Spatial Ecology
The spatial ecology of chacma baboons of the Cape Peninsula
A quarter of the world's 230 primate species are currently threatened by the direct and indirect activities of humans. The Cape Peninsula in South Africa is a classic example of this trend, with urban sprawl greatly reducing the availability of suitable habitat to the local chacma baboon (Papio h. ursinus) population. Ironically these baboon troops are the only protected population of this species in Southern Africa. Despite their unique status their numbers are declining and the population is now classified as critically endangered.
In the Cape Peninsula, an absence of empirical information regarding the spatial requirements of the resident 11 baboon troops, has resulted in regional management efforts focusing almost exclusively on reducing physical contact between the baboon troops and human settlements. High baboon mortality rates and increased levels of human-baboon conflict throughout the Peninsula suggest that this strategy is inadequate and alternatives need to be considered as a matter of urgency. Officials charged with management of this species have repeatedly requested empirical data on the spatial and habitat requirements of these troops as a critical first step towards effective management.
The aim of this study is to perform a detailed Geographic Information System (GIS) based spatial analysis on all of the Peninsula baboon troops. Spatial analyses are currently considered to be a critical component of organismal and system ecology and the quantification of spatial patterns make inferences about the causation of behaviour, such as animal movement, possible. To achieve this we collect two kinds of data: Global Positioning Systems (GPS) data and observational data.
GPS data
Each troop is tracked for a one-year period using GPS tracking collars (see Tracking baboons with GPS collars Tracking baboons with GPS collars). The collars provide us with an extensive time slice of positional data that answer broad scale questions of area use. The GPS data points, which are recorded at predetermined intervals throughout the day, are analysed to determine the home range of each troop as well as the attributes - for example vegetation type, altitude and proximity to water sources – that determine the intensity at which different areas of the home range are utilised.
Observational data
To provide fine scale measures of habitat use within the home range extensive seasonal observations of each troop are done by field biologists. During the hot, dry summers and cold, wet winters, field biologists follow each troop on foot and collect detailed behavioural data (e.g. foraging frequencies and diet, social behaviours, movement patterns). Seasonal differences in home range dimensions, area residency and ranging patterns are then investigated. This observational data is recorded using Cybertracker software (www.cybertracker.co.za), which allows detailed troop-specific information to be recorded with ease and precision, and enables accurate and efficient means of both qualitative and quantitative data analysis.
Data analysis and study outcome
Using the GPS and observational data, preferences of baboons for particular habitats within the Peninsula, in terms of area, altitude, vegetation cover and proximity to water sources, will be determined. These preferences will be used to generate habitat suitability indices for each baboon troop. This information will then be disseminated to the key decision-makers (Table Mountain National Park, Cape Nature and South Peninsula Administration) charged with conserving this population of baboons. The ultimate objective of this project is thus to provide an empirical backbone upon which long-term baboon management solutions can be fleshed out to alleviate the untenable levels of human-baboon conflict in the region and thus ensure the preservation of this unique population of primates.
Volunteer opportunities
Volunteers with training and/or experience in field biology are invited to take part in troop observations during winter 2007 (June/July/August) and Summer 2007/08 (December/January/February). Volunteers must be able to participate for a miminum of one month, and must be able to fund their transport to South Africa, and their board and lodging whilst in the country. Please contact Tali Hoffman (hfftal001@uct.ac.za) if you are interested in applying for a volunteer position.
Tracking baboons with collars
Why use collars?
Studies that have compared primate home range determination by radio-tracking with home range determination based on direct observation reveal that radio-tracking allows more accurate estimates of home ranges and the inclusion of areas that would otherwise be inaccessible.
Records of successful baboon collaring exist for chacma baboons in the Suikerbosrand and Blyde River Canyon, South Africa, and for hamadryas baboons in Ethiopia. To date, two baboons have been collared in the Cape Peninsula. The first was a dispersing adult male baboon (Markus) from the Tokai troop who was collared in January 2007. The second to be collared was an adult female from the Cape Point troop, collared in April 2007. Both baboons have adjusted well to their new accessories, and there is no indication that either is suffering any adverse physical or social effects as a result of their collars.
Who do we collar?
Female baboons are more suitable candidates for collaring than male baboons when one is gathering data on the spatial ecology of an entire troop. Unlike male baboons, females do not disperse, but instead remain with their troop throughout their lives. Thus, the movement patterns recorded from a collared female represent a reliable long-term measure of troop movement. Only healthy adult females who are neither pregnant nor weaning an infant will be selected to be collared. One adult female from select Peninsula baboon troops will be collared.
Collar details
The collars used for this study are made by Africa Wildlife Tracking (www.awt.co.za). They are made with the latest in GPS (Global Positioning System) and GSM (Global System for Mobile Communication) technology. The intervals of collar readings can be programmed and adjusted from a remote computer source once the collar has been fitted to the animal, and positions are recorded within a 10m accuracy range. The data from the collar is downloaded from the internet. The battery of the collar will allow a minimum of one year of data to be recorded at the resolution required for home range analyses. The collar contains a VHF-tracking component that can be used in the event of battery failure, or lack of cell phone coverage.
These tracking collars are specifically designed for baboons. They are coloured to blend in with the greyness of baboon fur, making them as inconspicuous as possible. The collar is made out of conveyor belting as this material is strong and durable and will not break or tear. The stitching around the antenna is sunken and will not break/come loose when the collar rubs against the animal's skin.
Collars range in mass from 480g to 500g. Adult female baboons in the Cape Peninsula range in mass from 14kg (young adults) to 22kg therefore, even for small adult females the fitted collars constitute less than 4% of the baboon’s total body mass. This mass lies well within the tolerable weight limit (the total weight that can added to an animal in the form of a transmitter without causing impediment to behaviour, survival or well-being), defined as being 5% or less for mammals and birds.
How do we fit collars?
Each adult female is darted and sedated by an experienced wildlife veterinarian. Once sedated, the collar is fitted to the baboon, and adjusted accordingly. The collar is made sufficiently tight so that it may not be pulled over the baboons head, nor get caught in vegetation, but sufficiently loose so as to be comfortable and not hinder the animal’s respiration or ingestion. The veterinarian uses his/her hand to judge the gap required between the collar and the neck and fits the collar so that it is loose enough for the baboon to rotate its neck freely and groom the skin underneath the collar. The smooth inner surface of the collar, together with the thick mane of fur around the baboons neck, minimise the risk of chafing.
Once the collar has been fitted the baboon is placed into a cage until she has regained full mobility and awareness. Once recovered, the baboon is transported to her troop, where she will be released. She is monitored closely for several days after the collar has been fitted, and should deleterious affects be observed – such as improper balance, impeded movement or obvious discomfort – further veterinary intervention will go ahead.
All collars will be removed once a full year of data collection has taken place.
Limitations to collaring efforts
The costs of GPS collars are a major stumbling block that we face. Each collar costs in the range of R20 000, and at present endeavours to raise sufficient funds to cover these costs are underway. We would like to acknowledge the generous contributions of Back to Africa (www.backtoafrica.co.za) who funded the collar that was fitted to the dispersing male in Tokai in January 2007.
Should anyone be interested in assisting with sponsorship for this worthy cause, please contact Tali Hoffman (hfftal001@uct.ac.za).
