Altitudinal Gradient’s Effect on Woody Species’ Diversity, Structure, and Regeneration Status of Ethiopian Highland Forest, Hafursa

Abstract

This study investigated the effects of altitudinal variation on woody species’ diversity, structure, and regeneration status of dry evergreen Afromontane Hafursa forest in Ethiopia. The finding was based on 32 plots of 400 m2 size established systematically, and data on seedlings and saplings were collected from five subplots of 1 m2 size located at the four corners and center of the main plot. A total of 26 woody species belonging to 23 genera and 19 families were identified, with a Shannon-Wiener’s diversity index (H′) of 2.28 at higher altitudes and 2.41 at lower altitudes. The total basal area of the forest was observed to be 9.43 m2/ha for woody species ≥ 2.5 cm in DBH, with the total density of all woody species collected in the forest being 522 individuals per ha. In addition, the study found the predominance of certain species, such as Faurea rochetiana, Ilex mitis, Maesa lanceolata, and Hagenia abyssinica, which showed higher values in the important value index (IVI). An analysis of the population structure and regeneration status indicated that higher altitudes exhibit decreased species diversity and richness compared to lower altitudes. This trend was observed across both altitudes, with the majority of species exhibiting a poor regeneration status characterized by a higher number of mature individuals compared to seedlings and saplings. Therefore, attention should be given to the protection and rehabilitation of this forest’s biodiversity.