Vegetation data were collected from 72 sample plots laid on the four transects. The size of the main plot was 20 mx20m for tree species. Socio-economic data were analyzed using SPSS version 21 software packages. A total of 75 species of vascular plants belonging to 60 genera and 26 Families were identified from 72 plots from the study area. Out of these plant species, 20% were trees, 30.7 were shrubs, 33.3% were herbs and 16% were grasses. Fabaceae and Poaceae were found the dominant families in the study area. The Shannon diversity index of the woody and herbaceous species was 2.10, and evenness index was 0.50 in the study area. The total basal area calculated was 3.25 m2/ha for tree plants species. These studies indicated that most tree species was identified to have poor regeneration status while shrub species were good regeneration status which means expansion of unpalatable shrub species, which could be indicator on the beginning of bush encroachment in the study area. Most of the pastoralists believed that rangeland vegetation composition was dramatically changed from grassland to bush land within the past two decades, Due to this pastoralist tended to change their livestock herd structure into small ruminant.

Keywords: Ewa rangeland, plant community, Species diversity, pastoralist, herd structure