*4.3. Potential Limitations*

Potential limitations still exist in this study with respect to the data, the methods, and modeling. First, there are biases within the projected climate datasets. Our study was focused on detecting the regularity of hydrological changes in the future, so such biases could be neglected to some degree. Second, the RCP8.5 scenario that was considered in this study is much more extreme than others scenarios, and we only explored the hydrological response under this scenario. However, when only one scenario is considered, it may result in uncertainties, so additional scenarios should also be considered in future studies. Third, differences in the spatial resolution between the model and land cover data may induce uncertainties in the simulations. The spatial resolution in this study was 0.5◦ × 0.5◦, which was limited by the projected climate forcing datasets. Although the vegetation parameters were generated with 1 km × 1 km land cover maps and LAI datasets, there were also changes in smaller zones, especially some extreme events that could not be captured. Perhaps downscaling the forcing data to a finer resolution can be used to ease this problem to some degree. Finally, in this study we considered climate change and LCC as two independent factors. However, a grea<sup>t</sup> number of studies have suggested that there are links between them [42,43]. We kept the land cover condition unchanged when simulating, but the climate would change dramatically in future under RCP8.5 scenario, and the growth of vegetation in some areas may be threatened by the slightly increasing temperature. In our study, we intend to evaluate the hydrological effects of past LCC (or the progress that has been achieved by series of ecological restoration programs), rather than predicting how the hydrological regime would change in future, so this could be acceptable. If we want to do a more accurate projection in future researches, an improved VIC model which can couple dynamic vegetation parameters, reliable predicted land cover condition and LAI should be necessary.
