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• The 57.00% of the Yangtze River Economic Belt area exhibited a significant increase in annual NPP. • The response of NPP on climate factors was nonlinear, with greater sensitivity to temperature. • The impact of topographic factors on NPP changes had a threshold effect. Net primary productivity (NPP) of terrestrial ecosystems serves as a crucial carbon sink, playing a significant role in mitigating climate change. This study, focusing on the Yangtze River Economic Belt (YREB), a key area for both economic development and ecological conservation in China, evaluates the temporal and spatial changes in regional NPP and its responses to climatic factors against the backdrop of global change. Utilizing long-term NPP and meteorological grid data from 1981 to 2017, we analyzed the annual change patterns of NPP and its linear and nonlinear responses to climatic factors using copula functions. Our findings indicate that 57.00 % of the YREB has experienced a significant increase in NPP, with the most substantial decreases observed in Shanghai and its surrounding areas (P < 0.05). Temperature emerged as the primary climatic driver, positively correlating with NPP changes in over half of the study area (P < 0.05). Moreover, the nonlinear response of NPP to temperature and precipitation underscores the complex interactions between these factors, revealing a sensitivity to temperature variations that surpasses that to precipitation. The study also highlights the influence of solar radiation and topographic factors, with a significant positive correlation between NPP and solar radiation observed in 15.85 % of the area (P < 0.05). The practical significance of these findings lies in their implications for regional ecological management and climate resilience strategies. The positive correlation between temperature and NPP underscores the potential for targeted temperature management to optimize carbon sequestration across the YREB. Furthermore, the identified nonlinear responses and the role of solar radiation and topography in influencing NPP offer valuable insights for the formulation of adaptive strategies that enhance ecosystem productivity and contribute to achieving carbon neutrality goals. By elucidating the dynamics of NPP in response to a range of environmental factors, this study provides a foundation for informed decision-making in ecological conservation and climate change mitigation efforts within the YREB and similar regions globally. [ABSTRACT FROM AUTHOR]

The Sloping Land Conversion Program (SLCP), preferentially initiated to reduce water loss and soil erosion in the Loess Plateau of China in 1999, is the largest eco-restoration project in the world in recent decades. This massive effort improved the vegetation conditions markedly and was expected to have a great potential to enhance terrestrial carbon (C) sequestration. However, the spatially-explicit C consequences of the SLCP remain largely unknown at the regional scale. Using Ansai County in the Loess Plateau as a case study, we assessed the impacts of the SLCP on ecosystem C dynamics based on the General Ensemble Biogeochemical Modeling System (GEMS). The results showed that ecosystem C stock (including C stored in biomass and soil) decreased slightly in the first five years after the implementation of the SLCP (i.e., 1999-2003) due to the low production of the newly forested land, and increased evidently (mostly in biomass) thereafter thanks primarily to the growth of young plantations. Overall, the study area functioned as a net C sink in the past three decades, yet the magnitude was greatly amplified by the SLCP, indicated by a C sink in 2004-2010 nearly twelve times that in 1978-1998 (41.5 vs. 3.5 g C m-2 yr-1). These results highlight the importance of the SLCP in promoting terrestrial C sequestration which may help mitigate climate change. Nevertheless, there were time-lags between the impact of the SLCP and the associated C dynamics in the eco-restored areas, particularly in the soil, calling for future efforts toward addressing long-term C consequences of the SLCP. [ABSTRACT FROM AUTHOR]

[Display omitted] • We compared two valuation approaches to assess carbon sequestration ecosystem service. • The retired lands in the "Grain for Green" project was used as an illustration. • The dynamic method obtained high economic value from carbon sequestration. • The dynamic method decreased the possibility of biomass harvesting. Carbon sequestration plays an essential role in climate regulation, and its monetary value is critical for decision-making. To encourage carbon sequestration and avoid expensing the ecosystem services for future generations, a dynamic monetary valuation perspective was developed by integrating a carbon dynamics model of ecosystems and an atmospheric carbon cycle model. A case study of biomass utilization in Northern Shaanxi was conducted to illustrative the performance of this approach by comparing with the conventional approach. The carbon dynamics in the available lands were simulated by the CENTURY model under the RCP4.5 climate change scenario. The results suggested that the carbon storage was doubled without biomass utilization in the projected 25 years. When biomass was harvested, carbon storage decreased slightly. The monetary value without biomass harvesting in the dynamic approach was higher than that in the conventional approach. After analogizing the monetary values of carbon sequestration and biomass utilization, there was a lower likelihood of biomass harvesting in the dynamic approach than in the conventional approach. [ABSTRACT FROM AUTHOR]