Forest In Sarawak Research Articles

Proboscis monkeys and their swamp forests in Sarawak

Proboscis monkeys, endemic to the island of Borneo, are declining in Sarawak. Their mangrove and peat swamp forest habitats are being degraded or destroyed and people continue to hunt them despite their protected status. Surveys between 1984 and 1986 established the status of this monkey and its habitats in this Malaysian state. The author who participated in the surveys, receiving some financial support from the Oryx 100% Fund, discusses the results and makes recommendations for future conservation action.

Relative Abundances of Frogs and Lizards in Forests of Southeast Asia

Large samples of frogs and lizards from eight lowland forested environments distributed in Borneo, Malaya, and northeastern Thailand are used to compare abundances. Frogs and lizards were divided into riparian and non-riparian subsamples, and each of those into arboreal and terrestrial categories. Non-riparian lizards were further divided into diurnal and nocturnal groups. The two forests in Thailand lie in an area having a pronounced dry season and prolonged intervals of extremely high temperatures in contrast to the Indo-Malayan environments which lack those features. The differential effects of drought and high temperatures on portions of the environment during the day and the varying susceptibilities of the taxonomic and ecological groups probably are responsible for differences observed in relative abundance. Frogs of all categories were more numerous in Borneo and Malaya than in Thailand. Diurnal arboreal lizards were much more abundant in Borneo and Malaya, whereas terrestrial ones, nocturnal and diurnal, were more abundant in both Thai forests. Nocturnal arboreal lizards showed a mixed picture. LARGE SAMPLES OF AMPHIBIANS and reptiles collected in lowland forests in Sarawak (10 37' N-3? 21' N), West Malaysia (30 11' N-30 22' N), and northeastern Thailand (140 30' N) provide material for comparison of abundances of these animals in various types of forests in Southeast Asia. Although we have only a single, time-limited sample from each locality, and only a single sample from several types of environments, the likelihood of replication is so small relative to likelihood of destruction of the forests that analysis seems justified in spite of these sampling deficiencies. Brown and Alcala (1961) reported on collections of amphibians and repriles from montane forests in the Philippines, but no comparison will be made with their samples in this paper because of the known effect of elevation on abundances of amphibians and reptiles (Scott 1976). Furthermore, low species richness in the Philippine samples adds another complicating factor. Comparison with Scott's (1976) analysis of densities of litter herpetofaunas in Central America is dealt with elsewhere (Inger 1980).

THE COMPOSITION AND BEHAVIOUR OF SOME MIXED‐SPECIES BIRD FLOCKS IN SARAWAK

SummaryMixed‐species flocks of birds feeding on insects were observed mainly in forest in Sarawak at a time of year when insect availability is known to be near its annual minimum. The approximate individual and specific composition of most flocks were noted. Twenty‐six species occurring in 25% of flocks were regarded as occasional members, 15 species occurring in 40% of flocks being classed as regular members.Recording species' feeding behaviour was the main priority and few observations of inter‐ and intra‐specific interactions within the flock, horizontal distribution or vertical stratification were made, although the last proved to be of potential significance. From the analysis of feeding behaviour two groups of species were distinguished. The larger group contained those usually having an exclusive common feeding pattern and showing very little overlap with the other such species. Fewer species used a wide range of feeding methods, all of which were shared with other species, but the least overlap was with other members of the same category.The observed composition of these flocks, in terms of regular members, might be interpreted as ensuring a low level of inter‐specific competition and it is suggested that the less specialized foragers may occur in the flocks by utilizing the ‘gaps’ between, and absences of, specialists.The possible advantages of membership of mixed‐species flocks are briefly considered and the likelihood of the selective advantage in any situation being the result of a balance of factors emphasized. In the apparent absence of regular potential predators the existence of these flocks is interpreted primarily as an adaptation for augmenting available insect food, particularly perhaps at critical times of year, by flushing insects as a result of the foraging activities of flock members. It is suggested that the varied responses of insects on being disturbed coupled with the different and fairly specialized feeding techniques of the birds could ensure benefit for all members of the flock.

