Table of Contents

1. Overview


Invasive alien species (IAS) are species that have been introduced into an area and are able to out-compete and displace indigenous or useful alien species.

They may be plants, animals or microbes, including diseases, and are widely regarded as among the biggest threats to the productive use of land and water, the ecological functioning of natural systems, the populations’ health and the economy. By way of example, the water lost to invasive alien plants could sustain 120 000 hectares of crops to increase food production, or supply 3.38 million households of four members for one year.

The impact of these invasive species on the country’s economy is estimated in the hundreds of billions of rands, and the impact is rapidly increasing.

Source: and Helen Gordon, WWF SA Water Balance Programme manager.  


2. Legislation

South Africa has numerous Acts, administrated by different government departments, which deal with different aspects of invasive alien species. The ones most relevant to farmers are the Acts of the Department of Agriculture, dealing mainly with weeds and plant invaders, crop pests and diseases of livestock.

CARA (Conservation of Agricultural Resources Act 1983) (Act No. 43 of 1983)

CARA has certain regulations that provide for the control of weeds and invader plants. This act is currently under review regarding regulations 15 and 16 that are in the process of changing. The current CARA will thus be discussed. In terms of these regulations 15, there are 3 categories of regulated plants:

  • Category 1 – Declared Weeds. These are plants that must be controlled on land or water surfaces by all land users. These plants may no longer be planted or propagated and all trade in seeds, cuttings or other propagation material is prohibited. They may not be translocated or be allowed to disperse. These species carry a fine. Category 1 plants include Lantana, Pom pom weed, Water hyacinth, Yellow oleander etc. Most of the aggressive species fall in this category. Category 2 species without a permit are treated as category 1 species.
  • Category 2 – Declared Invaders (Invasive plants with commercial or amenity value). These are invader plants that pose a threat to the environment but nevertheless can be exploited for timber, fruits, fuel wood, medicinal plants, animal fodder, building material or shelter or to stabilise soil. These species are only allowed to occur in demarcated areas that carry a permit. If the plants are used for commercial purposes, land users have to obtain a water use licence as these plants consume large volumes of water. Where plants occur outside demarcated areas they have to be controlled. Category 2 plants include Black wattle, Sisal, Grey poplar and Weeping willow (not to be confused with indigenous willows). The landowner needs to approach the Department of Agriculture, Forestry and Fisheries (DAFF) to obtain a permit for the category 2 species; the decision to grant a permit is the responsibility of DAFF.
  • Category 3 – Declared Invaders (Invasive plants with ornamental value). These are plants that have the potential of becoming invasive but are considered to have ornamental value. In terms of Regulation 15 of CARA, these plants will not be allowed to occur anywhere except in biological control reserves unless they were already in existence when these regulations came into effect (30 March 2001). This means that the existing plants do not have to be removed by the land user; however, they must be kept under control and no new plant may be initiated, propagated or dispersed and the plants may no longer be sold. Category 3 plants include Jacaranda, Syringa, Australian silky oak, St Joseph’s lily etc.

Agricultural Pests Act, Act No. 36 of 1983

This Act provides for measures by which agricultural pests may be prevented from entering the country, and by which existing pests may be combated. It specifies, amongst other things, that any products or materials that might harbour agricultural pests, require an import permit before they can be imported into the country.

Animal Diseases Act, Act No. 35 of 1984

This Act aims at protecting the national animal (and human) population, as well as our export markets, against animal diseases. These diseases are caused mainly by alien invasive pathogens. In terms of this act, each consignment of animal and/or animal products for importation into South Africa must be accompanied by an original veterinary import permit, issued by the National Directorate Animal Health, and an original health certificate, issued by the competent veterinary authority of the exporting country.

National Environmental Management: Biodiversity Act (NEM:BA), No. 10 of 2004

This is a more recent piece of legislation, administrated by the Department of Environmental Affairs, which aims to protect the country’s biodiversity by, amongst others, controlling alien and invasive organisms. Chapter 5 of this act requires permits for carrying out restricted activities involving any alien species that has not been exempted, or any listed invasive species. The restricted activities include importation, having under one’s control, propagating, selling, buying and translocating a specimen of the specific species. Organisms that are indigenous to the country but occur outside their natural range are also defined as alien species for the purposes of this act.

In 2014 the Department of Environmental Affairs published amended regulations on Alien and Invasive Species (AIS) in terms of the National Environmental Management: Biodiversity Act. The AIS Regulations are aimed at preventing the introduction of more species that may be potentially invasive. This includes monitoring the deliberate and accidental introduction of species through airports, harbours, land borders and mail.