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The influence of catastrophic forest fires in 2021 on the vegetation cover and soils of the middle taiga on the territory of distribution of light soil-forming rocks of Central Yakutia has been studied. Obtained results showed the cardinal dynamics of species diversity and productivity of the larch and pine forests surface vegetation in their natural state and in burnt areas. The stock of grass-shrub cover aboveground phytomass on the control larch and pine forests is higher for 5 and 10 times than that in the burnt areas, respectively. The work carried out revealed the effect of forest fires on the morphological structure (formation of pyrogenic layer, manifestation of pyro- and cryoturbations), the depth of thawing, the water regime of permafrost soils under larch and pine forests on control and burnt sites in the first year after strong fires. The soils in the study area are predominantly permafrost illuvial-ferruginous podzols. The study revealed an increase in the permafrost table depth of these soils, an increase in the level of ground water, and a decrease in acidity in the upper part of the profile. Intense ash formation was found due to the burning of litter. The characteristic of the current state of vegetation and soil cover is given.

Abstract Recent increases in global temperature have stimulated permafrost degradation associated with landform deformation caused by the melting of excess ground ice (thermokarst). Central Yakutia is underlain by ice-rich continuous permafrost, and there are complicated permafrost-related features in forested and deforested areas. This situation makes thermokarst monitoring necessary over a wide area to achieve a better understanding of its dynamics. As a case study, we applied L-band InSAR analysis to map surface subsidence due to thermokarst in this area and to demonstrate the suitability of L-band SAR for such monitoring. Our results show that InSAR detected subsidence/uplift signals in deforested areas and alasses; whereas, there were few ground deformation signals in forested areas with middle coherence. The InSAR stacking process, including both seasonal and inter-annual displacements, showed subsidence in deforested areas during 2007–2010 and 2015–2018, in the range of 0.5–3 cm yr−1. We also estimated the inter-annual subsidence to be up to 2 cm yr−1 during 2015–2018, using InSAR pairs that spanned the same seasonal interval but in different years. The magnitude of subsidence and the spatial patterns are qualitatively reasonable as thermokarst subsidence compared to observations using field surveys and high-resolution optical images. L-band InSAR was effective in maintaining coherence over a long period for a partially forested thermokarst-affected area, which resulted in deriving the inter-annual subsidence by the stacking using four interferograms. The advantage of the persistent coherence in L-band InSAR is crucial to better understand thermokarst processes in permafrost regions.

Alas landscapes are unique ecosystems, which are dynamic, geochemically closed thermokarst landforms of the permafrost zone. Alases have a limited capacity in their active layer, and specific conditions for soil, flora and fauna formation. A comprehensive study of alas landscape functionswas carried out in Central Yakutia from 1988 to the present time using conventional methods of geobotany, zoology, entomology, etc. This paper presents long-term observations of lake fluctuation cycles and changes in the spatial structure of meadow spaces. The dynamics of the spatial structure lead to significant fluctuations in the productivity of alas phytocenoses. It was revealed that wet and normal alas meadows have the highest vegetation productivity. The long-term course of their productivity tends to decrease, which shows the influence of anthropogenic pressure since the main haymaking areas are located in these meadows. With sharp fluctuations in interannual weather conditions, which determine the microclimatic and soil characteristics of grass growth, the productivity of the edge phytocenoses tends to increase. The productivity of the steppe phytocenoses of the alas remains practically at the same level. Over the years of observation, the economic capacity of alas pastures and hayfields was calculated. Additionally, the paper presents the important role of fauna within closed alas ecosystems, which directly affects the functioning of alas landscapes and is directly involved in soil formation and the circulation of matter and energy.

This article is devoted to the study of the distribution of ground ice volumes in the upper layers of 5–10 m permafrost in the permafrost landscapes of Arctic Yakutia. Compilation of such a map will serve as a basis for assessing the vulnerability of permafrost to global warming, anthropogenic impact and forecasting the evolution of permafrost landscapes. The map was compiled using ArcGIS software, which supports attribute table mapping. The ground ice map of Arctic Yakutian permafrost landscapes shows that about 19% of the area is occupied by ultra ice-rich (above 0.6 in volumetric ice content) sediments. Very high ice volumes (0.4–0.6) are cover approximately 27%, moderate ice volumes (0.2–0.4)—25% of the area, and low ice volumes (less than 0.2)—about 29% of Arctic Yakutia.

Central Yakutia is in one of the most northern agricultural centers of the world. In this territory a notable area of arable land was made by removing the boreal Taiga with the primary purpose of crop cultivation. Such a method of cultivation significantly changes soil total carbon (STC, soil organic carbon + soil carbonate carbon) balance, because of the destroyed upper humus horizon. Soil organic carbon (SOC) of cultivated arable lands is almost a half of that in forest. In abandoned arable lands with grass vegetation, the recovery of SOC has increased to 30% in comparison with cultivated arable lands. On arable lands recovering with new growth of trees, the SOC is related to the abandonment period. Soil carbonates carbon (SCC) content was significantly lower than SOC and showed significant difference among abandoned and other types of arable lands. Objectives of this study are to identify how STC stocks change in response to conversion of the forests to agricultural land and to analyze the arable land system’s recovery process after abandonment. Furthermore, after transformation of forest to arable land, a significant decrease of STC was observed, primarily due to mechanical loss after plant residue removal. It was also identified that the restoration and self-recovery of STC in abandoned arable lands of Central Yakutia continuously and slightly increase. Grass vegetation regenerates STC for 20 years. While the difference of average STC of forests and cultivated arable lands reached 41%, a new growth of forest on some abandoned arable land follows the tendency of STC decrease due to a low productivity level and suppressing effect on grass vegetation.