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Under the dual influence of climate change and land-use change, different protection policies in Qinling Mountains lead to different hydrological responses. On the basis of land-use and climatic changes in the Qinling Mountains of Shaanxi province, we constructed a response model among land use, climate, and runoff in the Qinling Mountains through the Soil and Water Assessment Tool (SWAT) model. The Patch-generating Land Use Simulation (PLUS) model was used to predict and simulate land-use types of the Qinling Mountains in 2025 and 2030. On the basis of the current ecological protection policy in China, two scenarios of land use were set up to find the best method for forestland protection. The results show the following. The SWAT model is applicable to the Weihe River and Hanjiang River basins of the Qinling Mountains, the simulation results were verified, and the Nash coefficient was above 0.6. Under future climate change and land-use patterns, runoff in the Qinling Mountains watershed shows an upward trend, and the runoff in the Hanjiang River basin increased by more than that in the Weihe River basin, with change rates of 47.471 and 33.356 m3/10a, respectively. According to the future trend of the two different scenarios, the increase degree of runoff in the natural scenario of Weihe River basin was 16.567 m3/10a higher than that in the woodland scenario, and the increase degree of runoff in the Hanjiang River basin was 17.692 m3/10a higher than that in the woodland scenario. Therefore, blindly increasing the forestland area in Qinling Mountains cannot achieve a better hydrological effect. [ABSTRACT FROM AUTHOR]

It is of great significance to study on the shift of temperature zone boundaries for revealing the climate change pattern and its environmental effects. Based on daily average temperature data from 32 standard meteorological stations in the Qinling Mountains from 1964 to 2015, the growing season start and end (GSS and GSE) of the climatic growing season parameters were calculated based on a temperature threshold of 10 °C, and the growing season length (GSL) was obtained by subtracting GSE from GSS. We have analyzed the spatiotemporal variations of these parameters in the Qinling Mountains and the shift rules of the warm temperate zone and northern subtropics zone boundaries in China over the past 52 years. Our research generated three primary results. First, the spatial distribution and changing trends of the GSS, GSE, and GSL were significantly different before and after abrupt changes in temperature. After the abrupt change, the coverages of the three were all gradually expanding to the higher altitude areas. The change rates of the three were faster, the trends were more significant, and the differences between the north and the south were obvious, especially in the northern slope. Second, the boundaries of both the warm temperate zone and the northern subtropical zone in China showed upward position shifts, and the area coverage changed along the northern and southern slopes of the Qinling Mountains, and the change amplitudes were even greater after the abrupt change in temperature. Third, there was a significant north–south difference in the response of China's temperature zones to climate change. The temperature zone on the northern slope was more sensitive to climate warming. It is worth emphasizing that the shifts of the temperature zones did not change the fact that the Qinling Mountains are the boundary between China's subtropical and the warm temperate zones. The north subtropical zone is still located on the southern slope of the Qinling Mountains, and the northern slope is still in the warm temperate zone. [ABSTRACT FROM AUTHOR]