Nonlinearity of China's Carbon Sink Increasing and Its Nonlinear Relationship With Land Use Patterns

作者：Zheng Wang, Chuanzhuang Liang, Huiyu Liu, Xiaojuan Xu, Peng Xue, Haibo Gong, Fusheng Jiao, Mingyang Zhang, Xiangzhen Qi · 发表于：Land Degradation and Development · 年份：2025 · DOI：10.1002/ldr.5637 · 被引用次数：4 · 研究领域：Land Use and Ecosystem Services、Forest Management and Policy、Remote Sensing and Land Use

ABSTRACT China's terrestrial carbon sink, quantified by net ecosystem productivity (NEP), has exhibited significant yet spatially heterogeneous growth over the past four decades, driven by climate change, land use transitions, and ecological restoration policies. However, the nonlinearity of NEP enhancement and its coupling mechanisms with dynamic land use patterns remain poorly understood. This study integrates linear trend analysis, ensemble empirical mode decomposition, and boosted regression tree (BRT) modeling to systematically unravel the nonlinear characteristics of NEP trends (1981–2019) and their landscape‐mediated drivers across four ecoregions. Key findings reveal that: (1) While 43.75% of China's land area showed a linear increase in NEP, only 13.46% exhibited monotonic growth (Trend IN ), whereas 16.46% displayed trend reversals (Trend DE‐TO‐IN ), highlighting dominant nonlinear dynamics. (2) Land use pattern indices (LUPI)—spanning fragmentation (PD), dominance (LPI), connectivity (CONTAG), shape complexity (AWMPFD), and diversity (SHDI)—demonstrated divergent trajectories: South China and the Tibetan Plateau (TP) experienced increasing fragmentation (PD increases) alongside declining connectivity (CONTAG decreases), while Northwest China (NWC) showed inverse patterns, reflecting region‐specific anthropogenic and ecological pressures. (3) Trend IN regions (e.g., NWC and TP) were governed by LPI in NWC and CONTAG, where threshold exceedance (slope > 0) stabili...