BACKGROUND : Alien organisms are not only introduced from one biogeographical region to
another but also spread within regions. As South Africa shares land borders with six countries,
multiple opportunities exist for the transfer of alien species between South Africa and other
African countries; however, the direction and importance of intra-regional spread is unclear.
OBJECTIVES : The aim of this study was to gain a greater understanding of the introduction of alien
species into Africa and the spread of species between South Africa and other African countries.
METHOD : We developed scenarios that describe the routes by which alien species are introduced to
and spread within Africa and present case studies for each. Using data from literature sources and
databases, the relative importance of each scenario for alien birds and insect pests of eucalypts was
determined, and the direction and importance of intra-regional spread was assessed.
RESULTS : Alien species from many taxonomic groups have, through various routes, been
introduced to and spread within Africa. For birds and eucalypt insect pests, the number of
species spreading in the region has recently increased, with South Africa being a major
recipient of birds (14 species received and 5 donated) and a major donor of eucalypt insect
pests (1 species received and 10 donated). For both groups, many introduced species have not
yet spread in the region.
CONCLUSION : The intra-regional spread of alien species in Africa represents an important and
possibly increasing threat to biosecurity. To address this threat, we propose a framework that
details how African countries could cooperate and develop a coordinated response to alien
This paper was initially delivered at the 43rd Annual Research Symposium on the Management of Biological Invasions in
South Africa, Goudini Spa, Western Cape, South Africa on 18-20 May 2016.