Factors affecting the population size and distribution of the grevy's zebra (equus grevyii) in Northern Laikipia district
Abstract
This study aimed at comparing the ecology of the Grevy's zebra in private
and communal ranches in terms of human-livestock interactions, habitat
quality, population size and. structure and spatial temporal distribution. The
study was carried out in a privately managed Mpala Ranch and communally
managed Koija ranch in the Northern Laikipia District.
Data collection involved physical observations and road counts for fauna data
while vegetation data was collected using step point method and spatial point
mapping with habitat assessment being done using a rangefinder technique.
Descriptive and inferential statistics were used in the analysis.
Comparatively, Mpala Ranch had more forage quantity in both dry and wet
season than Koija Ranch (Dry; U=6.5, d.f=23, p= 0.001 and Wet; U=7; df=23
p=O.001). At the same time the ranch had more grass species diversity
relative to Koija Ranch which on contrary had more herb species diversity (H'
index Mpala; 2.7 and Koija; 1.7). The latter is an indication of overgrazing and
reduced rangeland quality in the community ranch. In terms of Grevy's zebra
population numbers, there was no significant difference between Mpala and
Koija ranches in the wet season (t=0.57, d.f=7, p>0.05). However, in the dry
season when forage was limited, no Grevy's zebra species were recorded in
Koija Ranch contrary to the situation in ~p'~la Ranch which registered an
increase in their population; mainly due to -1Ttfjuxes from the surrounding
ranches. The study noted that there was no significant difference between the
habitat openness of Mpala and Koija (t=2.02, d.f=23, p>0.05), nevertheless,
the Grevy's zebra were found to prefer the more open areas (u=ii, d.f=5
1'=0.001) especially In Mpala Ranch perhaps 85 a precaution against
predators. The study also found out that the Ewaso Ng'iro River is an
important source of water for Grevy's zebra in both seasons, and particularly
so in the community ranch. The dams were distributed close to the Bernas
and as such people and their livestock monopolized the dams during the day.
The study concludes that the private ranch has much better quality habitat in
terms of forage cover and quality of the grass and herb species and attracts
Grevy's zebra in the dry and wet seasons. Although, predation is a real threat
in the private ranch, the Grevy's zebra seem to exercise caution by preferring
the more open areas where they can detect predators from far. The
community ranch is degraded with less forage cover and inhabited by
unpalatable species and is used as only wet season dispersal areas by the
Grevy's zebra.
Range rehabilitation, livestock number regulation, proper grazing system, and
provision of water are important factors in the conservation of the Grevy's
zebra especially in the community ranch.
Publisher
Department of Geography and Environmental Studies,University of Nairobi
Description
Master of Arts (Environmental Planning and Management),