A07 - Modelling biogeochemical processes in rainforest transformation systems in Sumatra (Indonesia)

Land transformations in tropical landscapes alter biogeochemical processes of the carbon, nitrogen and water cycles, which are fundamental for ecosystem services and thus human well-being. While observational data from individual plot measurements provide insights into selective processes at current
conditions, a biogeochemical modelling approach is now needed to scale up process data from plot to landscape and to assess the impact of various management options. In this new subproject, we aim to integrate all data relevant for biogeochemical processes from CRC phase 1 and new data from phase 2 into one common modelling framework and to explore the impact of various land-use scenarios and related management on the biogeochemical cycles of carbon, nitrogen and water. We plan to use a process-based land surface model, the open-source Community Land Model (CLM) that includes the description of biogeochemical processes and simulates spatially explicit carbon, nitrogen and water cycles at the soil, plant, atmosphere interface. The model will be adapted to the dominant land-use types in Jambi Province in Sumatra (Indonesia). The model will then be validated against the wealth of observational data from CRC phase 1, e.g. plant and soil carbon and nitrogen pool, trace gas and water fluxes, leaf area index, biophysical properties of plants and soil, and remote sensing data. Once validated, we will assess the impact of historic and current land transformation on landscape-level biogeochemical properties. The resulting understanding of biogeochemical process dynamics will be used to enhance the existing agent-based ecological-economic model of B10 Wiegand/Lay. Based on the scenarios of future land-use options developed in Focus 4, we will quantify the impact of alternative future land-uses on landscape-scale biogeochemical cycles.