毕节试验区石漠化时空演变过程和演变特征

基于RS和GIS技术,解译了2000、2005和2010年3期毕节试验区石漠化数据,利用空间分析和数理统计分析方法,在探讨石漠化时空演变总体特征的基础上,选取演变方式、演变方向和演变速率等指标,重点分析了不同石漠化强度之间的内部转移特征,演绎了10年间毕节试验区石漠化演变过程。研究表明:(1)10年间,石漠化总面积呈现先增加后趋稳的演变态势,石漠化扩张趋势虽然初步遏制,但局部地区还在恶化,防治形势仍很严峻;(2)石漠化演变方式以渐变式为主,跳跃式为辅,返变式最少;(3)石漠化演变的方向既存在改善也存在恶化,且轻度改善和轻度恶化的面积均比较大,一边治理、一边破坏的现象还没有根本遏制;(4)非石漠化与石漠化相互转换非常活跃,潜在石漠化虽被定义为非石漠化,但并不稳定,容易转变为石漠化;(5)石漠化演变速率分为转入速率、转出速率和综合速率,中度石漠化综合速率最高,转入速率大于转出速率,潜在石漠化和轻度石漠化是中度石漠化增加的主要来源;(6)石漠化时空演变特征与生态环境建设及社会经济发展具有一定的相关性。该研究成果为喀斯特山区生态环境保护和石漠化防治提供了有益的参考。

Spatial-temporal evolution process and its evaluation characteristic of rocky desertification in Bijie experimental area

Based on spatial analysis and statistical analysis methods, the spatial-temporal evolution process of rocky desertification in Bijie experimental area, in terms of change pattern, direction, and rate, was analyzed using 3-phase distribution maps, which were interpreted by the decision tree method from Landsat images in 2000, 2005 and 2010. In particular, the interchanges among different degrees of rocky desertification were investigated. The results are listed below. (1) From 2000 to 2010, the total area of rocky desertification first increased and then stabilized, indicating that the expansion of rocky desertification was controlled preliminarily. However, the rocky desertification in some areas was still worse, and the effects of prevention and control were not optimistic. (2) The change patterns of rocky desertification were mainly gradual change, followed sequentially by leaping change and returning change. (3) The change directions of rocky desertification included both forward (improvement) and backward (deterioration), but the areas of slight improvement and slight deterioration were both very large. The co-occurrence of destruction and treatment has not been changed. (4) The potential rocky desertification, though not included as rocky desertification, was not stable and could be easily transformed into rocky desertification. (5) The change rates of rocky desertification were divided into three types: transfer-in rate, transfer-out rate, and comprehensive transfer rate. The comprehensive transfer rate of moderate rocky desertification was the largest compared with other types of rocky desertification, and the newly-formed moderate rocky desertification mainly came from light and potential rocky desertification. (6) The spatial-temporal evolution process of rocky desertification was closely correlated with ecological environment construction and socioeconomic development. This study provides theoretical foundations for preservation of ecological environment and comprehensive treatment of rocky desertification.