Virgin Jungle Reserves Research Articles

GC-MS Evaluation, Antioxidant Content, and Cytotoxic Activity of Propolis Extract from Peninsular Malaysian Stingless Bees, Tetrigona Apicalis.

Introduction Propolis has been used traditionally in several countries for treating various diseases as it possessed healing properties including antioxidant and anticancer qualities. In Peninsular Malaysia, Tetrigona apicalis is one of the species of stingless bees mainly found in virgin jungle reserves which largely contribute to propolis production. Therefore, this study is designed to evaluate the phytochemical contents, antioxidant properties, and the cytotoxic effect of ethanolic crude of propolis extract against MCF7 and MCF 10A cell lines. Method The ethanolic extract of propolis (EEP) was extracted using 80% ethanol. Identification of phytochemical contents and antioxidant properties of EEP was analysed by gas chromatography-mass spectrometry (GC-MS) and using 2, 2′-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) method, respectively. The EEP cytotoxic activity was evaluated on MCF7 and MCF 10A using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Results Phytochemical contents of EEP demonstrated 28 compounds in which caryophyllene (99%), β-amyrin (96%), α-amyrin (93%), and caryophyllene oxide (93%) were the main compounds. The percentage of ABTS+ scavenging activity of EEP showed an inhibition of 9.5% with half-inhibitory concentration (IC50) value of 1.68 mg/mL. The EEP reduced MCF7 cells viability at IC50 value of 62.24 μg/mL, 44.15 μg/mL, and 32.70 μg/mL at 24, 48, and 72 hours, respectively. The IC50 value of MCF 10A was 49.55 μg/mL, 56.05 μg/mL, and 72.10 μg/mL at 24, 48, and 72 hours, respectively. The EEP cytotoxic effect of T. apicalis was more selective towards MCF7 at 72-hour incubation with a selectivity index (SI) of 2.20. Conclusion The EEP has been shown to have antioxidants and potential bioactive compounds and inhibited proliferation of the MCF7 cells. Further studies on the EEP role in the apoptosis pathway and its screening towards other cell lines will be evaluated.

Mangrove Productivity Estimation using Modelling Approach and Tree Parameters Assessment

This study used productivity models and above ground biomass to investigate productivity in different sites of MMFR. Ninety Rhizophora apiculata leaf samples were collected from different compartments (18, 31, 71, 74, 42 and 55) based on tree age and management. For biomass calculation, tree height and diameter were measured in plot of 10m x 10m in compartment 18, 31, 71, 74 and 67. The age of the trees were as follows: compartment 18 and 31 with 15-year-old, compartment 71 and 74 with 25-year-old and compartment 67 with 30-year-old mangrove trees. Compartment 42 and 55 are classified as virgin jungle reserve (VJR). Compartment 67 was not taken as a sample site due to technical reason and compartments in VJR were not considered for biomass estimation. Sixteen variables; stable isotopes (δ13C, δ15N), macronutrients (C, N, P), cations (Ca, Mg, Na, K) and trace elements (Cd, Cu, Fe, Mn, Pb, Zn) were analyzed. Productivity models and calculated biomass for investigated compartments showed similar trends. In 15-year age group; compartment 18 showed higher productivity than in 31. For the 25-year age group; compartment 74 had higher productivity than 71. No prominent increase was observed in biomass between 15-year old and 30-year old trees. Furthermore, with moderate N and δ15N loading input, compartments showed more productivity. The results conclude that MMFR is a sustainably managed mangrove forest and its productivity could be monitored using nutrient productivity models.

Effects of different land-use on suspended sediment dynamics in Sabah (Malaysian Borneo) – a view at the event and annual timescales

Suspended sediment concentrations (SSC) and the duration of high SSC are important for river ecology and water resource conservation. Using annual and storm-event datasets, this paper explores the hypothesis that key suspended sediment variables increase along a land-use disturbance gradient in hilly terrain in Sabah (Malaysian Borneo). Five small (1.7–4.6 km2) catchments of increasing disturbance history – primary forest, old growth virgin jungle reserve, twice-logged forest, multiple-logged forest and mature oil palm – were instrumented from late 2011 with dataloggers and sensors to record river stage, turbidity and rainfall. The oil palm catchment had 4–12 times greater mean discharge-weighted SSC (587 mg L–1), annual sediment yield (1128 t km–2 y–1), median event peak SSC, and duration of SSC above 1000 mg L–1 than in the other catchments. The multiple-logged catchment (last logged around 2004) has SSC characteristics close to values for primary forest, possibly due to increased ground protection against erosion afforded by low understorey regrowth and/or depletion of erodible sediment by multiple logging episodes. Results demonstrate that in hilly terrain even heavily logged rainforest has high value in safeguarding water quality and reducing erosion, whereas oil palm requires careful land management, especially of road runoff and ground cover.

