How officials can fight biological invasion

Over the last decade, 32 new alien species were either illegally or accidentally introduced into South Africa.

This is according to a report titled “The 3rd National Status of Biological Invasions and their management in South Africa”, launched by Forestry, Fisheries and the Environment, Minister Barbara Creecy. The research shows that new alien species continue to arrive every year via several pathways.

“Over the last decade (2013–2022), 32 new alien species were either illegally or accidentally introduced, a rate of approximately three introductions per year. This is slightly lower than the numbers seen for 2010-2019, which were an average of about four new species introduced per year,” Creecy said.

“South Africa is confronted with a multitude of invasive species that have taken root in our ecosystems, altering native habitats, out-competing indigenous species and disrupting essential ecological processes. These invaders, introduced through human activities such as trade and travel, have demonstrated their ability to spread rapidly and wreak havoc on our fragile ecosystems,” Creecy said.

Invasive species, in particular trees and freshwater fishes, have significantly negative impacts on people and nature across the country by reducing South Africa’s water resources, degrading pastureland and exacerbating wildfires.

“In mountain catchments, we are seeing pine trees using up water, increasing the intensity of fires and crowding out biodiversity. Alien freshwater fishes are invading South Africa and reducing the diversity of our native fishes and other aquatic organisms,” Creecy said.

Invasive species were also devastating the unique and sensitive biodiversity of the Prince Edward Islands.

Biological invasions were the main threat to biodiversity on the islands.

The findings show that there are 44 alien species on Marion Island, over half of which are invasive, while there are eight alien species present on Prince Edward Island, all of which are invasive.

Creecy said the government invested over R1.5 billion to address biological invasions between 2020-2022; targeting priority areas such as strategic water source areas, protected areas and biodiversity hot spots.

These interventions have also created much-needed employment, especially in rural areas. Several initiatives by NGOs raised over R180 million from the private sector to fund the control of invasive freshwater fishes and alien plants in the water catchments around Cape Town.

“This model could be replicated across other catchments and priority areas,” Creecy said.

Biological invasions on the Prince Edward Islands were being addressed through effective biosecurity and on-island management, she said.

“The house mouse is the most harmful alien species on Marion Island.

The mice feed on plants, invertebrates and endangered sea birds. They also affect ecosystem processes such as sediment movement rates and nutrient cycling. Bold plans to eradicate the house mouse from Marion Island have been developed and are due to be implemented in 2027. The eradication of mice from Marion Island is essential if its unique biodiversity is to be preserved.

“There is still much work to be done. Addressing the challenges posed by biological invasions requires a coordinated and collaborative effort. No single entity can tackle this issue alone.

“Governments, academics, civil society organisations and communities must come together, pooling their knowledge, resources and expertise to develop effective prevention, early detection and control strategies.

“We must enhance our efforts to prevent the introduction of new invasive species through vigilance at our borders and risk analyses. Early detection and rapid response systems should be strengthened to identify and eradicate invaders before they become established,” Creecy said.

Cape Times