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

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.