A07 - Spatio-temporal scaling of the impacts of land-use and climate change in land transformation systems in Indonesia

In A07, we aim to investigate the impact of land transformation and climate change on biogeochemical cycles using the Community Land Model. After developing new components for oil palm and rubber in Phase 2, we use now CLM5-EFForTS to focus on management and plantation age effects as well as on spatio-temporal scaling. In WP1, we perform leaf gas exchange measurements within the Landscape Assessment to improve model parameterisation. In WP2, we incorporate findings from the Oil Palm Management Experiment on N fertilisation. In WP3, we assess how carbon, water and nitrogen fluxes vary in space and time. In WP4, we will quantify how land-use and climate change affect biogeochemical fluxes in Indonesia.

Land transformations in tropical landscapes alter biogeochemical processes of the carbon, nitrogen and water cycles, all of which are fundamental to ecosystem services. Up-scaling plot-level observations and projecting future changes requires spatially explicit land surface modelling. In phase 2, we developed new modules for the Community Land Model (CLM) to simulate oil palm and rubber plantations, parameterized the soil module for tropical conditions, and performed first regional-scale simulations. Based on these model improvements, on the improved capabilities for land-use change (LUC) simulations in the new ‘upstream’ version of CLM (CLM5), and on results from the Oil Palm Management Experiment (EFForTS-OPMX), we will focus in Phase 3 on management effects, plantation age effects and on spatio-temporal scaling. The low number of plots available for calibration limits the confidence in model results when up-scaling to larger areas. We will tackle this problem by using a hierarchy of model-data integration approaches. To better constrain the model, model-relevant plant traits across different land-use types (including shrublands) will be obtained by performing leaf gas exchange measurements within the Landscape Assessment area. CLM5-EFForTS, the model calibrated and validated with core plot-level measurements, will be further improved with these measurements and used to scale up fluxes to the area covered by the Landscape Assessment and the airborne laser scanner (ALS) measurements (see Z02 Scheu/Knohl/Erasmi). In this Landscape Assessment and ALS area, we will examine how biogeochemical fluxes vary in space and time under different land use and climate change scenarios. We will particularly investigate the effects of land management, such as fertilizer effects and nitrogen limitation in the model, the effect of changes in the soil water budget (e.g. caused by rainfall variability and water redistribution) and consider processes related to plantation ageing. Further, the model will be used for simulations at the regional (province of Jambi) as well as larger scale, to predict impacts of land-use and climate change, providing insights of societal relevance. To this end, we plan to collaborate within EFForTS as well as with external partners.

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Fig. 1. Members of the A03 and A07 team at the international EFForTs symposium 2018.
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Fig. 2. Gross and net primary productivity (GPP and NPP) of Jambi province before land-use change simulated with the community land model.