关键词: 植被覆盖度, 遥感监测, 时空变化, 气候响应, 湖南省

Abstract: Exploring the spatiotemporal variations of vegetation and its response to climate change is crucial for regional ecological protection and sustainable development. We divided Hunan Province into four main geographical regions utilized Landsat image data to construct the green fractional vegetation cover (GFVC) based on the green normalized difference vegetation index (GNDVI). By using trend analysis, correlation analysis, and lag-effect tests, we examined the spatiotemporal variations of GFVC in different regions of Hunan Province, elucidated the impact mechanisms of temperature and precipitation on GFVC, and disclosed the influence of human activities on vegetation succession. The results showed that: (1) There were significant spatiotemporal variations in GFVC across different regions of Hunan. The Changsha-Zhuzhou-Xiangtan region, Dongting Lake region, and south-central Hunan exhibited significant growth of GFVC, with the distribution type being mainly the medium-high vegetation cover. The GFVC in western Hunan did not show significant growth, with the distribution type being primarily high vegetation coverage.  (2) The trend of vegetation succession in all the four regions was generally improving, with degradation trends accounting for a relative low proportion. Among them, the proportion of slight degradation was higher in western Hunan, accounting for 30.0%, while it was lower in the other regions. (3) The vegetation succession trend in all regions was primarily characterized by continuous improvement, particularly in the Changsha-Zhuzhou-Xiangtan region, Dongting Lake region, and south-central Hunan, where the continuous improvement areas accounted for 63.9%, 59.6%, and 69.8%, respectively. In contrast, the area of continuous improvement in western Hunan was relatively lower, accounting for 48.5%. (4) In all regions except western Hunan, GFVC was significantly negatively correlated with precipitation and positively correlated with temperature. There was avarying degree of lag effects between GFVC and climate factors in each region. (5) Human activities significantly stimulated vegetation restoration in Hunan Province, but the environmental threats from urbanization and industrial expansion should not be overlooked. In conclusion, this study revealed the regional heterogeneity of vegetation succession trends in Hunan Province, and clarified the impacts of climate change and human activities, which provides a theoretical basis and data support for formulating region-specific ecological protection strategies.

Key words: vegetation cover, remote sensing monitoring, spatiotemporal dynamics, climate response, Hunan Province