Wetland Vegetation Change Detection, Walpole Island, Ontario

摘要

Walpole Island in Southern Ontario has extensive cattail marsh distribution. However, in recent years, the invasion of fast spreading Phragmites is affecting the ecosystems and wildlife habitat. In this research, a series of optical satellite images, including Landsat TM, SPOT and IRS, were examined to monitor the recent growth of Phragmites and to locate the areas subject to the loss of cattail. The post classification comparison method was applied for change detection. Textural classification of a single-elate Radarsat image was used to resolve the cloud cover effect on the Landsat TM data. Maps showing the loss of cattail to Phragmites were created for different years. These maps were combined and a final map showing the total loss of cattail to Phragmites in five-year period from 1992 was generated. Results indicated that all three sources of satellite imagery can be used for wetland vegetation change detection in marsh wetlands. This study also showed a successful application of Radarsat data to resolve the cloud cover problem in optical data.