The impact of land use and land cover change on net primary productivity on China’s Sanjiang Plain

Land use and land cover change (LUCC) have a significant influence on regional ecosystems and on the carbon cycle. The Sanjiang Plain is one of the largest grain production bases in China, and has experienced rapid land cover change, making it a critical area in which to assess the environmental impact of LUCC and propose strategies for minimizing its impact on net primary productivity (NPP). In this study, land cover was estimated from remote sensing images to quantify LUCC on the Sanjiang Plain from 2000 to 2010. A moderate resolution imaging spectroradiometer dataset of photosynthetically active radiation absorbed by vegetation canopy, a land cover map, meteorological data and other field data were used to develop a CASA productivity model and obtain NPP for the study area. The spatial and temporal changes of NPP from 2000 to 2010 were then analyzed. Finally, the effect of LUCC on regional NPP was estimated. The land cover maps indicated that farmland expansion and wetland reduction were the most significant landscape changes on the Sanjiang Plain from 2000 to 2010. NPP loss totaled 2900 Gg (1 Gg = 109 g) of carbon from 2000 to 2005. By 2010, NPP had increased by at least 731 Gg of carbon, corresponding to 1184 Gg of net dioxide carbon sequestration. It was thus confirmed that LUCC has a significant, direct influence on regional NPP on the Sanjiang Plain.