Artiodactyla Id code: amd337
Bovidae
Cephalophus maxwellii
(H. Smith, 1827)
(Eng) Maxwell's duiker
(Fre) Céphalophe de Maxwell
Taxonomic notes
Sometimes included in C. monticola (Groves & Grubb, 1981) it is regarded here as distinct according to Wilson & Reeder (1993) and East (1996).
IUCN threat category
Lower Risk, near threatened (LR: nt).
Available information
A detailed review of the ecology of the species is found in Ralls (1973), and no specific studies on the ecology of the species have been conducted since. Geerling & Bokdam (1973) investigated its presence in a protected area of Ivory Coast; the authors give a brief description of the habitat in which the species is found there. Some notes on habitat use are also found in Coe (1975), who assessed the species' presence at Mount Nimba (Liberia). General information on the species' ecology is reported in Haltenorth & Diller (1977), Kingdon (1997) & Stuart & Stuart (1997). Status and distribution, together with some ecological notes, are discussed in East (1990).
Known extent of occurrence
Maxwell’s duiker occurs in the lowland forest area from Senegal to south-western Nigeria (Wilson & Reeder, 1993), and is present in Benin, Burkina Faso, Gambia, Ghana, Guinea, Guinea Bissau, Ivory Coast, Liberia, Nigeria, Togo (East, 1996). Its eastern limit is represented by the Niger River, to the west of which the allopatric species C. monticola occurs ( Ralls, 1973). The first rough distribution map was obtained from Ralls (1973), and updated on the basis of the more recent information found in country maps from East (1990), as indicated by Dr. R. East (23 June '97) (Fig. 8.6.53.a).
Categorical-discrete (CD) distribution model
Primarily found in rainforest, the species appears to be common in riverine forests and forest patches in savanna woodland zones. It is also reported to occur in moister savannas and other dense vegetation near permanent water (Coe, 1975; East, 1990; Stuart & Stuart, 1997; Ralls, 1973; Kingdon, 1997).
Based on these environmental preferences, the following scores were assigned (Fig. 8.6.53.b) (8.6.53.a):
|
Score (*) |
|
|
1 |
Forests. |
|
2 |
Forest mosaics; moist savannas. |
|
3 |
Croplands; dry savannas. |
|
(*) Scores increased for vegetation types occurring inside a 1-km buffer around permanent water |
|
suitable |
moderately suitable |
unsuitable |
Total |
|
km2 |
% |
km2 |
% |
km2 |
% |
km2 |
% |
|
495 088 |
42 |
614 776 |
52 |
80 486 |
7 |
1 190 350 |
100 |
Tab 8.6.53.a: Cumulative size (km 2) 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 |
939 |
21 |
414 |
27.46 |
1.44 |
25.11 |
|
moderately suitable |
841 |
29 |
701 |
45.8 |
1.37 |
34.15 |
|
Total AO |
95 |
468 |
4 496 |
99.19 |
1.42 |
8.61 |
Tab 8.6.53.b: Area of Occupancy fragmentation indexes.
Probabilistic-continuous (PC) distribution model
The output of the probabilistic-continuous (PC) distribution model is shown in Fig. 8.6.53.c.
Validation
Less than 1% of EO within the four sample areas.
Comments and conservation issues
The known EO is mostly suitable, even though it appears to be an intricate mosaic of suitable and moderately suitable areas (small MPS). The high AWMSI indicates that the most relevant patches are also highly fragmented, and this may be linked to the species' association to riverine areas. The CD model classifies the part of the range in southern Senegal as unsuitable and a more complete survey of the area is advisable. Less than 5% of the total AO is included in existing protected areas, but the species is not endangered.
|
SUITABILITY CLASS |
inside |
outside |
Total |
|
suitable |
1.45 |
40.14 |
41.59 |
|
moderately suitable |
3.02 |
48.62 |
51.65 |
|
unsuitable |
0.45 |
6.31 |
6.76 |
|
Total |
4.92 |
95.08 |
100 |
Tab 8.6.53.c: Percent of environmental suitability classes within EO (as obtained from the categorical-discrete distribution model) inside and outside the protected areas.
References
Coe M.J. (1975). Mammalian ecological studies on Mount Nimba, Liberia. Mammalia: 39, 523-581.
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.
Geerling G., Bokdam J. (1973). Fauna of the Comoé National Park, Ivory Coast. Biological Conservation: 5(4), 251-257.
Groves C.P., Grubb P. (1981). A systematic revision of duikers (Cephalophini, Artiodactyla). Afr. Small Mammal Newsletters: Spec n° 4, 35.
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.
Ralls K. (1973). Cephalophus maxwellii. Mammalian Species: 31, 1-4.
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.
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