Estimation of Net Primary Production in Japan under Nitrogen-Limited Scenario Using BGGC Model

抄録

　The Bio-Geographical and GeoChemical model (BGGC) is a process-based mathematical model that can be used to assess future impacts of climate change on the distribution and functioning of terrestrial ecosystems. This model can simulate the cycling and fluxes of carbon and nitrogen in vegetation, soils and exchanges with atmosphere, as well as estimate potential distribution of natural vegetations. One of the strengths of the BGGC model is to estimate net primary production (NPP) under scenarios where nitrogen is limiting. This is accomplished by a material cycling module that can simulate processes of vegetation competition due to nitrogen limitation. The objective of this study was to use BGGC model under various climate change scenarios to test its applicability in evaluating changes in NPP with limiting nitrogen availability across the diverse geographical regions of Japan.
　Results of simulation showed that nitrogen interacts with elevated CO₂ and temperature, decreasing NPP with increasing nitrogen limitations. The terrestrial ecosystem was generally predicted to be a net sink for carbon but it could be over-estimated without the nitrogen limiting the photosynthesis.