摘要
根据1994年和1999年的两期Landsat TM数据,在FCD Mapping model原理和方法的基础上,得到北京北部山区昌平、怀柔、密云和平谷的植被覆盖率图,并利用FRAGSTATS软件对所得的植被覆盖等级图从斑块大小、斑块数、斑块密度、斑块平均面积、分形维数和聚集度等角度进行了空间格局变化的剖析。结果表明:1)各研究区均显示无植被覆盖类型占据着景观中的优势地位。1994～1999年期间,研究区总的植被覆盖率除平谷降低外,其它三个区均呈现增长趋势,其中昌平增长最显著。说明平谷的植被覆盖状况逐渐变差,而昌平、怀柔和密云的植被覆盖状况逐渐转为良好。然而各研究区的植被仍需进一步进行保护。2)1994～1999年期间,景观整体的斑块密度都在减少,其中平谷减少的最多,说明景观整体的破碎化程度降低;多样性指数和均匀度指数也呈现降低趋势,其中密云减少最为显著,表明景观越来越由少数植被覆盖等级类型所控制。3)各研究区中景观整体的分维数相差不大,各景观组分的分维数标准差均较低,说明山区的斑块形状主要取决于自然地貌及自然环境条件。4)1994～1999年期间,蔓延度指数均呈现增长的趋势,聚集度指数的变化不显著,但都接近于1,说明景观整体的聚集程度较高。
Based on the FCD mapping model, the fraction of green vegetation in Beijing mountain area was calculated using the Landsat-TM data (with two digital images taken in 1994 and 1999, respectively). The landscape pattern of change in the fraction of green vegetation during this period was studied using a landscape pattern analysis program FRAGSTATS by analyzing path area, number of patches, fractal dimension, landscape diversity index and cohesion index and so on to show the changing feature of landscape pattern. The result indicates that the cover type of none vegetation is main components of land cover in two periods' data of Beijing mountain area, but the vegetation covers level in the whole are increased. All of these results of indices analysis emphasize that the eco-environmental system in Beijing mountain area is stable and the fragmentation level in the last five years is decreasing. But the temporal and spatial characteristics of change of landscape are different a-mong different types of Beijing mountain area. The spatial structure analysis can help to identity the vegetation coverage spatial distribution and structure stability. So it is another important factor for Beijing mountainous e-cology system evaluation.
出处
《山地学报》
CSCD
2003年第3期272-280,共9页
Mountain Research
基金
北京市科委"十五"重点项目(NO.95542100)
北京市自然科学基金(NO.6031001
NO.4022005
NO.6012006)
关键词
遥感
植被覆盖率
景观格局分析
北京山区
植被指数
裸土指数
阴影指数
remote sensing
fraction of green vegetation
landscape pattern analysis
Beijing mountainous area
vegetation index
bare soil index
shadow index
