Biodiversity Data Journal :
Research Article
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Corresponding author: Abd Rahman Mohd-Ridwan (armridwan@unimas.my)
Academic editor: Chelmala Srinivasulu
Received: 29 Mar 2024 | Accepted: 15 Jun 2024 | Published: 24 Jun 2024
© 2024 Tukiman Nur-Aizatul, Abd Rahman Mohd-Ridwan, Mohammad Noor-Faezah, Roberta Chaya Tawie Tingga, Mohamad Fhaizal Bukhori, Jayasilan Mohd-Azlan, Azroie Denel, Muhammad Abu Bakar Abdul-Latiff, Badrul Munir Md-Zain
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Nur-Aizatul T, Mohd-Ridwan AR, Noor-Faezah M, Tingga RCT, Bukhori MF, Mohd-Azlan J, Denel A, Abdul-Latiff MAB, Md-Zain BM (2024) Preliminary assessment of group composition and activity pattern of the critically endangered Bornean Banded Langur Presbytis chrysomelas chrysomelas in Tanjung Datu National Park. Biodiversity Data Journal 12: e124196. https://doi.org/10.3897/BDJ.12.e124196
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The Bornean banded langur (Presbytis chrysomelas chrysomelas) is critically endangered species primarily found in Sarawak, Malaysia. Albeit this species is in peril, the ecology knowledge of this endemic species of Borneo is still scarce. Thus, a rapid survey employing total count and scan sampling method was conducted between July to August 2023 at Tanjung Datu National Park (TDNP), Sarawak to observe the social interaction of species with the environment. The behaviour of langur was recorded by employing scanning sampling method at 10 minutes intervals. This study sought to provide preliminary data on behavioural ecology of the Bornean banded langur within the national park. During the survey, three groups (consisting two to seven individuals) and a solitary male Bornean banded langur were recorded. The langurs were observed in both dipterocarp forests and coastal forests within the park. The daily activities of the Bornean banded langurs in TDNP were predominantly resting (31%), moving (29%), feeding (26%), vocalizing (14%), but not engaging in other social activities such as grooming, playing and mating. Knowing the behavioural ecological status as well as understanding ecology by identifying the activity pattern of langur is essential to government authorities and pertinent stakeholders to implement conservation strategies for the Bornean banded langur and their habitats.
Colobine, threatened species, behaviour, conservation
Tanjung Datu National Park (TDNP), located in Sarawak, Malaysia, is one of the smallest national parks in the region, covering an area of 1379 hectares. Despite its size, it serves as a prime habitat to five diurnal primate species namely long-tailed macaque (Macaca fascicularis Raffles, 1821), pig-tailed macaque (Macaca nemestrina Linnaeus, 1766), silver leaf monkey (Trachypithecus cristatus Raffles, 1821), Abbott gibbon (Hylobates abbotti Kloss, 1929) and the most threatened species, the Bornean banded langur (Presbytis chrysomelas Müller, 1838) (
Nevertheless, in recent years, P. c. chrysomelas is restricted in its range to five specific areas in Sarawak, namely Tanjung Datu National Park (TDNP), Samunsam Wildlife Sanctuary (SWS), Maludam National Park (MNP), Similajau National Park (SNP), and Pueh National Park (PNP) (
Bornean banded langur groups are often found in three to seven individuals, with one male, multi females and their offsprings. The species is known to eat 25% to 65% of fruits and leaves (
In comparison with other Presbytis species, the information on the ecology of P. c. chrysomelas is limited and inconclusive with the research on ranging behaviour conducted by
Despite the reported decline in the population of P. c. chrysomelas (
This study was conducted at Tanjung Datu National Park (TDNP), Lundu, Sarawak, Malaysia (
Four surveys were conducted at TDNP between July and August 2023 to record the population size and behaviour activities of Bornean banded langur. Surveys were done around the park’s headquarters and three main trails namely, Belian Trail, Telok Melano Trail and Pasir Antu Laut Trail. Data collection, including population census and behaviour surveys were conducted twice per day; 6.30 am to 10.00 a.m. and 12.00 noon to 6.30 p.m. These periods were chosen based on previous reports of the active and foraging time for the silvered langur (
Behaviour | Description |
Moving |
Walking, jumping, leaping or climbing |
Resting |
Inactive, sleeping, sitting, or lying |
Feeding |
Foraging, manipulating, and ingesting the food materials |
Vocalization |
Emit sound, or long calling. |
Others |
Grooming, playing, mating, and aggression |
Overall, three groups and one solitary of Bornean banded langur were recorded with a total of 17 encounters during the survey (Fig.
