A PRACTICAL GUIDE TO MANAGING INVASIVE ALIEN PLANTS

A practical handbook published by WWF South Africa in 2021 designed to empower land users in the Cape Floral Region to identify, plan for, and manage invasive alien plants (IAPs). The guide covers legal obligations, technical clearing methods, health and safety protocols, and long-term rehabilitation strategies.

• The Cape Floral Region is a global biodiversity hotspot and World Heritage Site containing more than 9,000 species, with over 20% of Africa's plant species hosted in an area covering only 0.5% of the continent. It is a critical part of South Africa's Strategic Water Source Areas, contributing 50% of the country's water supply from only 10% of its land.
• Invasive alien plants (IAPs) cause severe environmental and economic damage in South Africa, including the loss of up to 2,500 million m3 of water annually. They increase wildfire intensity by adding biomass and flammable compounds, reduce agricultural production, lower land values, and outcompete indigenous biodiversity.
• Effective IAP management is based on two core principles: acting early to reduce long-term costs and performing consistent follow-up to prevent regrowth. The process is divided into three phases: initial control to reduce populations, follow-up to manage seedlings and suckers, and annual maintenance.
• Landowners have strict legal obligations under the National Environmental Management: Biodiversity Act 10 of 2004 and the Conservation of Agricultural Resources Act 43 of 1983. Failure to control Category 1 invasive species can result in fines up to R10 million or imprisonment for up to 10 years.
• IAP clearing should follow a strategic priority sequence: preventing new invasions, prioritizing follow-up over initial clearing, targeting high-wildfire-risk areas, and starting with low-density stands. Operations should physically move from the highest point (upslope) downwards to prevent reinfestation from upstream seeds.
• Four primary control methods are available: manual (hand pulling, ring barking), mechanical (chainsaws, bulldozers), chemical (foliar spray, cut stump treatment), and biological. Mechanical use of heavy machinery is legally restricted to already disturbed areas to prevent soil compaction and biodiversity loss.
• Chemical control requires rigorous safety and calibration. Herbicides must be applied during active growth, not in rain or temperatures exceeding 30 ⁰C, and must be stored in sealed, ventilated buildings with concrete floors and bunded doorways to contain spills.
• Biocontrol involves introducing host-specific natural enemies from an IAP's country of origin. While it is a long-term strategy (often taking 10 to 20 years to be effective), it is cost-effective and environmentally responsible. Examples include the use of gall rust fungus for Port Jackson willow.
• Long-term rehabilitation is necessary when ecosystems cannot self-restore. It follows four phases: site assessment, planning, implementation, and monitoring. Methods include passive rehabilitation (natural recovery), active rehabilitation (planting/seeding), and manipulated succession (staged thinning).
• Funding for IAP management can be sourced through government programmes like LandCare and the Natural Resource Management (NRM) Programme, or through 'beneficiation'—processing cleared biomass into saleable products like charcoal, pellets, or poles to offset costs.

APA

Martens, C., Deacon, G., Ferreira, D., Auret, W., Dorse, C., Stuart, H., Impson, F., Barnes, G., & Molteno, C. (2021). A PRACTICAL GUIDE TO MANAGING INVASIVE ALIEN PLANTS. WWF South Africa. https://wwfafrica.awsassets.panda.org/downloads/a_practical_guide_to_managing_invasive_alien_plants_web.pdf

Chicago

Martens, Chris, Guy Deacon, Dean Ferreira, Willie Auret, Clifford Dorse, Helen Stuart, Fiona Impson, Garth Barnes, and Clarrisa Molteno. A PRACTICAL GUIDE TO MANAGING INVASIVE ALIEN PLANTS. WWF South Africa, 2021. https://wwfafrica.awsassets.panda.org/downloads/a_practical_guide_to_managing_invasive_alien_plants_web.pdf.

Wikipedia

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BibTeX

@techreport{martens2021practical, author = {Martens, Chris and Deacon, Guy and Ferreira, Dean and Auret, Willie and Dorse, Clifford and Stuart, Helen and Impson, Fiona and Barnes, Garth and Molteno, Clarrisa}, title = {{A PRACTICAL GUIDE TO MANAGING INVASIVE ALIEN PLANTS}}, institution = {WWF South Africa}, year = {2021}, url = {https://wwfafrica.awsassets.panda.org/downloads/a_practical_guide_to_managing_invasive_alien_plants_web.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }