水利工程对别拉洪河流域湿地景观结构的影响

Study on the Influence of the Drainage Works on the Changes of Wetland Landscape in the Bielahong Watershed of Sanjiang Plain

论文利用小三江平原区域的土地利用-湿地景观数据库,提取别拉洪河流域地形、土地利用和排水工程等数据,进行流域景观制图,包括3个时期,1967、1983和2005年,并将该流域划分上、中、下游3个分区。在此基础上利用Arcview3.2软件的空间分析功能,辅助FRAG-STATS生态学软件对湿地景观图计算和分析6个景观格局指标。结果表明:排水工程之前,各分区自然湿地覆盖率均达到90%以上,且呈大块连续状分布,自然状态保存完好;排水渠大量修建之后,由于水文条件的改变,导致湿地类型的演替和湿地格局的变化。沼泽地因排水基本消失,草甸及其他沼泽类型也大片被排干,取而代之的是大面积的旱地等非湿地景观,湿地以小的斑块体镶嵌其中。文章最后提出下一步的研究工作。

The Bielahong river watershed, as a typical wetland watershed, in the Sanjiang Plain of Northeast China, had its more than 90% of the area covered by wetland landscape before the initiation of the drainage works. During the past 40 years, the rapid development of drainage works in the watershed resulted in the change of watershed eco-hydrological pattern and water level in wetland, and about 80% of the wetlands have been lost in the Bielahong river watershed. In this study, based on relief map and land use map, according to the theory and methods of landscape ecology, using the GIS techniques software, the land use/wetland landscape map is compiled. We first analyzed the intensity of drainage works in different parts and different periods of the watershed, and found that the effects of drainage channels were different. The wetland landscape in the upper and middle reaches of the river changed greatly before 1983, and the lower reaches of the river changed little. After 1983, because of the construction of greater number of the drainage degenerated channels, the wetland area in the whole watershed decreased, and large parts were and lost. Finally we calculated various landscape metrics of each sub-drainage areas in 1967, 1983 and 2005, using the powerful landscape structure analysis program, FRAGSTATS, including area, patch density and size, diversity and so on. The result indicated that the develop- ment of drainage project is the direct reason for the wetland landscape changes. In 1967, the landscape of the three sub-drainage areas, except dryland without practising drainage works, which had the biggest wetland cover was kept in natural state and had the best environment. Nowadays, all the three sub-drainage areas are dryland, and the remained wetland is only 24. 51%. Quantifying the landscape pattern and its change could provide useful information for effective monitoring, assessing and managing wetland watershed.