Land cover succession for recently drained lakes in permafrost on the Yamal Peninsula, Western Siberia

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 land cover unit retrieval scheme developed specifically for the Arctic tundra biome. The complementarity between land cover units and Normalized Difference Vegetation Index (NDVI) analyses is shown. Land cover units were linked to DLB ages (years passed since a drainage event occurred). The data were divided into bioclimate subzones, and the land cover units were grouped according to their characteristics, first related to vegetation and second to wetness gradients (dry, moist and wet). Regression analyses of NDVI values and fraction of each land cover 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) between NDVI and the fraction of the "Wet"group. The inconsistency in the association between those variables underlines the need to complement NDVI analyses with a scheme representing wetness, such as the use of land cover units to describe changes in wetland areas. Finally, our results showed different trajectories in the succession of land cover units in recently drained lake basins with respect to different bioclimate 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 1 % for all subzones after 5 to 10 years since drainage. The results of this study contribute to an improved understanding of DLB land cover change in permafrost environments and to a better knowledge base of these unique and critically important landforms.