Diversity and Geographical Ranges of Insects in Crocker Range Forest Reserve, Sabah, Malaysia

An insect diversity survey was carried out in May, 2011 in the Crocker Range Forest Reserve. This is a Class VI Forest Reserve (Virgin Jungle Reserve), gazetted in 1967 and then regazetted in 1984. It comprises an area of 3,279 ha. The nocturnal insect diversity was very high, with an average of 148 insect species from 207 individuals in a square metre of the light-trapping cloth. The mean Shannon, Simpson and Fisher Alpha indices are H’ = 4.77 (>3.0), D = 322.49 and S = 417.04 respectively. Apart from having the highest diversity of nocturnal insects in all the 20 forest reserves surveyed within the Heart of Borneo area in Sabah, it has also recorded a number of endemic species. Some beetles are hyper-endemics, such as Cyclommatus chewi, Odontolabis schenki and Odontolabis katsurai (all Lucanidae beetles) which are found only in Mt. Alab of the Crocker Range F.R. At least 10 butterfly species are known to be confined to the Crocker Range, including the Kinabalu Tiger, Parantica crowleyi, which was sampled during the survey. A stick insect, Orthonecrosia felix, was recorded and it is only confined to the Crocker Range. New species are still being described. Such interesting scientific insect data from this survey and also from past records support the need to enhance biodiversity conservation in this Virgin Forest Reserve. In view of the high diversity and intriguing insect fauna, Crocker Range F.R. has potential in nature tourism for special interest tourists who contribute to Sabah’s economy. A private initiative, Kipandi Park set up adjacent to the forest reserve, not only showcases the diversity of insects in Sabah but is also doing its part in studying the life cycle of rare and endemic insects which contributes towards insect conservation. The park also cooperates with government agencies in promoting conservation of biodiversity. In this paper, some of the issues pertaining to insect diversity and conservation are discussed.

Vertical stratification of adult mosquitoes (Diptera: Culicidae) within a tropical rainforest in Sabah, Malaysia.

BackgroundMalaria cases caused by Plasmodium knowlesi, a simian parasite naturally found in long-tailed and pig-tailed macaques, are increasing rapidly in Sabah, Malaysia. One hypothesis is that this increase is associated with changes in land use. A study was carried out to identify the anopheline vectors present in different forest types and to observe the human landing behaviour of mosquitoes.MethodsMosquito collections were carried out using human landing catches at ground and canopy levels in the Tawau Division of Sabah. Collections were conducted along an anthropogenic disturbance gradient (primary forest, lightly logged virgin jungle reserve and salvage logged forest) between 18:00 and 22:00 h.ResultsAnopheles balabacensis, a vector of P. knowlesi, was the predominant species in all collection areas, accounting for 70 % of the total catch, with a peak landing time of 18:30–20:00 h. Anopheles balabacensis had a preference for landing on humans at ground level compared to the canopy (p < 0.0001). A greater abundance of mosquitoes were landing in the logged forest compared to the primary forest (p < 0.0001). There was no difference between mosquito abundance in the logged forest and lightly logged forest (p = 0.554). A higher evening temperature (p < 0.0001) and rainfall (p < 0.0001) significantly decreased mosquito abundance during collection nights.ConclusionsThis study demonstrates the potential ability of An. balabacensis to transmit P. knowlesi between canopy-dwelling simian hosts and ground-dwelling humans, and that forest disturbance increases the abundance of this disease vector. These results, in combination with regional patterns of land use change, may partly explain the rapid rise in P. knowlesi cases in Sabah. This study provides essential data on anthropophily for the principal vector of P. knowlesi which is important for the planning of vector control strategies.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-016-1416-1) contains supplementary material, which is available to authorized users.

