Impact of area closure on vegetation cover, woody species structure and soil chemical properties in Kelala Dalacha Mountain, Oromia, Ethiopia

Abstract

This study was undertaken in Kelala Dalacha Mountain in Oromia, Ethiopia to determine the impacts of ecosystem rehabilitation on vegetation cover, woody species structure and soil chemical properties. A random sampling method was used to collect vegetation data from a total of 31 quadrats of 400 m2 each. Four satellite images of the study area, distributed between 1988 and 2018 were analyzed using Arc GIS software to assess the Land Use Land Cover (LULC) changes of the area. Composite sampling was used for soil sample collection and soil was analyzed for selected chemical properties. Data were analyzed using both descriptive and inferential statistics. Result indicated that the vegetation cover was 58.1% in 1988, 64.47% in 1998, 80.32% in 2008 and 88.43% in 2018, showing the positive contribution of area closure in ecosystem rehabilitation. The bare land in 1988 was changed to either woody species or grasses nowadays. Similarly, area closure had a positive impact on vegetation structure. Woody species in the study area displayed an inverted J-shaped pattern of distribution. The lower DBH classes were found to have relatively higher number of individuals than that of the middle and the top classes indicating the importance of area closure. Mean values of soil pH, EC, CEC, OC, TN, P and K were 6.64, 0.082, 30.92, 2.44, 0.213, 3.91 and 219.38, respectively. Area closure is a viable strategy for restoring degraded ecosystems as it had positive impact on vegetation cover, woody species structure and soil chemical properties. Therefore, it was recommended to ensure wide scale applications of area closure on all mountains for restoration of ecosystem function and biodiversity conservation.