泾河流域景观稳定性与类型转换机制  

Landscape stability and its pattern transition in Jinghe watershed.

作　　者：谢高地[1] 甄霖[1] 杨丽[1] 郭广猛[1] 

机构地区：[1]中国科学院地理科学与资源研究所,北京100101

出　　处：《应用生态学报》2005年第9期1693-1698,共6页Chinese Journal of Applied Ecology

基　　金：国家重点基础研究发展规划资助项目(2002CB111506).

摘　　要：以泾河流域为例研究景观格局的变化.结果表明,泾河流域1986～2000年间,景观结构变化不大,以草地景观和耕地景观为主.草地景观和农耕地景观占流域总面积的85%以上,其次为林地景观,约占10%,其他景观类型仅占5%左右,说明流域的宏观景观格局不会在10～20年的时间尺度上发生结构性改变.大流域内景观类型之间可以相互转换,在5年和10年尺度上,主导景观类型的自稳定强度均在89%以上,转换为其他类型的强度在11%以内.不同景观类型组分中,占比例越小的景观类型转换为其他类型或消失的速度越快.同一大类景观类型中的亚景观类型之间相互转换幅度较大.流域内景观特征表现出一定的时空变化规律.从上游到下游,景观特征变化的趋势是优势度、聚集度增加,分维数下降,斑块密度由低到高,再由高到低;在时间尺度上,优势度、聚集度下降,分维数保持稳定,斑块密度增加.自2000年实行草地围封和退耕还林政策以来,泾河流域NDVI低值区由7.4%减至0.8%,NDVI高值区由29.8%减至25.1%,较高值区由18.3%增加到25.7%,最高值区由2.3%增至5.5%,表明该流域景观质量呈现增高趋势.Based on remote sensing and GIS, this paper analyzed the landscape change patterns in the Jinghe watershed of northwest Loess Plateau, one of the areas most suffered from soil and water erosion. The results indicated that the landscape structure in the watershed did not change very much over the past 15 years, and was dominated by grassland and arable land, which occupied 85 % of total watershed area. Forest and other land use accounted for 10 % and 5 % of total area, respectively. A transition of landscape patterns occurred at large-scale watershed level. During 1986-- 2000, the inter-transitions between different landscape types were very complicated, mainly occurred among woodland, grassland and arable land. The self-stableness of dominant landscape patterns was 〉 89 %, and only 11% of them transferred into other types. Among landscape types, the one sharing small percentage of the total had a high speed of vanishing or transferring into other types. A significant transition was found between sub-patterns of a large landscape pattern, e. g., the transition of medium- into low-coverage grassland during 1986-- 1995 and the reverse during 1995-- 2000 was occurred, implying a situation of grassland degradation and improvement over the decades. The spatial-temporal changes of landscape features were observed in the watershed. In terms of spatial change, the dominance index and contagion index of the landscape showed an increasing trend, fractal dimension index showed a decreasing trend, while patch density showed an increasing trend, followed by a decreasing trend from upper to down streams. For temporal change, both landscape dominance and contagion decreased to a certain extent, fractal index remained stable, while patch density increased, showing a fragmentation direction of the landscape in the watershed. The NDVI value changed since the implementation of the policy of conversing farmland into grassland and forest in 2000, which was from 7.4 % to 0.8 % in low value class, from 29.8 % to 25.1% in high value cl

关 键 词：泾河流域 景观宏观稳定性 景观类型转换 景观特征时空变化 景观质量 

分 类 号：Q149[生物学—生态学]