Safeguarding Ecological Infrastructure Against Invasive Alien Plant Species

21 Sep 2023 by Jillian Fredericks

Invasive alien plant species are one of the main causes of biodiversity loss and threaten many indigenous species. To address this issue, government laws, specifically the Conservation of Agricultural Resources Act 43 of 1983 (Act NO. 43 of 1983) and the National Environmental Management: Biodiversity Act, 2004 (Act NO. 10 of 2004), legally obligate landowners to monitor, control, and eradicate alien invasive plants. Many non-indigenous plants thrive outside of their natural habitat due to the absence of natural enemies and competition, altering ecosystems, endangering indigenous biodiversity, and even impacting human well-being.

Approximately 7% of South Africa is covered by invasive alien plants, with the Western Cape province being affected the worst. Invasive alien plants out-compete indigenous vegetation, and this can disrupt ecological infrastructure. The term ecological infrastructure refers to semi-natural or natural structural elements of landscapes and ecosystems, as depicted in Photo 1. Indigenous vegetation provides valuable services to wildlife, prevents soil erosion, and maintains water quality and quantity.

Strategic Water Source Areas are important for water security, contributing 50% of South Africa’s surface water. A total of 22 surface water Strategic Water Source Areas are identified as nationally important, and six of these are entirely located within the Western Cape and a further two are partly located in the Western Cape. CapeNature manages parts of five of these surface water Strategic Water Source areas. The presence of invasive alien plants in Strategic Water Source Areas threatens Western Cape’s water security by depleting both water volume and quality through high water consumption, contributing to fire fuel loads, and resulting in sediment buildup, as depicted in Photo 3.

To safeguard these areas, CapeNature prioritizes restoring and maintaining ecological infrastructure, particularly in mountain catchments that are also Strategic Water Source Areas. As highlighted in the CapeNature Annual Report of 2021/2022, collaboration with the World Wildlife Fund South Africa, Working on Fire High Altitude Teams, and The Nature Conservancy of South Africa resulted in the successful clearing of 54,300ha of invasive alien plants in high-priority catchments within Strategic Water Source areas under CapeNature’s jurisdiction.

Overall, monitoring, controlling, and eradicating invasive alien plants remains of the utmost importance to maintain the integrity of ecological infrastructure, thereby securing water resources for the people of the Western Cape.

Section of the mountain catchment area included in the Marloth Nature Reserve. Mountain catchments are examples of important ecological infrastructure regarding water security.

Upstream view onto the upper Sonderend River, and part of its mountain catchment area, that eventually feeds into the Theewaterkloof dam. This catchment forms part of the national Boland surface and groundwater Strategic Water Source Areas.

A view onto a section of the Vyeboom wetland, which is also part of the upper Sonderend River system that feeds into the Theewaterskloof dam. Here depicted is Black Wattle infestation and associated erosion.


Related News

10 Dec 2023 by Carl Brown
A Call for Responsible Engagement with Cape Fur Seals

CapeNature would like to shed light on a matter of growing concern within the region, especially the areas surrounding Cape Town - human-wildlife interactions, specifically those involving Cape fur seals.

Bios Cape blog
22 Nov 2023 by Dr Andrew Turner
Harnessing the Power of NASA’s Technology to Detect Alien Species

When NASA isn’t spending its time exploring the depths of outer space, its lending its technology for the ambitious BioSCape project, which seeks to detect patterns of biodiversity and ecosystem health in the fynbos biome.

Cape Vulture De Hoop 2016 09 14 2
8 Nov 2023 by Kallyn Gunkel
Guardians of the Sky: Cape Vultures in South Africa's Potberg Mountains

The Cape vultures of the Potberg Mountains are not just ecological linchpins but also cultural symbols in parts of southern Africa. CapeNature has been dedicated to the conservation and monitoring of these majestic birds for many years within CapeNature's De Hoop Nature Reserve, where the Potberg Mountains provide vital breeding habitat for the only population of Cape vultures in the Western Cape.

Whats App Image 2023 07 24 at 1 48 31 PM
29 Sep 2023
Cape Zebra Reunites With Family

On July 22, 2023, the CapeNature team from Kammanassie Nature Reserve carried out a critical rescue mission involving a Cape Mountain Zebra (CMZ) on the Diepprivier farm property in the Noll area, situated approximately 30 kilometers from Kammanassie.

Whats App Image 2023 09 28 at 13 14 51
29 Sep 2023
CapeNature and a Community Rally to Save More Than a Thousand Seahorses

CapeNature’s marine rangers led a herculean effort with the support of the community and up to now more than a thousand seahorses were rescued and 720 have been returned to their natural habitat. They are being put back into the estuaries where they usually occur and where there is a huge eelgrass bed where they seek refuge and shelter and where they find their food.

21 Sep 2023 by Kallyn Gunkel and Martine Jordaan
Monitoring of Critically Endangered Geometric Tortoise

The geometric tortoise (Psammobates geometricus), classified as Critically Endangered, ranks among the top 25 most imperilled tortoises and turtles globally. Its future remains uncertain, with an estimated wild population of fewer than 3000. This species is highly specialised in its habitat requirements, historically found in the low-lying renosterveld shrublands of the Swartland, Upper Breede River Valley, and Ceres Valley.