PRIMATES

Full screen Primates Id code: amd075

Cercopithecidae
Colobus polykomos

(Zimmermann, 1780 )

(Eng) Western black-and-white colobus

(Fre) Colobe blanc-et-noir d’Afrique occcidentale

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). As suggested by Oates & Trocco (1983) and Oates (1996) C. vellerosus C. angolensis and C. satanas have been considered fully distinct species here, while Wilson & Reeder (1993) as well as other authors consider C. vellerosus as conspecific with C. polykomos.

IUCN threat category

Lower Risk, near threatened (LR: nt).

Available information

Taxonomy and phylogeny discussion of this species are discussed in Oates & Trocco (1983). Information on the species' ecology and distribution is found in Kingdon (1997) and Stuart & Stuart (1997), while eco-ethological notes are reported by Galat & Galat-Luong (1985). Status, threats, and conservation issues are discussed in Oates (1996).

Known extent of occurrence

According to the above classification, C. polykomos and C. vellerosus are allopatric species separated by the Bandama River, the former occurring to the west of it and ranging from Ivory Coast to Gambia and Senegal (Wilson & Reeder, 1993; Oates, 1996; Kingdon, 1997). A first rough distribution map was obtained from the overlay of the two maps published by Estes (1991) and Oates & Trocco (1983), but it was then revised and updated to match the river network and other reliable published distribution records (Oates, 1996; Kingdon, 1997). The map (Fig. 2.3.35.a) should not be considered to reflect this monkey's present range accurately; further information is required.

Categorical-discrete (CD) distribution model

This species occurs mostly in forests and gallery forests (Kingdon, 1997; Booth, 1979).

Based on these environmental preferences, the following scores were assigned (Fig. 2.3.35.b) (Tab. 2.3.35.a):

Score (*)
1	Forests.
2	Forest mosaics.
3	Savannas and croplands.
(*) Scores increased for vegetation types occurring inside a 1-km buffer around permanent water.

suitable		moderately suitable		unsuitable		Total
km²	%	km²	%	km²	%	km²	%
228 210	44	165 531	32	127 063	24	520 804	100

Tab 2.3.35.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	238	955	12 033	46.83	1.34	19.99
moderately suitable	667	249	2 131	13.35	1.43	9.37
Total AO	153	2 571	30 156	95.18	1.48	10.86

Tab 2.3.35.b: Area of Occupancy fragmentation indexes.

Probabilistic-continuous (PC) distribution model

The output of the probabilistic-continuous (PC) distribution model is shown in Fig. 2.3.35.c.

Validation

No occurrence of the species within the four sample areas.

Comments and conservation issues

The known EO, rather abruptly cut at the Bandama River, extends into Senegal to include the Gambia River gallery forests. However, the largest patches of unsuitable areas appear to be mostly in the easternmost parts of the range and they should be verified for the species’ presence. Forest continuity throughout the range appears ensured by the contribution of different classes of forests and forest mosaics, and the overall fragmentation of the AO is thus limited. The LPI of the suitable areas is 46.83% indicating a significant continuous good patch, but the AWMSI also shows that the shape of these suitable areas is such that they are highly interspersed with other less suitable areas. Although the species is classified as Lower Risk, it is poorly protected by the existing protected areas which include less than 4% of the total AO.

SUITABILITY CLASS	inside	outside	Total
suitable	1.65	42.17	43.82
moderately suitable	1.48	30.30	31.78
unsuitable	1.76	22.64	24.40
Total	4.88	95.12	100

Tab 2.3.35.c: Percent of environmental suitability classes within EO (as obtained from the categorical-discrete distribution model) inside and outside the protected areas.

References

Booth A.H. (1979). The distribution of primates in the Gold Coast. In: Sussman R.W. (Ed.). Primate Ecology. Problem-oriented field studies. Wiley, Chichester & New York: chap. 7: 139-154.

Estes R.D. (1991). The Behavior Guide to African Mammals. Including Hoofed Mammals, Carnivores, Primates. The University of California Press.

Galat G., Galat-Luong A. (1985). La communauté de Primates diurnes de la foret de Tai, Côte d'Ivoire. Revue de Ecologie (La Terre et la Vie): 40, 7-32.

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

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.

Stuart C., Stuart T. (1997). Field guide to the larger mammals of Africa. Struik Publishers.

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.