Leaf Area and Biomass Dynamics of a Thorn-Shrub Savannah Ecosystem in the Borana Zone, Ethiopia
- Publikations-Art
- Kongressbeitrag
- Autoren
- Seckinger, C., Pfister, J., Giese, M., Asch, F.
- Erscheinungsjahr
- 2013
- Veröffentlicht in
- Agricultural development within the rural-urban continuum
- Herausgeber
- Tielkes, E.
- Verlag
- Cuvillier Verlag , Göttingen
- Seite (von - bis)
- 325
- Tagungsname
- Tropentag 2013
- Tagungsort
- Hohenheim
Many uncertainties exist concerning the quantification of the carbon sequestrationpotential in savannah ecosystems. Biomass and carbon pools are highly variablewithin the different vegetation types of this zonal ecosystem, and very often mostbasic and sufficient accurate information related to biomass dynamics are not avail-able.Here we present a methodological non-destructive approach to determine high-reso-lution data of leaf area index (LAI) and above-ground biomass (AGB) from a thorn-shrub savannah ecosystem in southern Ethiopia, representative for the African Sahel-Zone with bimodal rainfall distribution.Optical and destructive LAI measurements were taken from 5 dominant shrub andtree species in weekly intervals during one rainy season. We correlated the resultsof multiple biomass harvestings with the non-destructive optical method. Multipleoptical LAI measurements performed in different horizontal vegetation layers at a 5 mgrid allowed us to upscale LAI and biomass information collected at the species to theplot level of the shrub-tree formations. Established allometric equations for above-ground biomass estimations of dominant shrub and tree species were additionallyused to validate our method.We discuss our results towards the option to use this optical method for estimatingabove-ground net primary production (ANPP) and, thus, the carbon sequestration po-tential for shrub-tree dominated savannah ecosystems. The results indicated that spa-tial and temporal biomass heterogeneity at species and plot level resulting from thesystem’s high natural variability will be the main methodological challenge to copewith.Consequently, optical biomass monitoring will be a key-method to determine thespatial and temporal variability of ANPP from tree and shrub dominated savannahecosystems and should therefore be subjected to a scientific discussion as promisingapproach to estimate the carbon sequestration potential of this major tropical ecosys-tem.