The Restoration of Erica verticillata

Abstract

The Threatened Species Programme at the South African National Biodiversity Institute, Kirstenbosch National Botanical Garden, is integrated to include both ex situ and in situ conservation activities. Plant conservation is driven by South Africa’s Strategy for Plant Conservation which was developed in response to the Global Strategy for Plant Conservation.
 This case study examines the conservation of Erica verticillata (whorl heath), a flagship for threatened species at Kirstenbosch, and documents the integration of ex situ with in situ conservation at three areas on the Cape Flats. The whorl heath was thought to be extinct by 1950. Horticulturists have since rediscovered eight clones in botanic gardens worldwide, the Heather Society and commercial growers. Ex situ conservation in botanic garden collections and the Millennium Seed Bank has since allowed in situ conservation in the critically endangered Cape Flats Sand Fynbos vegetation type. The process of restoring the whorl heath presented many challenges. Initially attempts were hampered by limited available knowledge on suitable niche habitats. Pioneering work carried out at Rondevlei Nature Reserve identified the suitable habitat and this was applied in subsequent in situ work at Kenilworth Racecourse Conservation Area and at Tokai Park – the only natural areas remaining in or near this species’ historical distribution range. Successful re-establishment of this species depends upon its capacity to recruit after fire, which is an essential ecological process in the fynbos. Many clones have been in cultivation for a long time and are poor seed producers: seed production was first recorded at Rondevlei only after additional clones were planted together. Only one population (Rondevlei) to date has seen a fire and thus has recruited seedlings; however these are competing with vigorous companion plants.
 The study continues and is currently exploring the role of herbivory in the restoration process. The key lesson learnt to date is the need to include sustainable management of the entire ecosystem in the restoration process and not limit it to single species. Success in restoring a species depends upon a healthy stand of the vegetation type in place, along with pollinators and other key fauna and other natural ecosystem processes. It is recommended that successful re- establishment of a species in fynbos requires the reintroduced population to survive three fire cycles.