苏北侵蚀型海岸湿地景观时空演变特征及驱动机制

Temporal-Spatial Variation of Erosional Coastal Wetland Landscape in North Jiangsu and Its Driving Forces

  • 摘要: 运用RS、GIS技术和景观生态学方法,对盐城国家级自然保护区侵蚀型海岸湿地1987、1997和2007年3个时相的景观数据进行分析,辨识侵蚀型海岸湿地景观格局时空演变特征。结果表明,1987-1997年,研究区光滩面积比例由76.91%下降至58.37%,碱蓬湿地由18.68%下降至5.51%,芦苇湿地由4.42%上升至13.01%,并出现了米草湿地和养殖池景观类型,1997年其面积比例分别为13.35%和9.76%。1997-2007年,碱蓬湿地退化消失,养殖池减少,芦苇湿地、米草湿地、光滩面积增加,其比例分别为15.85%、14.50%和60.86%。就景观异质性而言,多样性指数先升后降,景观优势度持续下降。景观空间演替呈现单向性特征:1987-1997年,从陆地向海洋方向演替;1997-2007年,从海洋向陆地方向演替。海岸地貌过程和植物覆被类型的连续变化导致湿地景观演变呈连续变化,但干扰往往使生态过程的连续性发生改变。

     

    Abstract: With the aid of the technologies of RS,GIS and landscape ecology,landscape data of the erosional coastal wetland of Yancheeng Nature Reserve in 1987,1997 and 2007 were analyzed to characterize spatial-temporal variation of erosional coastal wetland landscape.It was fornd that during the period from 1987 to 1997,the area of bare shoals decreased from 76.91% to 58.37% in proportion and that of salsa wetlands from 18.68% to 5.51%,while that of reed wetlands increased from 4.42% to 13.01%,and that of spartina wetlands and aquicultural ponds appeared accounting for 13.35% and 9.76%.During the period from 1997 to 2007,salsa wetlands degraded and then vanished,breeding pools decreased in area while reed wetlands,spartina wetlands and bare shoals increased in area,accounting for 15.85%,14.50% and 60.86%,respedtively.In terms of landscape heterogeneity,its landscaped diversity index rose first and then fell,and its landscape dominance index continued to decline.The spatial succession of the landscape displayed a mono-direction feature.In the years from 1987 to 1997,the landscape evolved from land to sea; while in the years from 1997 to 2007,it did reversely.Under the influence of ocean tides,continuous changes in geomorphic process and successinon of the vegetationlead to continuing succession of the weland landscape.However,external ingerfernce tend to disrupt the continuity of the ecological processes.

     

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