Home – Home – Jornals – Contemporary Problems of Ecology 2020 number 4

High-detailed images acquired by means of unmanned aerial imaging allowed for description of certain type of thermokarst depression structural features. These depressions developed in yedoma deposits in southern part of typical tundra subzone in Lena Delta. Geomorphology and vegetation of the model depression were characterized by the combination of GIS-analysis and ground survey. Detailed mapping showed that the surface of the depression bottom consists of “baidjarakh” field covered by the complex vegetation of highly productive plant communities dominanted by grasses and graminoids. Comparison of satellite images and topographic maps from different years showed that depression appeared from the shallow thermokarst lake drained not later than 40 years ago. Depression terrain and vegetation are determined by its origin and the composition of surface geological substrate. Depression vegetation is quite contrast to zonal tundra by its structure and floristic composition. It contains few species which tend to be more typical for southern distribution. Such spots serve as feeding places for herbivorous animals and in the past could be an important part of the Pleistocene megafauna forage. Thermokarst events were typical for the ice-complex through the whole period of its formation, but might differ in intensity and area depending on climate conditions. Nowadays size and lifetime of thermokarst lakes depends on their position in terrain and thermoerosion intensity. In tundra landscape thermokarst plays an important role in creation of new habitats and plants and animals biodiversity support.