Researchers tracked roan and sable in Mudumu National Park to determine how they were using the landscape
Roan and sable antelopes in Namibia avoid predation by staying clear of water sources teeming with predators like lions.
The recent discovery is important for wildlife managers deciding the best way to conserve a wide suite of species.
Mudumu National Park lies in the northeastern panhandle of Namibia, sandwiched between Botswana to the south and both Angola and Zambia to the north. The park sits in the Kavango Zambezi Transfrontier Conservation Area, which spans five countries along the titular rivers and surrounding areas.
Neither roan (Hippotragus equinus) nor sable (H. niger) antelopes, the latter pictured above, are considered under conservation threat in Africa, at least according to the International Union for Conservation of Nature. But this is due to a paucity of information about the two species, said Lineekela Nauyoma, who recently completed a PhD in wildlife conservation and management at the University of Namibia.
Roan, made up of six recognized subspecies, range widely in several different regions of Africa. The one occurring in Mudumu is H. e. equinus.
Sable have a smaller range, mostly in southern Africa, and are made up of four recognized subspecies. One of them occurs in the general Kavango-Zambezi region: the southern sable antelope (H. n. niger) typically found in Mudumu.
The numbers of both species are declining in general and face threats from poaching and habitat fragmentation. Neither is doing very well in the Mudumu area—both inside and outside the park, Nauyoma said.
In a study published in the Wildlife Society Bulletin, Nauyoma and his colleagues set out to learn more about the ways that these antelopes used the landscape in Mudumu. In 2021, during the wet season from March to May and the dry season from June to September, the team set out about two dozen trail cameras in different parts of the national park.
High grass and no water
Analysis of the trail camera images showed that both roan and sable antelopes seemed to select areas with higher grass cover. Both species are relatively tall grazers and have a narrow mouth, which allows them to feed on higher grasses compared to species like African buffalo (Syncerus caffer), pictured above, which are short grass grazers with broad mouths. These buffalo keep the grasses shorter and unfavorable for roan and sable, Nauyoma said.
The team found that the roan and sable typically selected areas farther from the Kwando River, both in the wet and dry seasons. While the results didn’t show a similar pattern with sable in the wet season, a relatively small sample size could have skewed the findings. Nauyoma believes that sable typically select areas farther from water sources as well.
Staying away from water sources likely helps antelopes steer clear of predators like lions (Panthera leo), which stay close to water that typically attracts other kinds of prey like Burchell’s zebras (Equus burchelli). The latter also have a tendency to keep the grass around them at a lower height that is unsuitable for roan and sable, as they have wider mouths than those antelopes.
“I believe that roan and sable are avoiding all these problems by staying far from the river and other ungulates,” Nauyoma said about the predators and zebra near the river. Typically, he said, roan and sable only visit the river for short periods to drink every three to four days.
Termite attraction?
Camera trap analysis also revealed that termite mounds affected roan and sable presence. In the dry season, roans occurred more in areas with termite mounds, while sables avoided these areas, but only in the wet season.
Nauyoma said sables may be avoiding termite mounds in these periods because of ticks, which can be fatal. Meanwhile, in the dry season, termite mounds may provide beneficial salts and nutrients to roan. They could absorb these from eating grasses around the mounds or from licking the mounds directly, Nauyoma said.
Managers can use this information to benefit these species, Nayoma said. Termite mounds can be translocated, for example, by moving a chunk of an existing mound somewhere new. The termites may begin to rebuild it again in the new location.
The findings about water also have implications for management actions. Sometimes, for example, managers place artificial troughs in some areas to supplement the water for various species. But Nauyoma said this study suggests that these features may not benefit sable or roan, which typically seem to avoid water sources as much as possible.
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