Undocumented invasive exotic woody plants of Mabira Central Forest Reserve, Uganda.

Invasive exotic species are problematic to biodiversity conservation. However, the knowledge of exotic invaders in tropical forests remains limited. Lessons from sites elsewhere suggest that the problem could be worse than is known. To increase our understanding of this problem, we surveyed exotic woody plants in Mabira Central Forest Reserve, Uganda. The site has a long history of anthropogenic disturbance. Seven woody exotic species were encountered, three of which had population structures indicative of invasiveness and distributions suggestive of the early stages of invasion. One of these species Senna spectabilis (DC.) H.S.Irwin & Barneby was localised to an 8.6 ha site north of the reserve. Terminalia superba Engl. & Diels occurred mainly in an 8.7 ha patch south of the reserve, while Artocarpus heterophyllus Lam. was more widely distributed. T. superba has been reported to be invasive in two other countries, but it is not yet clear whether or not the reported invasions are occurring in protected forests. A. heterophyllus is reported to be invasive in various countries, yet rarely quantitatively demonstrated outside the Brazilian Atlantic forests. S. spectabilis is a common invasive in forests throughout the tropics, and this is the first report of its invasiveness in this reserve. [ABSTRACT FROM AUTHOR]