| Wetlands are the transitional zone between aquatic and terrestrial ecosystem.As one of the three major global ecosystems coordinated with the ocean and forest,the diversity natural resources and ecological functions provide the material conditions for human survival,which is one of the crucial living environment of human being.In this paper,the remote sensing satellite technology with the advantages of widely regional scale,multi-resolution,multi-temporal,dynamic monitoring of wetland changes,and GIS spatial information processing and analysis functions were utilized.14 scenes Landsat 8 / GF-1 images with multi-sources and multi temporal in 2014 were selected,which were used for extraction of wetland information in Nanjishan Wetland,based on the object-oriented classification method of the eCongnition 8.6 platform,the spatiotemporal distribution information of the wetlands in Nanjishan Wetland was obtained,and the spatio-temporal distribution and seasonal transformation of the different wetland types in the Nanjiashan Wetland Nature Reserve was quantitatively analyzed.This research draw the following conclusions:(1)The object-oriented classification method can integrately utilized the information of the spectrum,texture,shape,context and other information which were contained in remote sensing images,sufficiently mining the image information for extraction of wetlands information in Nanjishan Wetland.The accuracy evalution of wetland classification results indicated that: the Object-oriented classification method can obtain high precision wetland classification results,the classification results can be more reliable and accurate reflection of the current distribution of Nanjishan Wetland.(2)The distribution of Nanjishan wetland displayed obvious spatial and temporal dynamic characteristics.From January to August in 2014,the distribution range of deep water and shallow water occured obvious expansion from north and east to southwest.From September to December,The water area shrink to the northeast of Poyang Lake main lake.The change of grassland range is characterized by the opposite characteristics of the water,From January to April,during the first growing season of grassland in the Nanjishan Wetland;April to September,with the rise of water level in Nanjishan wetland,the range of grassland atrophied;from September to December is the second growing season of Carex grass in the Nanjishan wetland,grassland distribution range appeared the expansion of the centre of Poyang Lake;mudflat is transitional zone of deep water,shallow water and sparse grassland grassland,which presented a ringlike distribution characteristics in the lakeside lowland.(3)Comparing the two groups of correlationship results between water level and wetland area extracted from only 9 scenes Landsat 8 images and the water level and wetland area obtained from Landsat 8 / GF-1 multi-source images in 14 periods,the research indicated that the correlationship between wetland area obtained from 14 multi-source images and water level is remarkable(R> 0.84),and the correlation coefficients with the high confidence level(P<0.001)were verified,and via collecting multi-source multi-temporal images to construct complete time series research data,which were applied to extract the wetland information of Nanjishan wetland,which can more accurately represent the dynamic response of various wetland areas in Nanjishan Wetland to water level.(4)With the seasonal variation of the water level of the Nanjishan Wetland,the distribution of shallow water,deep water,sparse grassland,lush grassland and mudflat area also showed significant dynamic characteristics.In addition,the wetland types of the Nanjishan Wetland have a mutual transformation relationship.The change of spatial distribution pattern of Nanjiashan Wetland from spring to summer is mainly due to the transformation of grassland to water.From Summer to autumn reflect the change of water to grassland.The range of waters continues to decrease from autumn and winter,which is further replaced by mudflat and grassland,And the characteristics of wetland type dynamic transformation are matched with the seasonal change characteristics of which water area expand in flood season but recede in dry season/grassland grow variation with two flourish and two perish seasons. |
PDF Full Text Request