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Biodiversity Evidence

Biodiversity Evidence

Invasive alien species pose a significant threat to human livelihoods, economic development and biodiversity. The Directorate aims to reduce the impacts and cost of managing invasive alien species by detecting and managing all emerging invasions. To combat these new incursions, SANBI’s Directorate on Biodiversity Evidence was established with funding from Working for Water and the Department of Environmental Affairs. The Directorate aims to raise awareness to all South Africans about emerging invasive species that remain eradication targets.

Our key messages are:

• Invasive species are harmful. Its introduction and spread threatens our environment, the economy and people, including human health.

• Stopping invasive species is possible if we change our behaviours.

• We all share the responsibility to help stop the spread of alien invasive species and only through increased prevention, detection and improved management plans can we provide significant economic benefits.

• Government support and actions can help prevent the spread of invasive species.

• Regulation and increased funding can make a difference to control and prevent the spread of invasive species.

• Prevention and control requires extraordinary cooperation and collaboration of all publics.

• Invasive species spread across borders and boundaries and threatens the survival of native species.

The programme is structured around the activities of early detection of plant or animal invasions, identification and verification, risk assessment and response planning, more importantly, immediate response actions.

Early detection

There are few highly knowledgeable and dedicated experts who are able to ‘spot’ invasive plants amongst the 22 000 indigenous and over 8 000 exotic species already present in the country. Thankfully there are numerous individuals who spend time observing the vegetation they walk and work in and can determine changes in plant communities and identify particularly noticeable plants, if well trained. These individuals are more commonly referred to as “Spotters”. Early detection will make use of both the experts and the observers in order to survey areas that may be subject to invasion. The efforts of both experts and observers are managed by the Directorate’s Regional Co-ordination Units.

Identification and verification

Plant specimens gathered by the early detection spotters and regional co-ordination units are identified, confirmed and verified by our resident taxonomist. Other taxonomic experts are based at herbaria and universities across the country. SANBI has three herbaria; the National Herbariums in Pretoria, KwaZulu-Natal and Cape Town.

Risk Assessment

The Alien Species Risk Analysis Review Panel (ASRARP) was set up to provide independent scientific advice to the Department of Forestry, Fisheries and the Environment (DFFE) on a range of issues pertaining to the risk of biological invasions, including the evidence underpinning the regulatory lists. Since 2018, the ASRARP has been involved in reviewing and approving risk analyses. The goal is for a risk analysis approved by the ASRARP to be available for all taxa included on the regulatory lists, and to collate the scientific evidence for any future changes to the list. It will take time to complete all this work. As of April 2021 around 10% of the regulated taxa have had a risk analysis completed on them, but the process is beginning to speed up.

Rapid response planning and implementation

The Alien Species Risk Analysis Review Panel (ASRARP) gives a recommended course of action for dealing with a newly detected invasion. The Regional co-ordinator then consults with appropriate representatives of provincial and local government and control experts and compiles a regional eradication, follow up and management plan appropriate to the specific circumstances and invasive alien plant or aquatic weed.

The Directorate on Biodiversity Evidence team reports their planned actions to representatives from the national government departments of Agriculture, Forestry, Fisheries and Environmental Affairs. Regional co-ordinators within SANBI will provide the necessary information to co-ordinate the work of the appointed rapid response teams.

Frequently Asked Questions

1. What is an invasive species?

An invasive species is classified as any species that is non-native to a specific region and has a harmful effect on the ecosystem.

2. What is the difference between native and non-native species?

Species that naturally occur within an ecosystem and has been able to sustain a population over many years are known as native species. Non-native species are species that have been introduced into a new ecosystem outside their natural population distributions.

3. Are all non-native species invasive?

No, a non-native species only becomes invasive when it starts impacting the ecosystem negatively by out-competing native species for habitat, water and food; by rapidly reproducing and spreading.

4. What is a biological invasion?

A biological invasion occurs when an invasive species out-competes the native species within the ecosystem resulting in reduced or locally extinct native species populations. Thus the invasive species becomes the dominant population within the ecosystem causing the loss of biodiversity and negative impacts on the ecosystem.

5. Why are biological invasions a problem?

Because biological invasions may cause threats to native species, disease, alter the ecosystem, threaten human health and affect the economy.

6. Are biological invasions only terrestrial?

No, biological invasions can be caused by a variety of species such as terrestrial, marine, aquatic, vertebrates, mammals, invertebrates, fungi, birds, reptiles and bacteria

7. How do biological invasions affect humans and impact the economy?

Biological invasions can cause the spread of diseases, the shortage of food and water, impact tourism, agriculture and other ecosystem goods and services.

8. What are the main pathways of biological invasions?

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