象山港流域景观生态风险格局分析

Patterns of landscape ecological risks in Xiangshangang Bay Basin of China

分析评估海岸区域的生态景观和生态风险,对维持海岸带资源环境的可持续发展有重要意义。以1985、1995、2005及2014年4个时期的TM遥感影像为象山港流域景观格局分析的主要数据源,构建景观生态风险格局演变模型,对流域生态风险的时空特征进行分析。结果表明:(1)1985-2014年,研究区内景观结构发生了较大的变化,耕地、林地以及滩涂面积均呈减少态势,建设用地、未利用地和养殖用地及盐田面积呈增加态势;(2)近30年来,研究区内的景观生态风险在时间演变过程上发生了显著变化。1985年,象山港流域景观以低、较低等级生态风险区为主,分别占全区总面积的48.01%和34.35%,1995年低、较低等级生态风险区面积均有不同程度减少,中等生态风险区面积显著增加。至2014年,低生态风险区面积进一步减少,而高、较高生态风险区面积增加明显;(3)从风险格局演变来看,1985-2014年象山港流域景观低、较低等级生态风险区不断向流域上游迁移,面积呈减少趋势,中等、较高和高生态风险区在沿海地区不断扩展,侵占生态风险等级相对较低区域,以沿海平原的淤泥质海岸尤为典型。

To analyze and assess the ecological landscapes and the ecological risks of the coastal areas, it has a great significance for maintaining the sustainable development of the coastal natural resources and environment. Taking TM remote sensing image of 1985, 1995, 2005 and 2014 four periods as the main data source for the analysis of the landscape pattern in Xiangshangang Bay Basin, the paper constructed the evolution model of the pattern on landscape ecological risks and made an analysis on the spatial and temporal characteristics of river basin ecological risks. The results show that：（1）From 1985 to2014, major changes of the landscape pattern have taken place in the study area. The arable land, woodland and tidal flat take on a downward trend while the construction land, unused land, farming land and salt field tend to have an increasing momentum;（2） In recent 30 years, the regional landscape ecological risk has changed dramatically in the course of time evolution. In 1985, the ecological risk areas of low and lower levels took a large part in Xiangshangang Bay Basin landscape, covering 48.01 % and 34.35 % of the total area of the district respectively. By the end of 1995, the sizes of ecological risk areas of low and lower levels reduced in different pace, and the size of medium ecological risk area increased significantly. In 2014, the area of low ecological risk had a further fall while the area of high and higher ecological risks increased conspicuously;（3） On the evolution of the risk pattern, from 1985 to 2014, the ecological risk area at low and lower levels of Xiangshangang Bay Basin landscape was constantly shrinking to the upstream, therefore the size of the area was on the decline. The ecological risk area at medium, high and higher levels expanded constantly in the coastal region, occupying the ecological risk area of low level and the muddy coast in the coastal plain was the typical case.