广西北部湾经济区1990-2009年景观格局变化

Landscape Pattern Changes of Guangxi Beibu Gulf Economic Zone from1990 to 2009

该文利用1990、2001和2009年三期TM影像数据解译的土地利用与覆盖数据,运用fragstats3.3软件选取多样性指数、优势度指数、均匀度指数等景观指数结合斑块密度、动态度等的统计与计算。结果表明:(1)耕地和林地占总面积的近95%以上,是该地区占据绝对优势的两种斑块类型,其它斑块类型面积比重很小,各类型的面积差异较大;(2)1990—2009年间,斑块面积减少数量最大的两类是耕地和草地,分别减少了737.27km2和678.09km2,斑块面积减少幅度最大的两类是未利用地和草地,分别减少了62.32%和59.73%,两者合计降低到了总面积的0.78%,建设用地面积大幅度增加1 793.85km2,增加了5.65倍,林地面积前期增加,2001年后快速下降,水体面积变化幅度较小;(3)1990—2009年景观斑块总数增加了83 226个,其中2001年后增加的占70.01%,耕地、建设用地和林地斑块数量均大幅度增加,斑块密度也快速增加;草地和未利用地斑块数量、平均斑块面积均呈减小趋势,景观破碎化程度不断加大,景观多样性也相应提高。

Guangxi Beibu Gulf Economic Zone is a new hot spot for enhancing development activi‐ties in Chinese Southeast Coast ,w here the landscape pattern is undergoing rapid changes .Based on the land cover datasets in 1990 ,2001 and 2009 ,by using Fragstats 3 3. software ,this paper quantita‐tively analyzed the change process and regularity of landscape pattern in this area ,with selecting land‐scape diversity index ,landscape dominance index ,landscape evenness index ,and some other indices such as patch density ,dynamic degree ,average patch area .The results show that :(1) The total area of cultivated land and woodland account for approximately over 95% of the entire area ,and the area of other patch types are very small ;(2)From 1990 to 2009 ,the two largest reduced areas of cultivated land and grassland reduced respectively by 737 2.7km2 and 678 0.9km2 ,While the reduced rate of the ar‐ea of unused land and grassland is the largest two types with reduction rate of 62 3.2% and 59 7.3% , w hich reduced to 0 7.8% of the entire area in 2009 .T he area of construction land in 2009 increased sig‐nificantly by 1793 8.5km2 ,5 6.5 times larger than that of 1990 .The area of woodland increased before 2001 and then reduced rapidly after that .Changes in water area were slight .(3) The total number of patches increased by 83 226 from the year 1990 to 2009 ,among w hich 70 0.1% is from 2001 to 2009 . The patch numbers of cultivated land ,construction land and woodland all increased sharply ,and of which the patch density increased rapidly at the same time .The number and average area of grassland and unused land decreased ,and the fragmentation degree of landscape was increasing constantly .