1 Invasive Species: an Alien Idea to African Publics? Day, R.K., Witt, A., Asaba, J.F., 1 Simons, S., Chege, K. CABI Africa and 1 Global Invasive Species Programme Nairobi, Kenya Abstract Targets for curbing species extinctions by 2010, International Year of Biodiversity, will not be met. One of the main culprits, addressed in Article 8(h) of the Convention on Biological Diversity, is invasive species. Invasive species have negative impacts on many different sectors, so there are many publics with whom scientists need to engage if the problem is to be adequately addressed. In African agriculture invasive species threaten food security; in the environment they threaten natural habitats and the wildlife that draws so many tourists; they compromise scarce water resources; and diseases cause widespread sickness. Although general awareness of invasive species is said to be low in Africa, we identify several publics, who in different ways, are becoming engaged in discourse on invasive species. We discuss several aspects of this developing discourse, which has parallels with other debates on the interaction between science and society in Africa. Introduction The year 2010 is the International Year of Biodiversity designated by the United Nations to draw attention to the importance of biological diversity to human existence, and to the fact that human activities are having a significant detrimental impact on biodiversity. In 2002 targets were set for curbing species extinctions, to be achieved by 2010, but the Secretariat of the Convention on Biological Diversity (2010) admits that these targets are not being met. The 2010 Global Biodiversity Outlook (GBO-3) further warns that the pressures leading to biodiversity loss are at best constant and in some cases are increasing. GBO-3 lists five main pressures, one of which is invasive species. The topic of invasive species is therefore on the international environmental agenda, and the wide range of causes and impacts of invasive species means there are many interested parties. But the issue of invasive species is not without controversy, so a consideration of invasive species publics, and the surrounding debate on the topic is pertinent to the theme this workshop. What are Invasive Species? There is no widely agreed definition of invasive species, which Valéry et al. (2008) argue is due to lack of precision on the notion of biological invasion itself. However, the term is used by the Convention on Biological Diversity (usually including the additional adjective “alien”, a further cause for debate), and so their definition of this and other related terms commonly used is reproduced in Table 1. However, invasive species have a wide range of impacts beyond biodiversity (Mack et al., 2000), so for the purposes of this discussion an invasive species is one whose establishment and spread causes economic and or environmental harm. We touch further on the issue of language in a later section.