Study On "Source-Sink" Structure Of Non-point Source Pollution In Jiulongjiang Estuary Based On Remote Sensing Technology

For study the relationship between landscape pattern, its changes and non-pointsource pollution in space differentiation and its changes in estuary region, so as toprovide technical support and scientific basis for environmental planning inJiulongjiang estuary region, high resolution remote sensing image in2003and2008had been used in this study and visual interpretation method had been applied toobtain the land use landscape pattern distribution and its dynamic characteristics inJiulongjiang estuary region in these two stages. On this basis, landscape ecologytheory and the theory of sources and sinks were used to analysis the “source-sink”structure of non-point source pollution and its dynamic characteristics in Jiulongjiangestuary region, and landscape pattern optimization recommendations based onnon-point source pollution control had been proposed. The main conclusions are asfollows:(1) Interpretation from high resolution remote sensing images shows, the majorlandscape type in Jiulongjiang estuary region is residential land, paddy field,aquaculture, orchard, glass and forest. Influenced by human activities, these six typesof features of land use had taken obvious change during5years between2003~2008,the paddy field, aquiculture and grass decreased noticeably, while the built-up land,developing land and orchard increased noticeably, the land use change speed was fast.The mainly land use landscape type conversion was orchard, paddy field, aquaculture-developing land; paddy field-aquiculture, built-up land; glass-orchard, forest;developing land-built up land. Spatial distribution of different land use landscapetypes in the slope, relative elevation was regular.(2) The Grid source-sink Landscape contrast Index (mGLCI) analysis, whichbased on land use landscape shows, most part of Xiamen Island and part of the regionnear the riparian zone in Haican, Gangwei and Shima were strong non-point sourcepollution source, while southwest of Xiamen Island, west of Shima were strongnon-point source pollution sink in2003; there were strong increase of non-pointsource pollution source in most part of Haican, east of Jiaomei and the region nearriparian zone in Ganwei. During2003~2008, the minimum value of mGLCIdecreased, mGLCI increased noticeably in Haican, Gangwei and part of Shima,while mGLCI decreased noticeably in the region near the riparian zone in Zini, andpart of Haican, Gangwei and Shima. Non-point source pollution source area increased, while sink area decreased in Jiulongjiang estuary region during2003~2008. TheLocation-weighted Landscape contrast Index analysis (LCI) shows, N, P and NP LCIof distance, slope and relative height in Jiulongjiang estuary region in2003and2008were more than0. For the distance, slope and relative height, the value of N LCI ismore than P LCI. N, P and NP LCI of the distance, slope and relative height isincrease during2003~2008.(3) Put forward landscape pattern optimization suggestion for the non-pointsource pollution prevention. Non-point source pollution can be controlled by thelandscape types, features, landscape spatial difference adjustment and key arearecognition. In this study, we suggested that paddy field, dry land above15degreeconvert to forest, inferior paddy field near the riparian zone convert to forest, increasethe area of mangrove shoal and salt marsh based on landscape land use in Jiulongjiangestuary in2008, and LCI of which was calculated again, the result shows that, thesuggestion reduce the non-point source pollution of Jiulongjiang estuary from estuaryregion to some degree.