Seasonally consistent small home range and long ranging distance in Presbytis rubicunda in Danum Valley, Borneo

Seasonal fluctuation in food availability is a universal problem for wild animals. One common response to dietary changes is to modify ranging patterns. We studied the ranging pattern of one group (8–12 individuals) of red leaf monkeys (Presbytis rubicunda) in the lowland dipterocarp forest of Danum Valley, Borneo from December 2006 to December 2008. The seasonal availability of fruits varies significantly in this forest because of mast fruiting. We tested the hypothesis that changes in ranging pattern are linked with seasonal changes in diet in this species. We recorded activity, foods eaten, and location every 10 min from around 06:00 until 16:00 h, 5–10 days/mo. The home range size was 21.4 ha over the 25-mo study (95% kernel contour). There were no statistically significant relationships between feeding times on the four major nonexclusive dietary components (all species of seeds, all species of young leaves, young leaves of Spatholobus macropterus, and other species of young leaves) and either the home range (95% kernel contour) or the core area (50% kernel contour). The areas used in the seed-eating and non-seed-eating seasons overlapped to a large extent. The daily path length was 1160 ± 340 m (mean ± SD, range: 550–2140 m). Neither daily path length nor monthly mean travel rate was significantly related to feeding time on any of the four major dietary components. The group’s ranging patterns may be related to the unusual fallback strategy of this population, which depends on the young leaves of an abundant liana (S. macropterus), which are available in small patches. The monkeys need only a small home range because of the high abundanceof these leaves. However, they range a relatively long distance because the patches of S. macropterus are easily depleted; thus the ranging distance does not decrease in nonseed-eating periods

Annual periodicity of fruiting in temperate forests in Yakushima, Japan

Fruiting phenology, assessed by seed fall, in five warm- and cool-temperate forests on Yakushima Island, southern Japan, was studied for two years in one 50 m × 50 m plot and for four years in four 100 m × 50 m plots. The elevation of the plots ranged between 170 and 1200 m a.s.l. Seed fall phenology showed annual periodicity in all five plots. This was clear when assessed by the number of species but became less clear when assessed by the biomass of seed litter. Community-level annual periodicity was based on the prevalence of population-level annual periodicity and interspecific synchronization of the fruiting peak from autumn to winter. Fleshy fruits had peaks of seed fall in a wider range of months than non-fleshy fruits, since it is sometimes beneficial to bear fruit outside the community-level fruiting peaks in order to avoid interspecific competition for animal seed dispersers. No consistent effect of climatic factors on seed fall phenology was detected

Interspecific Encounters Among Diurnal Primates in Danum Valley, Borneo

Polyspecific associations, in which individuals of multiple species move together, have not been reported in Asian primates. However, only one study in India has shown this lack of association quantitatively. We collected data on interspecific encounters among 5 species of diurnal primates in Danum Valley by censusing 4 predetermined routes of 9.9 km, covering 1544.3 km, and tracking red leaf monkeys (Presbytis rubicunda) for 423 h over 25 mo. We tested the null hypothesis that the frequency and duration of encounters did not differ from chance levels. During censuses, we detected primates 373 times and found 2 species on the same 100-m segment only 6 times. This frequency was not significantly different from the chance level. While following red leaf monkeys, the frequency of encounters was lower than expected by chance with Müeller’s gibbons (Hylobates muelleri) but higher than expected by chance with Bornean orangutans (Pongo pygmaeus) in the nonfruiting season. Interspecific encounters accounted for 6.4% of tracking time, and the encounter duration was significantly longer than expected by chance for orangutans. Red leaf monkeys did not change their rate or direction of travel on meeting another species. We could not distinguish the association between red leaf monkeys and orangutans in the nonfruiting season from the possibility that the two species were independently attracted to the same place. In conclusion, we show the absence of active and consistent polyspecific association and identify avoidance in some species pairs in an Asian primate community

Effects of river width on sleeping-site selection by proboscis monkeys (Nasalis larvatus) in Sabah, Malaysia

Previous studies have suggested that Proboscis monkeys sleep in trees located by riverbanks and cross rivers at their narrower points effectively avoid land-based and aquatic-based predators

Habitat use by a primate community in a lowland dipterocarp forest in Danum Valley, Borneo

Knowledge of niche partitioning with respect to habitat is indispensable to understand the mechanism of coexistence of multiple species. Among primates, however, data are still deficient because repeated survey for a sufficiently long time, covering seasonal changes over a large area, is the only way to clarify habitat segregation within a seasonally fluctuating environment. Southeast Asia is particularly interesting because of the supra‐annual, highly unpredictable seasonality in fruiting known as mast fruiting. We conducted repeated route census, habitat monitoring, and group tracking for 25 months in two study sites (ca. 10 km apart) in the largely primary lowland dipterocarp forest of the Danum Valley Conservation Area, eastern Sabah, northern Borneo, Malaysia. The five species of diurnal primates (Bornean orangutan Pongo pygmaeus , Müeller's gibbon Hylobates muelleri , red leaf monkey Presbytis rubicunda , long‐tailed macaque Macaca fascicularis , and southern pig‐tailed macaque M. nemestrina ) did not show horizontal spatial segregation. Red leaf monkeys showed preferences for places with short tree height, but their distribution was not confined to such places. In response to the fruiting peak observed once during the study period, orangutans increased their numbers simultaneously in the two study sites. The average tree height used by the five species was different, but their range overlapped substantially. Compared with other primate communities, the lack of horizontal spatial segregation and the suggested long‐distance movement of orangutans seem to be unique characteristics in Borneo, although the use of different forest strata is a widespread phenomenon among primate communities throughout the world

