Spatiotemporal foresting of soil erosion for SSP-RCP scenarios considering local vegetation restoration project: A case study in the three gorges reservoir (TGR) area, China

Variation characteristics of soil erosion and their response to landscape patterns in a typical basin in the Upper Yangtze River

Soil erosion is undeniably a significant cause of a variety of problems in the Upper Yangtze River (UYR), including floods, land degradation, and sedimentation in rivers. Recognizing alterations in soil erosion and its influencing variables in this area recently is a crucial scientific challenge requiring prompt solutions in regional soil erosion control. This study examines soil erosion and its influencing factors in the Jialing River Basin (JRB) from 1990 to 2018 using RUSLE and geographical detector. It focuses on the relationship between land use, landscape patterns, and soil erosion in this typical basin in the UYR. The results indicated that: (1) The average soil erosion modulus of the JRB decreased during 1990-2018, with predominant slight (< 500 t·km-2·a-1) and light (< 2,500 t·km-2·a-1) erosion intensity. Moderate and higher grades of erosion mainly occurred in the middle and lower JRB. (2) Cultivated land, forest land, and grassland accounted for over 97% of the JRB's land use from 1990-2018, with cultivated land dominating the middle and lower areas. Over the years, there was an increase in forest land and construction areas, while cultivated land decreased. The landscape pattern was characterized by diversity, fragmentation, and decentralization. (3) The soil erosion control area (SECA), primarily situated in the middle and lower JRB, was predominantly cultivated land. Between 1990 and 2018, the SECA area underwent significant changes, with the most notable changes occurring in the lower Fujiang River Basin (FRB) and the western and middle parts of the Qujiang River Basin (QRB). The area experienced more fluctuations on the left bank of the JRB and the right bank of the JRB, specifically in the QRB and FRB. The research can serve as a reference for future decision-making on land use planning and soil erosion management in the UYR.

Towards a more comprehensive scenario analysis: Response of soil erosion to future land use and climate change in the Central Yunnan Urban Agglomeration, China

Rapid urbanization and climate change exacerbate soil erosion globally, threatening ecosystem services and sustainable development. However, current predictive studies on future soil erosion often lack comprehensive consideration of the interactions between land use and climate change. This study proposed a comprehensive scenario analysis framework that integrated four Shared Socioeconomic Pathways (SSPs) from CMIP6 with four bespoke land-use scenarios (Inertial Development (IDS), Urban Development Priority (UDPS), Ecological Protection Priority (EPPS), and Farmland Protection Priority (FPPS)) to create 16 future scenarios, allowing for a more nuanced understanding of potential soil erosion trajectories. The results indicated that (1) compared to the baseline period (2000-2020), future soil erosion in the Central Yunnan Urban Agglomeration (CYUA) would improve, albeit with significant differences among the scenarios. The most notable improvement was under EPPS + SSP1-2.6 scenario (ScC1). (2) The lower Jinsha, upper Nanpan, and Red river basins were high-risk areas for soil erosion in the CYUA, each dominated by different factors, necessitating differentiated soil erosion control measures. (3) Land-use and climate change jointly influenced the direction of erosion development, with the lightest erosion occurring under the EPPS and heaviest erosion occurring under the FPPS. The largest decrease in erosion occurs under SSP1-2.6, whereas the smallest decrease occurs under SSP5-8.5. (4) Climate change had a more significant impact on soil erosion than land-use change, with the reduction rates of the soil erosion modulus and area between different climate change scenarios relative to the past 20 years being 9% and 3.77%, respectively, approximately eight and four times the magnitude of change under different land-use scenarios. This study recommends reducing carbon emissions, enhancing vegetation cover, and controlling slope land development to effectively mitigate the soil erosion risk in CYUA and promote regional sustainable development. The proposed comprehensive scenario analysis method provides new insights into future global small-scale regional predictions.

Trade-offs between grain supply and soil conservation in the Grain for Green Program under changing climate: A case study in the Three Gorges Reservoir region

Understanding the trade-offs between ecological benefits and cost of grain supply caused by ecosystem restoration is essential for decision-making. Nevertheless, due to climate change, the benefits of ecosystem restoration and cost of grain supply change across various spatial locations, thereby complicating the trade-offs. Taking one of China's largest scale ecosystem restorations, the Grain for Green Program (GGP), as an example, this study used the Three Gorges Reservoir (TGR) region as the case study area and combined the crop environment resource synthesis (CERES)-Crop model, future land-use simulation (FLUS), and the revised universal soil loss equation (RUSLE) to simulate future grain supply and soil erosion during 2021-2050 under three climate change and socioeconomic development scenarios (SSP1-2.6, SSP2-4.5, SSP5-8.5) in the TGR region. The results showed that: (1) Until 2050, the implementation of GGP would bring a large soil conservation benefit by reducing soil erosion of 2.47-5.68 million tons, at the cost of 130,277-660,279 tons decrease in grain production in the TGR region. (2) Under SSP5-8.5 climate change scenario with the highest rainfall in the future, the GGP would maintain the greatest soil conservation benefits, resulting in a total amount of soil erosion decrease by 2.55 to 5.68 million tons. (3) Trade-offs between benefit of reducing soil erosion and cost of grain supply vary considerably across income. Specifically, GGP benefits are greater under low-income and higher-emission scenarios, with significant gains in soil erosion control and less impact on grain supply. In contrast, in high-income and low-emission scenarios, the GGP results in less soil erosion control and greater impact on grain supply.

Past dynamics and future prediction of the impacts of land use cover change and climate change on landscape ecological risk across the Mongolian plateau

Land use/land cover (LULC) change and climate change are interconnected factors that affect the ecological environment. However, there is a lack of quantification of the impacts of LULC change and climate change on landscape ecological risk under different shared socioeconomic pathways and representative concentration pathways (SSP-RCP) on the Mongolian Plateau (MP). To fill this knowledge gap and understand the current and future challenges facing the MP's land ecological system, we conducted an evaluation and prediction of the effects of LULC change and climate change on landscape ecological risk using the landscape loss index model and random forest method, considering eight SSP-RCP coupling scenarios. Firstly, we selected MCD12Q1 as the optimal LULC product for studying landscape changes on the MP, comparing it with four other LULC products. We analyzed the diverging patterns of LULC change over the past two decades and observed significant differences between Mongolia and Inner Mongolia. The latter experienced more intense and extensive LULC change during this period, despite similar climate changes. Secondly, we assessed changes in landscape ecological risk and identified the main drivers of these changes over the past two decades using a landscape index model and random forest method. The highest-risk zone has gradually expanded, with a 30% increase compared to 2001. Lastly, we investigated different characteristics of LULC change under different scenarios by examining future LULC products simulated by the FLUS model. We also simulated the dynamics of landscape ecological risks under these scenarios and proposed an adaptive development strategy to promote sustainable development in the MP. In terms of the impact of climate change on landscape ecological risk, we found that under the same SSP scenario, increasing RCP emission concentrations significantly increased the areas with high landscape ecological risk while decreasing areas with low risk. By integrating quantitative assessments and scenario-based modeling, our study provides valuable insights for informing sustainable land management and policy decisions in the region.