WOODY SPECIES COMPOSITION AND CARBON STOCK POTENTIAL OF AWASH NATIONAL PARK, ETHIOPIA

Abstract

This study was conducted in Awash National Park, Ethiopia, to analyse woody species composition and estimate carbon stock potential of woody species in different vegetation types. A total of 80 quadrats of 20m x 20 m, 5m x 5m and 1m x 1m with 16 horizontal transect lines were used to collect information on tree, shrub, and litters and soil respectively in the four vegetation types. A total of 52 woody species belonging into 23 families with stem number of 1369 individual/ha were recorded in the study area. The overall species richness, Shannon- Wiener Diversity Index (H`) and evenness values for the entire study area were 8.38, 1.78 and 0.87, respectively. Woody plant species diversity, richness and evenness significantly varied among the vegetation types (p<0.001). The mean total carbon stock density of the park was found to be 170.65 ton/ha, of which 49.38 ton/ha, 9.88 ton/ha, 0.13ton /ha and 111.26 ton/ ha comprised by above ground biomass, below ground biomass, litter carbon and soil organic carbon respectively. The AGC and BGC had significant variations among the vegetation types (p<0.001). However, riverine forest had significantly highest value than other vegetation types (bushland, woodland and open grassland) (p<0.0001) and open grassland had considerably least values. But, there was no significant variation between open grassland, bushland and woodland. Similarly, soil organic carbon had significant variations among the vegetation types (p<0.001). But, there was no significant variation between open grassland with woodland and bushland with riverine forest vegetations (p>0.05). The litter biomass contributed only a small fraction of C and had insignificant values among vegetation types. Due to the overall carbon pools, the total carbon stock had significant variations among the vegetation types of Awash National Park (p<0.001). The results of this study suggest that protected area can be important for C stocks. However, human induced disturbance in the park can affect its carbon storage potential. Thus, conservation efforts focused on protected area based biodiversity conservation may benefit ecosystem services linked to carbon storage and hence, climate change mitigation. Therefore, the park should enhance further conservation and management actions to maximize the carbon reservoirs.