Analysis of changes in the ecohydrological situation and its driving forces in the Li River Basin

ABSTRACT Quantifying river ecohydrological conditions and their drivers is essential for protecting river ecosystems. Using runoff data from the Shimen Hydrological Station, we quantified changes in the basin's ecohydrological situation with the RVA method. Based on the ABCD model and Budyko's hypothesis, we quantified the differences in runoff drivers on time scales, such as yearly, quarterly, and monthly. The results showed that after the sudden change in the river basin in 1983, the runoff depth was reduced by 51.31 mm, and all five groups of ecohydrological indicators reached more than moderate alteration. The number of reversals was altered by 90.85%, resulting in drought impacting the bottom-mobile streamside organisms. Differences in the contribution of drivers at different time scales were more pronounced. At the annual scale, human activity was the dominant factor in runoff change; at the seasonal scale, human activity was more heavily weighted in winter, accounting for 30.5% of the total. On the monthly scale, human activities contributed more significantly in April, June, October, and December, with 82.91, 78.83, 58.01, and 97.09%, respectively, and climate change was the main driver in the rest of the months (50.26–89.64%).