College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830046, China.
College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi 830046, China; Xinjiang Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi 830046, China.
Sci Total Environ. 2024 Dec 1;954:176663. doi: 10.1016/j.scitotenv.2024.176663. Epub 2024 Oct 1.
As the issue of global climate change becomes increasingly prominent, the grassland ecosystems in Central Asia are facing severe challenges posed by the impacts of climate change. However, the dominant factors, impact pathways, and cumulative and time-lagged effects of climate factors on various grassland indices remain to be explored. This study selected data from 1988 to 2019, including Fractional Vegetation Cover (FVC), Leaf Area Index (LAI), Net Primary Productivity (NPP), and Vegetation Optical Depth (VOD), to characterize grassland coverage, greenness, biomass accumulation, and water content features. Utilizing multiple linear regression, path analysis, and correlation analysis, this study investigated the dominant effects, direct impacts, indirect influences, and cumulative and time-lagged effects of climate factors on various grassland indices from spatial and climatic zone perspectives. The research findings indicate that over time, the grassland FVC and NPP exhibited increasing trends, while the LAI and VOD showed decreasing trends. Grassland indices are primarily influenced by precipitation and soil moisture (SM). The direct impact of SM on grassland indices was higher than precipitation. Vapour pressure deficit (VPD) has a direct negative impact on grassland indices. Grassland indices are subject to positive indirect effects from precipitation via SM and negative indirect effects from VPD via SM. Precipitation and SM mainly exhibited no cumulative and time-lagged effects on the impact of grassland VOD. VPD primarily demonstrated cumulative and time-lagged effects on grassland indices. The research findings offer valuable insights for conserving grassland ecosystems in Central Asia, as well as for shaping socioeconomic strategies and formulating climate policies.
随着全球气候变化问题日益突出，中亚草原生态系统正面临气候变化影响带来的严峻挑战。然而，气候因素对各种草原指标的主导因素、影响途径以及累积和时滞效应仍有待探索。本研究选取了 1988 年至 2019 年的数据，包括植被覆盖度（FVC）、叶面积指数（LAI）、净初级生产力（NPP）和植被光学深度（VOD），用于描述草原覆盖度、绿色度、生物量积累和水分含量特征。利用多元线性回归、路径分析和相关分析，从空间和气候带的角度研究了气候因素对各种草原指标的主导效应、直接影响、间接影响以及累积和时滞效应。研究结果表明，随着时间的推移，草原 FVC 和 NPP 呈增加趋势，而 LAI 和 VOD 呈减少趋势。草原指数主要受降水和土壤湿度（SM）的影响。SM 对草原指数的直接影响大于降水。水汽压亏缺（VPD）对草原指数有直接的负面影响。降水通过 SM 对草原指数产生正的间接影响，而 VPD 通过 SM 对草原指数产生负的间接影响。降水和 SM 对草原 VOD 的影响主要没有累积和时滞效应。VPD 主要对草原指数产生累积和时滞效应。本研究结果为保护中亚草原生态系统提供了有价值的见解，也为制定社会经济战略和气候政策提供了参考。
