The effects of the invasive species, Lantana camara, on regeneration of an African rainforest

Abstract

Invasive plants adversely affect native communities by altering ecosystem function and disrupting natural regeneration. We investigate the effect of invasive Lantana camara L. (Verbenaceae) on forest regeneration in Kibale National Park, Uganda. We appraise the efficacy of cutting and uprooting Lantana for promoting native tree recruitment. Sample plots comprised three types: (i) currently invaded by Lantana; (ii) cleared of Lantana and now managed; and (iii) forest reference plots uninvaded by Lantana. Tree species numbering 51, 19 shrubs, and 17 herb species were identified. Lantana reduced tree, shrub, and herb cover and diversity, and suppressed tree regeneration. The short-term management of Lantana did not promote tree establishment. The tree community in cleared areas was not converging on uninvaded adjacent forest. Lantana is known to allelopathically suppress tree seedling establishment, but even at sites cleared of Lantana, tree species recruitment was poor. While insufficient time may have passed for tree recruitment, we argue that an increase in shrub and herb cover and diversity arrested forest tree regeneration. Sustained follow-up clearing of dense secondary shrubs and herbs and resprouted L. camara in cleared areas is key to ensuring long-term recovery of the forest tree community.