Primates Id code: amd034Cercopithecidae Colobus guereza Rüppell, 1835 (Eng) Guereza or eastern black-and-white colobus (Fre) Colobe guéréza Taxonomic notes The number of taxonomically distinct populations that can be identified within the genus Colobus and their phylogenetic relationships are still under debate (Oates & Trocco, 1983). However most authors agree in considering C. guereza as a distinct well-defined species, clearly separated from other populations (Oates & Trocco, 1983; Oates, 1996; Wilson & Reeder, 1993). IUCN threat category Not listed as a species, but regarded as Data Deficient (DD) as C. g. gallarum in Ethiopia. Available information Most of the literature available concerns the species' ecology in east Africa, while information available for central and west Africa is scarce. East Africa: An intensive study on the ecology of the guereza was carried out in the Kibale Forest (Uganda) by Oates (1977a, 1977b, 1978) and Struhsaker & Oates (1979). The authors investigate the main aspects of the ecology of this species, particularly the feeding habits and social behaviour. Information on feeding habits is also found in Clutton-Brock (1975). A specific study of the effects of human presence on this species was carried out by Oates (1977c). Information on the ecology of this Colobus was collected in Ethiopia (Dunbar & Dunbar, 1974a; 1974b; Fryxell, 1987); the authors mainly investigated social structure and population dynamics, but also give some information on feeding habits and habitat preferences. A comparative study on population density and group size was conducted in a disturbed and an undisturbed forested area of Kenya by Coe (1971). Notes on the species' ecology in Kenya are also found in Clutton-Brock (1975). Data on the species' presence are available for Ethiopia and Eritrea (Yalden et al. 1977; 1996). West and Central Africa: A comparative study of the feeding habits in primary consumers, including this species, in Gabon was carried out by Gautier-Hion et al. (1980). Status and distribution were recently assessed in Gabon (Blom et al., 1992) and part of Cameroon and Congo (Mitani, 1990; Usongo & Fimbel, 1995). General information on the species' ecology, with particular attention to the interspecific relationships among coexisting primates, is reported by several authors (Clutton-Brock, 1977; Dunbar, 1988; Eisenberg et al., 1979). Information on the species' ecology and distribution is also found in Kingdon (1997) and Stuart & Stuart (1997). Oates (1988) gives an overall view of the species' distribution. Conservation issues are discussed in Bourlière (1985) and Struhsaker (1981). Status and distribution are analysed in Oates (1996). Known extent of occurrence 
The guereza has the most wide-ranging geographical distribution of all the black-and-white colobus species. As shown in Fig. 2.3.34.a, it occurs from east Nigeria to Ethiopia, Kenya and north Tanzania. This map was obtained by overlapping the ones in Estes (1991) and Oates & Trocco (1983). Categorical-discrete (CD) distribution model Its presence is known from lowland tropical rain forests to the upper reaches of montane forests, as well as riverine forests throughout the savanna; in some areas it survives in relatively small patches of remnant forest (Yalden et al., 1977; Kingdon, 1997; Dunbar 1987; Oates, 1977c). Based on these environmental preferences, the following scores were assigned (Fig. 2.3.34.b) (Tab. 2.3.34.a):
Tab 2.3.34.a: Cumulative size (km2) of areas pertaining to each environmental suitability class within the Extent of Occurrence.
Tab 2.3.34.b: Area of Occupancy fragmentation indexes. Probabilistic-continuous (PC) distribution model The output of the probabilistic-continuous (PC) distribution model is shown in Fig. 2.3.34.c. Validation
Tab 2.3.34.c: Categorical-discrete (CD) distribution model validation parameters. Comments and conservation issues Only a third of the large EO of the species is classified by the models as suitable and further 25% is classified as moderately suitable. The species is associated to forests and forest mosaics and these vegetation types are highly fragmented outside the central part of the range in northern former Zaire and Congo. The Index of Accordance of 62.05% shows good correspondence between expected and observed occurrence data. Fragmentation indexes are very high (NP = 1413); the LPI and AWMSI confirm that although an interesting continuity of AO appears available, there is nevertheless an intricate mosaic of areas of different suitability classes. About 9% of the total AO is included in existing protected areas, but the species is not listed by the IUCN threat category system.
