LI Mengde1,2,3, LIU Libin1,2,3, NI Jian1,2
(1. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China;
2. Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, Puding 562100, China;
3. University of Chinese Academy of Sciences, Beijing 100049, China)
Abstract: Carbon cycle of plant, soil, and the whole ecosystem of plateau-type karst evergreen and deciduous broad-leaved mixed forest in Puding, central Guizhou was simulated from 1965 to 2014 based on the newly parameterized Forest-DNDC model and driven by interpolated daily climate data. Results showed that, compared with default parameter simulation and observations, the re-parameterized model can more accurately simulate soil respiration rates of spring, autumn and winter, but the summer soil respiration rate was under-simulated. However, statistical tests indicated that the modified Forest-DNDC model could generally simulate soil respiration of karst forest. Modelling errors from the default parameter simulation have been reduced. The model can be further used to simulate carbon dynamics of karst evergreen and deciduous broad-leaved mixed forest. Further simulations indicated that carbon fluxes of karst forest increased rapidly in the beginning of 3-4 years. Then with forest grew, the gross primary productivity (GPP) remained relatively stable, plant respiration (Rplant) and ecosystem respiration (Recosystem) increased continuously, and soil respiration (Rsoil) and net primary productivity (NPP) rapidly decreased. The net ecosystem exchange (NEE) reduced rapidly and achieved its minimum value of -0.17 tC/ha in 2013, implying that karst evergreen and deciduous broad-leaved mixed forest became from a CO2 sink to a weak CO2 source. Correlation analyses indicated that the annual mean temperature and annual total precipitation had no statistically significant effects on GPP and Rsoil, but had significant effects on NPP, Rplant, Recosystem, and NEE.
Key words: Forest-DNDC; karst；evergreen and deciduous broad-leaved mixed forest; carbon cycle
EARTH AND ENVIRONMENT Vol.45, No.1 Tot No.315, 2017, Page 96-105
