Are protected areas in Africa harbouring invasive species?

Protected areas, long thought of as safe refuges for animals and plants, are under increasing threats from invasive species which not only affect biodiversity but also people’s livelihoods. Protected areas can have huge social and economic value, particularly in Africa, where national parks are a major tourist attraction and a significant source of income. But according to the Global Invasive Species Programme, of which IUCN and CABI are partners, many managers of protected areas in Africa are not aware of the severity of the problem which is on their doorsteps nor how to address it.


Giant mimosa (Mimosa pigra) growing 4 m high in a dense, impenetrable single species thicket on the Kafue Floodplain in Zambia

“Habitat conservation is vital for stemming the decline in biodiversity and the establishment of protected areas is an important mechanism for achieving this aim,” says Sarah Simons, Director of the Global Invasive Species Programme. “But, with invasive species rapidly invading our ever-increasing protected areas unchecked, we are in danger of exacerbating one of the greatest threats to biodiversity.”

A negligible amount of the funding spent on biodiversity conservation projects each year is devoted to invasive species, even though they are the second biggest threat to biodiversity globally, and in some ecosystems, the biggest single threat to biodiversity.

Invasive species include the Giant Mimosa (Mimosa pigra), which is a spiny shrub, originally alien to Africa, that established on the Kafue Floodplain in a national park in Zambia in the early 1980s and has since spread to cover 3,000 hectares of prime floodplain habitat, pushing out many large and important aquatic antelopes, waterbirds, reptiles, amphibians, fish, invertebrates and plants from their natural habitat.

Mesquite (Prosopis juliflora) is one of the most widespread dryland invasive species in north and east Africa having already invaded 500 000 and 700 000 hectares in Kenya and Ethiopia, respectively. Under ideal conditions, it has the ability to double its range every 5 years.

"We need to build invasive species monitoring and management into regular protected area management routines," says Geoffrey Howard, IUCN Global Invasive Species Coordinator. “But the vast majority of protected areas in Africa don’t have the capacity or resources to recognise or identify invasive species. People are largely unaware of how damaging they can be and, more importantly, don’t possess the necessary information and equipment to actually manage them.”

Invasive species have been on the agenda in Nairobi, Kenya, this week at a meeting of the Subsidiary Body on Scientific, Technical and Technological Advice to the Convention on Biological Diversity, or SBSTTA. Decisions taken in Nairobi will provide a scientific basis for discussions that will take place in October in Nagoya, Japan, at the 10th meeting of the Conference of the Parties to the Convention on Biological Diversity.

“Governments must recognise that invasive species pose one of the biggest threats to protected areas in Africa and unless measures are taken to effectively manage this insidious problem, they may fall short of their critical role in biodiversity conservation on the continent”, says Arne Witt, Invasive Species Coordinator, CABI-Africa.

Editors notes

Information on the Giant Mimosa and the Mesquite provided by the UNEP-GEF project “Removing barriers to the management of invasive plants in Africa”.

Media team:

Nicki Chadwick, IUCN Media Relations Officer, m +41 79 528 3486, e

Work area: 
Protected Areas
Protected Areas
Invasive species
East and Southern Africa
West and Central Africa
North America
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