Population of Proboscis Monkey (Nasalis lavatus) in Manggar River, Balikpapan City, Indonesia

A population estimation of proboscis monkeys (Nasalis larvatus) has been conducted in Manggar River, Balikpapan. In this non-conservation area, the anthropogenic activities threaten the proboscis monkey habitat. Boat survey technique was applied along ± 17 km of the river in the morning and evening. The number of proboscis monkeys in the surveyed area was estimated to range from 57 to 69 individuals with estimated population density of 4.75 individuals/Km2. Moreover, the population of this primates was divided into 4 groups and the sex ratio between adult males and females was 1:2.33. The proboscis monkeys were distributed in the middle of the river to the upstream. The highest population was found in the upstream area with less human activities. Conservation efforts in the Manggar River need to be carried out considering the proboscis monkey habitat in the area has been fragmented and isolated. These efforts could involve local economic communities.

SEBARAN POHON PAKAN DI HABITAT BEKANTAN (Nasalis larvatus Wurmb.) DI HUTAN RIPARIAN AREAL PERTAMBANGAN PT JORONG BARUTAMA GRESTON

The variety of proboscis monkey habitat causes the composition of plants, the preparation of different habitats, including the type of feed and its composition. The aim of this research is to map the distribution of proboscis monkeys and inventory the proboscis monkeys. Retrieval of vegetation data is placed in an area where frequent activity of proboscis monkeys occurs. Data collection was carried out to determine tree species and undergrowth as macro habitat as well as the potential source of proboscis food that includes the leaves, buds, flowers, fruit or parts that are being eaten or already eaten. Sampling of feed tree sampling data using accidental sampling method is a method of recording accidentally or accidentally when finding proboscis probes that are eating or traces of food. The coordinates of the meeting point with the proboscis feed tree are made into the distribution map of the proboscis feed tree using GIS software. There are 9 distribution locations and 13 species of plants whose parts are eaten by proboscis monkeys in the Riparian forest of PT JBG areas such as Ficus racemosa, Hibiscus tiliaceus, Gluta renghas, Albizia chinensis, Eugenia sp, Uncaria sp, Dillenia indica, Oxyceros longifer, Syzigium sp, Calamus sp, Macaranga bancana, Premna corymbusa, Centrosema pubescens. These types are divided into two levels of vegetation, namely forage trees and undergrowth with edible parts such as shoots, leaves, flowers, fruit and umbut Habitat bekantan yang bervariasi menyebabkan komposisi jenis tumbuhan penyusunan habitat berbeda-beda, termasuk jenis pakan dan komposisinya. Penelitian ini bertujuan untuk melakukan pemetaan sebaran pohon pakan bekantan dan menginventarisasi jenis pohon pakan bekantan. Pengambilan data vegetasi diletakkan pada areal yang sering terjadi aktivitas bekantan. Pengambilan data dilakukan untuk menentukan jenis pohon dan tumbuhan bawah sebagai habitat makro serta potensi sumber pakan bekantan yang meliputi bagian daun, pucuk, bunga, buah atau bagian yang sedang dimakan atau sudah dimakan. Pengambilan data sampling pohon pakan menggunakan metode accidental sampling yaitu metode pencatatan secara kebetulan atau tidak sengaja saat menemukan bekantan yang sedang makan atau jejak bekas makanan.pada lokasi tempat ditemukannya pohon pakan atau bekas makanan bekantan lalu ditandai titik koordinatnya menggunakan GPS. Koordinat titik pertemuan dengan pohon pakan bekantan dibuat menjadi peta sebaran pohon pakan bekantan dengan menggunakan software GIS. Terdapat 9 titik lokasi persebaran dan 13 jenis tumbuhan yang bagian-bagiannya dimakan oleh bekantan di hutan Riparian areal PT JBG seperti jenis Ficus racemosa, Hibiscus tiliaceus, Gluta renghas, Albizia chinensis, Eugenia sp, Uncaria sp, Dillenia indica, Oxyceros longifer, Syzigium sp, Calamus sp, Macaranga bancana, Premna corymbus, Centrosema pubescens. Jenis-jenis ini terbagi menjadi dua tingkatan vegetasi yaitu pohon pakan dan tumbuhan bawah dengan bagian yang dimakan seperti pucuk, daun, bunga, buah dan umbut.

