The WWF Nedbank Green Trust is funding a project to rehabilitate the diverse Renosterveld biome in the Western Cape, writes Heather Dugmore
A portrait of the Western Cape 300 years ago would show rolling expanses of a vegetation type with an extraordinary diversity of bulb species. Renosterveld was grazed by large numbers of big game, including the extinct
bluebuck and quagga, and the eland and black rhino that gave it its name.
The herds of game have gone and the Renosterveld is down to 5% of its original expanse, with less than 50 remaining fragments in the Overberg that are more than 100ha and fewer of this size in the Swartberg.
An emergency response is required to prevent the extinction of this jewel in the Cape Floristic Region: the smallest and richest plant kingdom on Earth. What is required is the restoration of the watercourses that link and feed these fragments, which are the only source of intact biodiversity in the region’s farming landscape. The WWF Nedbank Green Trust is funding this through a three-year project that started in September 2015.
“Renosterveld is one of the richest ecosystems in the world, mostly due to its extraordinary bulb diversity.
“However, 95% of it has been replaced by large-scale commercial agriculture, mainly wheat, barley and canola, which are rotated with oats and lucerne,” says Odette Curtis, director of the Overberg Renosterveld Conservation Trust, who is heading the project.
In its original state, Renosterveld was probably a far more grassy system, with a higher rooigras (Themeda triandra) component and a significantly higher plant diversity. The combination of free-ranging grazing and browsing game maintained its diversity and structure. As agriculture encroached on this land, the historic disregard for Renosterveld was emphasised in its description as “wasteland” or “uitvalgrond”.
Curtis and her team have identified ecological corridors in the form of streams, rivers and seepage areas that link the
disparate patches of Renosterveld between farms in the Overberg Rûens. Many of the watercourses are badly degraded.
“Numerous rivers, streams and wetlands have been
invaded by alien invasive vegetation, with advanced soil erosion and water pollution or destruction by ploughing,” she says. “Restoring these watercourses and assisting landowners in managing them, paves the way for water conservation, ecosystem restoration and better land management in this fragile system.
“Partnering with farmers and landowners is the only way in which we can restore the health of the watercourses and this unique habitat from an otherwise inevitable extinction. What is so encouraging is how many farmers are interested and on board and have come to us for advice and help since the project started in September 2015.”
Part of the reason for the success of this project is the manner in which project manager Keir Lynch engages with farmers and landowners. Formerly the stewardship extension officer at CapeNature, he has the experience and expertise in developing strong, mutually beneficial partnerships with landowners to conserve and expand critical biodiversity areas.
“We are currently working with about 50 farmers who are invited to sign a conservation easement or memorandum of understanding with the Overberg Renosterveld Conservation Trust,” says Lynch. “This is a conservation servitude on their title deed or a written commitment to manage the watercourses and Renosterveld habitat on their land according to the conservation and biodiversity management plan.”
The project team assists farmers with controlled, ecological burns at the right time of the year and provides them with a full-colour report of the Renosterveld habitat on their land.
Some of the rare and endemic Renosterveld plant species include Moraea elegans — a bulb in the iris family, with a yellow flower and striking green and orange markings.
Polhillia curtisiae is an electric yellow member of the legume family that was named after Curtis, who found it in the WWF-owned Haarwegskloof Renosterveld Reserve in the eastern Overberg between Bredasdorp and Swellendam, where the Renosterveld Research Centre and guesthouse are situated. Hesperantha kiaratayloriae is a bright pink bulb, found only on two sites on Renosterveld quartz thus far.
The project team has mapped the Renosterveld fragments they will be targeting and has started alien vegetation and watercourse restoration in two tributaries on the eastern side of the Breede River — the Dipka and Doring rivers – between Heidelberg and Swellendam, which are infested with alien invasive trees.
They are also working on the Ouka River, which hardly flows and is significantly eroded. This is a typical Renosterveld seepage stream that flows into the Riviersonderend River between Riviersonderend and Swellendam. Polhillia brevicalyx is
an endemic member of the legume family found only on this watercourse.
The Hansjes River near Napier has major erosion dongas. On parts of the Sout River, that crosses the Overberg and feeds the De Hoop Vlei near Bredasdorp, is one of the only wetlands the team has located so far in the Renosterveld, with visiting flamingoes and rare plant species.
“We applaud the farmers who are partnering us in this initiative,” says Curtis. “Through this initiative, many farmers have stopped ploughing up the Renosterveld remnants and watercourses and there is encouraging commitment to biodiversity conservation to improve the health and supply of water to this region.”
Written by : Heather Drugmore