Fredrick Ssali, Robert Baluku, Gilbert Drileyo and Moses Muhumuza recount their experience investigating the invasive flowering plant Lantana camara and its impact on common native species in western Uganda.
Researchers at the Uganda Wildlife Research and Training Institute (UWRTI) teamed up with scientists from two Ugandan Universities and explored associations between Lantana camara and common native species in Queen Elizabeth National Park in western Uganda. Lantana camara is a flowering plant, an angiosperm, that belongs to the Verbenaceae family. It is a species of management concern, an introduced invasive species. It is locally abundant, occurring over 66 km2 of the park. This invasive species is hard to eradicate, as it flowers and fruits throughout the year and is readily dispersed by many native bird species. It also reproduces vegetatively and has a persistent seed bank. The invader can be brought under control by integrating various mechanical, biological, chemical and land management techniques into conservation practice. For example, people may harvest the plant regularly until it is eliminated.
Data Collection
We set out to explore associations between L. camara and common native species. We wanted to find out: (1) whether floristic composition varies between L. camara invaded and uninvaded areas and (2) which large herbivores forage in areas with L. camara. Such knowledge is important for improved management of biological invasions. Fieldwork was both intensive and exciting, with the team spending long hours walking through thick vegetation as we travelled from plot to plot. We often came very close to megaherbivores (that is, elephants and buffaloes).
Findings
We found large differences between invaded and uninvaded sites. Of particular concern is the finding that some palatable species were virtually absent from invaded areas and the fear that L. camara might spread to more areas in the park. Our data also revealed that large herbivores were absent in several plots in invaded areas. The avoidance of invaded areas was mainly exhibited by the Uganda kob, which frequently utilised areas without Lantana. If large herbivores keep avoiding these areas, L. camara invasion will likely worsen due to reduced opportunities for recolonisation by herbivore-adapted species. Interestingly, the highest ranking species occurring in invaded areas were also common in uninvaded areas. Park managers could use them as seed sources to promote rapid recovery.
Furthermore, major invasive plant species are known to occur within or near our inventory plots. In our data set, nearly one in ten of the taxa recorded were alien species and two of these occurred more commonly in invaded than in noninvaded areas. This points to the need for restoration interventions aimed at controlling a broad suite of invaders that may come in after the eradication or decline of Lantana. This study is part of a long-term vegetation monitoring programme which aims to investigate the different techniques, methods, and approaches for eradicating invasive plant species from the park.
Read the full article: “Associations between Lantana camara L. (Verbenaceae) and common native species in an African savanna” in Ecological Solutions and Evidence.
