Woody Species Richness and Diversity Following Successional Stages at Jello-Muktar Dry Afromontane Forest, South-eastern Ethiopia

摘要

The study was carried out at 8°55＇N-90°5＇N latitude and 40°50＇E-40°51＇E longitude, at Jello-Muktar dry Afromontane forest South eastern Ethiopia to analyze changes in species composition, diversity and species richness under three successional stages. Three sites were selected each with 10 sample plots from each succssional stage. The average distance between the plots was 200 m and the radius was 30m. In each plot, identification, counting and measurement of diameter at breast height (DBH) of all trees and shrubs (DBH≥10cm) was conducted. Comparison of richness (S) between sites and successional stages was analyzed by Chao2 estimator and Rarefaction was performed to compare species richness among sites and successional stages, for unequal number of individuals in sites. The Shannon-Wiener (H') and the Pielou indices (E) were used to assess the species diversity and evenness indices. A total of 114 species corresponding to 76 tree and 38 shrub species were recorded in the three successional stages. The MS forest was found to have the highest species richness followed by IS and ES successional stages. Analysis of Chao 2 estimator revealed that an average of 89.6% of the total species expected had been found for each successional stage. The MS sites were also found to have the highest mean H' and H'E indices. The Overall mean measure of evenness was about 0.86 which indicates that the relative homogeneity of the species in the samples was 86% of the maximum possible even population. Different conservation priorities should be implemented to maintain plant species at different successional stages.