西南典型喀斯特地区石漠化时空演变特征——以贵州省普定县为例

为揭示我国西南典型喀斯特地区石漠化时空演变特征,选取贵州省普定县为研究对象,基于Landsat、DEM等影像数据,提取了坡度和4期植被覆盖度、岩石裸露率分布图,并利用地理探测器获得各自的贡献率,反演了1990—2015年4期石漠化空间分布信息,进而讨论了石漠化时空演变特征。结果表明:(1)在1990—2015年间,普定县石漠化演变复杂,经历了由好转到恶化再到好转的阶段,总体趋势在好转,局部恶化,石漠化治理仍需加大力度;(2)中度以上石漠化集中分布在三岔河沿岸附近,轻度以下石漠化则分布较散乱;(3)潜在和轻度石漠化演变方向复杂,潜在石漠化平均变化速率最大(2.75 km2/a),在1997—2006年间更是达到了16.5 km2/a;(4)植被覆盖度与岩石裸露率的变化主要呈负相关,前者的增加主导了石漠化的好转,而后者的增加则控制了石漠化的恶化;(5)石漠化演变存在突变,在三岔河沿岸附近,存在无/潜在石漠化突变为重度以上石漠化的现象;在靠近城乡居民地附近,存在重度以上石漠化突变为无/潜在石漠化的现象;(6)植被覆盖度、岩石裸露率、坡度能较准确反演石漠化,贡献率分别为44%、42%、14%。本文提供的石漠化反演方法快速高效,制作的图件、数据为同行提供了参考,得出的结论为石漠化治理提供了科学支撑。

Spatio-temporal characteristics of rocky desertification in typical Karst areas of Southwest China: A case study of Puding County, Guizhou Province

To reveal the spatiotemporal evolution characteristics of rocky desertification in the typical Karst region of Southwest China, we selected Puding County of Guizhou Province as the research subject. Based on Landsat and DEM image data, we extracted the Slope and the four-stage Fractional Vegetation Coverage and the Rock exposedness rate distribution map; then, we used geo-detectors to obtain their respective contribution rates, and retrieved the spatial distribution information for the four stages of rocky desertification in 1990-2015. Finally, we discussed the temporal and spatial evolution of characteristics of rocky desertification. The results showed that:(1) In the period of 1990-2015, the evolution of rocky desertification in Puding County was complex, it ranged from good to deterioration and then back to improvement, but the overall trend was improving with local deterioration, so the control of rocky desertification still needs to be intensified; (2) Moderate rocky desertification was concentrated in the vicinity of the Sancha River, and the light rocky desertification was distributed. (3) The evolution direction of potential and light rocky desertification were complex, the average change rate of potential rocky desertification was a maximum of 2.75 km²/a, reaching 16.5 km²/a in 1997-2006; (4) Fractional Vegetation Coverage was negatively correlated with the change in Rock exposedness. The increased Fractional Vegetation Coverage led to the improvement of rocky desertification, whereas the increased of Rock exposedness controlled the deterioration of rocky desertification;(5)There was a sudden change in the evolution of rocky desertification, and there was no/potential rocky desertification change to severe rocky desertification near the coast of the Sancha River. Near the urban and rural areas, there was a severe rocky desertification change to no/potential rocky desertification; (6) Fractional Vegetation Coverage, Rock exposedness, and Slope can be used to accurately retrieve rocky desertification, and the contribution rate was 44%, 42%, and 14%, respectively. The inversion method of rocky desertification provided in this paper is fast and efficient, the drawings or data are provided for reference, and the conclusions can provide scientific support for the control of rocky desertification.