South Africa has an extensive linear infrastructure network of roads, railways and powerlines, which is essential for human connectivity. However, it is not great news for primates. Approximately 18% of the world’s primates are directly impacted by linear infrastructure. In a recent paper* co-authored by EWT scientists, the impact of linear infrastructure on South Africa’s primate species was studied.

Within South Africa, many primates are killed in road collisions and powerline electrocutions every year. To get an indication of the extent to which primates are affected by wildlife, data was collated from the EWT’s database of vertebrate roadkill**, as well as from the EWT-Eskom Central Incident Register, which is a national database of wildlife incidents on electrical infrastructure, mainly electrocutions and collisions. The focal species for this study were the Vervet Monkey (Chlorocebus pygerythrus), Chacma Baboon (Papio ursinus), Thick-Tailed Bushbaby (Otolemur crassicaudatus), Southern Lesser Bushbaby (Galago moholi), and Samango Monkey (Cercopithecus albogularis).

The authors found that Vervet Monkeys were most reported in both roadkill and powerline collision incidents (see the figure below). The Southern Lesser Bushbaby was least frequently reported. The data also showed that several incidents involved more than one individual. When it came to roadkill, 4% of incidents involved between two and four individuals killed in one collision, whereas in electrocution incidents, 13% of cases had between two and six individuals killed in one incident.

Comparison of South Africa’s primate roadkill and electrocution mortalities (from Linden et al. 2022)

The authors recommended that mitigation measures, such as canopy bridges across roads and better insulation of transformers and substations, be more widely implemented to help conserve South Africa’s primate populations. Although South Africa leads the African continent regarding roadkill and electrocution data collection, key information, such as GPS coordinates and the age and sex of individuals, is missing. Data collection protocols can be improved to better inform mitigation measures and understand impacts on populations. Future Red List assessments should acknowledge linear infrastructure as a more significant threat to primates.

* Linden, B., Cuozzo, F. P., Sauther, M. L., & Jonker, W. C. (2022). Impact of linear infrastructure on South Africa’s primate fauna: the need for mitigation. Folia Primatologica, 1(aop), 1-19.

** The EWT has a free road watch app available to record any roadkill sightings. This will help us identify hotspot areas as well as the species most at risk.