main seed dispersal agents. Subsequently, we carried out germination experiments in the laboratory and field, in which we compared germination of the following: ingested seeds (seeds defecated in feces after feeding fruits to mammals), fallen seeds (seeds collected from the fruits that had fallen on the ground). In both experiments, ingested seeds and fallen seeds rarely germinated, suggesting that other factors affect seed germination in H.dulcis. This indicates that these frugivorous mammals contribute to dispersion of H.dulcis seeds.