Nonlinear spatiotemporal variability of gross primary production in China's terrestrial ecosystems under water energy...

Gross primary production (GPP) plays a crucial role in carbon cycling and ecosystem productivity, yet its variability is significantly influenced by climatic factors. This study investigates the spatiotemporal variability of GPP in China's terrestrial ecosystems, with a focus on water and energy limitations. It aims to clarify the relationship between GPP and climatic variables across different regimes. The results reveal nonlinear turning points in more than half of the country's regions, most turning points occurred in the 1980s and 2000s. Water-related factors predominantly influenced GPP changes, while energy limitations contributed to GPP decline in certain areas. Over the past decade, ecological restoration efforts focused on vegetation greening have enhanced habitat quality in China. However, future climate warming is projected to shift more regions into energy-limited conditions, leading to negative GPP sensitivity to temperature and SSRD, and potentially accelerating GPP degradation. These findings underscore the need for targeted management strategies in energy-limited regions to mitigate the adverse impacts of climate change on ecosystem productivity. This study provides critical insights into the interplay between climatic factors and GPP dynamics, offering a valuable framework for future research and policy development aimed at sustaining ecosystem services under changing climatic conditions.