粤北典型岩溶山区土地石漠化景观格局动态分析

Analysis on Landscape Pattern Dynamic of Rock Desertification in Northern Guangdong,China from 1988 to 2004

利用1988年和2004年的2期TM遥感数据,在GIS和FRAGSTAT景观格局分析软件支持下,定量地分析粤北典型岩溶山区及其4县(市)的土地石漠化类型变化及其景观格局时空动态特征。结果表明:16a来各种类型石漠化土地无论是在数量、面积和空间分布特征方面都发生了十分显著的变化,总面积减少721.67km2,斑块数减少了1 900块;2004年粤北4县(市)石漠化土地的面积占各区的比例分别是:连州为3.33%、阳山为7.28%、英德为1.54%、乳源为5.11%;粤北及其4县(市)石漠化土地的总体景观空间格局动态变化趋势基本一致,但在程度上有所差异,均表现为景观异质性减弱,破碎度降低,而景观优势度增加;随着相关石漠化治理措施地开展,中度与重度石漠化土地成为研究区内重点关注区域,尤其在阳山与乳源,这种空间格局变化的特征更为明显。

With GIS and landscape pattern theory, the typical Karst landscapes and spatial-temporal dynamic of rock desertification land change and their ecological conditions at the north of Guangdong were analyzed based on translated data from remote sensing images in 1988 and 2004. The results indicate that the area and the patch number of rock desertification decreased respectively by 721.67 km^2 and 1 900 blocks from 1988 to 2004. The area ratios of rock desertification land to the total of this region were 3.33%, 7.28%, 1.54% and 5.11% respectively at Lianzhou, Yangshan, Yingde and Ruyuan in 2004. All kinds of landscape index were calculated at class level and landscape level. Quantitative analysis showed that the spatial pattern chan- ges of rock desertification in the four counties have the same trend but are different at degree. In details, the landscape heterogeneity and fragmentation all declined, while landscape dominance increased. Along with the operation of rock desertification controlling countermeasures the moderate and severe rock desertification types of this region became the hot spot, the counties of Yangshan and Ruyuan showing more obvi- ous spatial pattern changes.