摘要
以若尔盖高原为研究区,选择1977年的Landsat MSS影像、2007年的Landsat TM影像和研究区90m分辨率的数字地形图为数据源,利用景观生态学方法及遥感和地理信息系统技术,对若尔盖高原1977年和2007年两个时期的沼泽湿地(包括沼泽和沼泽化草甸)景观格局进行了对比研究。结果显示,与1977年相比,2007年研究区沼泽与沼泽化草甸的面积比(沼泽面积/沼泽化草甸面积)发生了明显变化,沼泽与沼泽化草甸的面积比由1977年的1/3减少到2007年的1/7;2007年沼泽面积明显减少,其面积只占沼泽湿地总面积的13%;两个时期,研究区沼泽湿地景观都集中连片分布,聚集度均高于90;与1977年相比,2007年沼泽湿地景观的斑块数减少,景观类型趋于单一,而平均斑块面积和聚集度都在增加;研究区沼泽湿地90%以上分布在坡度小于5°的空间范围内,随着坡度的增大,沼泽湿地的退化程度显著增高;与1977年相比,2007年研究区沼泽湿地景观分布质心发生了一定的空间位移,沼泽质心向西南偏移了3.88km,沼泽化草甸质心向东北偏移了12.35km。
The Zoigê Wetland is one of the largest plateau wetlands in China. Since 1960s,wetlands in the Zoigê Plateau have confronted the degradation crisis due to integrated influence of natural events and human activities, which have greatly changed temporal - spatial distribution pattern of wetland. Marsh wetland is the main part of the Zoigê wetland,and the ratio of marsh wetland is more than 95% . In contrast,other wetland landscape com- ponents retain small proportion. Therefore,the primary aim of this paper was to study changes in landscape pat- tern of marsh wetland,including marsh and marshy meadow,in the Zoigê Plateau for 2 periods over the past three decades. In this paper,to choose Zoigê,Hongyuan,Aba,Maqu and Luqu counties as research area, based on Landsat MSS images in 1977 and Landsat TM images in 2007 and the 90 m resolution digital elevation model （DEM） of the study area,the comparison between landscape patterns of marsh and marshy meadow in the Zoigê Plateau in 1977 and 2007 were conducted and analyzed by using RS,GIS and landscape ecology method. The results showed that the area ratio of marsh and marshy meadow （ marsh/marshy meadow） in 2007 had changed significantly relative to that in 1977,the area ratio of marsh and marshy meadow reduced from 1 /3 in 1977 to 1 /7 in 2007. To compare that in 1977,marsh wetland in the Zoigê Plateau already had decreased obvi- ously in 2007 due to global climate changes and intense human interference; 61 988 hm2 marsh and 31 895 hm2 marshy meadow were lost by the end of 2007,the marsh degraded more severely than marshy meadow. During 2 periods,the marsh wetland landscape was characterized by concentrated distribution,with the aggregation degree of more than 90; the patch number of marsh wetland landscape was obviously reduced in 2007,and because of the lost marsh wetland landscape was made up of small patches,the average patch areas and aggregation in- creased. In addition,account for the marsh degraded more severely than marshy meadow lead to the diversity re- duced in 2007. In the Zoigê Plateau,more than 90% of the marsh wetland distributed in the 0° - 5° slope re- gion. When the terrain slope was less than 8°,there was a significant positive correlation between the decreasing rate of marsh wetland area and the terrain slope（r = 0. 96,n = 8,p 0. 01）,with the elevation of the terrain slope,the decreasing rate increased remarkably. The centroid of marsh and marshy meadow in 2007 has dis- placed relative to that in 1977. It was found that the centroid of marsh in 2007 moved towards the southwest for about 3. 88 km,and the centroid of marshy meadow moved 12. 35 km towards the northeast.
出处
《湿地科学》
CSCD
2010年第1期8-14,共7页
Wetland Science
基金
国家重点基础研究发展计划项目(2005CB422005)资助