STASIUN RISET BEKANTAN PADA LAHAN BASAH

Wetlands are a natural habitat for endemic animals of South Kalimantan, namely proboscis monkeys (Nasalis larvatus). These primates are one indicator in wetlands conservation, but now the status of proboscis monkeys is endangered which means wetlands are naturally also damaged. This makes The Indonesian Proboscis Monkey Friends Foundation worried about the preservation of these primates who are endangered in a side the number of foreign researchers who are interested in proboscis monkeys so it also weakens status proboscis monkeys as endemic animals.The Indonesian Proboscis Monkey Friends Foundation wants the proboscis monkey in South Kalimantan to become an identity in the area along with the wetland ecosystem which is the habitat of proboscis monkeys. Therefore a fundamental problem with the design of the Proboscis Monkey Research Station on Wetlands is how the design of the proboscis research station on wetlands is in harmony with natural conditions around it so that it can become the identity of the region. Settlement the problem was solved through the metabolism-organic method and the visual identity-metaphor method. The metabolism-organic method is the solution to the problem of harmony building with nature, while the visual identity-metaphor method is the solution in the matter of regional identity. Based on the two methods, the concept proposed for this design is the concept of "subject-object interaction" which is realized through the concept of "wetland ecology". This concept of "subject-object interaction and wetland ecology" is a concept that elevates interactions between researchers and wetland organisms such as proboscis monkeys by entering the wetland elements into the design of this research station.

The Conservation of Proboscis Monkey in Suwi River, East Kalimantan, Indonesia

Suwi River, which is a part of Kenohan-Suwi Wetland in East Kutai District, East Kalimantan is a habitat of endangered animals such as proboscis monkey (Nasalis larvatus). Therefore, this study aims to determine the habitat, distribution, threats, and conservation efforts of proboscis monkeys in the Suwi River. To achieve this, the boat survey method was adopted, while plot line samples were used for vegetation analysis. The results showed that the habitat is composed of riverine plant species, such as prupuk (Mallotus sumatranus; IV=121.84%), bungur (Lagerstroemia speciosa; IV=37.10%), and rengas (Gluta renghas; IV=34.76%). Furthermore, a minimum of 12 monkey groups was distributed in this area, however, their population is unknown. Illegal hunting by local people has caused population decline, this is in addition to other threats, such as habitat conversion, forest fire, and invasive plant species. The effort to protect the habitat of proboscis monkeys was made by developing Essential Ecosystem Areas Suwi-Mesangat. Other institutions that committed to protecting this area include Federal and local government, NGO, local community, and palm oil company

Factors influencing 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 benefits that each species receive from the aquatic environment are thought to vary depending on their social and ecological characteristics, and thus, elucidating those benefits 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 affecting riverine habitat utilization of two macaque species (Macaca nemestrina and M. fascicularis) were identified and qualitative comparisons were made with sympatric proboscis monkeys (Nasalis larvatus), which have different 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 affects the extent of predation pressure. Riverine utilization of macaques was greatly influenced 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 different anti-predator strategies resulting from their differing social structures.

Large male proboscis monkeys have larger noses but smaller canines

The uniquely enlarged noses of male proboscis monkeys are prominent adornments, and a sexually selected male trait. A recent study showed significant correlations among nose, body, and testis sizes and clear associations between nose size and the number of females in a male’s harem. However, to date, the analyses of other common male traits, i.e., canines, are lacking. Whereas male nose size had a positive correlation with body size, we unexpectedly found a negative correlation between body and canine sizes. We explain this by an interaction between sexual and natural selection. Larger noses in males may interfere with the use of canines, thereby reducing their effectiveness as weapons. Additionally, longer canines are opposed by natural selection because the larger gape it imposes upon its bearer reduces foraging efficiency, particularly in folivores. This unique case of decoupling of body and canine size reveals that large canines carry an ecological cost.

Factors influencing 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 benefits that each species receive from the aquatic environment are thought to vary depending on their social and ecological characteristics, and thus, elucidating those benefits 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 affecting riverine habitat utilization of two macaque species (Macaca nemestrina and M. fascicularis) were identified and qualitative comparisons were made with sympatric proboscis monkeys (Nasalis larvatus), which have different 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 affects the extent of predation pressure. Riverine utilization of macaques was greatly influenced 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 different anti-predator strategies resulting from their differing social structures.

First description of male worms of Enterobius (Colobenterobius) serratus (Nematoda: Oxyuridae), the pinworm parasite of proboscis monkeys

Males of Enterobius (Colobenterobius) serratus Hasegawa et al., 2003 (Nematoda: Oxyuridae) are described for the first time based on six individuals collected from the feces of proboscis monkeys, Nasalis larvatus, in the Lower Kinabatangan Wildlife Sanctuary, Sabah, Malaysian Borneo. The males show identical cephalic morphology to females, being readily distinguishable from their congeners by the serrated inner margins of the lips. The bicolored esophageal corpus, long thin spicule and developed spicular pouch with paired muscular bands are also remarkable characteristics, presumably shared by other Asian members of the subgenus.