Assessment of the impacts and extent of the invasive species Senna didymobotrya (Fresen.) H.S.Irwin & Barneby on plant diversity in a Southeastern Oromia, Ethiopia

This study explores the impact and extent of Senna didymobotrya (Fresen.) H.S.Irwin & Barneby, an invasive species on plant diversity, Southeastern Oromia Ethiopia, Using a mixed-methods approach, ecological data from 18 plots and socio-economic data from surveys (n=387), focus groups, and interviews were analyzed to assess the impacts of S. didymobotrya. Vegetation metrics, elevation, and LULC were examined using statistical and geospatial tools and seed output was quantified through hierarchical sampling. The analysis of species composition revealed that S. didymobotrya was the most dominant and invasive species, with the Fabaceae family being most represented. While vegetation metrics showed no statistically significant variation across elevations, a trend of higher values occurred above 1250 m asl., possibly due to favorable ecological conditions. The species’ high Invasive Woody Species Ratio (IWSR) confirmed its strong invasive nature, contributing to its widespread distribution in disturbed and undisturbed landscapes, including the encroachment into the ecologically sensitive Harenna Forest. The study also highlights the role of land use and cover change in facilitating the spread of S. didymobotrya, as well as the impact of human-assisted dispersal. Furthermore, local communities perceive the plant as a valuable resource, though its presence does not represent targeted control. The findings suggest that effective management strategies should integrate local knowledge, assess ecological impacts, and explore sustainable uses to mitigate the species’ spread. Further investigation is needed to understand long-term ecological impacts, specific dispersal pathways, and sustainable utilization within community management.