Assessing impacts of the Ecological Retreat project on water conservation in the Yellow River Basin.

The Ecological Retreat (ER) project significantly impacts water conservation functions in the Yellow River Basin (YRB). However, studies on the impact and benefit of different ER modes on ecological water effects still lack systematic and integral disclosure. In our study, CNLUCC (China land use/cover data sets) and the Markov transition matrix were used to simulate land pattern changes from 2000 to 2018. Water yield was chosen as an indicator of water conservation to explore the impact of the ER project by using the water yield module of the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model. After the ER project, the land pattern changed significantly because massive cropland was transformed into forest and grassland. Thus, the total water yields of the YRB increased by 46.32 × 103 hm3 from 2000 to 2018, and the overall water yield benefit was 12.39% larger than the water loss. Forest rehabilitation (FR) showed the highest average water yield capacity, while grassland restoration (GR) exhibited the most incredible total water conservation benefit. Wetland recovery (WLR) manifested a great capacity to improve average water yield, but its total benefit was far less than FR and GR, while waterbody recovery (WBR) showed a negative impact. The results indicate that FR and GR were effective restoration methods, and WLR showed great potential to improve water yield. By using the random forest and principal components analysis, precipitation (PRE), evaporation (AET and ET0), and variation of forest and grassland proved to be the most critical driving indicators affecting water yield changes. Additionally, the correlation and sensitivity between root depth (R_depth) and water yield indicate that increasing R_Depth can also enhance water conservation. The ER project provides a valuable restoration model for water yield and water conservation benefits. The results can provide theoretical support for eco-hydrology and land ecological restoration studies.

Assessment of the impact of the Poplar Ecological Retreat Project on water conservation in the Dongting Lake wetland region using the InVEST model.

The Poplar Ecological Retreat (PER) project is a significant environmental protection initiative implemented to protect the Dongting Lake wetlands ecosystem in China, and the ecological impacts of this project have gradually become a hot topic. In this study, water conservation was selected as an indicator of ecosystem function to explore the impact of the project by using the water yield module of the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model and geographic statistical methods. Water yield and land-use changes were quantitatively evaluated, and significant changes in the wetland landscape configuration occurred after the PER project because forest beach, moss marshland and mudflat areas were transformed into a poplar-retreat area. Thus, the proportion of the poplar-retreat area and average water yield increased. By using the principal component and cluster analysis methods, climate change and landscape patterns were shown to be the dominant driving factors affecting water conservation under stable meteorological conditions. Moreover, the landscape heterogeneity that resulted from the landscape patterns had a greater impact than climate change, which means that reducing human activities can enhance water conservation. Additionally, the correlation between landscape heterogeneity and water yield indicated that reducing landscape fragmentation and improving aggregation also benefit water conservation. Therefore, the PER project is successful at enhancing ecological functions and protecting wetland environments, and it represents a good example of maintaining ecological sustainability despite local economic performance restrictions. This project serves as an important reference for the establishment of sustainable wetland ecological policies by national governments, and the results can provide theoretical support for landscape ecology and eco-hydrology research.