We assessed the importance of host trees in influencing invasion patterns of the alien tree Schinus molle L. (Anacardiaceae) in semi-arid savanna in South Africa. Recruitment of S. molle is dependent on trees in its invaded habitat, particularly
Acacia tortilis Hayne. Another leguminous tree, the invasive alien mesquite (Prosopis sp.), has become common in the area recently, but S. molle rarely recruits under
canopies of this species. Understanding of the association between these species is needed to predict invasion dynamics in the region. We conducted experiments to test whether: (i) seedling survival of S. molle is better beneath A. tortilis than beneath mesquite canopies; (ii) growth rates of S. molle seedlings are higher beneath A. tortilis than beneath mesquite. Results showed that growth and survival of S. molle
did not differ significantly beneath the native A. tortilis and the alien Prosopis species. This suggests that microsites
provided by canopies of mesquite are as good for S. molle establishment as those provided by the native acacia. Other factors, such as the failure of propagules to arrive beneath
mesquite trees, must be sought to explain the lack of recruitment beneath mesquite.Centre of Excellence for Invasion Biolog