Enclosures to Enhance Woody Species Diversity in The Dry Lands of Eastern Tigray, Ethiopia

Abstract

Vegetation and soil seed banks were studied in exclosures and unprotected areas, to investigate the role of exclosures in the rehabilitation of degraded drylands. Woody vegetation was assessed in fifty plots in exclosures and 30 in unprotected areas, each measuring 20 × 20 m². Twenty-seven woody species representing eighteen families were observed in exclosures and fourteen woody species representing twelve families were recorded in open area. Higher abundance, density and basal area were found in the exclosure. An expanding population structure in exclosure, and obstructed population structure in open area, showed favorable succession in the set-aside area. In both cases, woody species were absent in the soil seed bank. Keywords : Degradation; Natural Regeneration; Rehabilitation; Soil Seed Bank East African Journal of Sciences Vol. 1 (2) 2007: pp. 136-147