Mountain Research and Development (May 2018)
Vascular Plant Species Composition, Relative Abundance, Distribution, and Threats in Arsi Mountains National Park, Ethiopia
Abstract
A study of vascular plant species composition, relative abundance, distribution, and anthropogenic threats to these species' survival was carried out in the Galama Mountains in Arsi Mountains National Park, Ethiopia. An Intensive Modified Whitaker nested plot design was used to sample vegetation in disturbed and undisturbed habitats across the landscape. A total of 191 plant species (including 5 identified only to the genus level) in 56 families were recorded. The dominant family was Asteraceae, followed by Poaceae. Twenty species (about one-tenth of all species recorded) are endemic to Ethiopia. The highest overall species richness was recorded in the dry evergreen Afromontane vegetation in the undisturbed plots and in the Erica (heath) habitat in the disturbed plots. Rare plant species were less frequent in the disturbed plots than in the undisturbed ones. Regression analysis indicated a significant decrease in total species richness with increase in elevation. It also indicated a significant decrease in species richness and average plant species ground cover with increasing amounts of fresh livestock dung. The rate of tree removal exceeds the rate of regeneration in the dry evergreen Afromontane vegetation. Myrsine melanophloeos, Schefflera abyssinica, and Juniperus procera were the dominant tree species in the lower elevations (2843 to 3200 m above sea level) and have been found to be overharvested. Based on the current anthropogenic pressures in the study area, we expect species diversity and frequency of occurrence to diminish over time. Urgent conservation measures including control of tree harvesting and livestock encroachment should be prioritized in Arsi Mountains National Park.
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