Oryx beisa

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA MAMMALIA CETARTIODACTYLA BOVIDAE

Scientific Name: Oryx beisa
Species Authority: (Rüppell, 1835)
Infra-specific Taxa Assessed:
Common Name(s):
English Beisa Oryx
Synonym(s):
Oryx gazella (Rüppell, 1835) subspecies beisa
Taxonomic Notes: This species was previously considered a subspecies of the Gemsbok Oryx gazella, but is here treated as distinct following Grubb (2005) and others. Two subspecies are recognized: Beisa Oryx (O. b. beisa) and Fringe-eared Oryx (O. b. callotis).

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): IUCN SSC Antelope Specialist Group
Reviewer(s): Mallon, D.P. (Antelope Red List Authority) & Hoffmann, M. (Global Mammal Assessment)
Justification:
Listed as Near Threatened as numbers have been estimated at ca. 67,000 and populations trends are declining apart from in a few protected areas. It had already declined heavily around the margins of its range. Threats from hunting and overgrazing are continuing and it is predicted that the overall level of decline will reach at least 25% over the last 3 generations (21-24 years), thus approaching the threshold for Vulnerable under criterion A2.

Geographic Range [top]

Range Description:This species formerly occurred widely in the semi-arid and arid bushland and grasslands of North-East Africa, from north-east Sudan throughout arid areas of Eritrea, Ethiopia, north-east Uganda and Kenya to Djibouti, Somalia and north-east Tanzania (Wacher and Kingdon in press). Their distribution has declined markedly in numbers and distribution, especially at the margins of its range, e.g., Uganda and Somalia, but still occur quite widely in areas of Ethiopia, northern and eastern Kenya and north-eastern Tanzania where human and livestock densities are low (East 1999).

There is no recent confirmation of Beisa Oryx occurrence in Eritrea, where its status is uncertain. Likewise, the failure to locate any oryx during a 1995 aerial survey of Bokora Corridor, Matheniko and adjoining areas of Karamoja suggests that it has either disappeared completely from Uganda or at best survives in very small numbers (East 1999).

Fringe-eared Oryx are distributed entirely south of the Tana River in eastern Kenya and north-east Tanzania, with a major centre of distribution in Tsavo (East) and the Galana Ranch region (Cobb 1976), spreading west and south to Mkomazi, Amboseli and sporadically appearing in Serengeti (Wacher and Kingdon in press).
Countries:
Native:
Djibouti; Ethiopia; Kenya; Somalia; South Sudan; Tanzania, United Republic of
Possibly extinct:
Eritrea; Sudan; Uganda
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population: Population estimates are available from aerial surveys of large parts of the species’ range. Summation of these estimates suggests total populations of about 25,000 Beisa and 8,000 Fringe-eared, but this makes no allowance for unknown levels of undercounting bias and areas for which no estimates of numbers are available. Citing various authors East (1999) indicates that population densities estimated from aerial surveys are typically low, e.g., 0.05-0.10/km² in areas such as the Awash Valley and Tsavo and 0.15-0.20/km² in areas such as Omo-Mago-Murule-Chew Bahir, Mkomazi and Tarangire.

East (1999), correcting for undercounting bias, gives estimated total populations of about 50,000 Beisa Oryx and 17,000 Fringe-eared Oryx (East 1999). Population trends are probably gradually downward over most of the species’ current range, with exceptions in areas such as Sibiloi and Laikipia (Beisa Oryx) and Kajiado, Tarangire and Mkomazi (Fringe-eared).
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: Occurs widely in the semi-arid and arid bushland and grasslands of North-East Africa. The condition of grazing and state of the soil influence seasonal movements (Wacher and Kingdon in press). They occur to altitudes of 1,700 m in Ethiopia (Yalden et al. 1996). Both subspecies eat a wide range of grass species and growth stages, taking more browse during the dry season (Wacher and Kingdon in press). Drinks regularly when water available, but can get by on water-storing melons, roots, bulbs, and tubers, for which it digs assiduously.
Systems: Terrestrial

Threats [top]

Major Threat(s): Poaching (for meat and hides) and encroachment by settlement and livestock remain the major threats to this species, especially since the majority of the population remains outside protected areas.

Conservation Actions [top]

Conservation Actions: Most remaining populations of Beisa Oryx occur outside protected areas (with only 17% of the population in Pas). The largest populations occur in the Awash N.P. in the Awash Valley and Omo-Mago-Muruie-Chew Bahir (Ethiopia) and Sibiloi National Park and the unprotected northern rangelands (Kenya).

About 60% of Fringe-eared Oryx are in protected areas, particularly in Tsavo, Kajiado and Kilifi (Kenya) and Tarangire and Mkomazi (Tanzania).

More effective protection and management of the remaining populations in areas where the species still occurs in substantial numbers but its populations are in decline, such as the Awash Valley, Omo-Mago-Chew Bahir, northern Kenya and Tsavo, would greatly enhance the long-term survival prospects of this species (East 1999).

Populations of Beisa Oryx are maintained in captivity.

Bibliography [top]

East, R. 1999. African Antelope Database 1999. IUCN, Gland, Switzerland and Cambridge, UK.

Grubb, P. 2005. Artiodactyla. In: D. E. Wilson and D. M. Reeder (eds), Mammal Species of the World. A Taxonomic and Geographic Reference (3rd ed), pp. 637-722. Johns Hopkins University Press, Baltimore, USA.

Wacher, T. and Kingdon, J. In press. Oryx beisa. In: J. S. Kingdon and M. Hoffmann (eds), The Mammals of Africa, Academic Press, Amsterdam, The Netherlands.

Yalden, D. W., Largen, M. J., Kock, D. and Hillman, J. C. 1996. Catalogue of the Mammals of Ethiopia and Eritrea 7. Revised Checklist, zoogeography and conservation. Tropical Zoology 9(1): 73-164.


Citation: IUCN SSC Antelope Specialist Group 2008. Oryx beisa. In: The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 01 October 2014.
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