# The Contributions of Climate and Human Activities to Water Use Efficiency in China's Drylands
## 3 Result
### Analysis of Driving Factors on Temporal Dynamics of WUE
The partial correlation between WUE and Solra was stronger in the central and Tibetan regions of the study area, while the positive correlation between GPP and ET and Solra was stronger in this region, and the positive correlation between WUE and Solra was weaker in this region (Figure 5j-l). The relative contribution rates of the four climatic factors to WUE, GPP, and ET for the various vegetation types are presented in Table 5. The relative contribution rates of Prec to GPP and ET were 31.47% and 33.31%, respectively. The Tem factor had a higher-than-average contribution rate to WUE in desert, shrub, and cultivated vegetation. The contribution rate of forest was lower than the average. Mixed forest had a higher contribution rate than the other forest types. The contribution rate of Prec to GPP was greater in cultivated vegetation, broadleaf forest, shrub, and grassland, whereas it was lower in swamp and alpine vegetation. The contribution rate of Prec to ET in broadleaf forest, grassland, and cultivated vegetation areas exceeded the average, while the contribution rate of Tem was lower than the average. Moreover, the contribution rate of VPD to ET in mixed forest and swamp areas was higher than average, and the contribution rate of Solra to ET in cultivated vegetation, swamp, and forest areas was higher than that in other vegetation types. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**WUE**} & \multicolumn{3}{c}{**GPP**} & \multicolumn{3}{c}{**ET**} \\ \cline{2-13}  & **Prec** & **Tem** & **VPD** & **Solra** & **Prec** & **Tem** & **VPD** & **Solra** & **Prec** & **Tem** & **VPD** & **Solra** \\ \hline China’s drylands & 25.58\% & 24.96\% & 23.54\% & 25.92\% & 31.47\% & 21.82\% & 22.78\% & 23.93\% & 33.31\% & 24.14\% & 20.96\% & 21.59\% \\ Coniferous forest & 25.93\% & 23.63\% & 24.35\% & 26.09\% & 28.18\% & 23.39\% & 23.67\% & 24.76\% & 29.68\% & 24.32\% & 22.34\% & 23.66\% \\ Mixed forest & 25.01\% & 24.70\% & 27.63\% & 22.65\% & 26.49\% & 15.95\% & 26.44\% & 31.12\% & 23.02\% & 22.12\% & 26.55\% & 28.22\% \\ Broadleaf forest & 26.30\% & 22.78\% & 22.80\% & 28.12\% & 33.56\% & 19.88\% & 23.26\% & 23.30\% & 33.04\% & 21.93\% & 22.29\% & 22.74\% \\ Shrub & 25.45\% & 25.16\% & 24.05\% & 25.34\% & 31.57\% & 20.61\% & 23.98\% & 23.83\% & 32.08\% & 23.09\% & 22.11\% & 22.72\% \\ Desert & 25.67\% & 27.15\% & 23.28\% & 23.90\% & 29.26\% & 23.37\% & 26.14\% & 21.23\% & 29.53\% & 27.12\% & 29.70\% \\ Grassland & 25.23\% & 24.73\% & 23.99\% & 26.05\% & 31.35\% & 20.62\% & 22.98\% & 23.61\% & 34.20\% & 24.78\% & 20.57\% & 20.45\% \\ Swamp & 28.34\% & 24.70\% & 24.19\% & 22.77\% & 23.12\% & 19.13\% & 25.33\% & 32.42\% & 24.91\% & 21.60\% & 25.76\% & 27.73\% \\ Alpine vegetation & 27.42\% & 24.57\% & 22.42\% & 25.59\% & 23.91\% & 25.50\% & 24.80\% & 25.79\% & 31.46\% & 26.21\% & 21.47\% & 20.86\% \\ Cultivated vegetation & 25.66\% & 25.47\% & 22.67\% & 26.20\% & 35.14\% & 20.05\% & 19.84\% & 24.97\% & 33.67\% & 21.97\% & 20.25\% & 24.11\% \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The contribution rate of climate factors of different vegetation types to the temporal change of WUE, GPP, and ET.