Abstract

In this study, we examined vegetation structure and regeneration status of woody plants in the Hallideghie wildlife reserve, Ethiopia. We collected data on abundance, height and diameter at breast height (DBH) of woody plant species with DBH >2.5 cm within sixty-six 20 m × 20 m sample plots and counted number of individuals of seedlings (that is, individuals with height <1.5 m) and saplings (height >1.5 m and DBH <2.5 cm) of each species within five 1 m × 1 m subplots nested within each main plot. To describe vegetation structure, we computed DBH and height size frequency distributions of individuals and species importance value indexes (IVI). Overall, we recorded 986 individuals of tree/shrub stems, belonging to 46 woody plant species. Both the number of species and individuals represented in each DBH size class and height size class showed decreasing trends with increasing size classes. However, different species showed varying patterns of DBH size structure. IVI of species varied from 0.3 to 69.1. The average density of seedlings, saplings and matured woody plants in the HWR were 1345, 899 and 374 individuals/ha, respectively. Balanites aegyptiaca and Acacia tortilis, species with high IVIs, were also among those species that exhibited poor regeneration status.

Key words: DBH, importance values index (IVI), Prosopis juliflora, density, invasive species.