Artiodactyla Id code: amd159Bovidae Connochaetes taurinus (Burchell, 1823) (Eng) Brindled gnu or blue wildebeest (Fre) Gnou à queue noire Taxonomic notes Five subspecies have been described (East, 1996). IUCN threat category Lower Risk, conservation dependent (LR: cd) as C. t. albojubatus (Eastern white-beared wildebeest) in Kenya, Tanzania; as C. t. cooksoni (Cookson’s wildebeest) in Malawi, Zambia; as C. t. johnstoni (Niassa wildebeest) in Malawi (ex), Mozambique, Tanzania; as C. t. mearnsi (Western white-beared wildebeest) in Kenya, Tanzania; and as C. t. taurinus (Blue wildebeest) in Angola, Botswana, Mozambique, Namibia, South Africa, Swaziland, Zambia, Zimbabwe. Available information The ecology of the blue wildebeest has been widely studied in most of its range of distribution. East Africa: Particular aspects of habitat use are analysed in two papers. A study on the effects of seasonal changes in water availability on several large mammals species, including the blue wildebeest, was conducted in Amboseli by Western (1975). In Lake Burungi (Tanzania), Moe et al. (1990) analysed the use of burnt areas by large herbivores and the effects on their distribution. In the Serengeti system, the migratory behaviour of the species was studied by several authors (McNaughton, 1976; Northon-Griffiths, 1973; Pennycuick, 1975). Information on the feeding habits is found in Murray (1993) and Stewart & Stewart (1971). A study of the role of food availability on the population mortality rate was also conducted in the area by Sinclair et al. (1985). Southern Africa: Habitat requirements and selection were analysed by Hirst (1975) and Ben-Shahar (1995), who both studied the species in the Transvaal lowveld; Ben Shahar (1991) also gives detailed information on its feeding ecology. Data on activity patterns are available from Berry et al. (1982) and Ben-Shahar & Fairall (1987). Studies on population structure and dynamics were carried out by Attwell (1982) in Kwa-Zulu Natal, and by Whyte & Joubert (1988) in the Transvaal lowveld, where its migratory behaviour was also investigated (Thrash et al., 1995; Eloff, 1966). Seasonal distribution in the Makgadikgadi Pans (Botswana) is described in Kgathi & Kalikawe (1993). Status and distribution has recently been accurately monitored in Botswana (Anonymous, 1993, 1994a, 1994b, 1995; Spinage, 1992). Data on distribution, status, and ecology are also available for some areas of South Africa (Lynch, 1983, 1989; Rowe-Rowe, 1994). A very detailed account of the ecology of the species in the subregion is found in Mills & Hes (1997) and Skinner & Smithers (1990), while general information on the species' ecology is given in Estes (1991) and Kingdon (1997). Status and distribution, together with some ecological notes, are discussed in East (1988, 1989). Known extent of occurrence 
Extinct in Malawi, this gnu still ranges in Angola, Botswana, Kenya, Mozambique, Namibia, South Africa, Swaziland, Tanzania, Zambia, Zimbabwe (East, 1996; Wilson & Reeder, 1993) with its southernmost limit along the Orange River (Estes, 1991). Its distribution map was obtained from Estes (1991), then refined using detailed country maps in East (1988, 1989) as indicated by Dr. R. East (23 June '97) (Fig. 8.6.4.a). Categorical-discrete (CD) distribution model Found mainly in short-grass savanna; the species is also found in open woodland and bushland. Water bound (Lynch, 1983; East, 1988, 1989; Hirst, 1975; Kingdon, 1997; Van der Walt, 1986; Ben-Shahar, 1995; Stuart & Stuart, 1997; Mills & Hes, 1997). Based on these environmental preferences, the following scores were assigned (Fig. 8.6.4.b) (8.6.4.a):
Tab 8.6.4.a: Cumulative size (km 2) of areas pertaining to the different environmental suitability class within the Extent of Occurrence.
Tab 8.6.4.b: Area of Occupancy fragmentation indexes. Probabilistic-continuous (PC) distribution model The output of the probabilistic-continuous (PC) distribution model is shown in Fig. 8.6.4.c. Validation
Tab 8.6.4.c: Categorical-discrete (CD) distribution model validation parameters. Comments and conservation issues The low Index of Accordance (48.84%) possibly reflects the limitations on the species distribution induced by the veterinary fences in Botswana, nevertheless it may suggest some caution in the interpretation of the results of the CD model. Most of the known EO is suitable for this species (92%) and this also reflects the possibility of drawing an accurate EO for large and visible mammals. The best areas are certainly very fragmented (NP and MPS) but the overall AO is not; the LPI of the total AO is quite high (80.22%) and the AWMSI shows that the patches are relatively compact. The most desert areas of Namibia and Botswana appear to be the least suitable according to the CD model. A significant portion of the AO is included in existing protected areas (almost 15%) and the average status of the species is classified as Lower Risk: local races may be more threatened.
