Plant Community Analysis along Environmental Gradients in Moist Afromontane Forest of Gerba Dima, South-western Ethiopia

Abstract

Background: This study was carried out in Gerba Dima Forest, South-Western Ethiopia, to determine the floristic composition, species diversity and community types along environmental gradients. Ninety sample plots having a size of 25 X 25m (625m 2 ) were laid by employing stratified random sampling. Nested plots were used to sample plants of different sizes and different environmental variables. All woody plant species with Diameter at breast height (DBH) ≥ 2.5 cm and height ≥ 1.5m were recorded in 25 m X 25 m plots. Within the major plots, five 3m x 3m subplots (9m 2 ) was used to collect shrubs with dbh < 2.5 cm and > 1.5m height. Within each 9m 2 subplots, two 1m 2 subplots were used to collect data on the species and abundance of herbaceous plants. Hierarchical (agglomerative) cluster analysis was performed using the free statistical software R version 3.6.1 using package cluster to classify the vegetation into plant community types. Redundancy Analysis (RDA) ordination was used in describing the pattern of plant communities along an environmental gradient. Result: One hundred and eighty plant species belonging to 145 genera, 69 families and comprising of 15 endemic species were recorded. Cluster analysis resulted in five different plant communities and this result was supported by the ordination result. RDA result showed altitude was the main environmental variable in determining the plant communities. The ANOVA test indicated that the five community types differ significantly from each other with regard to EC and K. Conclusions: The studied forest can play a significant role in biodiversity conservation since it harbours high species diversity and richness. Thus, all Stakeholders including Oromia Forest and wildlife enterprise (OFWE) and the regional government should work to designate the forest as a biosphere reserve and being registered under UNESCO. Keyword s: Gerba Dima; Indicator species; Moist Afromontane Forest; Species diversity

Woody Species Composition, Vegetation Structure, and Regeneration Status of Majang Forest Biosphere Reserves in Southwestern Ethiopia

“…e number of species composition in Majang forest biosphere reserves (56 families, 115 genera, and 158 plant species) is higher than other forest sites including Agama forest (35 families, 65 genera, and 72 plant species) [41], Maji forest (55 families, 115 genera, and 146 plant species) [42], Wurg forest (40 families, 64 genera, and 76 plant species) [43], and Oda forest (32 families, 54 genera, and 62 plant species) [44] but lower than Gerba- International Journal of Forestry Research Dima forest (69 families, 145 genera, and 180 plant species) [45], Yayu forest (72 family, 163 genera, and 217 plant species) [4], and Bonga forest (92 families, 207 genera, and 285 plant species) [42]. e variation of plant species over different habitats of the forest could be attributed to a number of environmental factors, which impose impacts in both temporal and spatial scales [46].…”