Category |
Group 1 |
Group 2 |
Group 3 |
Solitary |
Percent Composition |
Adult Male |
1 |
1 |
1 |
1 |
31% |
Adult Female |
3 |
1 |
1 |
38% |
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Sub-adult |
2 |
15% |
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Juvenile |
1 |
8% |
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Infant |
1 |
8% |
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Total |
7 |
3 |
2 |
1 |
13 (100%) |
The study spanned a total of 147 sampling hours. Three peaks of langur activities were observed in mid-morning 8 a.m. to 9 a.m., afternoon between 3 p.m. to 4 p.m. and early evening between 5 p.m. to 6 p.m. (Fig.
The composition of langur groups in TDNP varies, with group sizes ranging from one to seven individuals. Notably, this range roughly corresponds to the general trend reported among Bornean banded langurs, where group sizes typically vary from three to seven individuals per group (
The activity pattern of the Bornean banded langur indicates that a significant portion of their daily activities is allocated to resting. This finding aligns with similar observations made in other colobine species, including Banded langur (P. femoralis) (
Comparatively, the Bornean banded langur spend more time feeding (26%) than other closely related species such as P. femoralis, which allocate 21% of their time to feeding (
The percentage of moving activity was comparable both in the morning and evening, as langurs persistently engaged in movement until they have selected the ideal feeding trees required by the group (
Vocalization took up 14% of the day in this study compared to only 1.73% and 4% in P. femoralis (
Compared to other studies (
Data on primate ecology, particularly P. c. chrysomelas in TDNP is objectively essential for the park management unit to provide information on interspecific interaction among arboreal primates and engage in habitat conservation activities. These activities may include planting food plant species for enrichment and implementing visitor control measures. Obtaining data on P. c. chrysomelas population via monitoring the population growth and trend is needed to ensure the long-term survival of P. c. chrysomelas in TDNP. Study on behavioural ecology, notably activity budget analysis, is also of utmost importance for comprehending how primates utilise their environments, allocate resources, and respond to environmental changes (
The current population of the Bornean banded langur in TDNP is lower than the population recorded 20 years ago. Albeit an alarmingly low number, it is positive to note its existence in the park. This data establishes a baseline information for the observed group of P. c. chrysomelas in the park. The activity pattern of the species was divided into two parts; morning (A.M.) that was dominated by feeding activity (19%) and afternoon (P.M.) dominated by resting activity. Generally, langur allocated most of their time in resting, followed by moving, feeding and vocalization consistent with previous studies. The Bornean banded langur were found in both mixed-dipterocarp forest and beach forest. Their diet preference mostly consisted of leaves and fruits such as Resak Laru (Vatica pauciflora), Mengkudu Besar (Morinda citrifolia) and Kerueh (Lophopetalum pallidum). Knowing the population status as well as understanding ecology by identifying the activity pattern, feeding and habitat preferences of langur is essential to the government authorities and pertinent stakeholders to effectively execute conservation plans for the Bornean banded langur and its habitat. Furthermore, the present data serve as evident of importance of conserving TDNP as the prime habitat ensure survival of the critically endangered P. c. chrysomelas in Sarawak.
The authors express gratitude to the Sarawak Forestry Corporation for granting the research permit (SFC.810-4/6/1 (2023)–025) and to the TDNP staff for their assistance during the study. Appreciation is extended to Universiti Malaysia Sarawak for providing essential support. This study was funded by Ministry of Higher Education Malaysia through the Fundamental Research Grant Scheme (Grant Number: FRGS/1/2022/WAB11/UNIMAS/03/5). The authors also acknowledge The National Conservation Trust Fund for Natural Resources (NCTF), ST-2022-027, funded by the Ministry of Natural Resources and Environmental Sustainability, Malaysia.
Fundamental Research Grant Scheme (FRGS), The National Conservation Trust Fund for Natural Resources (NCTF)
FRGS/1/2022/WAB11/UNIMAS/03/5, NCTF ST-2022-027
Universiti Malaysia Sarawak, Universiti Kebangsaan Malaysia
The study was conducted in accordance with the legal standards of Malaysia and was approved by Sarawak Forestry Corporation (SFC) under research permit SFC.810-4/6/1(2023)–025.
TNA, ARMR,TRCT,MNF wrote the manuscript and conducted field sampling; TNA, ARMR conducted all the data analyses; JMA,MFB,ARMR,AD,MABAL,BMMZ critically revised the intellectual content; All authors read and approved the final version of the manuscript.