Effect of degraded land rehabilitation on carbon stocks and biodiversity in semi-arid region of Northern Ethiopia

This study evaluated the effects of exclsoures (EXs) on restoring woody species diversity and carbon stocks over the adjacent degraded open grazing land (DOGL). Two proximate sites were purposively selected. Then, systematic sampling method was employed. A total of sixty plots were surveyed for both tree/shrub inventory and soil sampling purposes. Overall, 49 woody species belonging to 45 genera and 28 families were identified, it comprising 46 woody species in the EX and 26 woody species in the DOGL. Species richness, Shannon and Simpson diversity indices were significantly higher in the EXs than DOGL. The total carbon stock was significantly higher in EXs (61.3 Mg C ha−1, it ranged from 54.3 to 68.3 Mg C ha−1) than DOGL (40.4 Mg C ha−1, it ranged from 35.1 to 45.7 Mg C ha−1). The conversion of the DOGL to EXs enhanced soil organic carbon and aboveground biomass carbon stock by 38 and 197% at the age of 12 years, respectively. Woody species diversity, abundance and richness were positively correlated with biomass and soil organic carbon stocks. This study revealed that EXs assisted with enrichment planting can be considered as a viable woody species recovery and carbon sequestration strategy. Abbreviations: EXs: Exclosures; DOGL: Degraded open grazing land: REDD+: Reduce Emissions from Deforestation and Forest degradation plus; SOC: Soil organic carbon; dbh: Diameter at breast height; AGB: Aboveground biomass; BGB: Belowground biomass