Abstract:
This
study used multispectral data acquired by Landsat satellites and a geographic information systems (GIS) program to evaluate change between 1988 and 1999 at two wetlands areas in Estonia-Endla Nature Reserve and Emaj5e Suursoo Mire Complex. Recent political changes in Estonia make this country a good location for this type of study. Estonia was a Soviet republic from 1944 until it because an independent nation in 1991. After Estonia became at independent nation, many environmental changes were made which should be reflected in improving conditions at the study areas.
GIS analytical techniques such as image differencing, image ratioing, normalized difference vegetation index analysis, tasseled-cap transformation analysis, and correlation analysis, as well as visual comparison ofthe images, were used to evaluate change that occurred between the image dates. Detailed image classification was not attempted due to the lack of georeferenced ancillary data and because no means was available by which error assessment could be performed.
The analyses show that change occurred in both study areas between 1988 and 1999. The most significant change occurred around the periphery of the reserves. The data suggest that Lake End1a had a greater biomass concentration in 1988 than in 1999. The water level of Lake Peipsi appears to have declined prior to the acquisition of the 1999 data. Vegetation appears more vigorous at both study areas in 1999 than in 1988. In general, the bogs themselves appeared to have been stable over the time period covered by the study.
The use of a GIS program and remote sensing data proved useful in identifying change in Estonian wetlands. The remote sensing data would need to be augmented with larger scale data in order to perform more detailed analyses.
