Barbara Creecy | Invasion of alien species accelerates decline of biodiversity

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The picturesque Krom River is surrounded by invasive alien plants.                                        (Photo: supplied)
The picturesque Krom River is surrounded by invasive alien plants. (Photo: supplied)

Current estimates suggest the ecological costs of invasive alien plants and animals to be more than R6.5 billion each year, writes Barbara Creecy.

Science tells us that one of the key factors driving the accelerated decline of biodiversity is the invasion of alien species. Across the world, invasive species are known to impact on all sectors of society. 

Biological invasions impact biodiversity, the economy, human health and well-being, and sustainable development in our own country.

The Status of Biological Invasions and their Management in South Africa Report we launched recently makes a number of essential points in this regard:

Firstly, the number of alien species that have been established in South Africa has increased by 15% from 1 637 to 1 880, about a third of which are invasive.  

Current estimates suggest the ecological costs of invasive alien plants and animals to be more than R6.5 billion each year. The main costs associated with losses are a decline in ecosystem services such as water and grazing and agriculture crop loss resulting from invasive pests.

Invasive trees 

The second finding is that invasive trees use up 3–5% of South Africa’s surface water runoff each year, a severe 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 exact impact occurs in other drought-stricken areas, such as the Eastern Cape.

The third finding is 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 complicated.

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.

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 seventy per cent of this valuable natural asset. This will reduce the capacity of natural rangelands to support livestock production, thereby threatening rural livelihoods and food production.

READ | Opinion: Mapping alien trees to protect our forests

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 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 our country.

Our country’s alien and invasive species regulations, first promulgated in 2014 and revised early in 2021, are comprehensive and innovative.

Through permitting and regulation, we ensure that people who import, grow and trade with invasive species that have commercial value are appropriately licenced to do so, provided that they reduce the risks of the species harming.

Compliance and enforcement action are to ensure that importers and landowners follow requirements to reduce the risk of introducing new species and the impacts of species already here. In 2019, as a result of enforcement action, we secured our first successful prosecution.

New technologies have been developed to support actions to prevent the introduction of listed species. However, we recognise that accidental imports will continue to occur.

Billions spent on clearing

For this reason, the Department of Forestry, Fisheries and the Environment is spending over a billion rand 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 average three follow up treatments.

To date, more than R10 billion has been spent on clearing, with more than R1 billion during 2020/21 alone. Over the years more than 2000 person years of employment has been created. During 2020/21 alone, it created more than 53 000 work opportunities, which includes retaining 23 000 opportunities that would have been lost if it was not for the Presidential Economic Stimulus programme.

Removals are of both plant and animal species. 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.

READ | Opinion: Wetlands are central to green economy recovery strategies

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.

We recognise that this is a multifaceted problem that needs a multidimensional approach. We need to cut through red tape and the silos of different government departments so we have a shared national approach.

As a department, we are 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. 

Collaborative approach 

The strategy's main objective is to facilitate a cohesive and collaborative approach by government, industry, and the broader community in identifying and managing biosecurity risks. The strategy and action plan will soon be published for public comment and input.

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 over R41 million over five years.

The project aims to directly mitigate the negative impacts of biological invasions on South Africa’s biodiversity whilst contributing to the improvement of rural food security and livelihoods.

The status of biological invasions and their management in South Africa has created an excellent foundation on which to build a comprehensive monitoring and reporting programme, which can guide research and implementation efforts.

Enhanced spatially explicit data on the extent and severity of invasions would greatly improve planning for interventions and reporting on the status of invasions.

- Barbara Creecy is Minister of Forestry, Fisheries and the Environment

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