A Study On The Changes Of Coastal Wetland’s Landscape Patterns Based On RS/CIS

The coastal wetland is one important type of wetlands. It is the transitional zone betweenthe land and the sea. Affected by the land and the sea forces, the wetland ecosystem enjoysenormous ecological pressure, which makes the coastal wetland a highly dynamic, complex,and fragile eco-region. The coastal wetland has a complex landscape structure and a diverseecosystem. It is a region where the natural factors and the human factors co-function. Underthe severe influence of the human factors, the landscape structure changed dramatically,making it one of the most severe damaged places by human activities. In the last50years, thewetlands in China degraded severely. Due to land reclamation and aquaculture, the area ofwetlands is shrinking constantly, the landscape fragmentation is getting more obvious, all ofwhich have a severe impact on the harmonious development of the human being, the livingcreature, and the environment.This study selects the coastal wetlands of the Wafangdian city as the research object. Onthe basis of landscape ecology, and combined with the RS and the GIS technology, this studytries to analyze the changes of the coastal wetland’s landscape patterns of the Wafangdian city.In the study, four images taken by LANDSAT5TM in September1995and in July2009areused. First, use the RS technology to do a series of processing work to remote sensing images.According to the needs of the study, select the informative waveband5,4,3to compoundpseudo colors. This research refers to the data of present land use and the wetlandclassification system; with the support of ENVI, use the Maximum Likelihood Method toclassify the remote sensing images, thus extract the data of the coastal wetlands of theWafangidian city. Second, use the GIS function to do the spatial overlay analysis, count thedata and calculate the transition matrix from the changes of coverage of the various types ofwetland, and then make the distribution map of the changes of coastal wetland’s landscapepatterns of the Wafangdian city in1995and2009. Finally, use landscape analysis softwareFRAGSTATS3.3to calculate each wetland landscape Index. By analyzing the changes of thecoverage, the transition matrix and the landscape pattern index to reveal the changes ofcoastal wetland’s landscape patterns of the Wafangdian city in the last14years.The study shows that in either1995or2009, for natural wetlands, coastal woodland andcoastal grassland cover most area of the coastal wetlands; for constructed wetlands, pondfarming covers most of the area. But from1995to2009, the proportion of wetland landscapetype changed dramatically. The proportion of coastal woodland and coastal grassland droppedsharply, at the decline rate of7.47%and8.88%respectively. The proportion of pond farming and paddy field increased rapidly, take pond farming for example, the coverage of it increasedfrom5.19%to10.56%. The coverage of non-wetland also increased dramatically, at a rate of11.46%. What’s more, for natural wetlands, the coverage of marshland and mudflat droppeddramatically. From1995to2009, the coverage of marshland decreased1283.69hm~2, andmudflat decreased5483.41hm~2. From the data we can draw the conclusion that under theinfluence of increasing human activities, a large number of coastal wetlands are transformingor have been transformed into non-wetlands. The coverage of coastal wetlands shrunkdramatically, accompanied with a serious degradation. Meanwhile, human activities such asthe construction of cities and towns, farmland reclamation, and marine reclamation arechanging the wetlands landscape patterns significantly. The degradation of wetlands is gettingmore and more severe, the heterogeneity of the landscape is increasing, the connectivitybetween patches is reducing, and the scale of landscape is getting more and more dispersed,with the trend of changing from planar, liner to tufted, scattered, and stripped.