The number of alien species that has been established in South Africa has increased by 15% from 1,637 to 1,880, about a third of which are invasive, says minister of forestry, fisheries and the environment Barbara Creecy. Biological invasions pose a major threat to South Africa's unique biodiversity, and to the livelihoods and health of the people in the country.
“Current estimates suggest the ecological costs of invasive alien plants and animals to be more than R6.5bn each year.
"The main costs associated with losses are a decline in ecosystem services such as water and grazing and agriculture crop loss as a result of invasive pests,” Creecy said on Friday, 28 May. The minister was addressing the launch of the Status of Biological Invasions and their Management in South Africa.
Formal assessments of the impact of invasive species are underway using a new United Nations scheme that was developed in collaboration with the South African National Biodiversity Institute (Sanbi) and Centre of Excellence for Invasion Biology scientists.
“The second finding is that invasive trees use up 3–5% of South Africa’s surface water runoff each year, a serious problem in an already water-scarce country that is increasingly prone to drought.
“Some scientists have calculated that Day Zero in Cape Town was brought forward by 60 days due to invasive trees sucking up water. The same impact occurs in other drought-stricken areas, such as the Eastern Cape,” Creecy said.
Increased risk of veld fires
The report also found that invasive trees increase the risk and intensity of veld fires, with 15% more fuel burnt in invaded areas.
“Consequently, fires burn at a higher temperature and containment measures are more difficult. Biological invasions are the third largest threat to South Africa’s biodiversity (after cultivation and land degradation), and are responsible for 25% of all biodiversity loss,” the minister said.
She said biodiversity loss is closely linked to the collapse of ecosystem services such as the provision of fresh water and grazing.
“Current estimates are that if we do not control the impact of biological invasions on grazing land, we could lose up to 70% of this valuable natural asset. This will reduce the capacity of natural rangelands to support livestock production, thereby threatening rural livelihoods and food production.
“Most disturbingly, the report highlights that new alien species continue to arrive every year in South Africa. A notable new invasive species is the polyphagous shot hole borer beetle,” the minister said.
Creecy said the polyphagous shot hole borer and its associated fungus have already killed thousands of trees in South Africa and it looks set to be one of the most damaging and costly biological invasions faced by the country.
Managing biological invasions
In an effort to manage alien and invasive species, the Department of Forestry, Fisheries and the Environment is spending over R1bn a year on projects to control biological invasions and create jobs.
“Since its inception, the Working for Water programme has cleared more than 3.6 million hectares of invasive alien plants, with an average of three follow up treatments. To date, more than R10bn has been spent on clearing, with more than R1bn during 2020/21 alone.
“Over the years, more than 2,000 person years of employment has been created. During 2020/21 alone, it created more than 53,000 work opportunities, which include retaining 23,000 opportunities that would have been lost were it not for the Presidential Economic Stimulus programme. Removals are of both plant and animal species,” the minister said.
A recent programme has successfully removed bass from selected wetlands and stretches of river, leading to rapid recovery of native fishes and biodiversity in general.
“The use of biological control against invasive alien plants has also been shown to have very high positive returns on investment. This is a critical and well-regulated tool to manage biological invasions, with South Africa recognised as a global leader in the field,” the minister said.
She noted that the challenge is s a multifaceted problem that needs a multi-faceted approach.
“We need to cut through red tape and the silos of different government departments so we have a common national approach. Accordingly, our department is in the process of developing a policy on the management of biological invasions. Its implementation will be supported by a 10-year National Invasive Species Strategy and Action Plan,” the minister said.
Cohesive, collaborative approach
The main objective of the strategy is to facilitate a cohesive and collaborative approach by government, industry and the broader community in identifying and managing biosecurity risks.
Creecy said the strategy and action plan will soon be published for public comment and input.
In addition, South Africa, through financial support from the Global Environmental Facility, under the biodiversity focal window, has secured funds for a project to enhance the efficient and effective management of high-risk biological invasions.
The financial commitment is $3m over five years.
“The project is aimed at directly mitigating the negative impacts of biological invasions on South Africa’s biodiversity, whilst contributing to the improvement of rural food security and livelihoods. It is envisaged that the project will have a significant contribution towards the efforts to mitigate the impact of biological invasions on South Africa’s biodiversity,” the minister said.