A comprehensive survey of Grevy’s zebra in Kenya was undertaken in the year 2000 (Nelson & Williams 2003), resulting in an estimated national population of 2,571 (± 136). In response to this sharp decline in Grevy's zebra numbers, conservation efforts for the species were stepped up. With effective accounting of Grevy's zebra numbers, we can assess how successful these conservation efforts are proving to be, and we can plan future conservation action more effectively.
In November 2008, a national survey of Grevy's zebra in Kenya was undertaken using standard aerial survey methods. The Grevy's Zebra Technical Committee teamed up with the MIKE (Monitoring of Illegal Killing) count of elephants in the same region.
The goals of the survey were:
- to determine the distribution and provide a minimum count of Grevy's zebra across Kenya;
- to identify locations where populations have declined and those where populations have increased based on survey results;
- and, to institutionalize a periodic count of Grevy's zebra in Kenya. The survey used a standardised minimum count methodology to count Grevy’s zebra within a 46,391 km2 survey area.
The total number of Grevy’s zebra counted was 2,407. Results showed that the highest concentrations of Grevy’s zebra were found in the Laikipia and Wamba management zones. In Wamba, Grevy’s zebra were found chiefly in community conservancies. More than 60% of Grevy’s zebra sightings occur on community land, demonstrating that pastoralist communities in northern Kenya are critical to the survival of this species. Communities of particular importance are Meibae, West Gate and Kalama Conservancies in the Wamba management zone, and Koija and Kirimon in the Laikipia management zone.
In Laikipia, Grevy’s zebra were found mainly within private ranches. Both the Lewa Wildlife Conservancy and Ol Jogi remain important refuges for the species. Eleven percent of all Grevy’s zebra sighted were found outside conservancies within community trust land, indicating that healthy sub-populations of the species exist even where there is no formal protection in place.
In February 2010 we undertook a three-week expedition to re-assess the status of Grevy’s zebra and other large mammals in the Marsabit region of northern Kenya. We were a team of 10 from four different organizations including the Saint Louis Zoo, Marwell Wildlife, Grevy’s Zebra Trust and Denver Zoo.
This survey built upon previous surveys of the region undertaken in 2000 by Alastair Nelson and Stuart Williams and in 2005 by Marwell Wildlife, Lewa Wildlife Conservancy and the Northern Rangelands Trust. The survey used a combination of sociological questionnaires, transect counts and interviews with key local respondents to assess the status of Grevy’s zebra and other wildlife species.
Preliminary results confirm the conclusion by the 2005 survey that Grevy’s zebra persist around Sibiloi National Park and in the eastern Chalbi Desert and that these populations appear vulnerable to localised extinction.
While we have not completed a full analysis of results, it is possible to draw several key observations as to why this decline has occurred:
- livestock outnumbered wildlife by many orders of magnitude and is likely to displace wildlife spatially
- access to water is a critical issue for Grevy’s zebra and other large mammals. The availability of water for wildlife was often restricted to livestock watering locations, some of which have recently been developed to prevent animals from accessing the water directly and therefore improve water quality for people. Grevy’s zebra were observed in areas where water is freely accessible and therefore cannot be easily developed
- poaching also appears to be a major issue, with a proliferation of guns and an erosion of cultural taboos leading to more widespread hunting