Tab 2.3.34.d: Percent of environmental suitability classes within EO (as obtained from the categorical-discrete distribution model) inside and outside the protected areas. References Blom A., Alers M.P.T., Feistner A.T.C., Barnes R.F.W., Barnes K.L. (1992). Primates in Gabon - current status and distribution. Oryx: 26(4), 223-234. Bourlière F. (1985). Primate communities: their structure and role in tropical ecosystems. Int J. Primatol.: 6, 1-26. Clutton-Brock T.H. (1975). Feeding behavior of red colobus and black and white colobus in East Africa. Folia Primatol.: 23, 165-207. Clutton-Brock T.H. (Ed.) (1977). Primate Ecology: Studies of Feeding and Ranging Behavior in Lemurs, Monkeys and Apes. Academic Press, London and New York. Coe M.J., 1971: Notes on the black and white colobus monkey in Kenya. E.Afr.Wildl.J., 9:172-175. Dunbar R.I.M. (1987). Habitat quality, population dynamics and group composition in colobus monkeys (Colobus guereza). Int J. Primatol.: 8, 299-329. Dunbar R.I.M. (Ed.) (1988). Primate Social Systems. Croom Helm Publishers Ltd, London. Dunbar R.I.M. & Dunbar P. (1974a). Ecology and population dynamics of Colobus guereza in Ethiopia. Folia primatol. 21: 188-208. Dunbar R.I.M., Dunbar E.P. (1974b). Ecological relations and niche separation between sympatric terrestrial primates in Ethiopia. Folia Primatol.: 21, 36-60. Eisenberg J.F., Muckenhirn N., Rudran R. (1979). The relations between ecology and social structure in primates. [reprinted from Science (1972), 176: 863-874]. In: Sussman R.W. (Ed.). Primate Ecology. Problem-oriented field studies. Wiley, Chichester & New York. chap. 23: 455-484. Estes R.D. (1991). The Behavior Guide to African Mammals. Including Hoofed Mammals, Carnivores, Primates. The University of California Press. Fryxell J. (1987). Seasonal reproduction of white-eared kob in Boma National Park, Sudan. Afr. J. Ecol.: 25, 117-124. Gautier-Hion A., Emmons L.H., Dubost G. (1980). A comparison of the diets of three major groups of primary consumers of Gabon (primates, squirrels and ruminants). Oecologia (Berlin): 45, 182-189. Kingdon J. (1997). The Kingdon field guide to African Mammals. Academic Press, London and New York: Natural World. Mitani M. (1990). A note on the present situation of the primates fauna found from South-eastern Cameroon to Northern Congo. Primates: 31(4), 625-634. Oates J.F. (1977a). The Guereza and its food. In: Clutton-Brock T.H. (Ed.). Primate Ecology: Studies of Feeding and Ranging Behavior in Lemurs, Monkeys and Apes. Academic Press, London and New York:chap.10: 276-313. Oates J.F. (1977b). The social life of the black and white colobus monkey, Colobus guereza. Z.Tierpsycol. 45: 1-60. Oates J.F. (1977c). The Guereza and Man: How man has affected the distribution and abundance of Colobus guereza and other Black Colobus Monkeys. In: Bourne G.H. (Ed.). Primate Conservation. Academic Press, London and New York. Oates J.F. (1978). Water-plant and soil consumption by guereza monkeys (Colobus guereza): A relationship with minerals and toxins in the diet? Biotropica 10: 241-253. Oates J.F. (1988). The distribution of Cercopithecus monkeys in West African forests. In: Gautier-Hion A., Bourlière F., Gautier J., Kingdon J. (Eds). A Primate Radiation: Evolutionary Biology of the African Guenons. Cambridge University Press, New York: pp 79-103. Oates J.F. (1996). African Primates Status Survey and Conservation Action plan. IUCN/SSC Primate Specialist Group. Oates J.F., Trocco T.F. (1983). Taxonomy and phylogeny of black-and-white colobus monkeys: inferences from an analysis of loud call variation. Folia Primatol.: 40, 83-113. Struhsaker T.T. (1981). Forest and primate conservation in East Africa. Afr. J. Ecol.: 19, 99-114. Struhsaker T.T., Oates J.F. (1979). Comparison of the behavior and ecology of red colobus and black-and-white colobus monkeys in Uganda: a summary. In: Sussman R.W. (Ed.). Primate Ecology. Problem-oriented field studies. Wiley, Chichester & New York: chap.:9, 165-183. Stuart C., Stuart T. (1997). Field guide to the larger mammals of Africa. Struik Publishers. Usongo L., Fimbel C. (1995). Preliminary survey of arboreal primates in Lobeke forest Reserve, south-east Cameroon. African Primates IUCN/SSC Primate Specialist Group: 1 (2), 46-48. 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. Yalden D.W., Largen M.J., Kock D. (1977). Catalogue of the mammals of Ethiopia 3. Primates. Monitore Zoologico Italiano: suppl. IX, 1-52. Yalden D.W., Largen M.J., Kock D., Hillman J.C. (1996). Catalogue of the mammals of Ethiopia and Eritrea. 7. Revised checklist, zoogeography and conservation. Tropical Zoology: 9, 73-164.
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||