SA sees increase in alien biological species invasions

The number of alien species that have been established in South Africa has increased by 15 per cent 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 R6.5 billion each year. The main costs associated with losses are a decline in ecosystem services such as water and grazing and agriculture crop loss as a result of invasive pests,” Creecy said.

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 three to five per cent of South Africa’s surface water runoff each year, a serious problem in an already water scarce country that is increasingly prone to drought.

The report also found that invasive trees increase the risk and intensity of veld fires, with 15 per cent more fuel burnt in invaded areas.

“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.