关键词: 植被覆盖度, 时空分析, 驱动影响, Landsat遥感数据, 时空地理加权模型, 巢湖流域

Abstract: Based on Landsat remote sensing data from 2001 to 2021, we investigated the vegetation cover changes in Chaohu Lake Basin, and further delved into the driving effects of terrain, climate and human activities by using Geographical and Temporal Weighted Regression (GTWR). The findings reveal several key points: 1) The average vegetation coverage within the basin stood at 0.75, exhibiting a consistent upward trajectory over the past two decades, with an annual growth rate of 0.12%. Notably, a declining trend prevailed before 2009, followed by a subsequent upswing. 2) A substantial majority (89.79%) of the area exhibited vegetation coverage exceeding 0.6, with forested land boasting the highest coverage, followed by dry farmland, sparse vegetation, irrigated farmland, urban built-up area, and wetland in descending order. The low vegetation cover in wetlands can be attributed to water management functions such as storage and drainage. 3) Over the past two decades, 34.78% of the region witnessed changes in vegetation coverage, predominantly characterized by an increasing trend encompassing 62.73% of the total area. These changes were notably concentrated in the historical urban core of Hefei, mountainous forest regions, plains along the northern river bank, and wetlands surrounding Chaohu Lake. Policies of ecological conservation and watershed governance exerted an evident positive influence on vegetation coverage. Conversely, diminishing trends were observed in the periphery of the city and in some cultivated land areas, reflecting adverse impacts of urbanization and cultivation practices. Particular attention should be paid to the declining vegetation coverage along the construction line of Paihe River to Dongfei River segment of the Water Diversion Project from Yangtze River to Huaihe River, as well as the Zhegao River basin. 4) Prior to 2010, the influence of topographical factors exhibited a declining trend, while climatic effects gradually intensified. Conversely, after 2010, topographical factors intensified and emerged as the predominant driving force of vegetation changes. 5) Human activities exerted an overall increasing influence on vegetation cover, contributing to ecological environment at an enhancement rate of 0.013% per decade.

Key words: vegetation coverage, spatio-temporal analysis, driving effect, Landsat remote sensing data, geographical and temporal weighted regression, Chaohu Lake Basin