SPECIES DIVERSITY, STRUCTURE AND REGENERATION POTENTIAL OF WOODY VEGETATION IN BABILE ELEPHANT SANCTUARY, EASTERN ETHIOPIA

Abstract

The research was conducted in Babile Elephant Sanctuary in East Hararge zone of Oromia Regional state of Ethiopia with the aim of identifying the plant community and analyzing their diversity, structure and regeneration status. A total of 80 quadrats of 20mx20m (400m2), 5mx5m (25m2), and 1mx1m (1m2) were laid along 16 horizontal line transect for vegetation data collection on tree, shrub and regeneration status respectively. Vegetation data was analyzed statistically by using R-software (version 3.5.1). A total of 67 woody plant species within 33 family and 46 genera were identified from the study area. Out of the total species, shrubs and tree species constituted 52% and 31% respectively, whereas tree/shrub and climber species accounted relatively a minimal percent (12% and 5% for each). Family Fabaceae was the dominant family in the area, which had 16 species (24%). Vegetation classification was done stastically following R-software package(version 3.5.1) outputted in three community type, namely, Trachilia emetic- Acacia robusta- Acacia bussei, Acacia robusta- Acalypha fruticose- Lantara camara and Acacia seyal - Acalypha fruticose- Acacia bussei. The Shannon-Wiener Diversity index (H') and evenness values of the study area (BES) were 2.57 and 0.87. Sorensen’s similarity among the communities revealed that, communities III and I had the highest similarity value (97%) while the lowest similarity value was observed between community I and II (71%). A total density of 21483.7 individual per hectare was calculated for woody plant species, from which shrubs accounted about 53% followed by tree (32%), tree/shrub (12%) and climber (4%). The presence of higher number of species with large and aged ones in C I, made it to companies higher basal area with 63.3 m2/ha followed by C III and C II (26.2 m2/ha and 13.9 m2/ha. Both the diameter and height class distribution of the population in the three-community type displayed inverted J-shape, which indicate that most of the species in the area were under healthy conditions. A total of 9479 individual seedling (42%), 7298 individual saplings (32%) and 5760 individual mature plants (26 %) were counted in the study area. The result exhibit that, the regeneration stratus in the three community type were in good condition as number of regenerating population xvii (seedling and sapling) was higher than matured ones, as seedling > sapling > matured woody plants. From nine selected species, three population distribution patterns were revealed i.e. inverted J-shaped, J-shaped and bell -shaped. Generally, the study revealed that, small sized individuals were identified as the dominant in the sanctuary. Thus the study area need strong and instantaneous ecological policy support and technological intervention to promote biological diversity and stabilize the current status of the sanctuary for the best benefit of the local communities livelihood in particular and for the country in general.