ARTIODACTYLA

Artiodactyla Id code: amd154

Bovidae
Cephalophus jentinki

Thomas, 1892

(Eng) Jentink's duiker

(Fre) Céphalophe de Jentink

Taxonomic notes

General agreement exists concerning the taxonomic status of this species (Wilson & Reeder, 1993; East, 1990; Meester & Setzer, 1971).

IUCN threat category

Vulnerable (VU: criteria A1c, C1).

Available information

Information available on the ecology of the Jentink’s duiker is very poor. The species' presence was assessed quite recently in part of Sierra Leone by Davies & Birkenhagen (1990) and Wilson & Wilson (1990). The authors mentioned above also gathered some information on its ecology from local hunters, particularly on habitat preferences and feeding habits. A brief description of the main aspects of the species' ecology and distribution is found in Haltenorth & Diller (1977) and Kingdon (1997). Status and distribution, together with some ecological aspects, are discussed in East (1990).

Known extent of occurrence

One of the larger duikers in Africa, it is found only in the western part of the Upper Guinea forest block, stretching into Sierra Leone, Liberia and west Ivory Coast (Wilson & Reeder, 1993; East, 1996; Davies & Birkenhager, 1990; Wilson & Wilson, 1990). A first rough map representing its geographic range was acquired from Haltenorth & Diller (1980), later updated for Sierra Leone in accordance with Davies & Birkenhager (1990). A general revision was obtained using East (1990), while a preliminary output was revised by Dr. R. East (23 June '97) (Fig. 8.6.51.a).

Categorical-discrete (CD) distribution model

The species occurs primarily in forests, but can also utilise forest edges and forest mosaics (Davies & Birkenhager, 1990; East, 1990).

Based on these environmental preferences, the following scores were assigned (Fig. 8.6.51.b) (8.6.51.a):

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

	suitable		moderately suitable		unsuitable		Total
OCCURRENCE	km²	%	km²	%	km²	%	km²	%
certain	74 761	58	43 400	33	8 819	7	126 980	98
possible	904	1	1 090	1	660	1	2 654	2
Total	75 665	58	44 490	34	9 479	7	129 634	100

Tab 8.6.51.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	51	1 471	9 693	58.27	1.58	15.02
moderately suitable	161	280	1 537	14.44	1.4	6.84
Total AO	8	15 016	38 963	98.31	1.91	5.31

Tab 8.6.51.b: Area of Occupancy fragmentation indexes.

Probabilistic-continuous (PC) distribution model

The output of the probabilistic-continuous (PC) distribution model is shown in Fig. 8.6.51.c.

Validation

No occurrence of the species within the four sample areas.

Comments and conservation issues

The small patches of EO in Sierra Leone are probably remnants of a former larger distribution, but their size poses a clear risk to the survival of the species there. The main part of the EO is in Liberia and Ivory Coast, but the suitable areas are only 39% of the total. Including the moderately suitable areas, however, raises the percentage of the AO to 74% of the EO. It is not highly fragmented as shown by the LPI (58.27%) and the relatively small number of patches. The AWMSI of the suitable areas indicates an intricate boundary of these areas, as expected where forest mosaics are interspersed with clearings and agricultural areas. About 5.5% of the AO is included in existing protected areas, and the species, due to the small AO and the intensive hunting and trapping, is correctly classified as Vulnerable.

OCCURRENCE	SUITABILITY CLASS	inside	outside	Total
certain	suitable	3.41	54.26	57.67
	moderately suitable	1.87	31.61	33.48
	unsuitable	0.22	6.59	6.80
possible	suitable	0	0.70	0.70
	moderately suitable	0	0.84	0.84
	unsuitable	0	0.51	0.51
Total		5.50	94.50	100

Tab 8.6.51.c: Percent of environmental suitability classes within EO (as obtained from the categorical-discrete distribution model) inside and outside the protected areas.

References

Davies A.G., Birkenhager B. (1990). Jentink's duiker in Sierra Leone: evidence from the Freetown Peninsula. Oryx: 24(3), 143-146.

East R. (Ed.) (1990). Antelopes Global Survey and Regional Action Plans. Part 3: West and Central Africa. IUCN/SSC Antelope Specialist Group.

East R. (Ed.) (1996). Antelope survey update. IUCN/SSC Antelope Specialist Group: n° 2.

Haltenorth T., Diller H. (1980). A field guide to the mammals of Africa, including Madagascar. Collins, London.

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

Meester J., Setzer H.W. (Eds) (1971). The Mammals of Africa, an Identification Manual. Smithsonian Institution Press, Washington D.C.

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.

Wilson V.J., Wilson B.L.P. (1990). Notes on the duikers of Sierra Leone. Arnoldia Zimbabwe: 9(33), 451-462.