陕北黄土高原景观破碎化及其土壤裸露效应  

Landscape fragmentation and soil bareness study in north Shaanbei Loess Plateau

作　　者：李正国[1] 王仰麟[1] 张小飞[1] 

机构地区：[1]北京大学环境学院,北京100871

出　　处：《生态学报》2005年第3期421-427,i002,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金重大研究计划资助项目 (90 10 2 0 18)~~

摘　　要：破碎化是黄土高原典型的景观特征 ,深刻影响着区域的景观格局与功能。为深入探讨黄土高原景观破碎化的格局特征及其生态效应 ,选择陕北黄土高原为研究区 ,结合景观格局指数与主成分分析对破碎化程度进行量化 ,并针对研究区相应的景观格局特征、造成破碎化的景观类型及土壤裸露程度 ,进行组成、分布及动态分析。研究结果发现陕北黄土高原景观格局中的斑块密度特征对破碎化有较强的指示意义 ,其次则是景观的空间构型特征。草地和农地等与人为活动关系较为密切的景观类型是造成研究区景观破碎化的主要原因 。The study of landscape fragmentation is an important means to reveal regional ecological processes. Using remote sensing data of 1987, 1997, and 2002, some representative quantitative indices of the landscape spatial structure and landscape fragmentation were calculated to investigate the relationship between landscape ecological structure and landscape pattern in Shaanbei Loess Plateau using FRAGSTATS. Through the analysis of the types of fragmented landscape, we found that the main contribution to regional landscape fragmentation came from cropland and grassland. Furthermore, with the increasing of percentage of grassland, landscape became more fragmented, but forestland coverage has inverse effects on the fragmentation. Based upon the well-defined characteristics of this region's evolving landscape fragmentation, the relationship of landscape fragmentation and spatial pattern was investigated. More fragmented landscape is always with less patch area variation, more dispersed spatial configuration and complicated patch shape. In conclusion,landscape fragmentation has high sensitivity with percentage of similarity adjacencies, aggregation index,edge density, interspersion and juxtaposition index. The relationship and feedback between landscape pattern, function and process serve to describe the behavior of a regional landscape. Based on landscape function characteristics such as biological productivity, soil nutrient content, soil bareness, etc, a quantitative method and digital model for evaluating soil bareness in study area were devised. To get large-area images accurately and promptly is very important for monitoring of ecological process in regional scale. Moderate-Resolution Imaging Spectroradiometer (MODIS) images were used to derive soil bareness information calculated with Linear Spectral Unmixing (LSU) based on Mixture Spectral Analysis (MSA). As a result, the extent of fragmentation contributed mostly to the soil bareness in cropland, grassland and forestland, but lack of obvious rel

关 键 词：景观破碎化 陕北黄土高原 土壤 景观格局 草地 生态效应 景观类型 景观特征 指示意义 空间构型 

分 类 号：Q149[生物学—生态学] S157[生物学—普通生物学]