Spatio-temporal Variation and Driving Forces of the Coastal Wetland Resources Based on the Transition Matrix in Jiangsu Province

Jiangsu Province is one of the dominant areas with broad coastal wetland which accounts for 14.2% of the whole coastal wetland in China,and moreover the yearly growth of the shoals are the important potential resources of Jiangsu.Coastal wetland landscape maps of the year 1987,1997 and 2007 were figured from the three related maps.This study mainly investigates the spatio-temporal variation and driving forces of the coastal wetland resources of Jiangsu Province during 1987 to 2007 based on the remote sensing and GIS techniques and the method of conversion matrix.The results indicate: 1) in the past 30 years(from 1987 to 2007) the trend of evolvement of the coastal wetland was that the natural wetland transferred into artificial wetland.The natural wetland area decreased by 247.37km2 and 465.64 km2 respectively in the two periods(from 1987 to 1997 and from 1997 to 2007),while during the whole study period the artificial wetland and non-wetland areas increased by 204.01 km2 and 261.56 km2 respectively.The decrease of the natural wetland is mainly due to the remarkable reduction of reed-swamp and Suaeda-swamp while the Spartina-swamp was increasing as an invasive species during the whole study period.By 1997,the area of Suaeda-swamp had decreased by 33.38%,and the area of it in the year 2007 was just 7.10% of that in 1987.In the first period reed-swamp decreased by 37.97% with an overall decrease of 47.12% by 2007.The increase of the artificial wetland was mainly from the fish pond culture and during the study period it increased by 14.25%.The variations of the non-wetland were the increases in the cultivated land and residential land and the decrease of the forest land.2) What influence the evolution of the coastal wetland resources of Jiangsu Province are the human activities and the invasive species.The factors of human activities are mainly about the national state policies,the expanding populations and the transfer of the industrial model.The expanding of the area of Spartina altemiflora was the vital natural driving force for the evolution of the coastal wetland resources of Jiangsu Province and the invasion of the Spartina altemiflora would restrain other ordinary species to survive.By 2007,the area of Spartina-swamp had increased by 71.94%,becoming a banding landscape in the coastal zone of Jiangsu Province.