PrimatesId code: amd064
(Eng) Red-tail guenon
(Fre) Cercopithèque ascagne
According to Kingdon (1997) up to five subspecies may be recognised: C. a. ascanius (Angola red-tail guenon) from lower Zaire and Kasai Rivers to the Cuanza River; C. a. katangae (Katangae red-tail guenon) from north Angola and south Zaire basin to the Lomani and Lualaba Rivers; C. a. atrinasus (Spectacled red-tail guenon) in the Lunda plateau; C. a. whitesidei (Yellow-nosed red-tail guenon) from the Zaire to the Kasai Rivers; C. a. schmidti (Uganda red-tail guenon) north of the Zaire River from the Ubangi River to Uganda and west Kenya and east of the Lualaba River to the Lukuga River.
IUCN threat category
The main aspects of the species’ ecology were investigated in the Kibale Forest by Struhsaker (Struhsaker, 1980, 1988; Struhsaker & Leland, 1988); the author focused mainly on its behaviour, particularly coexistence and relationships with other primates. Habitat use and preference, density, and interspecific relationships with other primates were studied in the Lomako Forest (former Zaire) by McGraw (1994). Information on its habitat in Bioko Island can be found in Gonzalez-Kirchner (1996). Notes on the species’ ecology in the Ikela region (former Zaire) are reported in Maté et al. (1995). Data on the species’ distribution are available from Colyn (1987, 1988); Lernould (1988) and Rahm & Christiaensen (1966); the authors quoted include notes on the species’ ecology, particularly its habitat. General information on the species’ biology is found in Kingdon (1997) and Stuart & Stuart (1997). Status and conservation issues are discussed in Oates (1996).
Known extent of occurrence
C. ascanius occurs in Congo, Uganda, Rwanda, Burundi, former Zaire and Angola, and marginally in C.A.R., west Kenya and Tanzania, apparently being limited by the Sangha and Zaire Rivers on the north and west, and by the Cuanza and lower Kasai rivers system on the south and east. A rough distribution map was obtained from Rahm (1970), but revised on the basis of Kingdon (1997) and the river network (Fig. 2.3.5.a).
Categorical-discrete (CD) distribution model
This species occurs in lowland and montane forests and in gallery forests (Gonzalez-Kirchner, 1996; Kingdon, 1997; Colyn, 1988).
Based on these environmental preferences, the following scores were assigned (Fig. 2.3.5.b) (Tab. 2.3.5.a):
Tab 2.3.5.a: Cumulative size (km2) of areas pertaining to each environmental suitability class within the Extent of Occurrence.
Tab 2.3.5.b: Area of Occupancy fragmentation indexes.
Probabilistic-continuous (PC) distribution model
The output of the probabilistic-continuous (PC) distribution model is shown in Fig. 2.3.5.c.
Tab 2.3.5.c: Categorical-discrete (CD) distribution model validation parameters.
Comments and conservation issues
The known EO of the species is large as it includes most of the forest areas in central Africa. However, only half of the EO appears to be suitable and another 25% is moderately suitable. The unsuitable areas are more frequent in the southern and eastern parts of the EO, where the mosaic of areas of different suitability class becomes more intricate. In northern Angola, eastern former Zaire and western Uganda the species appears to be more obviously restricted to the remnants of forest patches and along gallery forests. The 55.7% accordance with field work results provides a sufficient level of reliability for the CD model even though only 4.9% of the EO falls within the sample areas. Fragmentation is high (small MPS) but the high LPI also shows that at least one large suitable area is available, even though it appears to have a very irregular shape (comparison of MSI and AWMSI). If the moderately suitable areas are also considered, the total AO becomes an almost continuous patch, although the AWMSI again shows a complex shape due to interspersion with unsuitable areas. About 4% of the total AO is included in the existing protected areas but the species is not listed as threatened.
Tab 2.3.5.d: Percent of environmental suitability classes within EO (as obtained from the categorical-discrete distribution model) inside and outside the protected areas.
Colyn M.M. (1987). Les primates de la foret ombrophile de la Cuvette du Zaire: interprétations zoogéographique des modèles de distribution. Rev. Zool. Africaine: 101, 183-196.
Colyn M.M. (1988). Distribution of guenons in the Zaire-Lualaba-Lomani river system. 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 104-124.
Gonzalez-Kirchner J.P. (1996). Notes on habitat use by the Russet-eared guenon (Cercopithecus erythrotis Waterhouse 1838) on Bioko Island, Equatorial Guinea. Tropical Zoology: 9, 297-304.
Kingdon J. (1997). The Kingdon field guide to African Mammals. Academic Press, London and New York: Natural World.
Lernould J. (1988). Classification and geographical distribution of guenons: a review. 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 54-78.
Maté C., Escobar M., Colell M. (1995). Preliminary observations on the ecology of forest cercopithecidae in the Kikofe-Ikomaloki region (Ikela, Zaire). Folia Primatol.: 64, 196-200.
McGraw S. (1994). Census, habitat preference and polyspecific association of six monkeys in the Lomako Forest, Zaire. Amer. J. Primatol.: 34 (4), 295-308.
Oates J.F. (1996). African Primates Status Survey and Conservation Action plan. IUCN/SSC Primate Specialist Group.
Rahm U. (1970). Ecology, zoogeography and systematics of some African forest monkeys. In: Napier J.R., Napier P.H. (Eds). Old World Monkeys. Evolution, Systematics and Behavior. Academic Press, London and New York:pp 591-626.
Rahm U., Christiaensen A. (1966). Les mammiferès de l'Ile Idjwi (Lac Kivu, Congo). Les mammifères de la foret equatoriale de l'est du Congo. Ann. Mus. Roy. Afr. Cent.: n° 149.
Struhsaker T.T. (1980). Comparison of the behaviour and ecology of red colobus and redtail mokeys in the Kibale Forest, Uganda. Afr. J. Ecol.: 18, 33-51.
Struhsaker T.T. (1988). Male tenure, multi-male influxes, and reproductive success in redtail monkeys (Cercopithecus ascanius) in the Kibale Forest , Uganda. 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 340-363.
Struhsaker T.T., Leland L. (1988). Group fission in redtail monkeys (Cercopithecus ascanius) in the Kibale forest, Uganda. 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 364-388.
Stuart C., Stuart T. (1997). Field guide to the larger mammals of Africa. Struik Publishers.