Biofuels and invasive species from an African perspective – a review

A large number of proposed biofuel crops share the same traits as known invasive plant species, many of which are already present in Africa and include species such as Prosopis glandulosa Torrey (Mimosaceae), P. juliflora (Sw.) DC, Leucaena leucocephala (Lam.) de Wit (Mimosaceae), Azadirachta indica A. Juss. (Meliaceae), and others. In this paper, we mainly assess the impacts of invasive Prosopis species in Africa, particularly in Kenya and South Africa. Introduced Prosopis species have invaded over 4 million hectares in Africa, threatening crop and pasture production, reducing underground water reserves, and displacing native plant and animal species. This has major implications for millions of people who depend on natural resources for their survival. It is therefore suggested that known invasive or potentially invasive plant species not be introduced to countries or regions for biofuel production. If (after a stringent cost–benefit analysis) the introduction of a potentially invasive species is deemed critical for economic development and the benefits clearly outweigh the potential costs, countries should endeavour to abide by the Principles and Criteria for Sustainable Biofuel Production developed by the Roundtable on Sustainable Biofuels.