Abstract
Deforestation and fragmentation have posed a serious threat to tropical forests, leading to a loss of biodiversity and ecological disturbance. This study aimed to investigate the effects of forest fragmentation and anthropogenic disturbances on the diversity, structure, and regeneration status of woody species. Systematic sampling approach was employed to assess woody vegetation and human disturbances across four forest fragment sizes (FFSs) in 122 sample plots, each measuring 20×20 m. One-way ANOVA and Pearson correlation analyses were conducted to evaluate the impacts of fragmentation and disturbances on woody species diversity, structure, and regeneration status. The results showed that very large FFSs had higher mean species richness (S) (31.55), Shannon diversity (H´) (2.96), and evenness (E) (0.86) than large (S = 26.44, H´ = 2.68, E = 0.81), medium (S = 24.57, H´= 2.48, E = 0.78), and small FFSs (S = 22.28, H´ = 2.22, E = 0.76), with significant differences (p < 0.001) between very large and small FFSs. Disturbance levels varied significantly, with small FFS experiencing higher mean index (34.37). Mean stem density ranged from 613.2 to 985 individuals/ha, showing significant differences between small and very large FFSs. Mean basal area density varied from 27.68 to 60.66 m²/ha, with significantly higher values in very large FFSs. Larger FFSs and reduced disturbances positively influence tree species regeneration. These findings underscore the negative effects of forest fragmentation and disturbances on woody species richness, diversity, structure, and regeneration in southwest Ethiopia. Urgent conservation strategies are necessary to protect these forest fragments and their biodiversity and ecosystem services.