Alien vegetation in Fernkloof Nature Reserve.
Alien vegetation in Fernkloof.
Several mainly Australian plant species were introduced to the Western Cape in the first half of last century to help stabilise dunes in coastal areas and to provide a source of wood fuel. Unfortunately these species have spread prolifically and now pose a serious threat to the local indigenous fynbos vegetation. The principal alien invasives are wattles, eucalypts and hakeas from Australia and pines from the Mediterranean Basin and California. These areas all have a climate very similar to parts of the Cape Floristic Region.
Experts also believe that the aliens, which are larger and more tree-like than the indigenous fynbos, are reducing fresh water runoff from mountain catchment areas by up to 50%. Dense stands of the alien trees also pose a fire hazard. Voluntary hack groups are working on the mountains above Hermanus to help fight back the invaders.
- Acacia cyclops (rooikrans) forms dense thickets on the alkaline coastal sands as well as on sandy patches in the limestone landscape.
- Acacia saligna (Port jackson willow) and A. longifolia (long-leaved wattle) are the main invaders of acid sands. Fortunately biological control agents are slowing the spread of these two species.
- Acacia mearnsii (black wattle) is a rampant invader of strearnside habitats where it alters the hydrology and ecology of river systems.
- In the past decade Leptospermum laevigatum (myrtle) has spread rapidly over large areas of the Southern Overberg and has become the major invasive threat. However, biological control agents have recently been introduced to counter its advance.
Below are some of the successful hacking projects
- Mossel river rehabilitation project
One of the most successful hack stories started in 1998 with a dedicated group of hackers under the auspices of the Hermanus Botanical Society singlemindedly setting out to eradicate aliens clogging the Mossel River area.
Residents in the area joined with hardcore hackers, municipality staff and alien control teams. Funds were raised to employ workers for heavy cutting and backup work. Gradually the river began to run free once more ; the blue fonteinbos , pink pelargoniums and gold aspalathus blossomed in profusion as the mass of wattle, sesbania, gum and port jackson was killed off.
Flat Street wetland area.
The momentum shifted to the Flat Street wetland area and also to the
where section leaders of the Cliff Path Management Group together with Coastcare battle kikuyu and garden escapees.
Hermanus Hacking group
This active group has been funded by the Hermanus Botanical Society, Table Mountain Fund (TMF) an associated trust of WWF Wildlife South Africa
and individual sponsors. By the end of 2014 close to R2000 per week was being spent on labour. The areas tackled by HHG have been Northcliff, Elephant Path and adjacent mountainside , Hoy's Koppie and more recently the start of Rotary Way. It is now targeting the invasive daisy Senecio pterophorus(see photo below)
Charyn Vosloo - HHG - 028 314 0847
David Beattie - CPMG - 028 312 1358
Bob Hill - HBS - 028 312 1463