[Effects of Topography on Vegetation Coverage Changes in Rural Areas Under Multi-scale Scenarios]

Revealing the characteristics of vegetation coverage change and the effects of topography on vegetation coverage change in rural areas since the reform and opening up has direct implications for further understanding of human-land coupling processes and resource and environmental changes and provides a reference for ecological environment protection in rural revitalization. Using the Taihua Town in Yixing City, Jiangsu Province, as a rural case study, we revealed the basic features of rural vegetation coverage change from 1986 to 2020. Furthermore, using 0.25 km²（scenario 1）, 0.50 km²（scenario 2）, and 1.00 km² （scenario 3） as scale scenarios in the study area, both the single and comprehensive topographic effects on vegetation coverage change were explored. The study produced several important results： ① Vegetation coverage in the study area generally maintained an upward trend from 1986 to 2020, during which the spatial pattern of vegetation coverage distribution was generally high in the southeast and southwest and low in the north （northwest）. During this period, the vegetation coverage in the study area increased from 74.15% to 83.44%, and the spatial pattern of vegetation coverage distribution generally remained similar. ② Under the multi-scale scenarios, the vegetation coverage distribution in the study area generally maintained a similar spatial pattern from 1986 to 2020, excepting a few local differences. Under the same-scale scenario, Moran's index of vegetation coverage in the study area was higher in 2020 than in 1986. Taking scenario 1 as an example, Moran's index of vegetation coverage in the study area increased from 0.603 to 0.652 between 1986 and 2020. ③ Under the multi-scale scenarios, from 1986 to 2020, vegetation coverage in the study area generally maintained an upward trend with increase of elevation, slope, and topographic relief. As an example of the vegetation coverage change with elevation, in scenario 1 in 2020, the vegetation coverage in the study area increased from 64.50% in the area with elevations of 0-50 m to 98.77% in the area with elevations above 350 m. ④ Under the multi-scale scenarios, the comprehensive topographic effects on mean vegetation coverage change in the study area from 1986 to 2020 showed that elevation, slope, and topographic relief all had positive effects, and their effects were greater in scenario 3 than in scenario 2 and then in scenario 1 for the same topographic factor. According to the comprehensive topographic effects on mean vegetation coverage change in the study area from 1986 to 2020, the equation simulation coefficients of elevation under scenarios 1, 2, and 3 were 0.271, 0.281, and 0.283, respectively. The respective slope values were 0.283, 0.289, and 0.294, and the topographic relief values were 0.283, 0.292, and 0.295. This suggests that the scale variation has impacts on the comprehensive topographic effects. The results of this study are valuable for understanding the changes in the rural ecological environment under multi-scale scenarios since the reform and opening up.