Cao Feifei, Liu Leizhen, Rong Yuping, Jiang Nan, Zhao Lin, Zhang Qian, Wu Zhitao, Zhao Wenhui, Li Sheng
College of Grassland Science and Technology, China Agricultural University, Beijing 100083, China.
College of Grassland Science and Technology, China Agricultural University, Beijing 100083, China.
Sci Total Environ. 2025 Feb 25;966:178570. doi: 10.1016/j.scitotenv.2025.178570. Epub 2025 Feb 8.
Northern China's grasslands play a pivotal role in livestock production, energy utilization, and ecosystem balance, both domestically and globally. However, they exhibit pronounced temporal variability and marked spatial heterogeneity. Since most existing studies rely on single vegetation indices and regional-scale analyses, they may introduce biases in interpreting grassland dynamics and their underlying drivers. To address this gap, we integrated both functional and structural indices - Gross Primary Productivity (GPP), solar-Induced chlorophyll fluorescence (SIF), Normalized Difference Vegetation Index (NDVI), and Leaf Area Index (LAI) - to systematically investigate spatiotemporal trends across various grassland types in northern China. Using partial derivative analysis, we quantified the relative contributions of climate change and human activities to these observed vegetation trends. Results indicated that over 70 % of grassland areas, especially temperate grasslands, showed an overall increase in vegetation indices, while a decline was observed in the southwestern alpine grasslands. Climate change was the primary driver of grassland greening (56.55 %-63.83 %), primarily through increased precipitation in temperate grasslands and rising temperatures in alpine grasslands. Human activities contributed substantially to greening (36.17 %-43.45 %), especially in desertified temperate grasslands (e.g., Mu Us Sandy Land, Gansu, Ningxia, Xinjiang) and Qinghai alpine meadows, mainly through farmland restoration and desertification control. Conversely, human activities also served as the primary driver of grassland degradation (51.70 %-69.64 %) in certain alpine regions, where overgrazing and population growth - compounded by rising temperatures and declining soil moisture - led to significant vegetation losses. Moreover, 72.66 % of temperate grasslands demonstrated strong coupling between vegetation structure and function, whereas 57.59 % of alpine grasslands exhibited increasing GPP alongside declines in both LAI and SIF. Overall, these findings underscore the spatial heterogeneity of grassland responses to climatic and anthropogenic drivers, highlighting the necessity of employing multiple vegetation indices to guide targeted and effective grassland management strategies.
中国北方的草原在国内和全球的畜牧业生产、能源利用及生态系统平衡方面都发挥着关键作用。然而，它们表现出明显的时间变异性和显著的空间异质性。由于大多数现有研究依赖单一植被指数和区域尺度分析，在解释草地动态及其潜在驱动因素时可能会引入偏差。为弥补这一差距，我们整合了功能和结构指数——总初级生产力（GPP）、太阳诱导叶绿素荧光（SIF）、归一化植被指数（NDVI）和叶面积指数（LAI）——以系统地研究中国北方不同草地类型的时空趋势。通过偏导数分析，我们量化了气候变化和人类活动对这些观测到的植被趋势的相对贡献。结果表明，超过70%的草地面积，特别是温带草原，植被指数总体呈上升趋势，而西南高寒草原则出现下降。气候变化是草地绿化的主要驱动因素（56.55%-63.83%），主要是通过温带草原降水增加和高寒草原气温上升实现的。人类活动对绿化也有很大贡献（36.17%-43.45%），特别是在荒漠化温带草原（如毛乌素沙地、甘肃、宁夏、新疆）和青海高寒草甸，主要通过农田恢复和荒漠化治理。相反，在某些高寒地区，人类活动也是草地退化的主要驱动因素（51.70%-69.64%），过度放牧和人口增长——再加上气温上升和土壤湿度下降——导致植被大量损失。此外，72.66%的温带草原植被结构和功能之间表现出强耦合，而57.59%的高寒草原GPP增加的同时LAI和SIF均下降。总体而言，这些发现强调了草地对气候和人为驱动因素响应的空间异质性，突出了采用多种植被指数来指导有针对性和有效草地管理策略的必要性。
