关键词: 石漠化, 植被覆盖度, 景观指数, 空间自相关, 生态修复

Abstract: Vegetation restoration is crucial to prevent and control karst rocky desertification. Previous studies have extensively evaluated species changes in plant communities during vegetation restoration by field investigation. However, few studies have explored the spatial dynamics of vegetation. Such evaluation can reveal the interactions among vegetation patches, and better understand the process and mechanism of vegetation restoration. In this study, we explored the dynamics of fractional vegetation coverage and the spatial patterns by using 1.6 cm high-resolution remote sensing data from the unmanned aerial vehicle and field survey with a chronosequence approach in Yunnan Shilin Geopark. The results showed that in naturally restored vegetation, the total fractional vegetation coverage increased from 63.40% to 96.50% with succession, with the coverage of woody vegetation being increased from 4.29% to 96.50%. Furthermore, vegetation patches in the later succession stage was less fragmented, larger in mean patch size, and with simplified patch edges. Additionally, the global Moran’s I of vegetation increased first and then decreased, and peaked at the 10^th year of natural restoration, indicating strong aggregate of vegetation patches at this stage. These changes indicate that the restoration of large vegetation patches reduces the risk of karst ecosystem degradation to bare land. Overall, our results revealed the dynamics of fractional vegetation coverage and vegetation spatial pattern in natural succession, which could provide insights for ecological restoration practice in rocky desertification areas.

Key words: rocky desertification, fractional vegetation coverage, landscape metrics, spatial autocorrelation, ecological restoration