Title: Invasive plant species in Lesotho's rangelands: species characterization and potential control measures

Final project
Year of publication:
invasive species, Lesotho rangelands


Lesotho is experiencing rangeland degradation manifested by invasive plants including Chrysochoma ciliata, Seriphium plumosum, Helichrysum splendidum, Felicia filifolia and
Relhania dieterlenii. This threatens the country’s wool and mohair enterprise and the Lesotho Highland Water Project which contributes significantly to the economy. A literature review-based study using databases, journals, books, reports and general Google searches was undertaken to determine species characteristics responsible for invasion success.

Generally, invasive plants are alien species, but Lesotho invaders are native as they are traced back to the 1700s. New cropping systems, high fire incidence and overgrazing initiated the process of invasion. The invaders possess inherent characteristics such as high reproduction capacity associated with a long flowering period that ranges between 3-5 months. They are perennial, belong to the Asteraceae family and therefore have small seeds with adaptation structures that allow them to be carried long distances by wind. These invaders are able to withstand harsh environmental conditions. Some are allelopathic, have an aggressive root system that efficiently uses soil resources. As opposed to preferred rangeland plants, they are able to colonize bare ground. Additionally, F. filifolia and R. dieterlenii are fire tolerant while H. splendidum and S. plumosum have woolly coverings that limit water loss when temperatures are high. S. plumosum has the ability to shield other plants as it grows fast and produces volatile oils to guard against herbivory. S. plumosum and H. splendidum limit transpiration by reflecting sunlight and rolling leaves to the underside, respectively. 

The literature suggests various control methods to curb these invasive plants. Based on the current study, I suggest using integrated weed control that should incorporate education and social aspects. Research should be engaged to map areas and stages of invasion, trace the history of the vegetation, determine and prevent new invasions. Lesotho also should give land resources a monetary value, which will draw attention to sustainable land management.

Documents and links