Brief Report A preliminary investigation into comparative foraging ecology of reticulated giraffe (Giraffa camelopardalis reticulata) and domestic camels (Camelus dromedarius) in Laikipia Kenya. June 13 – August 12 2011 J Could two heavyweights of the ungulate world -­‐ reticulated giraffe (Giraffa camelopardalis reticulata) and d omestic camels (Camelus dromedarius) -­‐ theoretically be facing off in East Africa? Research Overview For a large mammal, giraffes are surprisingly understudied, with much left unknown about their ecology. In fact a recent conference was entitled Giraffe – The Forgotten Megafauna. There are several subspecies of giraffe, the exact number is still debated, but concensus seems to be growing that there are nine. Two subspecies have been formally red-­‐listed by IUCN, and some of the other sub species are in decline. “All over Africa, giraffes are in serious decline. Some 30% may have been lost in the past 10 years alone. The principal reasons are believed to be poaching, especially for meat, and loss of habitat” (Reticulated Giraffe Project, 2011). The reticulated giraffe, inhabits northern East Africa, seems to be in trouble. Although exact population figures are unavailable, it’s estimated that they have declined more than 80% from perhaps 30,000 a decade ago to about 5,000 today. In the face of such challenges, it is ever more important to gather as much data as possible about giraffe ecology and social structures. Domestic camels are increasing in popularity and stocking levels in many parts of East Africa due to their ability to resist drought and access browse, coupled with the developing premium market for camel milk. Laikipia is no exception to this trend, with a camel herd being introduced at Mpala ranch in 2007. Stocked in the traditional pastoralist fashion, little work has been done how domestic camel herds interact and impact their environment, the vegetation and wildlife, and whether camels are more or less sustainable than cattle or shoats in a rangeland ecosystem. •
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Female camels actively browse over a wide range of heights, from ground level up to 3 meters. Traditionally, due to their being browsers, their dispersal ability and elevated foraging level, giraffes have been thought to be able to co-­‐exist with traditional pastoralist livestock species, however with the introduction of the larger and taller browsing camels, could this alter the status quo, and potentially affect giraffes ability to coexist with livestock? Due to time and budget constraints, this study gathered base-­‐line preliminary data on the foraging ecology of camels and giraffe at Mpala ranch to try to understand whether there are indicators of overlap in their resource utilization. Data were gathered on: the foraging ecology and activity budgets of camels and giraffe in different habitats and vegetation structure, giraffe photo data to identify individuals based on neck patterning, and camel resource usage distribution through GPS collars. Additionally, by using the GPS locations of giraffe encounters, the density of giraffe at Mpala may also be elicited. Camel foraging observations were
conducted on foot, following the herd
Brief Methodological overview: as they browsed throughout the day.
This preliminary study made use of multiple methods not only to try tackle the study goals, but also to assess which methodologies would be most appropriate for a full-­‐
blown research project. All field research was conducted at the Mpala Research Centre, Laikipia, Kenya. Camels Feeding heights were assessed by measuring fifteen sample camels in the boma prior to release, as well as by measuring bite marks on browsed vegetation. Feeding Height Category Mature Female (n=15) Feeding High 3.0m (max) Feeding Level 1.5m Feeding Below 0.7m Feeding Ground 0m Camel observations were conducted by following a camel herd as they browsed throughout the landscape. Observations started in the morning as camels were released from the boma, continuing until the herd returned to the safety of boma in the evening. During the day, multiple 1-­‐hour observations consisting of two-­‐minute group scans of 15 adult females were completed, recording camel activity, feeding height and plant species. Each hour-­‐long observation period was tracked using GPS. Eight full camel browsing orbits were collected: A homemade GPS collar was attached to a camel and its track recorded. Browsing intensity and dry-­‐weight leaf biomass data were collected inside camel browsing orbits and compared to control sites for a favorite food species (Acacia brevispica). Vegetation structure assessments/transects were conducted in areas where the camels were herded. Camera traps were set up to capture qualitative data on how the presence of the camel boma affects wildlife. •
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A preliminary Google map snap shot shows the browsing orbits (blue lines) of eight GPS-collared camels (each orbit was
recorded on a different day). The green circle in the center is the location of the camel boma. The camel in the photo can
be seen sporting the first iteration of my homemade GPS collar used to track their movements.
