Evaluation of hydrological regime alteration and ecological effects in the middle and lower of the Yangtze River, China

Abstract

The flow regime is regarded as the key driver of the structure and function of riverine ecosystems. This study uses an ecologically meaningful indicator (range of variability approach method) to assess the dynamic runoff process in the middle and lower reaches of the Yangtze River, whose changes negatively affect the ecosystems in the study area. In addition, the study quantitatively analyzed the contribution rate of human activities and climate change to flow change. The effects of ecological index changes on four famous major carp species (FFMC) resources in the middle and lower reaches of the Yangtze River were studied. The results show that after the Three Gorges Dam (TGD) operation, the hydrological changes of Yichang Station, Hankou Station, and Datong Station were 65, 58, and 46%, respectively. The weight of the impact of human activities on runoff is smaller the farther away from the TGD. The impact weights of human activities at the three hydrological stations in the middle and lower reaches of the Yangtze River are 73.69, 67.98, and 56.84%, respectively. The operation of the Three Gorges Project caused changes in the hydrological regime of the Yangtze River, which adversely affected the structure and quantity of FFMC populations.

Inter‐ and intra‐annual fluctuations and attribution analysis of runoff and sediment transport in the middle and lower Yangtze River

“…This test is widely used because it does not require the sequence to follow a normal distribution and is not confounded by missing values. The calculation procedures are described in detail in Guo et al (2022). The $$$ {Z}_C $$$ statistic value is examined using the M‐K method to determine the trend.…”

“…Statistical analysis methods, such as regression models (Yin, Gao, Huang, et al, 2023), double cumulative curves (Jiang et al, 2021), and the slope change ratio of cumulative quantity (Wang, Ma, et al, 2023), can be used to identify each factor's contribution to runoff variability based on its correlation with runoff. Guo et al (2022) used the slope change ratio of the accumulative quantity method to calculate the proportion of contribution of climate and anthropogenic disturbance to runoff alterations in the middle and lower regions of the Yangtze River. Their findings suggest that anthropogenic factors have a significant impact on runoff changes.…”

Variation of heat flux and ecological impact on fish reproduction in the middle reaches of Yangtze River

“…It has exceptional applicability to the analysis of non-normally distributed hydrometeorological data since the data does not need to conform to a particular distribution and is not affected by a few outliers. Please refer to the corresponding references for the calculation process 35 .…”

How does the daily regulation hydropower station reduce the hydrological regime impact? A case study in upper Yellow River

“…Summarizing both plots over three periods, the differences between P1 and P2 are much larger those them between P1 and P3 periods, meaning that the additional of regulation daily hydropower makes the hydrological regimes go close to the natural station. Guo et al (2022b) and Singh & Jain (2021) believe that the occurrence time of extreme flow may affect the life cycle and death pressure of various aquatic species under flood and drought conditions, so the additional regulation of daily hydropower stations will be favorable for fish breeding and habitat recognition.…”