| 定量评估气候变化对长江中下游地区植被GPPGS变化的影响 |
| 摘要点击 584 全文点击 131 投稿时间：2023-04-18 修订日期：2023-05-30 |
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| 中文关键词 总初级生产力(GPP) 不同类型植被 生长季 通径分析 气候因子 直接影响 间接影响 |
| 英文关键词 gross primary productivity different vegetation types growing season path analysis climate factor direct effect indirect effect |
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| 中文摘要 |
| 在区域和植被类型尺度上定量厘定气候因子对长江中下游地区生长季植被GPP（GPPGS）的直接、间接和综合影响，可为全球气候变化背景下区域植被资源管理与恢复提供科学依据.利用MODIS GPP数据、气象数据和植被类型数据，结合Theil-Sen Median趋势分析和Mann-Kendall显著性检验探究长江中下游地区植被GPPGS时空变化特征，并通过通径分析揭示气候因子对长江中下游地区整体和不同类型植被GPPGS变化的直接影响、间接影响和综合影响.结果表明：①2000~2021年长江中下游地区植被GPPGS呈波动上升趋势，上升速率（以C计，下同）为2.70 g·（m2·a）-1 （P<0.01）.不同类型植被GPPGS均呈极显著上升趋势（P<0.01），其中，灌丛上升速率最高，为3.31 g·（m2·a）-1，栽培植被上升速率最低，为2.54 g·（m2·a）-1.②长江中下游地区GPPGS呈上升趋势的面积占比为88.11%.不同类型植被GPPGS呈上升趋势的面积占比均大于84%.③通径分析结果表明，降水和最高气温对植被GPPGS的直接影响呈显著正向影响（P<0.05），而太阳辐射呈不显著正向影响（P≥0.05）.最高气温、降水和太阳辐射对植被GPPGS的间接影响均呈非显著负向影响（P≥0.05）.在直接影响和间接影响的综合作用下，降水和最高气温对植被GPPGS呈不显著正向影响（P≥0.05），而太阳辐射对植被GPPGS呈不显著负向影响（P≥0.05）；不同植被类型上，降水是影响栽培植被GPPGS变化的主要气候因子，最高气温是影响针叶林、阔叶林、灌丛和草丛GPPGS变化的主要气候因子.④长江中下游地区植被GPPGS变化主要受最高气温、降水和太阳辐射的直接影响，降水的直接影响对植被GPPGS变化的主导区域占56.72%.研究结果可为量化长江中下游地区植被固碳潜力和全球气候变化背景下制定因地制宜的生态恢复治理政策提供参考. |
| 英文摘要 |
| Quantitatively determining the direct, indirect, and comprehensive effects of climatic factors on the growing season of the vegetation GPP (GPPGS) in the middle and lower reaches of the Yangtze River at the regional and vegetation type scales can provide a scientific basis for the management and restoration of regional vegetation resources under the background of global climate change. Using MODIS GPP data, meteorological data, and vegetation type data, combined with Theil-Sen Median trend analysis and the Mann-Kendall significance test, the spatiotemporal characteristics of the GPPGS in the middle and lower reaches of the Yangtze River were investigated at different temporal and spatial scales. Path analysis was used to further reveal the direct, indirect, and comprehensive effects of climate factors on GPPGS variation in different vegetation types. The results showed that:① from 2000 to 2021, the vegetation GPPGS in the middle and lower reaches of the Yangtze River showed a fluctuating upward trend, with a rising rate (in terms of C, same below) of 2.70 g·(m2·a)-1 (P<0.01). The GPPGS of different vegetation types all showed a significant upward trend (P<0.01), with shrubs having the highest upward rate of 3.31 g·(m2·a)-1 and cultivated vegetation having the lowest upward rate of 2.54 g·(m2·a)-1. ② The proportion of the area with an upward trend in GPPGS in the middle and lower reaches of the Yangtze River was 88.11%. The proportion of the area with an upward trend in GPPGS was greater than 84% for all different vegetation types, with shrubs (49.76%) and cultivated vegetation (44.36%) having significantly higher proportions of the area with an upward trend than that in other vegetation types. ③ The path analysis results showed that precipitation and the maximum temperature had a significant positive direct effect on vegetation GPPGS (P<0.05), whereas solar radiation had a non-significant positive effect (P ≥ 0.05). The indirect effects of maximum temperature, precipitation, and solar radiation on vegetation GPPGS were all non-significantly negative (P ≥ 0.05). Under the combined effects of direct and indirect influences, precipitation and maximum temperature had a non-significant positive effect on vegetation GPPGS (P ≥ 0.05), whereas solar radiation had a non-significant negative effect on vegetation GPPGS (P ≥ 0.05). Among different vegetation types, precipitation was the main climate factor affecting the changes in GPPGS of cultivated vegetation, whereas the maximum temperature was the main climate factor affecting the changes in GPPGS of coniferous forests, broad-leaved forests, shrubs, and grasslands. ④ The changes in vegetation GPPGS in the middle and lower reaches of the Yangtze River were mainly influenced by the direct effects of maximum temperature, precipitation, and solar radiation, with the direct effect of precipitation dominating 56.72% of the changes in GPPGS. The research results can provide a reference for quantifying the carbon sequestration potential of vegetation in the middle and lower reaches of the Yangtze River and formulating ecological restoration governance policies tailored to local conditions under the background of global climate change. |
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