MAPPING OF DISTRIBUTION OF INVASIVE SPECIES IN RUHANDE ARBORETUM

Abstract

The biodiversity of Ruhande Arboretum is threatened by many alien invasive species. Lantana camara, Thitonia diversifolia and Agave sisalana as invasive species found within that forest, outcompete the established species in their plots and to date, there is no study demonstrating the areas covered by those invasive species. Using GPS and QGIS, skimming the whole forest in a walking census moving around each patch covered by each of those species, we aimed to map the distribution and land cover of Lantana camara, Thitonia diversifolia and Agave sisalana and identified the dominant species among the 3 invasive plant species within Ruhande Arboretum. Of latter, we used stratified random sampling method to determine the abundance of invasive plant species of our interest, determining the proportion of susceptibility of the vegetation types found in Ruhande Arboretum. The findings indicated that among those 3 invasive species, Lantana camara were more distributed followed by Agave sisalana in Ruhande Arboretum. Lantana camara covering 36.13% (74.70 ha) was more dominant than others followed by Tithonia diversifolia with 2.98% (6.16 ha) and Agave sisalana with 2.51% (5.18 ha) of the whole forest. The Eucalyptus species was the most attacked by invasive species of our species of interest, compared to other vegetation types of Ruhande Arboretum. For better management and conservation of Ruhande Arboretum, we recommend to Rwanda Water and Forestry Authority (RWFA) to remove those invasive species and to assess the distribution of other invasive species such as Tecoma stans and Calliandra calothyrsus that can outcompete the established species.