近20年间云南省石漠化演变过程及特征分析

Analysis on the Evolution Process and Characteristics of Rocky Desertification in Yunnan Province in the Past 20 Years

在宏观尺度下精确识别石漠化斑块信息并对其演变过程进行定量分析,有助于正确认识区域石漠化的空间分布及动态变化规律,可为石漠化综合治理提供重要的决策依据。以我国西南地区典型的石漠化分布区域——云南省为研究区,以2000—2020年的Landsat TM/OLI卫星遥感影像为材料,对研究区石漠化等级的空间分布进行遥感识别和提取,分别对云南省石漠化的空间分布特征和动态演变过程进行量化分析。结果显示:(1)近20年间,云南省石漠化总面积呈减少之态势,其内部结构已发生较大变化,整体趋于向低等级的转移。(2)石漠化演变方式由大到小排序为无变化、渐变方式、跳变方式、返变方式,其中,跳变方式和返变方式的石漠化面积占比之和与渐变方式仅相差8.55%,此占比值相较同类研究明显提高,说明云南省石漠化内部结构转移的跳跃性相比同类研究明显偏高。(3)在石漠化的演变方向中,基本不变的面积占比最大,石漠化改善的面积占比远高于恶化的面积占比。(4)石漠化的时空演变特征与当地的社会经济发展存在相关性,云南省经济落后区域仍存在“越穷越垦、越垦越穷”的现象。

The accurate identification of rocky desertification patches at macroscopic scale and the quantitative analysis of their evolution can help to correctly understand the spatial distribution and dynamic changes of rocky desertification,which can provide an important decision basis for the comprehensive management of rocky desertification.Based on remote sensing images from Landsat TM/OLI satellite,the spatial distribution of rocky desertification in the study area was identified and extracted,and the spatial distribution characteristics and dynamic evolution of rocky desertification in Yunnan Province were quantified and analysed respectively.The study shows that:(1)In the past 20 years,the rocky desertification in Yunnan Province has shown a decreasing trend,its internal structure has changed greatly,and the overall trend is to transfer to a lower level.(2)The evolution pattern of rocky desertification was ranked from largest to smallest as no change,gradual change,jump change and return change,among which the sum of the area of jump change and return change was only 8.55%different from that of gradual change.(3)In the evolutionary direction of rocky desertification,the largest proportion of the area was basically unchanged,and the proportion of the area where rocky desertification has improved was much higher than the proportion of the area where it has deteriorated.(4)There was a correlation between the spatial and temporal evolution of rocky desertification and local socio-economic development,and the phenomenon of“the poorer the reclamation,the poorer the reclamation”still existed in economically backward regions of Yunnan Province.