The Yangtze River Basin (YZRB) and the Yellow River Basin (YRB), which are crucial for ecology and economy in China, face growing challenges to ecosystem service (ES) functions due to global population growth, urbanization, and climate change. This study assessed the spatiotemporal dynamics of ESs in the YZRB and the YRB between 2001 and 2021, comprehensively encompassing essential aspects such as water yield (WY), carbon sequestration (CS), soil conservation (SC), and habitat quality (HQ) while also analyzing the trade-offs and synergies among these ESs at the grid cells. The GeoDetector was employed to ascertain individual or interactive effects of natural and anthropogenic factors on these ESs and their trade-offs/synergies. The results showed that (1) from 2001 to 2021, the four ESs exhibited significant spatial disparities in the distribution within two basins, with the overall trend of ESs mainly increasing. YZRB consistently exhibited substantially higher ES values than the YRB. (2) Complex trade-offs and synergies among these ESs were apparent in both basins, characterized by distinct spatial heterogeneity. The spatial relationships of WY–CS, WY–SC, CS–SC, and CS–HQ were mainly synergistic. (3) Precipitation, potential evapotranspiration, elevation, land use and land cover (LULC), and slope influenced ESs in both basins. Notably, interactive factors, particularly the interactions involving LULC and other factors, demonstrated more robust explanatory power for ESs and their trade-offs/synergies than individual drivers. These findings significantly affect the refined ecosystem management and sustainable development decision-making in large rivers or regions.

Central Yunnan, constantly in a state of water shortage, is a region of fragile ecological environment whose regional agricultural production and economic development are seriously restricted by drought, despite its relatively developed social economy and dense population. In order to study the drought situation in this area, Landsat TM\OLI remote sensing image data of the region in 2008, 2011, 2014, and 2017 was selected for the construction of the NDVI-LST characteristic space temperature vegetation drought index (TVDI) using the normalized difference vegetation index (NDVI) and the land surface temperature (LST). The validity of TVDI was verified by Standardized Precipitation Index (SPI), Palmer Drought Severity Index (PDSI) and Potential Evapotranspiration (PET), and the TVDI calculation results were divided into 5 drought levels: wet, normal, moderately dry, dry and severe dry. It is shown that: (1) The TVDI values of different land use types have obvious changes and good applicability; (2) TVDI can effectively reflect the characteristics of drought and spatial-temporal changes in central Yunnan, and the severe drought is mostly distributed in the west and southwest; (3) In the past 10 years, the dynamics of drought in this area have changed significantly, mainly from drought to slight drought, and the overall drought has decreased with time. It is concluded that TVDI model accurately reflected the drought situation in central Yunnan and thus is an instructive tool for regional drought monitoring.

Context: Under global climate change and intensified human activities, the Yangtze River Basin (YZRB) and Yellow River Basin (YRB) face escalating challenges to ecosystem services (ESs), including water scarcity and biodiversity loss. Understanding ES dynamics is essential for sustainable landscape management. Objectives: This study aimed to (1) predict spatiotemporal changes in land cover and ESs from 2030 to 2100 under SSP1–2.6, SSP3–7.0, and SSP5–8.5 scenarios, and (2) quantify pixel-scale ES trade-offs/synergies and their driving factors. Methods: An integrated SSP–LUH2–PLUS–InVEST/CS framework was developed, combining climate scenarios, land use simulations, and ES assessments. The framework was applied to both basins to project future land cover changes and quantify ES responses under varying radiative forcing scenarios. Results: Forests expanded notably in the YZRB under SSP1–2.6 and SSP3–7.0, largely replacing grasslands and croplands, whereas grasslands remained in the YRB. Water yield (WY), soil conservation (SC), and habitat quality (HQ) improved the most under SSP1–2.6, whereas carbon sequestration (CS) peaked under SSP5–8.5. Synergies prevailed among WY–SC, CS–SC, and SC–HQ across all scenarios, whereas CS–HQ shifts to trade-offs under SSP5–8.5. ES interactions were scenario-dependent, with precipitation, temperature, potential evapotranspiration, land cover, and elevation as key drivers, shifting from land use-driven under low emissions to climate-driven under high emissions. Conclusions: Future ES management in the YZRB and YRB should adopt scenario-specific strategies, optimizing land use under low-emission pathways and applying climate-adaptive interventions under high-emission scenarios to sustain ES provision.

As an extreme event driven by global climate change, drought poses a severe threat to terrestrial ecosystems. The Yangtze River Basin (YZRB) and Yellow River Basin (YRB) are key ecological barriers and economic zones in China, holding strategic importance for exploring the evolution of drought patterns and their ecological impacts. Using meteorological station data and Climatic Research Unit Gridded Time Series (CRU TS) data, this study analyzed the spatiotemporal characteristics of drought evolution in the YZRB and YRB from 1961 to 2021 using the standardized precipitation evapotranspiration index (SPEI) and run theory. Additionally, this study examined drought effects on ecosystem carbon sequestration (CS) at the city, county, and pixel scales. The results revealed the following: (1) the CRU data effectively captured precipitation (annual r = 0.94) and temperature (annual r = 0.95) trends in both basins, despite significantly underestimating winter temperatures, with the optimal SPEI calculation accuracy found at the monthly scale; (2) both basins experienced frequent autumn–winter droughts, with the YRB facing stronger droughts, including nine events which exceeded 10 months (the longest lasting 25 months), while the mild droughts increased in frequency and extreme intensity; and (3) the drought impacts on CS demonstrated a significant threshold effect, where the intensified drought unexpectedly enhanced CS in western regions, such as the Garzê Autonomous Prefecture in Sichuan Province and Changdu City in the Xizang Autonomous Region, but suppressed CS in the midstream and downstream plains. The CS responded positively under weak drought conditions but declined once the drought intensity surpassed the threshold. This study revealed a nonlinear relationship between drought and CS across climatic zones, thereby providing a scientific foundation for enhancing ecological resilience.