Comparison of Woody Species Diversity and Population Structure Along Disturbance Gradient in Babile Elephant Sanctuary, Ethiopia

Abstract The study was conducted at Babile Elephant Sanctuary (BES), to identify and document the list of woody species, and to analyze the diversity, richness, evenness, and population structural status of woody species. The diversity of plant species and population structure of woody species were analyzed from 60 quadrats, each with 20 m x 20 m for trees and 5 m x 5 m for shrubs and climbers, using systematic sampling methods with three levels of disturbances regime, namely, low disturbed (LD), moderately disturbed (MD) and heavily disturbed (HD) sites. Vegetation parameters such as diameter at breast height (DBH), richness, evenness, and density of woody species were recorded. Shannon Weiner Diversity Index was used to analysis vegetation diversity and evenness. A total of 61 woody species were identified in the study area that falls within 29 families and 38 genera of which 50.8 % were shrubs, 39.3 % were trees and the rest 9.83 % were climbers. Fabaceae was represented by the highest number of species (14 species = 22.90). The highest plant species richness was recorded from the low disturbed sites, followed by moderately disturbed and heavily disturbed sites respectively. The population density of vegetation was significantly higher in the MD site, followed by the LD site. The total basal area of LD, MD, and HD were 27.2, 19.8, and 11.2 m2/ha, respectively. LD site had significantly (P= 0.04) highest Shannon’s diversity index value (3.21) than the others two disturbance levels. This result suggests that the consequence of human-induced disturbance on woody species diversity and population structure appeared to be negative depending on the type and intensities of the disturbances.