Encounter trends for steenbok, oribi, Cape grysbok and grey rhebok from the Coordinated Avifaunal Roadcount (CAR) project for South Africa

Abstract

The Coordinated Avifaunal Roadcount (CAR) is one of South Africa’s longest-running citizen science programmes, initiated in 1997 to monitor large terrestrial birds. Since 2012, the project has also recorded selected antelope species at the request of CapeNature, notably steenbok (Raphicerus campestris), Cape grysbok (Raphicerus melanotis), grey rhebok (Pelea capreolus) and, in parts of the Eastern Cape and KwaZulu-Natal, oribi (Ourebia ourebi). We analysed records from 2012–2022 to evaluate population trends. Steenbok were the most frequently observed, showing a slight increase in detection probability but no significant change in relative abundance. Grey rhebok exhibited a modest but consistent increase in both detectability and counts, suggesting potential local gains. Cape grysbok records were sparse, with no discernible trends in presence or relative abundance, while oribi were detected more often in winter surveys but showed no overall temporal change. These results highlight the value of CAR for monitoring mammals alongside its primary avifaunal focus. However, reduced participation in recent years limits inference and underscores the importance of sustained volunteer engagement and collaboration with conservation agencies to ensure the continued contribution of CAR to biodiversity monitoring in South Africa.