Tab 8.6.4.d: Percent of environmental suitability classes within EO (as derived from the categorical-discrete distribution model) inside and outside the protected areas. References Anonymous (1993). Aerial census of animals in northern Botswana. ULG Consultants LTD Birmingham Road, Satisford Warwick CV34 4TT England. Anonymous (1994a). Aerial census of animals in Botswana: wet season 1994. Wildlife conservation in northern Botswana. Anonymous (1994b). Status and trends of selected wildlife species in Botswana. Department of Wildlife and National Park: Research Division. Anonymous (1995). The status of wildlife in Botswana. Serondella News. Official newsletter of Chobe Wildlife Trust.: 6 (5), 1-12. Attwell C.A.M. (1982). Population ecology of the blue wildebeest Connochaetes taurinus taurinus in Zululand, South Africa. Afr. J. Ecol.: 20, 147-168. Ben-Shahar R. (1991). Selectivity in large generalist herbivores: feeding patterns of African ungulates in a semi-arid habitat. Afr. J. Ecol.: 29, 302-315. Ben-Shahar R. (1993). Does fencing reduce the carrying capacity for populations of large herbivores ?. J. Trop. Ecol.: 9, 249-253. Ben-Shahar R. (1995). Habitat classification in relation to movements and densities of ungulates in a semi-arid savanna. Afr. J. Ecol.: 33 (1), 50-63. Ben-Shahar R., Fairall N. (1987). Comparison of the diurnal activity patterns of blue wildebeest and red hartebeest. S. Afr. J. Wildl. Res.: 17(2), 49-54. Berry H.H., Stegfried W.R., Crowe T.M. (1982). Activity pattern in a population of free-ranging wildebeest (Connochaetes taurinus) at Etosha National Park. Z. Tierpsychol.: 59, 229-246. East R. (Ed.) (1988). Antelope Global Survey and Regional Action plans, Part I: East and North East Africa. IUCN/SSC Antelope Specialist Group. East R. (Ed.) (1989). Antelopes Global Survey and Regional Action Plans. Part 2: Southern and South-central Africa. IUCN/SSC Antelope Specialist Group. East R. (Ed.) (1996). Antelope survey update. IUCN/SSC Antelope Specialist Group: n° 2. Eloff F.C. (1966). Range extention of the blue wildebeest. Koedoe: 9, 34-36. Estes R.D. (1991). The Behaviour Guide to African Mammals. Including Hoofed Mammals, Carnivores, Primates. The University of California Press. Hirst S.M. (1975). Ungulate-habitat relationships in a South African Woodland/Savanna Ecosystem. Wildl. Monogr: 44. Kgathi D.K., Kalikawe M.C. (1993). Seasonal distribution of zebra and wildebeest in Makgadi Pans Game Reserve, Botswana. Afr. J. Ecol.: 31, 210-219. Kingdon J. (1997). The Kingdon field guide to African Mammals. Academic Press, London and New York: Natural World. Lynch C.D. (1983). The mammals of the Orange Free State. Mem. van die Nasionale Mus., Bloemfontein: 18, 1-218. Lynch C.D. (1989). The mammals of the north-east Cape Province. Mem. van die Nasionale Mus., Bloemfontein: 25, 1-116. McNaughton S.J. (1976). Serengeti migratory wildebeest: facilitation of energy flow by grazing. Science: 191, 92-94. Mills G., Hes L. (1997). The complete book of Southern African mammals. Struik Publishers. Moe S.R., Wegge P., Kapela E.B. (1990). The influence of man-made fires on large wild herbivores in Lake Burungi Area in Northern Tanzania. Afr. J. Ecol.: 28, 35-43. Murray M.G. (1993). Comparative nutrition of wildebeest, hartebeest and topi in the Serengeti. Afr. J. Ecol.: 31, 172-177. Norton-Griffiths M. (1973). Counting in the Serengeti migratory wildebeest using two-stage sampling. E. Afr. Wildl. J.: 11, 135-149. Pennycuick L. (1975). Movements of migratory wildebeest population between 1960 and 1973. E. Afr. Wildl. J.: 13, 65-87. Rowe-Rowe D.T. (1994). The ungulates of Natal. Natal Parks, Game & Fish Preservation Board, Pietermaritzburg, Natal, R.S.A. Sinclair A.R.E., Dublin H., Borner M. (1985). Population regulation of Serengeti wildebeest, a test of the food hypothesis. Oecologia (Berlin): 65, 266-268. Skinner J.D., Smithers R.H.N. (1990). The mammals of the Southern African subregion. University of Pretoria, Pretoria. Spinage C.A. (1992). The decline of the Kalahari wildebeest. Oryx: 26(3), 147-150. Stewart D.R.M., Stewart J. (1971). Comparative food preferences of five East African ungulates at different seasons. In: Spellberg I.F., Goldsmith F.B. (Eds). The Scientific Management of Animal and Plant Communities for Conservation. Blackwell Scientific, Oxford: pp 351-365. Stuart C., Stuart T. (1997). Field guide to the larger mammals of Africa. Struik Publishers. Thrash I., Theron G.K., Bothma J.D.P. (1995). Dry season herbivore densities around drinking troughs in the Kruger National Park. J. Arid Environ.: 29(2), 213-219. Van der Walt P.T. (1986). An evaluation of salient factors affecting habitat selection by larger animals in the southern Kalahari conservation areas. In: Anonymous(1986). Rangelands: a resource under siege. Proceedings II International Rangelands Congress, Cambridge University Press: 558-559.Western D. (1975). Water availability and its influence on the structure and dynamics of a savanna large mammal community. E. Afr. Wildl. J.: 13, 265-286. Whyte I.J., Joubert S.C.J. (1988). Blue wildebeest population trends in the Kruger National Park and the effect of fencing. S. Afr. J. Wildl. Res.: 18(3), 78-87. Wilson D.E., Reeder D.M. (Eds) (1993). Mammal Species of the World: A Taxonomic and Geographic Reference. Second edition. Smithsonian Institution Press, Washington D.C.
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||