# Impact of Climate Change on the Major Eco-Hydrological Parameters in the Dongting Lake Basin
## 3 Results and Discussion
### Contributions of Long-Term Changes to GPP and ET
#### 3.3.1 Relative Contributions of Climate Change to GPP and ET
With crops, trees, and grasses as the main vegetation types in the Zishui River Basin, temperature was found to play a major role in the variation of ET, with an average contribution of 53.53 \(\pm\) 8.10%. The relative contributions of precipitation (average contribution of 24.88 \(\pm\) 12.38%) and radiation (average contribution of 21.60 \(\pm\) 10.73%) were similar, with precipitation being slightly larger than radiation. In the Yuanjiang River Basin, the predominant form of vegetation cover is trees. The most significant climatic factor influencing the trend of ET change was found to be temperature, contributing an average of 67.34 \(\pm\) 12.18%. In contrast, radiation had a relatively minor effect on ET change, with an average contribution of 15.38 \(\pm\) 8.92%. The Lishui River Basin is largely dominated by trees as the main vegetation cover type, and some areas in the eastern part are covered by crops. In the region, changes in ET were primarily influenced by the temperature factor, which had an average contribution of 69.41 \(\pm\) 5.58%. Meanwhile, radiation had the smallest impact among the studied climatic factors, with an average contribution of 8.66 \(\pm\) 7.37%. The Dongting Lake region is mainly covered by crops, water, and grasslands. Temperature was found to play a dominant role in the variation of ET, with an average contribution of 77.40 \(\pm\) 8.14%. Radiation was the climate factor with the least important role, with an average contribution of 9.33 \(\pm\) 6.65%. An observation can be made that temperature played a dominant role in the variation of ET in the Dongting Lake Basin. It was also found to be the most important climate factor in all sub-regions of the basin, except for the Xiangjiang River Basin, where radiation had the least contribution. Since the Xiangjiang River Basin has more building coverage compared to other regions, it was inferred that natural vegetation was significantly affected by precipitation rather than radiation. ET can reflect changes in hydrology. The results of the present study show that temperature variation has a significant effect on hydrological parameters. Such results are consistent with those in research on other regions. Over the last 50 years, there has been a significant upward trend in global high temperatures, which has accelerated global water cycle processes [31]. Precipitation dominates the ET variability in most of China [32], which is evident in arid and semi-arid regions [33]. In the present study, temperature was the  
Figure 13: Probability density function plots of temperature, precipitation, and radiation on ET in Dongting Lake Basin and its different regions. (**a**) Dongting Lake Basin; (**b**) Xiangjiang River Basin; (**c**) Zishui River Basin; (**d**) Yuanjiang River Basin; (**e**) Lishui River Basin; (**f**) Dongting Lake region. main influencing factor for ET, which could be attributed to the abundance of rivers and surface water in the Dongting Lake Basin. As such, precipitation did not act as the most dominant influence on ET.