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Artiodactyla
Id code: amd215Bovidae
Raphicerus melanotis
(Thunberg, 1811)
(Eng) Cape grysbok
(Fre) Grysbok
Taxonomic notes
No significant taxonomic notes.
IUCN threat category
Lower Risk, conservation dependent (LR: cd).
Available information
The main source of information on the ecology and distribution of this species is Mills & Hes (1997) and Skinner & Smithers (1990). The authors give a general description of their habitat requirements and other aspects of its ecology, such as diet and habits. Lynch (1989) reports a map of distribution and locations of collected specimens. As the species is confined to a very small area of the Cape Province, the information available on its occurrence is probably quite satisfactory. No specific studies on the species' ecology have been conducted. Status and distribution, together with some ecological notes, are reported by East (1989). General information on the species' ecology and distribution is found in Kingdon (1997) and Stuart & Stuart (1997).
Known extent of occurrence
Endemic to South Africa, the Cape grysbok is recorded only from southern and south-western Cape Province (East, 1989, 1996; Wilson & Reeder, 1993). Its distribution map was obtained from Skinner & Smithers (1990) and revised by Dr. R. East (23 June '97) (Fig. 8.6.32.a).
Categorical-discrete (CD) distribution model
This species is almost entirely restricted to fynbos, inhabiting thick bushes and shrublands. It also occurs in orchards and vineyards areas (Tinley, 1969; Stuart & Stuart, 1997; Mills & Hes, 1997).
Based on these environmental preferences, the following scores were assigned (Fig. 8.6.32.b) (Tab. 8.6.32.a):
|
Score |
|
|
1 |
Shrublands, bushlands and their mosaics. |
|
2 |
Woodlands and woodland mosaics, forest mosaics and orchard and vineyard croplands. |
|
3 |
Other croplands, forests and desert. |
|
suitable |
moderately suitable |
unsuitable |
Total |
||||
|
km2 |
% |
km2 |
% |
km2 |
% |
km2 |
% |
|
151 638 |
62 |
62 955 |
26 |
28 065 |
12 |
242 658 |
100 |
Tab 8.6.32.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 |
73 |
2 075 |
15 902 |
63.96 |
1.39 |
8.39 |
|
moderately suitable |
173 |
361 |
2 249 |
13.65 |
1.4 |
4.98 |
|
Total AO |
35 |
6 111 |
35 348 |
99.22 |
1.27 |
5.77 |
Tab 8.6.32.b: Area of Occupancy fragmentation indexes.
Probabilistic-continuous (PC) distribution model
The output of the probabilistic-continuous (PC) distribution model is shown in Fig. 8.6.32.c.
Validation
No occurrence of the species within the four sample areas.
Comments and conservation issues
The species is restricted to a very small EO in southern Africa: most of it appears to be suitable as potential AO. The suitable areas are not significantly fragmented as shown by the low NP and high MPS. The LPI for the total AO is 99.22% showing a substantial continuity of suitable range. The PC model indicates a more fragmented distribution of suitability classes than the CD model. There are no large protected areas within the EO of the species which is classified as Lower Risk.
References
East R. (Ed.) (1989). Antelopes Global Survey and Regional Action Plans. Part 2: Southern and South-central Africa. IUCN/SSC Antelope Specialist Group.
East R. (Ed.) (1996). Antelope survey update. IUCN/SSC Antelope Specialist Group: n° 2.
Kingdon J. (1997). The Kingdon field guide to African Mammals. Academic Press, London and New York: Natural World.
Lynch C.D. (1989). The mammals of the north-east Cape Province. Mem. van die Nasionale Mus., Bloemfontein: 25, 1-116.
Mills G., Hes L. (1997). The complete book of Southern African mammals. Struik Publishers.
Skinner J.D., Smithers R.H.N. (1990). The mammals of the Southern African subregion. University of Pretoria, Pretoria.
Stuart C., Stuart T. (1997). Field guide to the larger mammals of Africa. Struik Publishers.
Tinley K.L. (1969). Dik-dik Madoqua kirki in South West Africa: Notes on distribution, ecology and behaviour. Madoqua: 1, 7-33.
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.