Researcher: Dr Kerry Slater
Region: Suikerbosrand, South Africa
The chacma baboon (Papio ursinus) is the only baboon species found in South Africa. Chacma baboons form multi-male – multi-female groups, with ratios of around 2/3 females. An alpha male runs a troop size from 28 to 103 individuals. Their home ranges vary from 4-40 square kilometres depending on seasonal availability of food in different plant communities. Although predominately frugivorous, baboons supplement their diets with insects, reptiles, birds and mammals, making them ecologically flexible, and therefore can be found in a wide range of habitats including open savannah, rocky outcrops, mountain ranges, woodlands and semi-deserts.
Other than being a prime food source for leopard and potential agents for insect population controls, baboons are primary seed dispersal agents. This is even more ecologically important in fenced areas where other seed dispersers (such as ungulates) are prevented from moving between areas.
Due to their dietary flexibility, baboons can and do exploit agricultural lands and can therefore potentially cause damage to crops. This has resulted in baboons being regarded as ‘problem’ animals and therefore being eradicated from many areas. This perception and attitude towards baboons gives many conservationists cause for concern as it is possible that they could become effectively exterminated outside unprotected areas. Their persecution could therefore ultimately contribute to a significant decline in biodiversity.
Currently only 4% of Gauteng and less than 1% of land contained within the urban edge is under some form of conservation protection; SBRNR contributes approximately 7% of Gauteng’s biodiversity targets. No recent research on the behavioural ecology of baboons at SBRNR has been published with the resultant lack of knowledge relating to their impact on the ecosystem and biodiversity of both SBRNR and surrounding agricultural farms. Due to historical misconceptions of baboons being ‘problem’ animals with no real value to ecosystems, potentially false perceptions relating to their impact on biodiversity and conflict with neighbouring farms has therefore been the norm.
During 2005 the SBRNR Management Plan Committee requested a project proposal that would address concerns relating to the perception that there may be too many baboons on SBRNR and complaints from surrounding agricultural farms with respect to crop raiding. A census conducted in October 2006 concluded that approximately between 611 and 764 baboons made up of 12 troops occurred on the reserve. 12 cellular tracking devices were fitted to a corresponding number of baboon troops distributed around the Reserve and a database of baboon distribution was collected over a period of 18 months.
- Determine the home ranges of the 12 troops known to occur on SBNR
- Provide a detailed habitat description and vegetation map of the home ranges of two selected troops
- Determine areas of high and low selectivity within the home range of these two troops
- Define the seasonal diet of the baboons in these two troops
- Establish at which times of the year baboons potentially pose a threat to surrounding farms
- Ascertain if areas of high selectivity correlate to food availability and specific plant communities
- Identify which plant species are potentially being dispersed by baboons
- Understand if there is a correlation between faecal scat size and age of baboons
- Obtain relevant information which will provide perspective on these perceived imbalances and provide suitable and scientifically-based management recommendations for the baboons on SBRNR.
Telemetric collars were placed on females from each of the 12 troops and cell phone telemetry point data (Long/Lat coordinates) were recorded over a period of 18 months. From this data, home ranges of the 12 troops have been identified. Within these home ranges, areas of high and low selectivity will be identified.
From the home range results, two troops – one core troop (home range remains within the core area of the Reserve) and a periphery group (home range overlaps with agricultural lands) will be habituated to a distance of at least 30m.
Vegetation and habitat surveys will be conducted in a number of sample plots by recording all of the plant species present and their density.
Each of the habituated troops will be followed for two days per month for one year. All observations of feeding will be recorded. Collection of fruits, seeds or pods observed to be eaten will also be collected to aid in identification during faecal scat analysis. To complement this method, twice a month 20 fresh faecal scats will be collected from each troop’s sleeping site and food analysis of the scats will be conducted. Seeds and other recognisable food items will be identified. The proportions of seeds, insects and other food items’ contribution to diet will be calculated to determine diet selection. Scats will be exposed to germination trials to determine species eaten and seed dispersal potential. Scan samples of the troops’ activity (walking, resting, socialising, foraging) will be conducted every 15 minutes. Faecal scats from individuals will be collected when observed defecating, to determine if there is a relationship between scat size and age class of baboons.