Monitoring vegetation changes on Finnmarksvidda, Northern Norway, using Landsat MSS and Landsat TM/ETM+ satellite images

摘要

During the 1980s the reindeer population in Finnmark expanded from about 100;000 animals to more than 200;000. The result was a considerable decline in lichen cover; a significant decrease in reindeer body-weights; increased mortality rates; especially during winters; and low calving capacity for several siidas/districts. The decline in lichen cover on Finnmarksvidda was monitored using Landsat MSS images from 1973 and 1980 and Landsat TM/ETM+ data for the years 1987; 1996 and 2000. The decline in lichen cover is expressed through vegetation maps produced for each year. In the most favorable winter district; lichen-rich vegetation covered more than one third of the total area until 1980. In 1987 this amount was decreased to 1376 km2; representing25.2 percent of the total area. In the years 1996 and 2000 a further decline to 11.9 and 6.0 percent occurred. In the same period; vegetation types without lichen cover increased correspondingly. This project demonstrates the advantage of using remote sensing data in mapping and monitoring the reindeer winter ranges. The research fundamentals of the project are based on the ability to detect lichen-rich communities in satellite images; and to distinguish them from other community types. This distinctionis mainly obtained in the visible part of the electromagnetic spectrum.