Effect of exclosure on dryland woody species restoration in northeastern Amhara, Ethiopia

Abstract

In Ethiopia, among many restoration efforts to reverse deforestation and land degradation, area exclosure is one of the most common practices to restore secondary forests with assisted natural regeneration. The present study in the Sekota district, northeastern Amhara region, Ethiopia evaluated the influence of areas exclosures on woody species diversity, population structure and regeneration status. A total of 36 and 27 quadrats, each 20 m × 20 m, were used to collect data in exclosures and non-exclosures, respectively. Within quadrats, four 5 m × 5 m and 2 m × 2 m quadrats at the corners were used to sample saplings and seedlings, respectively. In exclosures, 35 woody species representing 21 families and 29 genera were recorded; 19 woody species representing 13 families and 13 genera were recorded in the non-exclosure. Acacia etbaica was the most dominant species in the two land-uses. The Shannon diversity index was 1.77 ± 0.46 in exclosures and 1.39 ± 0.46 in non-exclosures. Shannon and Simpson diversity indices showed a significant difference between the two land-uses (p < 0.01). The regeneration status of all wood species in exclosures was good, only fair in non-exclosures. Area exclosures have thus played a great role in the restoration of degraded lands by improving vegetation diversity and regeneration status. The least dominant woody species should be maintained through active restoration. Continuous follow-up, maintenance of soil water conservation structure to improve soil fertility will further help enhance the woody species diversity and abundance.