Sambar deer (Rusa unicolor) on Table Mountain, Cape Town: rethinking the role of a non-native species in an urban-curated ecosystem

Abstract

Table Mountain, which is part of Table Mountain National Park and a World Heritage Site, is surrounded by urban Cape Town. Park officials aspire to removing all non-native species, including sambar deer (Rusa unicolor) to protect the endemic fynbos vegetation. Yet fynbos is too nutrient poor to support large herbivores. Fynbos is threatened primarily by invasive vegetation and urban policies of fire-suppression that facilitate forest expansion. In this urban-curated ecosystem, removing sambar deer simply because they are non-native (as typically recommended by invasion biologists for precautionary reasons) is questionable. Sambar deer might harm the ecosystem, but there is no research showing this–and it is plausible that they may even assist fynbos conservation by browsing the encroaching forest The paper begins with a review of the relationship between fire, forest and fynbos and provides a history of non-native herbivores on Table Mountain. It then draws on the international literature about sambar deer outside their native range and on local observations to sketch the first picture of these animals along the urban edge of Cape Town. The conclusion calls for more research on the Mountain’s changing ecology, including the niche occupied by sambar deer, to inform an evidence-based management strategy.