Population Estimation of Proboscis Monkey (Nasalis larvatus) in Sarawak, Malaysia

• Main Author: Ahmad Fitri, Aziz
• Format: Thesis
• Language: English; English
• Published: Universiti Malaysia Sarawak, (UNIMAS) 2019
• Subjects: QL Zoology
• Online Access: http://ir.unimas.my/id/eprint/35083/1/Population%20Estimation%20of%20Proboscis%20Monkey%20-%2024%20pgs.pdf; http://ir.unimas.my/id/eprint/35083/4/Ahmad%20Fitri%20bin%20Aziz%20ft.pdf; http://ir.unimas.my/id/eprint/35083/

A central practical problem in ecology is the estimation of population size. Last published report on the state-wide survey and population estimation of proboscis monkey (Nasalis larvatus) in Sarawak was in 1987. In this study, survey on proboscis monkey population has been conducted at eight selected sites in Sarawak to update...;the estimation of population size and density of this species. This study have successfully estimated the overall population based on the forest types surveyed which had not been taken into account in any previous studies of proboscis monkey before. Boat survey technique was applied in all survey sites except in Bako National Park within a period of 17 months, starting from April 2015 until August 2016. A cumulative total of 618.6 km of riverbank and 24.14 km of line transect was surveyed. Out of eight surveyed sites, two sites show no presence of proboscis monkey which were Ulu Sebuyau National Park and Rajang Mangrove National Park. A cumulative total of 860 individuals of proboscis monkey comprising of 105 groups was sighted from all surveyed sites. Three types of forests were identified from the eight surveyed sites where the proboscis monkeys were recorded which were mangrove forest, peat swamp forest and tropical heath forest with a sighted distribution of 527, 170 and 163 individuals, respectively. The total population estimation of proboscis monkey in all surveyed sites is 838 individuals. Maludam National, Park recorded the highest population estimation with 432 individuals. This was followed by Bako National Park, Samunsam Wildlife Sanctuary, Kuching Wetland National Park, Kuala Lawas Forest Reserve and Limbang Mangrove National Park with estimated population size of 105, 98, 82, 77 and 44 individuals, respectively. The overall population estimation of proboscis monkey in Sarawak based on the data from three types of forests surveyed was 9,778 individuals. In mangrove forest, the population of proboscis monkey was estimated to be 1,981 individuals with estimated population density of 1.25 individuals/km2 . In peat swamp forest, the population was estimated to be in the number of 6,174 individuals with estimated population density of 0.96 individuals/km2. While in tropical heath forest, the population was estimated to be 1,623 individuals with 2.76 individualslkm2 of estimated popUlation density. There was no sign~ficant difference .,"-. between the population density of proboscis monkeys and the forest types (F = 0.607, df = 2, P = 0.568). In addition, the popUlation sizes of proboscis monkeys in different forest types also did not show any significant difference (P = 0.353). A comparisons o! population estimates from different studies is complicate analyses. A standard method of analysis, in lieu of using forest types in the estimation is needed, so that the population estimates and the changes in the population size of the proboscis monkeys can be systematically compared and monitored in the future.