The Department of Environment, Fisheries and Forestry (DEFF) define Invasive Alien Plants (IAPs) as plant species introduced into countries, which are then able to out-compete the indigenous species for resources such as water, soil nutrients and light. Alien plant species are introduced into a country through anthropogenic means such as; via ships, on peoples clothing, planes, etc. Alien species are however not all classified as invasive. The rate of spread of a species and its ability to outcompete native species for resources classify an alien species as invasive or not.
IAPs are responsible for billions of rand’s worth of damage to South Africa’s economy yearly and are recognised as the single biggest threat to South Africa’s biological biodiversity. Apart from affecting the countries biodiversity, IAPs pose a direct threat to water security, ecological functioning of natural ecosystems and the productive use of land. They can also intensify the impact of fires, floods and increase soil erosion.
The National Environmental Management: Biodiversity Act (Act no. 10 of 2004) Alien and Invasive Species List of 2016 recognised 379 plant species as being Invasive Alien Species. Sites containing these listed species are required to have an eradication and control plan developed in order to mitigate the effects these species will have on the native biodiversity. Once the plan has been developed and accepted, the eradication and management process can then be conducted.
The eradication process is typically conducted over multiple growing seasons as not all seeds dispersed in a single season will all germinate together in the same season. Therefore, to ensure all AIPs are removed from a site, multiple removal events must occur every season across multiple seasons and be periodically managed thereafter to ensure that no AIPs have re-established on the site. Due to general time constrains, eradication event typically occurs during growing and flowering seasons.
Three main removal strategies for AIPs are practiced, namely: physical/mechanical, chemical, and biological. These strategies are often combined to achieve optimal results.
Mechanical – Hand cutting, felling, burning and uprooting of plants.
Chemical – Using environmentally safe herbicides. It is important to add that a detailed delineation of the IAPs that occur within the area where the eradication is set to take place is required for the correct selection of herbicides to be applied to the correct species of plant. This is due to IAPs reacting differently to different varieties of chemical compositions within herbicides. Herbicides should be applied directly to the IAPs to minimise the negative effects the herbicides could cause to the native vegetation. Specific herbicides should be used in watercourses if so required. This is however a last resort and mechanical methods should be attempted first.
Biological Control – Using species-specific insects or diseases from the alien plants origin. In these instances, the natural control agent of the IAPs is brought in from its country of origin in an attempt to control the species, however extensive research must be conducted prior to the use of this method to ensure that the disease or insect will not be harmful to the native plant species of the area.
Integrated control – The use of two or more of the above-mentioned strategies used in combination. This is frequently used to prevent enormous impacts.
IAPs eradication and control programmes are conducted in three (3) phases which are as follows:
Environmental Assurance (Pty) Ltd. (ENVASS) would like to take this opportunity to introduce our team of trained personnel who can be approached the undertake the physical eradication of IAPs within a specific site. This recent development within our diverse company stemmed from the legal requirement for all land owners, or proponents managing the land parcel to control and eradicate IAPs within their property boundaries. The eradication service is an extension of the already established terrestrial biodiversity division, which has been conducting numerous IAPs control and maintenance programmes in line with the legislated requirements for clients throughout Southern Africa. We are always willing to accept new challenges and compose competitive quotes for environmental specialist work required.
ENVASS is more than able to conduct site visits, identification, listing confirmation and the overall control and management programmes for the property to ensure compliance to the latest laws and regulations. Feel free to contact us on 012 460 9768 or at firstname.lastname@example.org for quotes on any environmentally related services!