Biodiversity of leaf-litter ants in fragmented tropical rainforests of Borneo: the value of publically and privately managed forest fragments

In view of the rapid rate of expansion of agriculture in tropical regions, attention has focused on the potential for privately-managed rainforest patches within agricultural land to contribute to biodiversity conservation. However, these sites generally differ in their history of forest disturbance and management compared with other forest fragments, and more information is required on the biodiversity value of these privately-managed sites, particularly in oil-palm dominated landscapes of SE Asia. Here we address this issue, using tropical leaf-litter ants in rainforest fragments surrounded by mature oil palm plantations in Sabah, Borneo as a model system. We compare the species richness and composition of ant assemblages in privately-managed forest fragments (‘high conservation value’ fragments; HCVs) with those in publically-managed fragments of forest (virgin jungle reserves; VJRs) and control sites in extensive tracts of primary forest. In this way, we test the hypothesis that privately-managed and publically-managed forest fragments differ in their species richness and composition as a result of differences in history and management and hence in habitat quality. In support of this hypothesis, we found that HCVs had much poorer habitat quality than VJRs, including lower sizes and densities of trees, less canopy cover, fewer dipterocarp trees and shallower leaf litter. Consequently, HCVs supported only half the species richness of ants in VJRs, which in turn supported 70 % of the species richness of control sites, with vegetation structure and composition explaining 77 % of the variation among forest fragments in ant species richness. HCVs were also much smaller than VJRs but there was only a weak relationship between fragment size and habitat quality, and species richness was not related to fragment size. VJRs supported 78 % of the 156 species found in extensive tracts of forest whereas HCVs supported only 22 %, which was only slightly higher than the proportion previously recorded in oil palm (19 %). These data support previous findings that publically-managed VJR fragments can make an important contribution to biodiversity conservation within agricultural landscapes. However, we suggest that for these HCVs to be effective as reservoirs of biodiversity, management is required to restore vegetation structure and habitat quality, for instance through enrichment planting with native tree species.

Using Habitat Characteristics to Predict Faunal Diversity in Tropical Production Forests

AbstractBiodiversity conservation in managed tropical forests is becoming increasingly important as forest area continues to decline. Accordingly, there is growing interest in developing conservation‐driven silvicultural prescriptions and identifying indicator habitat metrics (similar to indicator taxa) that could be easily assessed via routine vegetation sampling. Successfully achieving these goals, however, requires an understanding of how habitat characteristics affect biodiversity. The purpose of this study was to determine the associations between the species diversity of three taxa (ants, insectivorous bats, and dung beetles) and the habitat characteristics of hill dipterocarp production forests. We sampled both within (three samples) and adjacent to (six samples) six Virgin Jungle Reserves distributed throughout Peninsular Malaysia, and related habitat predictors to univariate diversity metrics (species richness and Shannon diversity) as well as multivariate compositional metrics. We found that influential predictors and directional effects differed across taxa. Ant diversity was most affected by stand density and canopy cover, and positively associated with both. Bat diversity was most strongly linked to primary forest area, with smaller reserves harboring greater bat diversity. Dung beetles were most affected by canopy cover and elevation, with greater diversity at lower elevation and with less canopy cover. Our multivariate analyses did not reveal any strong relationships between species composition and habitat variables. Overall, our results provide evidence that tropical forest structure is associated with biodiversity, but also suggest that it will be difficult to identify a single silvicultural prescription or landscape management strategy to maximize the diversity of all three taxa simultaneously.

Comparative Study of Understorey Birds Diversity Inhabiting Lowland Rainforest Virgin Jungle Reserve and Regenerated Forest

A comparative study of understorey birds inhabiting different habitats, that is, virgin jungle reserve (VJR) and regenerated forest (RF), was conducted in Ulu Gombak Forest Reserve and Selangor and Triang Forest Reserve, Negeri Sembilan, Peninsular Malaysia. The objective of this study was to assess the diversity of understorey birds in both habitats and the effects of forest regeneration on the understorey bird community. The mist-netting method was used to capture understorey birds inhabiting both habitats in both locations. Species composition and feeding guild indicated that understorey bird populations were similar in the two habitats. However, the number of secondary forest species such as Little spiderhunter (Arachnothera longirostra) in VJR is increasing due to its proximity to RF. This study discovered that RFs in both study areas are not yet fully recovered. However, based on the range of species discovered, the RFs have conservation value and should be maintained because they harbour important forest species such as babblers and flycatchers. The assessment of the community structure of understorey birds in VJR and RF is important for forest management and conservation, especially where both habitats are intact.

