Floristic composition and plant community distribution along environmental gradients in Guard dry Afromontane forest of Northwestern Ethiopia

Abstract

Background Dry evergreen montane forests of Ethiopia provide economic and ecological services for the community but it is under several threats of natural and anthropogenic disturbances. The study aimed to investigate the floristic composition, species diversity, and plant community distribution of Guard forest along environmental gradients. Methods A systematic sampling technique was used to collect vegetation and environmental data. Fifty eight plots each with 400 m2 (20 m X 20 m) were established for trees and shrubs and 2 m x2m (4 m2) for herbs along eleven transect lines. Shannon Weiner diversity index and evenness were used to assess the species diversity and richness. The similarities among plant communities were computed using Sorenson’s similarity index. The plant community types and vegetation-environment relationships were analyzed using hierarchical cluster analysis and Canonical correspondence analysis (CCA) in R software, respectively. Results A total of 137 plant species belonging to 111 genera and 55 families were identified. The most dominant families in the study area were Fabaceae and Asteraceae. Among the total plant species documented in the forest, 42(30.65%) were trees, 36 (26.28%) were shrubs, 48(35.04%) were herbs, and 11 (8.03%) were climbers. Of the total species, 14(10.22%) species are endemic to Ethiopia and Eritrea. Three plant community types were identified by cluster analysis. The Shannon-Weiner Diversity Index was 3.39 and evenness was 0.87 for the forest. The pattern of plant species distribution was significantly influenced by altitude, pH, BD, slope, and charcoal (P < 0.05). Conclusion Guard forest has good species diversity and richness, and supports different endemic plant species that show the potential of the area to support useful but some of the characteristics species are not found in the forest and others are rare in their existence due to the presence of disturbances and need immediate conservation to ensure sustainable use and management of the forest.