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 Program, 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 neither their doorsteps nor how to address it.

“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 Program. “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, water birds, reptiles, amphibians, fish, invertebrates and plants from their natural habitat.

Mesquite (Prosopis juliflora) is one of the most widespread dry land 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 recognize 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.