Population Status And Human Impact on Burchell's Zebra (Eqlllls Blll'chelli, Gray 1824) in Nechisar Plains, Nechisar National Park, Ethiopia
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Date
2003-01
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Addis Ababa University
Abstract
The population census of Burchell's zebra (Equus burchelh) and the human impact were
carried ollt in Nechisar plains, Nechisar National Park, 515 km south of Addis Ababa from
November 2001 to April 2002. Line transect count was used for population census. Social
and physical surveys carried out on the range of Burchell's zebra population to find out
human impact. The present population density estimate of Burchell's zebra in the Nechisar
plains was found to be 16.6 :f: 1.5/1m? The population abundance of Burchell's zebra in the
study area was found to be 4482 individuals. This estimate sholVS an increase in population
trend compared to the previous one. During the wet season, 57.3% preferred the Nechisar
open grassy plain. During the d'yseason, 53.5% preferred Hare hill plateau bushland.
Grass and water availability was identified as the main factor influencing the movements and
distribution of the Burchell's zebra population in Nechisar plains, especially during the dly
season. Observation of feeding processes showed that they feed upon most com ilIOn grasses
available but appeared to have prefenmce for particular six grass species. Their local
distribution range was contracted during the wet season, 95.9% were observed inside the
park. During the dl)1 season, 76.2% were observed inside the park while 23.8% were
observed outside the park boundmy. Non-territorial nomadic Burchell's zebra live in social
group. The average herd size of one-male harem and bachelor stallion herds was 10.8 and
6.4 individuals. The sex structure of Burchell's zebra population in the Nechisar plains was
34.8% adult male, 41.5% adult female and the rest 23.7% were unsexed immature young.
The sex ratio of adult male to adult female was 1.0:1.19. The age stl1lcture of Burchell's
zebra population in the Nechisar plains was 76.3% adult, 14.7% subadult, 5.2% juvenile and
3.8% foal. Predators of Burchell's zebra in the Nechisar plains are 28.6% lion (Panthera
leo) and 6.5% spotted hyena (Crocuta crocuta), but the other causes of death, 14.5% old age
and 49.4% unknown. Burchell's zebras are diurnal herbivores. During the dly season, two
resting periods observed. The most important aspects of social behaviour communication
were 38.8% visual, 24.2% o!factol)l, 18.8% tactile and 18.2% vocal (or auditory). Agonistic
behaviour is observed during sexual display, danger and disputes. These were 53%
submissive traits, 25% fighting, and 22% aggressive traits. Larger plain wild and domestic
ungulates mix with Burchell's zebra in the Nechisar plains. These are 17.5% Gran! 's gazelle
(G. granti), 4.8% Swayne's hartebeest (A. II. swayni), 1.6% Greater kudu (T. sterepsiceros),
11% cattle and 1.6% domestic goats. The socia-economic survey confirmed that 250
households settled at eight villages in the Nechisar plains comprising 1640 Gllj'i Oromo
people and 7080 livestock. The present study indicated that the Burchell's zebra population
is at conservation risk because of the human impact that includes settlement encroachment,
overgrazing, recent bush invasion and human disturbance. Developing community based
wildlife conservation, improving the socio-economic standard and implementation of
effective educational program to the loati people can serve as a tool for the population
management of the Burchell's zebra.
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Population Status and Human Impact, on Burchell's Zebra