For the past 2 years, volunteers from Operation Wallacea have been carrying out research into the abundance of the Buton Macaque. Macaca ochreata brunnescens, the little-studied sub-species of Macaca Ochreata, appears to be confined to the islands of Buton and Muna. With the continuing habitat encroachment through deforestation in both these areas, it is important to try and establish a baseline population estimate. This should include comparisons between disturbed and undisturbed areas of Buton Island, in order to assess the effect of forest loss on the macaques and the subsequent increase in their numbers around village areas.

Previous studies by Operation Wallacea teams, on the abundance of this species have indicated a concentration of their population on forest/farmland boundaries, and preliminary hypotheses suggest this may be due to the increase in availability and abundance of food, in comparison to the rather more dispersed forest resources. An alternative hypothesis would suggest that a principal cause for such a pattern could be increasing destruction of their natural habitat, and disturbance of preferred food types, forcing the animals to the boundaries of these areas.

Large troupes of macaques living in close proximity to humans present a number of economic as well as health risks. If, as data from the Crop-Raiding projects suggests, the macaques are becoming an increasing pest to their surrounding human populations, then it is important to establish the root cause behind the movement of the macaques. If they continue to populate these areas, as the sizes of the human settlements continue to grow, the existence of this species may well become threatened as the villagers turn to more drastic methods of dealing with their presence. Although still relatively protected by the Islamic culture of the Butonese, it is possible that unless patterns of the macaque’s movement are more accurately deduced, their population may face threats similar to the N.Sulawesi Macaca nigra (Rosenbaum et al 1998). During the 1999 and 2000 seasons, data was gathered in 4 villages, and 2 areas of undisturbed forest, all concentrated in the South-westerly regions of Buton Island. Studies need to be repeated in this region in order to increase statistical reliability (Burnham et al 1980) as well as introduced in new areas, in order to gain as much information as possible on their numbers.

Concurrent studies on the behaviour of specific groups of these macaques, have served to build up the information base on which this work is undertaken, with increasingly accurate information on group structure, habitat / sleeping tree preferences and dietary composition. This should enable future population surveys to be more objective and productive. Alternative methods to the current Line Transect Sampling will also be looked at, in order that some methodological comparisons may be made.

• To use line transects to compare the abundance of the macaques in different areas of forest encroachment more thoroughly, with emphasis being given to the Kakenauwe and Lambusanga reserves.
• To use the work of previous Operation Wallacea projects, as well as concurrent botanical research to create clearly defined Primary, Secondary and Disturbed forest areas and assess the differences in abundance within each of these regions.
• To gain more detailed information on the presence and absence of certain preferred food resources in each of the forest habitats
• To carry out double count line transects in order to determine observer error and to build up a macaque sighting database.

Line Transects formed the predominant method of the 2001 research programme. These involved volunteers, accompanied by Butonese guides, walking linear paths, of varying length and type (clear-cut paths / natural vegetative paths). The transects were as straight as possible, with observers walking at approx. 2 km per hour, without extended pauses in order to cover as much ground as possible (Brockleman & Ali, 1987), as the longer the course, the more sightings reported (Marsh & Wilson, 1981). The transects were carried out in a range of ecological communities.  All results will be analysed using Line Transect Theory (See Burnham et al 1980; Bibby et al, 1992).

As well as walking standard line transects, a double count transect method was applied to both transect grids in the Kakenauwe and Lambusanga reserves. This involved two people walking a transect at the same time making independent observations. At the end of the transect the macaque sightings from the two observers were compared. 

Initial observations seem to suggest more sightings of macaques in the Kakenauwe grid when compared to the Lambusanga grid. In the Kakenauwe grid most sightings have been made towards the north end of the grid. This area borders farmland, therefore it may be hypothesised that this high frequency of observations is related to the high level of crop raiding in the area. In the Lambusanga grid the macaque sightings are distributed relatively randomly. The transects need to be walked many more times so that detailed maps of sightings within each grid can be produced. It will be possible to produce sighting maps for different times of the day once all the data has been inputted into an Excel database. It will also be possible to assess observer error based once all observations have been analysed to see how many sightings were made by one observer or by both. This will give useful information about the observational error of line transects.

After the 2002 season, when the grid transects have been walked many more times, a report entitled "The distribution of Macaca ochreata brunnescens within two contrasting forest habitats on Buton Island and the effectiveness of the double count transect method in determining observer error" will be produced by Dr Mauvis Gore, Edinburgh Zoological Gardens, Phil Stanier, Operation Wallacea, and Graeme Cooper, Operation Wallacea.

Bibby J, Burgess T, Hill P (1992). Bird Census Techniques. Academic Press.

Burnham KP, Anderson DR, Laake JL (1980) Estimation of Density from Line Transect Sampling of Biological Populations (Wildlife Monogr No. 72). Washington, DC: The Wildlife Society.

Brockleman WY & Ali R (1987) Methods of Surveying and Sampling Forest Primate Populations. In Alan R. Primate Conservation in the Tropical Rain Forest p.23-62 Liss, Inc.

Marsh CW & Wilson WL (1981): A Survey of Primates in Peninsular Malaysian Forest. Cambridge: Universtiti Kebangsaan Malaysia and Cambridge University.

Rosenbaum B, O’Brien T, Canard M, Supriatna J. (1998). Population Densities of Sulawesi Crested Black Macaques (macaca nigra) on Bacan and Sulawesi, Indonesia: Effects of Habitat Disturbance and Hunting. American Journal of Primatology 44.Freddy Pangedja, Department of Forestry and Wildlife, Indonesia