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

Colobine forestomach anatomy and diet

The study supports the notion that a large gut capacity is an important characteristic by which herbivores survive on a high fibre diet, and that this large gut capacity may not be necessary for some species if there are seasonal peaks in fruit availability. The research collates literature on diet and compares tripartite and quadripartite species, focusing on Colobine monkeys and the praesaccus chamber where a commensal microbiome digests plant cell walls and possibly detoxifies defensive plant chemicals. Colobine monkeys are known for the anatomical complexity of their stomachs, making them distinct within the primate order.Japan Science and Technology Agency Core Research for Evolutional Science and Technolog

The diet and feeding behavior of the black-and-white colobus (Colobus guereza) in the Kalinzu Forest, Uganda

One of the goals for primate feeding ecology is to understand the factors that affect inter- and intra-specific variations. Therefore, a detailed description of basic feeding ecology in as many populations as possible is necessary and warrants further understanding. The black-and-white colobus (Colobus guereza) or guereza is widely distributed in Africa and is one of the well-studied colobines in terms of their feeding; they demonstrate considerable variation in their diets in response to local conditions. We studied the diet of a group of guerezas in the Kalinzu Forest, Uganda, for over 30 consecutive months using behavioral observation (4308 h in total), phenology, and vegetation surveys. A total of 31 plant species were consumed by the study group. This study group was predominantly folivorous; the majority of their feeding time was involved in feeding on young leaves (87%). However, during certain times of the year, fruits and seeds accounted for 45% of monthly feeding time. Young leaves of Celtis durandii were by far the most important food, which constituted 58% of the total feeding records. There was a significant increase in the consumption of fruits and flowers once young leaf availability was low, but their consumption of fruits did not significantly increase even when fruit availability was high. Their monthly dietary diversity increased as the number of available plants with young leaves declined, suggesting that much of the dietary diversity in the study group may be attributable to the young leaf portion of their diet. Our findings may help contribute to a better understanding of the dietary adaptations and feeding ecology of guerezas in response to local environmental conditions

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

Primate survey in a Bornean flooded forest: evaluation of best approach and best timing

Accurate determination of the abundance and distribution of animals, particularly endangered species, is a fundamental requirement for understanding their ecology and has important applications for their conservation. In Bornean flooded forests, various approaches have previously been used to conduct primate census, including foot-based land surveys and boat-based river surveys at different times of the day such as in the early morning and/or late afternoon. However, the accuracy of primate encounter frequencies and animal counts obtained using these methods has not been assessed. Therefore, in this study, we attempted to assess the accuracy of these methods used in different studies. We found that boat-based river surveys were more accurate than foot-based land surveys for evaluating the abundance and distribution of Bornean primates, particularly proboscis monkeys (Nasalis larvatus) and long-tailed macaques (Macaca fascicularis). Furthermore, based on our evaluation of boat-based river surveys at different times of the day, we recommend that such surveys be performed in the late afternoon to yield more accurate estimates of the abundances and distributions of Bornean primates

Primate survey in a Bornean flooded forest: evaluation of best approach and best timing

Accurate determination of the abundance and distribution of animals, particularly endangered species, is a fundamental requirement for understanding their ecology and has important applications for their conservation. In Bornean flooded forests, various approaches have previously been used to conduct primate census, including foot-based land surveys and boat-based river surveys at different times of the day such as in the early morning and/or late afternoon. However, the accuracy of primate encounter frequencies and animal counts obtained using these methods has not been assessed. Therefore, in this study, we attempted to assess the accuracy of these methods used in different studies. We found that boat-based river surveys were more accurate than foot-based land surveys for evaluating the abundance and distribution of Bornean primates, particularly proboscis monkeys (Nasalis larvatus) and long-tailed macaques (Macaca fascicularis). Furthermore, based on our evaluation of boat-based river surveys at different times of the day, we recommend that such surveys be performed in the late afternoon to yield more accurate estimates of the abundances and distributions of Bornean primates

The distribution and abundance of long-tailed macaques in the main campus of Universiti Malaysia Sabah and its vicinity

Long-tailed macaques (Macaca fascicularis) inhabit a wide range of natural and human-modified environments in Southeast Asia. Because of their ability to occupy the same space and utilise the same food resources as humans, long-tailed macaques have in some cases been regarded as nuisance and pest. As part of an effort to assess the status of human-macaque interactions in the main campus of Universiti Malaysia Sabah (UMS), we conducted a survey to determine the distribution range and estimate the abundance of the macaque population. We performed the survey monthly from April 2019 to March 2020 at 13 localities classified into three different habitat types i.e. secondary forest, forest edge and urban areas identified in the campus and its vicinity. The survey covered an overall area of 6.02 km2 . We recorded the group or individual locations and the number of macaques with each individual's age/sex information whenever possible. The macaques consisted of three different multimale-multifemale groups and a solitary individual. We recorded a minimum population size of 54 macaque individuals with an average group size of 17.7 individuals and a population density of 8.97 individuals/km2 in the surveyed areas. Macaques were encountered every month and in all habitat types defined in this study. However, they were mainly distributed at two habitat types i.e. urban areas and forest edges near Bukit UMS and the student residential colleges where anthropogenic influence appeared to be high. We speculate that the monthly availability of food resources, including anthropogenic food waste, may partly explain this distribution pattern. We suggest that further studies is conducted in this regard

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

Primate population dynamics : variation in abundance over space and time

The paper presents longitudinal data documenting changes in primate abundance over 45 years at eight sites in Kibale National Park, Uganda. Findings present a positive conservation message and indicate that the Uganda Wildlife Authority is being effective in managing its biodiversity. However, monitoring of deforestation and continued monitoring and modification of conservation plans are essential. The rapid disappearance of tropical forests, potential impacts of climate change, and increasing threats to wildlife such as bushmeat hunting, make it imperative to understand wildlife population dynamics. With long-lived animals this requires extensive, long-term data, but such data is often lacking.Canada Research Chairs ProgramNatural Science and Engineering Research Council of CanadaFonds Québécois de la Recherché sur la Nature et les TechnologiesNational Geographic Societ