Species richness and distribution of primates in disturbed and converted forest landscapes in northern Borneo

Knowledge of fundamental aspects of ecology such as species richness and distribution, and the factors affecting them, is increasingly used to identify priority areas for conservation and to effectively manage threatened species. We investigated the species richness and distribution pattern of non-human primate communities inhabiting 10 sampling sites in four different habitat classes corresponding to increasing habitat disturbance level, i.e. old growth forest, twice logged forest, repeatedly logged forest and oil palm plantation, in and around Kalabakan Forest Reserve, in central Sabah, Malaysian Borneo. By using direct and indirect survey methods, we confirmed the existence of nine, out of the total 10 primate species, found in Sabah, within the surveyed areas. Based on the monthly number of primate species detected, our results indicated a general trend of decreasing primate species richness with increasing habitat disturbance level. However, the response within the disturbed forest sites showed some variations with some sites in repeatedly logged forest displaying comparable primate species number to that of the undisturbed forest sites. We also found that within the forest habitats, tree density is a good predictor of the richness of the primate community with a positive effect. Hence, tree density may be a key indicator for evaluating primate communities in forest habitats. Overall, the results of our study suggest that although not equivalent to areas of undisturbed forest, degraded forests – including those that have been repeatedly logged – are still valuable for primate conservation. In contrast, oil palm plantations have mainly negative effects on the primate community

Factors infuencing riverine utilization patterns in two sympatric macaques

Many species of terrestrial animals, including primates, live in varied association with the aquatic (e.g., riverine or coastal) environment. However, the benefts that each species receive from the aquatic environment are thought to vary depending on their social and ecological characteristics, and thus, elucidating those benefts to each species is important for understanding the principles of wild animal behaviour. In the present study, to gain a more complete picture of aquatic environment use, including social and ecological factors in primates, factors afecting riverine habitat utilization of two macaque species (Macaca nemestrina and M. fascicularis) were identifed and qualitative comparisons were made with sympatric proboscis monkeys (Nasalis larvatus), which have diferent social and ecological characteristics. Temporal variation in sighting frequency of macaques at the riverbanks was positively related to the fruit availability of a dominant riparian plant species and negatively related to the river water level which afects the extent of predation pressure. Riverine utilization of macaques was greatly infuenced by distribution and abundance of food (especially fruit) resources, possibly in association with predation pressure. Additionally, qualitative ecological comparisons with sympatric proboscis monkeys suggest that the drivers of riverine utilization depend on the feeding niches of the species, and diferent anti-predator strategies resulting from their difering social structures

The distribution and persistence of primate species in disturbed and converted forest landscapes in Sabah, Malaysia: preliminary results

As disturbance and conversion of tropical rainforests due to man-made activities in many parts of the world continue at alarming rates, the future of many tropical rainforest species will depend more than ever on the effective management of a mixture of human-modified landscape. We studied the non-human primate community by direct and indirect sightings across a gradient of habitat disturbance - from old growth forest to heavily logged forest to oil palm plantation- in and around the Stability of Altered Forest Ecosystems (SAFE) Project experimental area in Kalabakan Forest Reserve, south central part of Sabah, Malaysian Borneo. Here we provide the preliminary analysis of our data. We confirmed the existence of nine, of the total of 10 species of non-human primates found in Sabah, within the surveyed areas. By using occupancy analysis we found no evidence of differential habitat disturbance effects on the primate community. We also found no evidence supporting differential habitat disturbance effects on the primate community based on animal body size or feeding habit. The lack in such evidences is surprising and it is likely due to the artifact of the small data set of this study. Interestingly, however, the presence of eight species of primates within the heavily logged forest sampling sites, which included Bornean endemic species and species of high conservation concern, e.g. orangutan, proboscis monkey and Bornean gibbon, shows that even highly disturbed forests in Sabah are still valuable for primate conservation

Stomach and colonic microbiome of wild Japanese macaques

Within the gastrointestinal tract, the physiochemical microenvironments are highly diversified among the different stages of food digestion. Accordingly, gut microbiome composition and function vary at different gut sites. In this study, we examine and compare the compositional and functional potential between the stomach and colonic microbiome of wild Japanese macaques (Macaca fuscata yakui) living in the evergreen forest of Yakushima Island. We find a significantly lower microbial diversity in the stomach than in the colon, possibly due to the stomach's acidic and aerobic environment, which is suboptimal for microbial survival. According to past studies, the microbial taxa enriched in the stomach are aero- and acid-tolerant. By functional prediction through PICRUSt2, we reveal that the stomach microbiome is more enriched in pathways relating to the metabolism of simple sugars. On the contrary, the colonic microbiota is more enriched with fiber-degrading microbes, such as those from Lachnospiracea, Ruminococcaceae, and Prevotella. Our study shows a clear difference in the microbiome between the stomach and colon of Japanese macaques in both composition and function. This study provides a preliminary look at the alpha diversity and taxonomic composition within the stomach microbiome of Japanese macaques, a hindgut-fermenting nonhuman primate