Climate and Land Use Impacts on Shrub Expansion and Carbon Budgets in the Serengeti Ecosystem, 2019

The Greater Serengeti-Mara ecosystem includes the persevered areas Serengeti National Park and the Maasai Mara nature reserve, in addition to adjoining areas that are used by the locals. The savannah in Serengeti consist of open grasslands with scattered trees. The amount of trees are dependent on precipitation, fires and the prevalence of grazing animals. In addition, climate changes and land use can lead to a higher presence of trees and bushes at the savannah. It is nevertheless unknown how this will affect the amount of carbon that is stored there. If carbon disappears from the ecosystem this can contribute to global warming. In this project, the amount of carbon in the savannah below and above the soil was measured along a gradient from little towards a large quantity of bush- and tree-layer. The Serengeti-Mara eco system in Tanzania and Kenya is productive, and transitions between grass-dominated and bush-dominated areas have the potential to change to a great degree the amount of carbon stored in the eco system, that has potentially important implications for the climate system. Alternation between grass-dominated and bush-dominated vegetation is driven by climate and land use, but the impact of carbon storages are unknown. The project seeks to expand the Norwegian network and cooperation towards the Horisont 2020 AfricanBioServices-project in order to quantify the ecosystem carbon storage in savannah eco system that alternate from a grass-dominated to bush-dominated vegetation along a climate gradient and border areas for different kinds of land use. Temporal changes to overgrowing (analysed by bush-demographic, aerial photos and remote sensing) will be tied to precipitation (weather measurements), fire frequencies (administration data, remote sensing), the density of livestock and wild grazers (counting, models and so on), as well as soil parameters (measured here). This will be carried out in localities along a precipitation gradient, which allows us to examine how the interactions between climate and land use will determine the layer of woody plants in savannah ecosystems. Ecosystem carbon storages will be calculated by adapting a procedure that has already been used with success in Norway. Vegetation, woody plants and storages of organic carbon in the soil will be estimated, as well as content of nitrogen and phosphorus in the soil in order to clarify the impact of nutritious substances in the soil in the layer of woody plants in savannah ecosystems. Big parts of the data related to land use and grazing are already collected in the AfricanBioServices-project. This project will therefore consist of both new data collected at the savannah but will also be based on data from the EU-project. This data set contains estimates of carbon pools in nine sites in the Serengeti ecosystem, Tanzania. The data are from 5 sites inside protected areas in Serengeti and neighbouring protected reserves compared to four sites outside the park in grasslands used for pastures. The below ground carbon pools are measured as soil carbon in depth of 0-5 cm and 5-20 cm. The above ground pools are measured as litter, deadwood, standing woody biomass and standing herbaceous biomass. All is calculated on m2 basis. A paper is under preparation that will present the methods and results of the study in more detail. It is expected to be submitted January 2020. Information on methods can also be found in the NTNU Natural Resource Management Msc programme, Msc thesis by Haukenes 2019.