Canopy gaps and the natural regeneration of Matang mangroves

Canopy opening or gap creation by lightning strike is an important form of exogenous disturbance in the mangroves of Matang in Malaysia. The almost circular shaped canopy gaps consist of a group of standing dead trees which decay simultaneously with the growth of new trees. This characteristic is chiefly different with terrestrial forests where canopy gaps are normally created by tree-falls. Lightning strike disturbance in mangroves has created a means for natural regeneration whereby dormant seedlings growing underneath the canopies have had the opportunity to progress and ultimately replacing the canopies of the dead trees. Historical and recent aerial photographs of the Virgin Jungle Reserve of Pulau Kecil in Matang were analysed to measure gap turnover rate and to calculate canopy turnover. The average (±SD) canopy turnover is 25.5±6.9years. This finding shows that the continuous dynamics of gap creation and closure have sustainably maintained the condition of the forest. The finding also supports the hypothesis that this disturbance prevents mangroves from reaching more senescent stage, thus, canopy gap creations are justified to be the key driver in the natural regeneration of the tropical Rhizophora-dominated mangroves. Curiously compared, the average turnover is almost similar to the existing 30-year rotation cycle system adopted by the Forestry Department for the management of forest compartments in Matang.

Geo-information Science for Sustainable Development of Mount Stong F.R., Kelantan, Malaysia

The state of Kelantan covers an area of 1.5 million hectares of which about 894,271 hectares or 60% is under forest cover. It is still very much endowed with a rich and diverse biodiversity, such as in the dipterocarp forests of the reserves, in the National Park, limestone hills of Gua Musang, mountain forests of the Main Range, and Virgin Jungle Reserves. It is fortunate in that it has vast areas of lowlands, high rolling mountains and hills, with a rich and unique biodiversity associated with those ecosystems. A scientific expedition to the Mount Stong Tengah Forest Reserve in 2003 discovered that the area has a unique and diverse ecosystem, rich in bio-diversity and many endemic species. These findings prompted the State of Kelantan to gazette the entire central Mt. Stong Permanent Forest Reserve, one of its prime production forests, totaling 21,950 hectares, into a state forest park. Consequently, the State Forestry Department of Kelantan planned to turn these mountain forest resources into the best managed and successful state forest park and to achieve this, an integrated and multi functional approach has to be adopted. Initially, a thorough study of the mountain forest park resources involving Universiti Putra Malaysia-Aeroscan Precision (M) Sdn Bhd’s airborne hyperspectral imaging technology system has been undertaken. Preliminary results indicated that airborne hyperspectral sensing can easily identify individual timber species, estimate their timber volume, locate and map cultural, historical, mountain peaks, caves, waterfalls, picnic and camping sites potential and suitable for forest eco-tourism and recreational activities in Mt. Stong to be developed as a state forest park. Once completed, a 100 Year Management Plan will be formulated to assist the state government to undertake the best strategies towards implementing programs such as forest eco-tourism, publicity, local or international events, research facilities, and infrastructure, appropriate for a best managed and successful mountain state forest park.

Choices for tree conservation

Choices for tree conservation

Population genetics ofIntsia palembanica(Leguminosae) and genetic conservation of Virgin Jungle Reserves in Peninsular Malaysia

A field survey of Virgin Jungle Reserve (VJR) compartments in Peninsular Malaysia allowed us to identify six populations of Intsia palembanica for this study. These were Pasoh Forest Reserve (FR) (Pasoh), Sungai Lalang FR (Lalang), Bukit Lagong FR (Lagong), Bubu FR (Bubu), Bukit Kinta FR (Kinta), and Bukit Perangin FR (Perangin). About 40 adult individuals were sampled in each population. In addition, progeny arrays were collected from nine mother plants at Lagong for a mating system study. A total of nine allozymes, encoded by 14 putative gene loci, were consistently resolved in I. palembanica. The mating system study showed that the species exhibited a mixed-mating system, with multilocus outcrossing rate of 0.766. The levels of diversity were comparably high (mean number of alleles per polymorphic locus = 2.4, mean effective number of alleles per polymorphic locus = 1.64, and mean expected heterozygosity (H(e)) = 0.242), and the majority of the diversity was partitioned within population (G(ST) = 0.040 and F(ST) = 0.048). Significant levels of inbreeding were detected in Bubu and Perangin. Probability tests of recent effective population size reduction using the Infinite Allele Model showed the occurrence of genetic bottlenecks on Lalang and Kinta. Two genetically unique populations (Pasoh and Perangin) were inferred using jackknife analysis. By using the neutral mutation rates, effective population size (N(e)) to maintain the H(e) was 80-800 000 individuals. A simulation study based on pooled samples, however, circumscribed the N(e) to 200 and 210 individuals. Implications of the study for managing the species and the VJRs are discussed.

