What are invasive alien species?
An invasive alien invader species is a species that is not from our country. They are called exotic, non-native or of foreign origin. This refers to any plant or animal species that has been introduced to South Africa from a different country.
The introduction of exotic species to countries or new areas has been happening for millenia. With the advent of global travel, ships carrying animals, food and people to different parts of the world have accelerated this. Over the past 500 years, there has been an explosion of Invasive Alien Species across the globe. A well documented consequence of this is the Small Pox pandemic that began spreading in the 6th century when increased trade with China and Korea took Smallpox to Japan. Historians have been able to trace the global spread of Smallpox to the growth of civilizations and exploration.
The rapid spread of COVId-19 and resulting global pandemic can be attributed to the planet being a GLobal Village with the movement of people across the globe nowadays being more than ever.
Invasive Alien plants and animals reach our shores from foreign countries through several mechanisms
- Some”hitch a ride”. The invasive alien species is present in food, other organic materials and the the clothing of people. These are unsuspectingly brought to a new country by a visitor. The TV series “Border Control” shows how serious countries like Australia are about keeping Invasive Aliens out of their country.
- People also “import” aliens on purpose. It is said that the weed Lantana was brought to South Africa and Kei Country by ladies who thought it was a pretty plant and cultivated it in their gardens.
- Many Alien Invasive plants have been introduced to countries on purpose for commercial use. A prominent example of this in South Africa is the deliberate introduction of pine and black wattle for commercial use.
- Some plants were introduced because they were erroneously thought to do a better job than the indigenous species. An example of this in the Eastern Cape is the introduction of Port Jackson to stabilise coastal dunes.
Why are Invasive Alien Species a problem?
Many Invasive Alien Species were introduced to South Africa for a purpose. These plants and animals were introduced without their natural predators, and when they ‘escaped’ into our natural habitats they began to threaten the natural plant and animal species.
According to Clive Brimelow, author of Problem plants and alien weeds in South Africa, “The spread of exotics or biological pollution, is one of the greatest threats to the earth’s biological diversity, and as a threat of extinction, bio-invasion may rank just behind habitat loss, which covers almost any physical disruption of existing habitats.
Invasive alien plants compete with natural vegetation for water and space, often out-competing natural vegetation. Without natural predators to keep their numbers in check, they reproduce and spread quickly. They often take up more water than the surroudning natural vegetation. The result of this is that more alien plants grow, and fewer indigenous plants are able to to grow. This results in a disrution and weakening of the ecosystem, with the indigenous animals no longer being able to rely on the plants they have evolve with over millenia for food also disappearing. The final result of this is a loss of biodiversity and a depletion of water resources.
The invasive plants often form dense stands of the same species,representing a high fuel load for veld fires. This unnaturally high fuel load leads to extremely hot veld fires, that in turn damage the structure of the soil.
What is being done about the problem?
The first efforts to control and eradicate invasive alien species in South Africa began with the fight to bring the prickly pear’s “scourge to agriculture” under control in the Eastern Cape, way back in 1906. Efforts to eradicate and control invasive alien species have been ongoing ever since. It is estimated that Invasive Alien Plants have become established in over 10 million hectares of land in South Africa, and control efforts cost the country more than R 600 million a year.
There is now legislation governing the introduction and control of invasive species in South Africa. The Department of Environmental Affairs manages Invasive Alien Species under the National Environment Biodiversity Act (NEMBA) 10 of 2004. This Act aims to provide the framework, norms and standards for the conservation, sustainable use, and equitable benefit-sharing of South Africa’s biological resources. Alien plants and animals are placed into three categories depending on the severity of their effect on the natural environment.
Invasive plant and animal species in South Africa
- 750 tree species
- 8 000 herbaceous species
- of these 1 000 are considered naturalised
- 379 plant species are invasive
- 238 are prohibited
- 4 invasive Marine Plants
- 41 invasive mammal species
- 24 invasive bird species
- 29 invasive reptile species
- 2 invasive amphibian species
- 15 invasive freshwater fish species
- 23 invasive invertebrate species
- 9 invasive freshwater invertebrate species
- 17 invasive marine invertebrate species
- 7 invasive microbial species
The full list can be downloaded here
On the 1st of August 2014, the Minister of Environmental Affairs published the Alien Invasive Species regulation. This regulation listed a total of 559 alien species as invasive in South Africa and 560 more species were listed as prohibited and may not be introduced into South Africa. The regulation places invasive alien species into the four categories below.
Invasive species requiring compulsary control
These are prohibited plants that must be eradicated.
These plants serve no economic purpose and possess characteristics that are harmful to humans, animals and the environment.
These plants need, by law, to be eradicated from the environment
Invasive species requiring compulsory control as part of an invasive species control programme
Remove and destroy.
These plants are deemed to have such a high invasive potential that infestations can qualify to be placed under government sponsored invasive speicies management programmes.
Declared invader plants with a commercial or utility value
These are ‘invaders’ with certain useful qualities, such as commercial for forestry, animal fodder, soil stabilisation etc.
These plants are allowed in demarcated areas under controlled conditions and in biocontrol reserves.
Mostly ornamental plants
These are plants that are currently growing in or have escaped from areas such as gardens, but are proven invaders.
No further planting is allowed, nor trade in propagative material.
Existing plants may remain, but must be prevented from spreading.
The alien invasive species Regulation also stipulates that “Organs of state in all spheres of government, including all municipalities, draw up an “Invasive Species Monitoring Control and Eradication Plan for land under their control.”
The Kei Mouth Ratepayers and Residents’ Association (KMRRA) Alien Invasive Management document elaborates on the steps taken by Great Kei Municipality to put a plan in place.
What can I do?
We each have a responsibility to preventing the spread of Invasive Alien Species. We can do this by:
Plant indigenous species from this area
Confirm that new plants in your garden are not invasive
Remove invasives and replace with indigenous species
How do I know if a plant is an alien invasive species?
We have tried to make it a little easier for Kei Country and put together a list of known Invasive Alien Plants in Kei Country.
We will be publishing a weekly series called “Know your Kei Country Aliens” The weekly series will highlight an invasive species in Kie Country, giving a bit of background to the history of the species in South Africa, how to identify it, what potential threats it poses to the environment, humans and animals, and how to control and eradicate the species.
There have been several books written on this topic. The book “Problem Plants and Alien Weeds of South Africa”, written by Clive Bromilow has become “an indispensable guide for anyone interested in knowing how to recognise, understand and control troublesome plants.”
- Cost: R 410,00 delivered to Kei Mouth. (Retail Price usually R 450)
(Contact Monica Maroun on email@example.com to order your copy and have it delivered to Kei Mouth Free of Charge.
Chat to Monica about cost of delivery to elsewhere in South Africa.)