Spatiotemporal variability of net primary production over the past half century in Inner Mongolia grassland of China

Understanding how the net primary production (NPP) of arid and semiarid ecosystems of the world responds to variations in climate factors is crucial for assessing the impacts of climate change on ecosystems. Here we investigated the spatial and temporal change of NPP and its key driving factors based on climate data over the past half century and a long-term data set from 9 natural arid and semiarid ecosystem sites across the Inner Mongolia steppe region in northern China. Our results showed that climate warming and drying strongly influenced ecosystems productivity, and NPP decreased gradually with decreasing mean annual precipitation from east to west in Inner Mongolia of China. NPP with lower values were distributed in the west part, while in the east part, high NPP values were found. At the same time, the areas of high values of NPP region were decreasing, and the areas of low values of NPP region were increasing from 1956 to 2006. Moreover, decreased precipitation and the subsequent increase in temperature and potential evapotranspiration caused a severe water deficiency, simultaneously, the allocation model of precipitation changed and rain-use efficiency (RUE) decreased, which may be the main climate factors limiting ecosystem productivity in Inner Mongolia. Our findings have important implications for understanding and predicting ecological impacts of global climate change and for management practices in arid and semiarid ecosystems region.