Why no gazelle at the southwestern tip of Africa?
Mediterranean-type climates, with dry summers and rainy winters, occur both in South Africa and along the Mediterranean coasts of North Africa and the Levant. And gazelles have been evolving and shifting their ranges across Africa and Asia for millions of years. However, a puzzling faunistic difference is that four species of gazelles (Gazella cuvieri, Gazella dorcas massaesyla, Gazella gazella gazella, and Eudorcas rufina) are indigenous to the northern area whereas no species of gazelle is indigenous to the southern area.
In South Africa there is one species of gazelle, namely the springbok (Antidorcas marsupialis, see https://www.inaturalist.org/observations/35692467). However, this has not naturally penetrated the mediterranean-type climate of Western Cape Province (the many observations in iNaturalist being of introduced populations). Furthermore, even within its distribution in South Africa the springbok avoids stony slopes, in contrast to Cuvier's gazelle in the Atlas ranges of Morocco-Algeria (see https://www.inaturalist.org/observations/39161994) and the mountain gazelle, which is named after its association with stony slopes in e.g. Israel (see https://www.inaturalist.org/observations/5305686).
Why are there these disparities? One partial explanation involves competing members of the ruminant fauna.
A crucial difference is that the grey rhebok (Pelea capreolus, see series of photos in https://animalia.bio/grey-rhebok), mountain reedbuck (Redunca fulvorufula), common eland (Taurotragus oryx, see http://shutterstock.puzzlepix.hu/kep/1614041191), steenbok (Raphicerus campestris, see https://www.zoochat.com/community/media/steenbok-raphicerus-campestris.488693/) and Cape grysbok (R. melanotis) of South Africa have no counterparts in North Africa or the Levant. These species were, until recently, common in the relevant environments near the southwestern tip of Africa. Among them, they arguably usurped the niche of gazelles.
The grey rhebok and mountain reedbuck prefer stony slopes, and the distribution of the former included most of the South African area of mediterranean-type climate. Both are similar in body size and partly similar in diet to the springbok. The common eland is extremely large (adult female about 500 kg) and the two species of Raphicerus smaller than gazelles, but all have diets which overlap those of gazelles enough for them to be potential competitors.
To 'rewild' the climatically similar stony slopes near Casablanca in the north and Cape Agulhas in the south of the same continent, we would reintroduce to the northern area only Cuvier's gazelle, but to the southern area at least three species: grey rhebok, common eland and steenbok/Cape grysbok. One would be naive to think that the same ecological function could be restored by simply 'reintroducing' the springbok in Agulhas National Park (see https://www.inaturalist.org/observations/3975537), even though it is by far the most similar antelope to Cuvier's gazelle that is available in the southern African fauna.