Abstract: Based on the air temperature and precipitation data from 13 meteorological stations in the ThreeRiver Headwaters (Yangtze River, Yellow River, and Lancang River) Region in 1960-2011, the climatic productivity in this Region was estimated by Thornthwaite Memorial model, and, through linear trend analysis, Kriging interpolation, MannKendall test, and Empirical Orthogonal Function (EOF) resolution, the spatiotemporal variations of the air temperature, precipitation, and climatic productivity were analyzed, with the responses of the climatic productivity to climate change studied. In this Region, the mean annual temperature and the mean temperature in winter and in summer in recent 52 years were featured by repeated cold and warm fluctuations, but overall, presented an obvious rising trend. The annual precipitation had no obvious variation trend, but the precipitation in winter and in growth season had an increasing trend. Spatially, the precipitation had opposite variation trend in the east and west as well as in the south and north. The climatic productivity had less increase before the 21st century, but increased obviously since then. The correlation coefficient of climatic productivity and air temperature was larger than that of climatic productivity and precipitation, illustrating that air temperature was the main factor limiting the climatic productivity. The warm and wet climate increased the climatic productivity by 8.67%, but the cold and dry climate decreased the climatic productivity by 8.91%. In the future, the region’s climate would generally be warm and wet, and thus, the climatic productivity would be increased, which would be conducive to the improvement of natural herbage yield.

Key words: food web foundation, stable isotope, Haizhou Bay, trophic structure.