Short-term movements and strong dependence on figs of binturongs (Arctictis binturong) in Bornean rainforests

Abstract

We evaluated short-term movements of three radio-collared binturongs in relation to food distribution in Bornean rainforests, in addition to the basic ecological information on their home-range size and diet. Mean 95% fixed kernel and 95% MCP homerange size were 4.24 ± 0.79 km2 and 1.54 ± 0.89 km2 , respectively (mean ± SD). We recorded 13 fig Ficus species and four nonfig species as their foods. Fig trees accounted for 87.5% of the feeding sites of the three collared binturongs, and 87.9% including uncollared individuals. Our results suggested that binturongs'short-term movements were strongly affected by food distribution, especially figs. They feed on various fig species and may remember the location and fruiting periods of fig trees. They may use the biggest fig species, F. punctata, as a fallback food when other foods are scarce. Although this is the first systematic study to describe movement and feeding habits of binturongs, further studies are needed to understand their ecology so that proper measures can be designed for their conservation.

Limited directed seed dispersal in the canopy as one of the determinants of the low hemi-epiphytic figs’ recruitments in Bornean rainforests

“…Binturongs consumed by far the largest number of fig fruits in the feeding patch followed by Mueller’s gibbons and helmeted hornbills. However, this does not indicate that a binturong is a quantitatively effective seed disperser at the population level of Ficus species because it tends to stay for a long time at a single feeding patch [29]. At the individual fig level, binturongs had more opportunities than the other two species to disperse hemi-epiphytic fig seeds.…”

“…In the uneven canopy of Bornean rainforests, defecating directly at the establishment sites is the most reliable dispersal method, compared to scattering feces from the air or upper canopy. Hemi-epiphytic fig species account for over 70% of the Ficus species that binturongs feed on in Bornean rainforests [29]. Therefore, eventually binturong behaviors lead to directed seed dispersal [52] of hemi-epiphytic figs.…”

“…Binturongs are the largest arboreal frugivorous carnivorans on Borneo. They weigh 6–10 kg [28] and fig fruits constitute nearly 90% of their diet [29]. Mueller’s gibbons are highly arboreal primates weighing 5–6.4 kg [28].…”

“…We located the microsites where we found feces of the study animals by individually tracking them after they left the feeding patches or when we found them by chance. Because of the nocturnality of binturongs, we radio-tagged three [29] and recorded their seed dispersal microsites at their feeding and sleeping sites by following them. We also recorded defecation microsites of non-radio-tagged binturongs at their feeding and sleeping sites.…”

“…We estimated the seed dispersal kernels [39] per study animal by combining the distance of animals from the origin at each hour and seed deposition time. The moving distance of animals at each hour was based on direct following of binturongs by radio-tracking (see [29]) and gibbons (S1 Table) in the study areas. Because of the small number of successful followings of helmeted hornbills from the feeding to defecation sites, we used hourly movement data of a similarly sized hornbill, great hornbill Buceros bicornis , in a mosaic of seasonally evergreen forest and grassland in Thailand (S1 Table) [40].…”