Longevity Records for Some Neotropical Land Birds

on survival rates in the tropics. Snow (1962a) found that male White-bearded Manakins (Manacus manacus) in Trinidad had an annual survival rate of at least 89%. This was based on a group of established adult males holding courts at a lek, which were followed over a 3-year period. An indirect estimate for the Golden-headed Manakin (Pipra erythrocephala), another lek-forming species, based on the proportions of males, females, and young birds in a trapped population, gave a similar figure (Snow 1962b). Fogden (1972) calculated a minimum annual survival rate of 86% for a sample of birds of many different species trapped in a forest in Sarawak, Borneo. These percentages are far higher than those recorded for European and North American passerines, for which annual survival rates of adults are predominantly in the 30-50% range (Lack 1954, Table 21). They are in fact much closer to the very high survival rates of the larger seabirds. Fogden's figure was based on one year only, during which conditions might have been either better or less good than usual. Snow's data for the manakins were based on

Opening remarks

First, I should like to say a word about the objects of the expedition. These were threefold. The most important one, of course, was to study an area of very great biological interest. The second was our belief that such a study would be of substantial aid to the Government in the plans which we understood they were making for the establishment of a National Park in the Mt Kinabalu region. This, I am glad to say, has in fact turned out to be the case. Our third object was to enlist the help of scientists living and working in that region in a co-operative enterprise in the hope that we might establish a tradition of scientific study of natural resources among the research and teaching staff of the Universities in the region. This again we were able to achieve in some measure and we hope to continue our co-operation in the next expedition. The expedition was led by Mr E. J. H. Corner, F. R. S., of the Botany School of Cambridge, and he was accompanied by Mr G. P. Askew of Newcastle, who took charge of the soil science investigations, and by Mr J. A. D. Stainton, who acted as photographer as well as a botanist. Mr Corner was also joined in the botanical work by Dr Chew Wee Lek from the Singapore Botanic Gardens. Professor J. L. Harrison, from the University of Singapore, was with the expedition for part of the time and studied small mammals and their parasites. Mr B. E. Smythies, Conservator of Forests in Sarawak, who is a prominent ornithologist, also spent some time with the expedition. The expedition was visited by interested people working in North Borneo, and this contributed substantially to the development of local understanding of the value of the area and of the scientific work that was being done in it.

The Structure of a New South Wales Subtropical Rain Forest

Descriptions of rain forest in New South Wales have already been given by various authors, as, for example, Brough, McLuckie & Petrie (1924) for the Mt Wilson area, and Fraser & Vickery (1938) for the Upper Williams River district. These papers include detailed accounts of the different communities, but owing to the difficulty of measuring tree height and canopy spread on standing trees, data such as those given by Richards (1936) for the Sarawak forests were not available. In order to obtain detailed information of this kind it was decided to select an area of virgin rain forest and to clear-fell a strip. With the help and co-operation of the New South Wales Forestry Commission a district was chosen in which logging operations were in progress but which still contained untouched forest. Since it was intended to carry out the investigation as part of the normal field exercises undertaken by the senior students in Botany of the University of Sydney,* the simpler Ceratopetalum apetalum (Coachwood) type of forest was chosen. Rain forest of this kind may be considered as a marginal type with a relatively small number of tree species. It adjoins on the one side to eucalyptus (sclerophyll) forests and on the other to the denser and more complicated rain forests with Ficus, Dysoxylum, Diploglottis, Cedrela, etc. The area chosen is situated at approximately 31? 30' S. and 152? E. about 50 miles to the west of Wauchope, and is known locally as Banjo. It is traversed by numerous spurs forming the eastern slopes of the New England Range. Topographically this region is young with narrow ridges, steep-sloping hillsides, and V-shaped gullies.