官司河流域土地覆被景观稳定性及其环境效应

以1995年和2005年官司河流域两期的TM遥感数据作为基本信息源,并借助RS、GIS和数理统计方法提取景观类型的矢量数据,通过基质比例、斑块数量和面积变化率、斑块密度变化率3个指标以及景观类型转化规律对流域的景观稳定性及其环境效应进行了初步研究。结果表明:(1)耕地是整个流域人工景观的基质,处在频繁耕作及动态变化中,马尾松林地作为半自然景观的基质,稳定性亦较低,但有所提高,二者对维持区域生态环境的良好发展起主导作用;(2)城镇及水域的斑块稳定性最高,马尾松林地、栎类林地和柏木林地次之,耕地与村庄的稳定性最低,这与流域作为典型农林复合生态区的地位与作用相吻合;(3)耕地与水域及有林地的转化最为剧烈,这与1998年以来流域实施的退耕还林工程密切相关,但水域及有林地的稳定性仍然取决于其自然稳定性,且景观格局呈现良好发展趋势;(4)中小斑块的马尾松林地及柏木林地的稳定性对流域的景观稳定性具有重要作用,处在生态环境变化趋向的节点位置,应予以合理的保护、规划及建设。

Landscape Stability and Environment Effect of Land Covers in Guansihe Watershed

TM remote sensing data of Guansihe watershed in the two periods of 1995 and 2005 was taken as the basic information source,and vector data of landscape types was extracted with the RS,GIS and mathematical statistics method.Three indices such as matrix proportion,change rate of patch number and area,change rate of patch density as well as transform rule of landscape types were used for landscape stability study in this watershed.The results showed that:(1) in the whole watershed,cultivated land was matrix of the artificial landscape which was in frequent farming and dynamic change,the stability was not high;Pinus massioniana woodland was matrix of the semi-natural landscape whose stability was also low,but had improved;both of them played a leading role in maintaining the regional ecological environment for the better development;(2) patch stability of town and water areas were the highest,Pinus massioniana woodland,Quercus aliena woodland and Cupressus funebrius woodland were ranked as the second place,cultivated land and villages were the lowest;this was consistent with the position of the watershed as a typical compound ecological agriculture and forestry areas;(3) dramatic transformation of cultivated land,water areas and woodlands were the most,which was closely related to the land conversion projects implemented in the watershed since 1998,but the stability of water areas and woodlands still depended on their natural stability,and the landscape pattern presented good development tendency;(4) stability of medium and small patches of Pinus massionian woodland and Cupressus funebrius woodland played an important role in the stability of the watershed,which were also in the node location of ecological environment change trend,should be protected,planed and constructed scientifically and reasonably.