Short term change detection in tundra vegetation near Umiujaq, subarctic Quebec, Canada

Local vegetation changes since the last 20 years are being investigated at the transition zone between the subarctic and the arctic region in Nunavik (Quebec, Canada). By using high resolution aerial photographs acquired at the end of summer 1994 and 2010 and image processing techniques, we established the dominant vegetation changes and created a ≪ from-to ≫ vegetation map. Results show a significant increase in shrub dominated cover and a loss of lichen dominated zones. Number and area of ponds have also diminished over time. Moreover, according to the change detection analysis, all major vegetation classes had the largest shift in favour of the shrub class. Thus, the final change map illustrates the general shrubification ongoing in the region and pinpoints permafrost degradation zones as principal areas affected by the expansion of shrubs.