Effects of Habitat Disturbance and Protected Areas on Mammals of Peninsular Malaysia

I studied a network of small forested areas (2-2744 ha) that are protected as forestry research control sites and nature reserves in Peninsular Malaysia. These areas are officially known in Malaysia as Virgin Jungle Reserves ( VJRs). They are unlogged and are usually part of a larger, generally logged forest. I examined the effects of habitat disturbance on the species richness and composition of the mammal communities in seven of these protected areas ( 70-304 ha) and in adjoining logged forest, exotic monoculture plantation, or "farm bush." Thirty-eight species of mammals were recorded through direct observation, identification of tracks, or other signs. The size of the remaining area of natural forest, including both logged and unlogged forest but not including exotic timber plantations, or farm bush, was the most important factor affecting the mammal communities in all seven areas. The presence of species followed a nested subset pattern. A loss of large herbivores and carnivores, in particular, was apparent between areas of natural forest of 6551 to ≥10,000 ha. When areas of natural forest of ≤459 ha were considered, size continued to be critical; a sharp loss in mammal species richness was apparent between 70 and 164 ha. The area of the natural forest in which a protected area was located largely determined the mammal species richness and composition in the protected area. Differences in habitat quality accounted for the differences in mammal communities between protected areas and their adjoining vegetation. The preservation of small undisturbed areas can effectively enhance certain mammal communities in a disturbed landscape. The survival of some mammal species, however, including the largest carnivores and herbivores, will be determined by the area of surviving forest as a whole. A positive management strategy would be to retain large, continuous areas of forest wherever possible, in preference to fragmenting forest, and to build on existing small protected-area networks, such as the VJR network in Peninsular Malaysia, so that logged forests contain a rich mix of undisturbed protected areas.

Soil-Eating by Red Leaf Monkeys (Presbytis rubicunda) in Sabah, Northern Borneo

A group of Presbytis rubicunda (red leaf) monkeys was observed for 13 months in the lowland dipterocarp forest at Sepilok, Sabah, northern Borneo. The main items in the animals' annual diet were young leaves, seeds, whole fruits, and flowers. Large, dry seeds made up over 85 percent of the diet in 2 months, but young leaves, fruits, and flowers were generally eaten when large seeds were unavailable. Soil eating was observed on nine occasions. The soil was always collected by breaking lumps off termitaria and never from the forest floor. Analytical comparison of termite-mound and forest-floor soils showed that both had similar clay contents, but the termitaria soil was of higher pH and had higher levels of the main cationic nutrients and lower levels of labile aluminium. The geophagy was observed at times when different items predominated in the diet. It was noted when the dietary items were highly digestible and contained few tannins, indicating that geophagy need not be primarily for tannin absorption, although it might have helped to absorb toxins. The main benefits are more likely to be the alleviation of digestive disorders, such as forestomach acidosis, and the supplementation of mineral nutrient uptake in a generally oligotrophic environment. There is no reason why geophagy should have a single function; it may serve different functions at different times. SOIL-EATING HAS BEEN RECORDED in many groups of mammalian herbivores, including colobine monkeys, such as Colobus species in Africa (Clutton-Brock 1972, Oates 1978, Marsh 1978) and Presbytis species in South Asia (McCann 1934, Poirier 1970, Ripley 1970, Hladik & Hladik 1972) and South-east Asia (Bennett 1983, Davies 1984). A particular aspect that has been noted for the colobine subfamily is the selection of soil material from termite mounds rather than general topsoil (e.g., Hladik & Hladik 1972, Marsh 1978, Davies 1984). In a study of the mineral content of termite-mound soils eaten by Presbytis senex and P. entellus, Hladik and Guegen (1974) concluded that the clay-rich soil from the termite mounds was probably eaten for its physio-chemical effects rather than to offset mineral deficiencies in the diet. In a discussion of why C. guereza ate clay-rich soil from a stream bank at Kibale, Uganda Oates (1978) noted the the high copper content of the soil might be significant, but suggested that the clay could have been ingested to absorb toxins in the food or to buffer the pH of the forestomach. In this paper observations on the diet of a group of red leaf monkeys (Presbytis rubicunda) from Sabah, northern Borneo, are summarised and the composition of termite mounds is compared with that of surrounding top-soil in an effort to determine possible reasons why termite-mound soils are selected. STUDY ANIMAL AND STUDY SITE Presbytis rubicunda is endemic to Borneo and the adjacent Karimata Islands (Medway 1970) and lives at population densities of about two groups/sq km (Payne & Davies 1981). Animals tend to live in groups of 3-12 individuals and are almost wholly arboreal and herbivorous (Davies 1984, Supriatna et al. 1986). The group described in this paper occupied a home range of about 70 ha on the northern boundary of the Sepilok Virgin Jungle Reserve

