PRIMATES

Primates Id code: amd004

Cercopithecidae
Lophocebus albigena

(Gray, 1850)

(Eng) Grey-cheeked mangabey

(Fre) Cercocébe à joues grises

Taxonomic notes

Formerly included in genus Cercocebus, this mangabey was put in a distinct genus by Groves (1978). According to Wilson & Reeder (1993), it includes L. a. aterrimus (Black mangabey), treated as a separate species by some authors (Oates, 1996; Kingdon, 1997).

IUCN threat category

Not listed as threatened, but L. a. aterrimus is considered at Lower Risk (LR: nt) in Angola and former Zaire, while L. a. opdenboschi is still classified as data deficient (DD).

Available information

Several studies have been conducted on the grey-cheeked mangabey, and information on some aspects of its ecology is very good. Most of the studies focused on the species’ behaviour, particularly intraspecific relationships and polyspecific associations with other primates (Aldrich-Blake, 1979; Chalmers, 1973; Eisenberg et al., 1979; Gautier-Hion & Gautier, 1986; Ham, 1995; Martin, 1995; Mitani, 1991; Struhsaker, 1979). Gautier-Hion & Gautier (1986), Maté et al. (1995) and Mitani (1991) give also some general information on other aspects on their ecology, particularly their feeding habits and spacing patterns. A comprehensive study on the feeding ecology of this species was conducted by Waser (1977) in the Kibale Forest (Uganda). With the exception of the research carried out in the Lomako Forest (Zaire) by McGraw (1994), no specific research on its habitat requirements has been done. Notes on the species’ presence in former Zaire are found in Rahm & Christiaensen (1966) and Colyn (1987). Status and distribution of this mangabey was recently investigated in Gabon (Blom et al., 1992) and south-east Cameroon (Mitani, 1990, Usongo & Fimbel, 1995). Mitani (1990) also gives some information on the species’ occurrence in northern Congo. General information on the species’ ecology and distribution is found in Kingdon (1997) and Stuart & Stuart (1997). Overall status, distribution, and some ecological notes are reported in Oates (1996).

Known extent of occurrence

This species occurs in equatorial forest block, from south-east Nigeria to Uganda and southward to north-east Angola. Its extent of occurrence was obtained joining locations in Groves (1978) and a map in Horn (1987); later the distribution range was updated on the basis of Kingdon (1997). The Zaire/Lualaba river system is the boundary between the albigenea (east side) and the aterrimus (west side) races. (Fig 2.3.26.a).

Categorical-discrete (CD) distribution model

This species occurs mainly in both primary and secondary rainforest (Kingdon, 1997; McGraw, 1994).

Based on these environmental preferences, the following scores were assigned (Fig. 2.3.26.b) (Tab. 2.3.26.a):

Score
1	Forests.
2	Forest mosaics.
3	Savannas and croplands.

suitable		moderately suitable		unsuitable		Total
km²	%	km²	%	km²	%	km²	%
1 751 384	60	708 052	24	462 059	16	2 921 495	100

Tab 2.3.26.a: Cumulative size (km²) of areas pertaining to each environmental suitability class within the Extent of Occurrence.

	Number Patches (NP)	Mean Patch Size (MPS) km²	Patch Size SD (PSSD) km²	Largest Patch Index (LPI) %	Mean Shape Index (MSI)	Area-Weighted Mean Shape Index (AWMSI)
suitable	898	1 950	55 707	67.88	1.23	28.35
moderately suitable	1 922	369	8 831	15.46	1.27	11.93
Total AO	345	7 132	129 358	97.79	1.27	20.92

Tab 2.3.26.b: Area of Occupancy fragmentation indexes.

Probabilistic-continuous (PC) distribution model

The output of the probabilistic-continuous (PC) distribution model is shown in Fig. 2.3.26.c.

Validation

% of EO in sample areas	Number of valid plots	Index of Accordance (%)
12.58	124	69.35

Tab 2.3.26.c: Categorical-discrete (CD) distribution model validation parameters.

Comments and conservation issues

The rather compact shape of the EO includes the entire forest block of central Africa. It appears to be largely suitable and the total AO accounts for 84% of the EO. Both models indicates lower suitability along the eastern and south-western parts of the EO where unsuitable areas and more extended patches of moderately suitable areas form a mosaic with the suitable areas. This mosaic is confirmed by the high value of the AWMSI of both the suitable areas and the total AO. The LPI also indicates a substantial continuity of suitable areas across the AO. The good Index of Accordance (69.35%) of the CD model can be related to the large quantity of information available on the ecology of the species. Less than 6% of the total AO is included in existing protected areas, but the species is not threatened and only local subspecies are at higher threat levels.

SUITABILITY CLASS	inside	outside	Total
suitable	2.86	57.09	59.95
moderately suitable	2.09	22.15	24.24
unsuitable	1.29	14.53	15.82
Total	6.23	93.77	100

Tab 2.3.26.d: Percent of environmental suitability classes within EO (as obtained from the categorical-discrete distribution model) inside and outside the protected areas.

References

Aldrich-Blake F.P.G. (1979). Problems of social structure in forest monkeys. In: Sussman R.W. (Ed.). Primate Ecology. Problem-oriented field studies. Wiley, Chichester & New York: chap. 21: 405-428.

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.

Chalmers N.R. (1973). Differences in behavior between some arboreal and terrestrial species of African monkeys. In: Michael R.P., Crook J.H. (Eds). Comparative Ecology and Behaviour of Primates. Proceedings of a Conference held at the Zoological Society. London, November 1971. Academic Press, London and New York: pp 69-100.

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.

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.

Gautier-Hion A., Gautier J. (1986). Sexual dimorphism, social units and ecology among sympatric forest guenons. Symposia of the Society for the Study of Human Biology: 24, 61-77.

Groves C.P. (1978). Phylogenetic and population systematics of the Mangabeys (Primates: Cercopithecoidea). Primates: 19, 1-34.

Ham R. (1995). Polyspecific association between grey-cheeked mangabeys (Cercocebus albigena) and four sympatric primate species in the Lopé Reserve, Gabon. [Abstract from 1995 Spring meeting Primate Society of Great Britain, Univ of Edinburgh; April, 95]. Folia Primatol.: 64, 100.

Horn A.D. (1987). Taxonomic assessment of the allopatric Gray-cheeked Mangabey (Cercocebus albigena) and Black Mangabey (C. aterrimus): Comparative socioecological data and the species concept. Amer. J. Primatol.: 12, 181-187.

Kingdon J. (1997). The Kingdon field guide to African Mammals. Academic Press, London and New York: Natural World.

Martin M.P. (1995). Individual social behaviour profiles and group social organisation: analysis of two species of Cercopithecinae. [Abstract 6th Sci. meeting Société Francophone Primatologie, University Montpellier II, Oct.'94]. Folia Primatol.: 64, 87.

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.

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.

Mitani M. (1991). Niche overlap and polyspecific association among sympatric Cercopithecids in the Campo Animal Reserve, Southwestern Cameroon. Primates: 32(2), 137-151.

Oates J.F. (1996). African Primates Status Survey and Conservation Action plan. IUCN/SSC Primate Specialist Group.

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. (1979). Correlates of ecology and social organisation among African cercopithecines. In: Sussman R.W. (Ed.). Primate Ecology. Problem-oriented field studies. Wiley, Chichester & New York: chap. 20: 391-404.

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.

Waser P.M. (1977). Feeding, ranging and group size in mangabey, Cercocebus albigena. 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. 7, 183-222.

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.