Landcover succession for recently drained lakes in permafrost on the Yamal peninsula, Western Siberia

Abstract

Abstract. Drained Lake Basins (DLBs) are dominant features in lowland permafrost landscapes of the Arctic. Here we present a novel approach describing and quantifying the succession progression of recently drained basins using a landcover unit retrieval scheme developed specifically for the Arctic tundra biome. The added value compared to commonly used Normalized Difference Vegetation Index (NDVI) trend analyses is demonstrated. Landcover units were linked to DLB ages (years passed since a drainage event occurred). The data were divided into bioclimatic subzones and the landcover units grouped according to their characteristics, first related to vegetation and second to wetness gradients (dry, moist and wet). A regression analyses of NDVI values and fraction of each landcover unit group provided the justification for the utility of the units in our research. The regression results showed the highest correlation with NDVI values for the wetness group ‘Moist’ and the vegetation group ‘Shrub Tundra’ (R2 = 0.458 and R2 = 0.444). There was no correlation (R2 = 0.066) found between NDVI and the fraction of group ‘Wet’ . This highlights the importance of an alternative to NDVI such as the use of landcover units to describe wetland area changes. Finally, our results showed different trajectories in the succession of landcover units in recently DLBs with respect to different bioclimatic subzones. Remaining water in the basin after a lake drainage event was highest for the most southern subzone (median 6.28 %). The open water fraction dropped below one percent for all subzones after five to ten years since drainage. The results of this study contribute to an improved understanding of DLB landcover change in permafrost environments and to a better knowledge base of these unique and critically important landforms.