1955~2010年小三江平原沼泽湿地景观格局变化及其对人为干扰的响应

以湿地变化较为剧烈的小三江平原为研究区域,以1955~2010年的地形图和Landsat TM遥感数据为数据源,采用网格分析法研究景观指数的时空分异规律,并分析不同时期人为干扰度对景观格局指数的影响。结果表明：① 从时间上看,1955~2010年小三江平原沼泽湿地的面积和最大斑块逐渐减小,斑块占景观比从52.87%下降到10.41%,最大斑块减少了47.6%,破碎化和分散性逐渐增加,连接度从1.02%增加到2.88%后下降为0.79%,呈先增加后降低的趋势,斑块的形状由复杂变得简单后又变得复杂,人为干扰度逐渐增加,从0.31%增加到0.6%;② 从空间上看,1955年研究区沼泽湿地景观由西南向东北破碎化逐渐减弱,1986年后变为由西南向东北破碎化逐渐增加的格局。沼泽湿地斑块类型所占景观面积比例和连接度指数的高值区主要分布在研究区的中部和东北部。人为干扰度的空间分布格局是由西南向东北逐渐减弱;③ 1955~2010年人为干扰对小三江平原沼泽湿地的邻近与连接程度的影响逐渐减弱,对沼泽湿地边缘密度影响逐渐增强,人为干扰对沼泽湿地斑块密度的影响主要受沼泽湿地面积的影响,人为干扰对沼泽湿地斑块的形状影响较小,沼泽湿地的优势景观控制力逐渐下降,人为干扰是小三江平原湿地面积减少的主要原因。

Landscape Pattern Change of Marsh and Its Response to Human Disturbance in the Small Sanjiang Plain, 1955-2010

With the research area being the small Sanjiang Plain whose wetland changes have been quite severe and with the source of data being the 1955-2010 topographic map and Landsat TM Remote Sensing Data, the grid analysis method was used to study the rules of spatial-temporal differentiation of the landscape index and the effects of the level of man-made interference on the landscape pattern index under different periods were also analyzed. The results show: 1) Looking at it from the aspect of time, in 1955- 2010 the area of the small Sanjiang Plain marsh wetland and the largest patch decreased gradually, patch accounted for landscape ratio from 52.87% decreased to 10.41%,the largest patch has reduced 47.6%, fragmentation and dispersibility increased gradually, connectivity increased at first then decreased, its trend embodys in connectivity from 1.02% increased to 2.88% then decreased to 0.79%, the shape of the patch changed from being complex to simple and then changed to being complex again, the level of man-made interference gradually increased,from 0.31% increased to 0.6%; 2) Looking at it from the aspect of space, in 1955 the fragmentation from the south-west to the north-east of the marsh wetland landscape of the research area diminished gradually. After 1986, it changed into a pattern where the fragmentation from the south-west to the north-east increased gradually. The high value areas of the marsh wetland with respect to its proportional area of the landscape and connectivity index are distributed in the central and north-eastern parts of the research area. The spatial distribution pattern of the level of man-made interference diminished gradually from the south-west to the north-east; 3) Effect that human interference had on the vicinity and connectivity of the marsh wetland of the small Sanjiang Plain diminished gradually in 1955-2010, but its effect on the marginal density of the marsh wetland increased gradually. The effect that human interference has on the density of the marsh wetland patch is mainly affected by the area of the marsh wetland. The effect that human interference has on the shape of the marsh wetland patch is quite small, the superior landscape controlling force of the marsh wetland declined gradually. Human interference is the main cause of the reduction in the wetland area of the small Sanjiang Plain.