A comparison of the floristics and leaf chemistry of the tree flora in two Malaysian rain forests and the influence of leaf chemistry on populations of colobine monkeys in the Old World

A comparative floristic survey of lowland tropical rain forest at Kuala Lompat, Krau Game Reserve, West Malaysia and at Sepilok Virgin Jungle Reserve, Sabah, East Malaysia, revealed significant differences in the composition of canopy species, notably in the relative paucity of Dipterocarpaceae and abundance of Leguminosae at Kuala Lompat. A further comparison with data from other sites in Malesia indicated that Kuala Lompat was rather atypical, representing an extreme example of the relatively legume rich and dipterocarp poor forests of West Malaysia. Conversely, the predominance of dipterocarps and lack of legumes at Sepilok was similar to other sites in Borneo. Young and mature leaves were collected from a representative sample of the canopy flora of the two study sites; the levels of nitrogen, fibre, total phenolics and condensed tannins, and degree of digestibility by cellulase and pepsin, were measured. Levels of fibre, nitrogen and phenolics differed significantly between the two floras; foliage from Kuala Lompat being, on the whole, richer in nitrogen but lower in phenolics and fibre. As a consequence of the lower levels of fibre, and less certainly of phenolics, the Kuala Lompat foliage was comparatively more digestible. Possible reasons for the differences in foliar biochemistry between the two sites are discussed. Differences in rainfall and in soil quality are regarded as potential evolutionary causes. A further comparison of the chemical profiles with data for other forests in India and Africa indicate that Sepilok is a site in which trees invest heavily in quantitative defences such as fibre and phenolics whereas trees at Kuala Lompat place a lower emphasis on the production of these. Finally, attention is drawn to the use of foliar chemical profiles in predicting the carrying capacity for colobine monkeys at each of the five Old World forests where data are available. It was found that the ratio of nitrogen to fibre correlated well with the biomass of colobines at the five sites.

Food selection by two South-east Asian colobine monkeys (Presbytis rubicunda and Presbytis melalophos) in relation to plant chemistry

The diets of the banded leaf monkey (Presbytis melalophos) at Kuala Lompat in the Krau Game Reserve of West Malaysia and the red leaf monkey (Presbytis rubicunda) in Sepilok Virgin Jungle Reserve, Sabah, East Malaysia have been examined in relation to plant chemistry. Both monkeys spent about half their time eating foliage, and about half their time eating fruits and seeds. They both favoured leaves with high digestibility (due to relatively low levels of fibre) and high levels of protein, a combination found predominantly in young leaves and some flowers. The monkeys appeared to favour seeds and fruits with high concentrations of storage carbohydrates or fats, but not those rich in simple sugars. Selection of seeds and fruits was not correlated with protein content. An analysis of the fibre and protein contents of foods showed that, on an annual basis, the two monkeys achieved a comparable intake for both items. However, these diets were obtained in radically different ways. Presbytis melalophos was able to eat foliage from many of the common tree species in its home range, whereas P. rubicunda relied on rare trees and lianas. This difference is attributed to the very high density of Dipterocarpaceae at Sepilok, a tree family that provides little food for colobines. The rarity of P. rubicunda's food plants at Sepilok is considered to be the main reason for the greater home range size and lower population density in comparison to P. melalophos. Finally, the biochemical profiles of the young leaf diet of these two monkeys were compared with previously published information on two African and one south Indian colobines. In many respects the intake of supposed critical components, protein and fibre, showed marked similarities between different animals, considering contrasts in their habitats.