The effects of disturbance on woody species composition, structure and regeneration status in the ura natural forest, Guangua district, Awi Zone, Ethiopia

Abstract

Ethiopia Province has diverse forest resources. However, it has decreased over time, leaving the country's forest with only remnant patches. Therefore, the present study was conducted to examine the species composition, structure and regeneration status of woody plant species along disturbance gradients. To collect the data, the forests were first stratified into low disturbed (LD), moderately disturbed (MD) and heavily disturbed (HD) groups based on information from reconnaissance site visits and consultations with key informants. Three transect lines were laid systematically 200 m apart, and rectangular plots 10 m∗20 m (200 m2) in length were laid at 50 m intervals along each transect, for a total of 27 plots. The DBH and height of all woody individuals with ≥5 cm and ≥2 m were measured. Seedling and sapling data were recorded in four subplots of 2 m∗5 m (10 m2) respectevly in the opposite corner of the main plot. Woody species density, richness, evenness, diversity, frequency and IVI were determined for each disturbance class, and one-way ANOVA and mean comparison tests were used to examine significant differences among disturbance classes. A total of 37 woody species and 27 families were recorded. Based on structural analysis, only Croton macrostachyus exhibited an inverted J shape. It is concluded that woody species composition was affected by human disturbance. Therefore, a concentrated form of forest conservation should be established to protect against excessive human disturbance.

Keywords

• Disturbance
• Importance value index
• Population structure
• Regeneration
• Woody species diversity