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Giraffe Mpala Ranch was divided into six areas. As far as possible each area was driven so it was sampled evenly in distance and time throughout the day. When giraffes were spotted, road/car-­‐based observations of giraffe were conducted. This comprised of two-­‐minute group scans of all individuals in view, recording the sex, activity, feeding height and plant species (where possible). Typical set-up for giraffe observations.
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GPS locations of the beginning and end of each encounter were recorded. Photographs of as many of the giraffes as possible were taken to allow for possible future photo-­‐ID. (This may be conducted in collaboration with the Reticulated Giraffe Project, using pattern-­‐ID software). The four feeding height categories were based on du Toit (1990) and assessed by measuring 15 samples of browsed vegetation for each height and each sex: Feeding Height Category Mature Male [height (n)] Mature Female [height (n)] Feeding High 4.8m (15) 4.1m (15) Feeding Medium 3.6m (15) 3.0m (16) Feeding Level 2.7m (16) 2.1m (18) Feeding Below 1.7m (17) 1.1m (12) •
Vegetation structure (species and height) was assessed along feeding tracks using a straight line transect from the beginning GPS point to the end GPS point of giraffe encounters. Preliminary Google map snapshot showing the giraffe driving transect route on the morning of August
8, 2011. The yellow line shows the route driven. The blue pins mark the two giraffe encounters. 384385 shows the start and end of one encounter. 385 is a separate encounter, where the giraffe walked
out of site.
Experience & Limitations My experience was simultaneously challenging and exhilarating. I was based at Mpala Research Centre in Laikipia Kenya. Mpala hosts a large quantity and diversity of wildlife as well relatively small livestock herds of cattle, shoats and camels. The livestock are managed in the traditional pastoralist fashion. My day-­‐to-­‐day experience was very much focused on fieldwork, since I was only in the field for a limited time, I was focused on gathering as much data as possible. For giraffe, I was conducting behavioral observations of wild mammals, which meant I had to drive to find them, often in dense bush, and then once I located the giraffe, try to observe them without impacting their behavior. My giraffe observations were road-­‐based. Mammals are most active in the mornings and evenings, so I would leave at daybreak to search for giraffe, return around 11am, then head out again about 3.30pm until sundown. The giraffe at Mpala were not accustomed to being observed, and were extremely skittish, often either running away, or (particularly for solitary animals) engaging in staring contests with me, which could last hours… Another, perhaps less monotonous challenge, was the special animal guest appearances made, particularly by elephants and buffalo, which often meant I had to cut short observations and make myself scarce. k Two of the most common challenges to observations, elephant charges and giraffe stare-downs.
When I was working with the camels, I had one of the better experiences. For my camel research, I would set out with the camel herds in the morning and walk with the camels and observe them as they were out browsing and herded around before returning to the boma in the evening. So I got to work side by side with the herders and really get to know them and chat to with them about their lives and day-­‐to-­‐
day challenges. The vegetation transects were conducted on foot along a straight-­‐line estimation of browsing routes of the camels and giraffes for which I had foraging ecology data. These transects could be up to a kilometer from the car, which again meant that occasionally we had to be fleet of foot to evade the elephants and buffalos we surprised. Thankfully, I was working with a Kenyan research assistant, who saved my life on at least two occasions. Results Data are currently being analyzed, to be completed Spring 2012. It’s hoped this study Occasionally camera traps were set too low for the
will act as a pilot for a multi-­‐year research project. study species….
Works Mentioned du Toit, J.T. (199) Feeding-­‐height stratification among African browsing ruminants. African Journal of Ecology. 28, 55-­‐61. Reticulated Giraffe Project web site. http://reticulatedgiraffeproject.net/home.html Appreciations Many thanks to Dr. Bilal Butt, Dr. John Doherty, Dr. Johannes Foufopoulos, Dr. Johan du Toit, Dr. Bryan Shorrocks, Dr. Truman Young, Dr. Bobbi Low and to Adam Ford for their time, advice and guidance. Special thanks goes to Jeremiah Long’or for all his assistance. This research was made possible by funding from: