Distribution and Effect of Echium Plantagineum L. on Floral Species Diversity in the Dejen District, Northern Ethiopia

Invasive plant species are considered the greatest global threat to the loss of biodiversity. Echium plantagineum L. an invasive species, is primarily found along roadsides and grazing lands in the Amhara Regional State of the Dejen district. The purpose of this study was to investigate the distribution and effect of E. plantagineum on the diversity of floral in the area of its occurrences. Reconnaissance survey was conducted to observe the distribution, spread, and effect of E. plantagineum on plant and animal species. As a result, 116 systematically established sample plots from the study were taken (58 invaded and non-invaded plots for each). To gather information on trees (shrubs) 10m x 20m sample plots were created on grazing land types. At each corner, a 1m ² subplot was taken to collect herbaceous plants. A 4m ² plot on roadside land units was created to gather information on the herbaceous flora, tree or shrub seedlings. Plants in each plot were recorded and named. Visual estimation was used to determine the percentage cover of herbaceous species. The study assessed species diversity using species evenness, Shannon Diversity Index, and Simpson Index of Dominance measures. These metrics were analyzed using PAST software. Similarity between invaded and non-invaded areas was evaluated using Jaccard’s similarity index and beta diversity. The relationship between the abundance of E. plantagineum and floral species abundance was examined through linear regression and correlation analyses. A total of 85 plant species from 32 families were discovered in the study areas. In non-invaded land units, 80 plant species from 30 families were recorded. In comparison, the invaded area contained 54 plant species grouped into 24 families. Thus, the number of plants was reduced by 32.5% in the E. plantagineum-invaded area compared to the non-invaded area. The findings also showed that the non-invaded areas have a higher Shannon Diversity index value was observed in plant (3.537) and also higher plant species evenness value (0.429) compared to the E. plantagineum invaded areas. The study also showed a negative relationship between the abundance of E. plantagineum invasives and the abundance of native plant species per study plot. It was concluded that E. plantagineum, the invasive plant species in the study area, has reduced floral species diversity. Therefore, it is strongly advised to implement adequate planning and strategies to detect or stop the spread and effects of E. plantagineum. This can be achieved by creating communication channels between the regional, zonal, and district agricultural offices .