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

Leaf monkeys are known to be leaf eaters, and thus, their potential role as seed dispersers has been neglected. However, they do also feed on fruits. To examine the role of leaf monkeys as endozoochorous seed dispersers, we studied the Javan lutung (Trachypithecus auratus) in Indonesia. We compared multiple aspects of seed dispersal processes (amount and diversity of seeds ingested, dispersal distance, and germination rate) of lutungs with that of the sympatric long-tailed macaque (Macaca fascicularis). Over the study period, 54 percentof lutung feces contained intact seeds, which was equivalent to the macaque feces contained seeds (62%). Seeds of at least six plant species were detected in lutung feces, which was less than those found in macaque feces (> 19 plant species). The main species of seeds defecated by both lutungs and macaques were Ficus spp. (seed size: 0.7 mm). Seed shadow, estimated from travel distance (range: 1–299 m) and gut passage rate (24–96 h), had a unimodal distribution with a peak at 51–100 m, and was shorter than that reported in published accounts of macaques and other similar and smaller-sized frugivores. Finally, germination rates of Ficus spp. seeds ingested by both lutungs and macaques were lower than that of control seeds. These results imply that the dispersal effectiveness of lutungs would be lower than that of sympatric primate frugivores. However, at a population level, lutungs could play a significant role as seed dispersers for small-seeded species, and, therefore, more research into their frugivorous habits is warranted.