Alderman Eddie Andrews, the City of Cape Town’s Deputy Mayor and Mayoral Committee Member for Spatial Planning and Environment, visited the historical Battle of Muizenberg site in Muizenberg, to see the clearing of invasive alien vegetation in action. The clearing is part of the City’s Biodiversity Management’s Invasive Species Programme. Read more below:
The alien clearing will expose more of the stone breastworks associated with the Battle of Muizenberg that took place in 1795 when the British first invaded the Cape under Admiral Elphinstone, commander of the British Fleet. These stone structures were constructed in some haste when the Dutch East India Company (VOC) got word that the English fleet was threatening to land in False Bay instead of Table Bay, which was well protected by a number of forts and fortifications. The fortifications were improved in the early 19th century with a gun emplacement on the site of Bailey’s Cottage. When the coastal boardwalk was built, a number of unused cannon balls were recovered.
The site is adjacent to Table Mountain National Park and contains endangered Peninsula sandstone fynbos.
Invasive Alien Species (IAS) in their many forms have severe, detrimental economic and ecological effects and economists and policy makers are starting to appreciate their extent.
An alien species is a species which is not native to the area it is found in, they are not necessarily invasive. An example of an alien species is the rose, which is not indigenous to South Africa but is not prolific and does not invade natural areas.
An invasive species is an alien species that has become naturalised and outcompetes indigenous species. They do not have natural predators and can cause harm to the environment, economy or even human health, depending on the species.
Examples of invasive species include the following:
• Port Jackson
• European paper wasp
• Water hyacinth and
• Rooikrans.
‘It is important that we do this because left unmanaged, alien vegetation can have devastating impacts on the environment and lead to serious repercussions for humans. Plant invasions alter ecosystems, as well as important natural processes such as fire frequency, nutrient cycling, erosion, hydrologic cycles and sediment deposition, which, in turn, result in significant negative environmental, and therefore socio-economic impacts for both current and future generations,’ said the Deputy Mayor and the Mayoral Committee Member for Spatial Planning and Environment, Alderman Eddie Andrews.
1. A variety of methods are employed to manage the plants, depending on the species. These include mechanical and chemical methods and the following process is followed:
2. Smaller plants can be hand pulled with the roots while bigger plants, like trees, can be cut down and have herbicide applied to the stump to prevent regrowth
3. Some species, such as pines, do not need herbicide. With certain shrubs, a foliar spray with a herbicide mix is used
4. Other species need to be dug out from the roots to be most effective in the prevention of regrowth
5. On the City nature reserves, we also make use of prescribed burns, whereby the cut down invasive plant material would be stacked into heaps or spread out over the site and then burned
6. Certain species can also be controlled using bio-control. Since they have no natural predators in the invaded area, a species from the plant’s native range is brought in. This natural predator is called a bio-control agent
7. With Water Hyacnith, we make use of a species of weevil to put pressure on the species and slow its spread.
The City is in the process of investigating the formal heritage protection of the site of the Battle of Muizenberg. The site contains not only the remnants of the stone breastworks but also archaeological deposits associated with indigenous groups who lived in and around the False Bay area prior to the establishment of the VOC outpost and anchorage at Simon’s Town in 1743.
‘I was fascinated by the clearing process and watching the team do it, made me realise what a responsibility it is to keep the invasive plants out. Especially since some of them can mislead and be appealing to people who have no knowledge about the plants. I understand that many are brought in for ornamental purposes. One such example is the Devil’s beard. It is a beautiful garden flower but has started to spread outside since it was first introduced. With no natural predators, the invasive plants can spread rapidly and become invasive. Other invasive species are an eyesore, nobody likes a dense stand of Port Jackson trees that also poses a fire risk,’ said Alderman Andrews.
Source: City Of Cape Town