| 2000~2020年长江流域植被NDVI动态变化及影响因素探测 |
| 摘要点击 1806 全文点击 605 投稿时间：2021-12-08 修订日期：2022-01-10 |
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| 中文关键词 长江流域 归一化植被指数(NDVI) 地理探测器 时空演变 影响因素 交互作用 |
| 英文关键词 Yangtze River basin normalized difference vegetation index(NDVI) geographical detector model spatiotemporal variation influencing factor interaction |
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| 中文摘要 |
| 研究植被动态变化并探测驱动其变化的影响因素，对区域生态环境质量监测和林业恢复工程效应评估具有重要现实意义.利用MODIS NDVI数据、基于站点的气象数据、DEM数据、人口密度数据和夜间灯光数据等，结合Theil-Sen Median斜率估计、Mann-Kendall显著性检验、稳定性分析和地理探测器，在多时空尺度下分析2000~2020年长江流域植被NDVI时空演变特征及稳定性，并探测驱动植被NDVI空间分异的主要影响因素.结果表明，2000~2020年长江流域植被NDVI整体呈波动上升趋势.除太湖水系外，其余流域单元植被NDVI均呈上升趋势.长江流域植被NDVI呈上升趋势的面积占84.09%，其中，呈极显著上升和显著上升的区域占53.67%，主要分布在乌江、宜宾至宜昌、嘉陵江、汉江和洞庭湖水系.除金沙江石鼓以上和太湖水系植被NDVI稳定性较差以外，其他流域单元植被NDVI整体较为稳定.海拔是影响各流域单元植被生长的重要因素，而气候因子对金沙江石鼓以上植被NDVI的影响程度最高，人文因子对乌江、湖口以下干流和太湖水系植被NDVI影响最大.长江流域影响因素双因子交互作用均表现为双因子增强或非线性增强，其中，海拔∩风速的q值最高，为0.68.影响因素生态探测结果表明，人文因子与除坡度以外的地形因子和除湿度指数以外的气候因子对长江流域植被NDVI空间分异的解释力存在显著性差异.研究结果可为制定考虑区域气候、地形和人类活动的长江流域植被资源管理方案提供依据. |
| 英文摘要 |
| Studies on the dynamic variation in vegetation cover and detecting its influencing factors are highly valuable for monitoring regional ecological environment quality and evaluating forestry restoration project effects. In this study, on the basis of the MODIS normalized difference vegetation index (NDVI), in situ climate data, digital elevation model, population density, nighttime lights using Theil-Sen Median analysis, Mann-Kendall significance test, stability analysis, and geographical detector model, the spatiotemporal variation and stability of vegetation cover in the context of multi-spatiotemporal scales were analyzed, and the dominant influencing factors that affect the spatial differentiation of vegetation cover were further detected. The results showed that the vegetation cover showed a fluctuant increasing trend, and the changing trend exhibited obvious spatial heterogeneity with the increasing rate being higher in the middle and lower in the east and west portion of the Yangtze River basin from 2000 to 2020. At the sub-basin scale, except for that in the Taihu Lake basin, the vegetation cover in all sub-basin units exhibited an increasing trend during the study period. The areas with an increasing trend accounted for 84.09% of the study area, in which the areas with extremely significant increases and significant increases accounted for 53.67%, which were mainly distributed in the Wujiang River basin, Yibin-yichang, Jialing River basin, Han River basin, and Dongting Lake basin. The vegetation cover showed lower stability in the upper reaches of the Jinsha-shigu River basin and Taihu Lake basin and higher stability in other sub-basin units of the study area. Elevation was an important factor affecting the vegetation variation in all sub-basin areas. Climatic factors presented the highest impact on vegetation variation in the upper reaches of the Jinsha-shigu River basin, and human activities exhibited the greatest impact on vegetation variation in the Wujiang River basin, lower reaches of Hukou basin, and Taihu Lake basin. The interaction of the two influencing factors on vegetation variation showed mutual and non-linear enhancement, and the interaction between elevation and wind speed presented the highest value, with an explanatory power of 68%. The ecological exploration results showed that human activities combined with topographic factors and climate factors, except for slope and relative humidity, significantly differed in the explanatory power of vegetation variation in the Yangtze River basin. These results can provide a basis for formulating comprehensive vegetation resource management in the Yangtze River basin that takes into account regional climate, topography, and human activities. |
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