Land-use/land-cover change (LULCC) and climate change are the primary driving forces for terrestrial ecosystem productivity, but their impacts are confounded. Understanding the integrated impacts of LULCC and climate change on terrestrial ecosystem productivity is critical for sustainable ecosystem management at global and regional scales. 

The Yangtze River Basin (YRB), located in central China, is one of the major afforestation zones and consequently has a strong impact on ecosystem productivity. During 2001-2010, the YRB has experienced tremendous LULCC, notable warming and drying trends. The first decade in the 21th century for the YRB provides a unique window to evaluate the effects of fast LULCC and rapid climate change on terrestrial ecosystem productivity in a large human-dominated landscape. 

Dr. ZHANG Yulong, under the supervision of Prof. ZHANG Quanfa from Wuhan Botanical Garden and Prof. SONG Conghe from University of North Carolina decoupled the effects of LULCC and climate change on terrestrial net primary productivity (NPP) in YRB during 2001-2010 using a light-use-efficiency model through different scenario designs. 

Prescribed model simulations indicated that LULCC alone had a significantly positive effect on total NPP (up to 6.1 Tg C yr^-1, p < 0.01) primarily due to reforestation and forest protection, while climate change alone showed an overall negative effect in the Basin (as much as -2.7 Tg C yr^-1, p = 0.11). The ensemble effect of LULCC and climate change on total NPP is approximately 3.9 Tg C yr^-1 (p = 0.26) during 2001-2010.  

This study provides an improved understanding of the effects of LULCC and climate change on terrestrial ecosystem productivity in the YRB, suggesting that reforestation and forest protection could significantly enhance terrestrial ecosystem productivity and hence mitigate global warming. It also suggests that NPP models with static LULC could lead to increasingly large errors with time. 

Results entitled “Effects of land-use/land-cover and climate changes on terrestrial net primary productivity in the Yangtze River Basin, China from 2001 to 2010” were published in Journal of Geophysical Research: Biogeosciences (DOI: 10.1002/2014JG002616). This research was partially supported by the National Natural Science Foundation of China, the US National Science Foundation, and the Chinese Academy of Sciences.