Knowledge of ecological patterns and processes is key to effective conservation of biodiversity hotspots under threat. Renosterveld is one of the most critically endangered habitats in the biologically unique Cape Floristic Region, South Africa. For the first time, we map and synthesize the current state of knowledge on renosterveld ecology and conservation. We investigated 132 studies for the themes, locations and taxa of renosterveld research and the fragmentation, threats, recommendations and barriers to renosterveld conservation. More studies focused on plants than any other taxa (48% of articles) and are conducted mostly in larger, intact renosterveld fragments. The most commonly identified threat to renosterveld was agricultural intensification; conservation recommendations spanned improved farming practices, formal protection and local patch management. Conservation implementation has been piecemeal and has depended largely on the goodwill of landowners, which can be constrained by costs of conservation measures and a lack of suitable restoration means. Citizen science is a promising potential solution to some barriers. Fragmented knowledge in such a transformed and relatively densely populated region highlights the scale of knowledge gaps for other biodiversity hotspots and has implications for ongoing conservation work.