Invasive Alien Vegetation & their effects/consequences in Fire

  • Increases the fuel load, as fynbos composition is naturally of small to medium high shrubs, with very few tree species;
  • Increase the intensity of the fire, having an extreme impact on indigenous vegetation, and increasing the likelihood of extreme or catastrophic loss to infrastructure and/or lives;
  • Can lead to uncontrollable flames and prolong the veldfire event;
  • These plants out compete most endemic and indigenous plants, which require fire to germinate, thus multiple fires over a short period leads to loss of species and biodiversity;
  • Burns for longer periods due to stumps and remaining embers, promoting flair-ups and cost for manpower and resources;
  • Erosion due to the adventitious root system of the invasive alien plants. A veldfire thus removes the vegetation holding the topsoil in place. The soil is loosened and is lost with the next rainfall event.


High priority areas to consider first when clearing IAV:

  • The area immediately around buildings if there is a risk of fire,
  • Low-density infestations, to keep the spread of invasive plants into the surrounding areas in check,
  • The tops of slopes, watercourses, and steep, long bare slopes, to inhibit the spread of seeds downhill or downstream, where they will infest new areas,
  • Sites where initial control work has been completed and regrowth is present, to prevent densification and further infestation,
  • Disturbed sites, to prevent new infestations from mass germination of alien seeds in the soil. Seedlings should be controlled while they are less than 0.5m tall to avoid costly control work later on.

Control of IAV

  • manual
  • mechanical
  • chemical
  • biological

Below are two tables listing control methods:

* Long-term success is achieved through a combination of these methods

Top 10 IAV of the Cape Peninsula

Common Name
Port Jackson
Long-leaved wattle
Black Wattle
Silky Hakea
Australian Myrtle
Cluster Pine
Spider Gum

Scientific Name
Acacia saligna
Acacia cyclops
Acacia longifolia
Acacia melanoxylon
Acacia mearnsii
Hakea sericea
Paraserianthes ophantha
Leptospermum laevigatum
Pinus pinaster
Eucalyptus lehmannii