Carbon Sequestration Potentials of Selected Wetlands at Lake Ziway, Ethiopia

Abstract

Wetlands are known for their high productivity owing to their high biomass content per unit area. This is however changing due to human needs to convert them to various land use types. The objective of this study was therefore to investigate the impact of wetland conversion on carbon sequestration potentials of selected wetland sites at shore area of Lake Ziway. Five sites were selected purposefully and triplicate vegetation and soil core samples were collected from each site in July and August 2015 and analyzed for above ground biomass, above ground plant carbon, and soil organic carbon contents. The results indicated that the least impacted wetland had significantly higher (p<0.05) plant and soil organic carbon content than the other land use categories. The above ground plant carbon ranged between 49.23 g C m^-2 in the converted grazing land to 2066.17 g C m^-2 in the least impacted wetland. Soil organic carbon content ranged between 7.36 g C kg^-1 in the converted cultivated land to 91.43 g C kg^-1 in the least impacted site. Soil organic carbon content was positively correlated (p<0.01) with above ground biomass and soil moisture whereas soil temperature showed significant negative correlation (p<0.01). The results showed that a high reduction of organic carbon storage of both the soil and above ground as one goes from un-impacted to impacted land use types in wetlands of lake Ziway, implying the need of improved management of wetlands so as to enhance the biomass  carrying capacity of such areas to mitigate carbon emissions.

Keywords: Carbon sequestration, Degradation, Lake Ziway, Management, Organic carbon, Wetlands