Impact of Invasive Alien Plant, Xanthium Strumarium, On Species Diversity and Composition of Invaded Plant Communities in Borena Zone, Ethiopia

Abstract

Biological invasion is considered as the second greatest global threat to biodiversity. An IAPS, Xanthium strumarium, is widely spread in the agricultural land, roadside, near stagnant water and disturbed land of Borena Zone, Oromia Region. However, its impact on diversity and floristic composition of the invaded plant communities has not been determined. Therefore, the objective of this study was to determine the impact of Xanthium strumarium, on the species diversity and composition of invaded plant communities in Borena Zone. Accordingly, to examine its effects of invasions on the species diversity and composition of invaded communities, ninety six 1m2 quadrats were sampled (48 quadrats for invaded and 48 for non-invaded or control).There were 70 species found in the non-invaded areas as compared to 31 in the invaded areas. The number of species decreased by 55.71% in Xanthium strumarium invaded area as compared to control. The mean evenness value of the entire invaded sampled study sites was 0.27 indicated that 27% of the plant communities had uniform distribution while the mean evenness value of the controls samples was 0.74 indicated that 74% of the plant communities had uniform distribution. Thus, the heterogeneity of the invaded study sites was reduced by 47%. The number of plant families was 24 in the control areas in contrast to only 15 in Xanthium strumarium invaded areas. The number of family decreased by 37.5% in invaded area as compared to control. Xanthium strumarium categorized as one of the dominant invasive alien plant species in the study area that reduced species diversity and composition of various plant species in invaded communities. Therefore, there is a need of better planning to control and eradicate the spread of Xanthium strumarium by establishing communication links between Regional, Zonal and districts Agricultural Office.