A milestone biodiversity report for South Africa, flagged the Western Cape as the most alien plant invaded province in the country.
The South Africa Biodiversity Institute (SANBI) released the first comprehensive national-scale assessment of the status of biological invasions and their management anywhere in the world.
”Biological invasions pose an enormous threat to South Africa’s ecosystems and the services they deliver, such as clean water and air, and biodiversity. South Africa is among the few countries that have legislation specifically aimed at managing this problem,” says Dr Moshibudi Rampedi, the Chief Executive Officer (CEO) of SANBI.
Key findings of the report found:
-2 034 alien species have established populations outside of cultivation or captivity in South Africa
-775 of the 2 034 alien species with established populations are invasive. More than a hundred of these invasive species (107) have caused large negative impacts on the environment
-Alien plants are the most diverse, widespread and damaging group of invaders in South Africa. Well over 100 new species have been recorded as naturalised or escaped from cultivation over the past decade, and the recorded ranges of almost all invasive plants has increased significantly over the past decade
-The rate of introduction of species is increasing, in line with increases in travel and trade – the estimated rate of introduction currently stands at seven new species per year
-The most invaded province is the Western Cape at 28%, followed by Mpumalanga, Northern Cape and KwaZulu-Natal. Invasive alien plants reduce surface water runoff by between 1 500 to 2 500 million cubic metres per year in more densely populated areas.
“The economic damage caused by biological invasions has been estimated at billions of Rands per year, and the problem is growing rapidly as more alien species are introduced,”said Rampedi.
The impacts of these invasive plant species include, reducing surface water runoff and affecting water resources. If nothing is done to reduce current plant growth and their influence on the water supply the reduction in resources due to their growth could almost double in the coming year.
Another serious threat the alien species pose to the Western Cape is adding fuel and increasing the severity of wildfires, making them more difficult to control and more destructive.
Responding effectively to biological invasions requires integrated interventions that focus on different aspects of the invasions process, from steps to prevent the introduction of high risk species, to the detection and eradication of early phase invasive species, and management of those that have already spread.
Government efforts have focused on bio-security, early detection of emerging invasions, and programmes such as Working for Water, which have the dual objectives of job creation and the control of biological invasions.
In the coming years the government hopes to strengthen their effort in various ways to tackle the growing problem while focusing their resources. As the Mother City heads into the warmer season we can only hope that their attempts prevail sooner rather than later.
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