Dynamics of the Overgrowth of Dry Sand Quarries in the Northern Taiga Conditions of Western Siberia for the Period from 1985 to 2021

Aim. One of the negative environmental consequences of the active development of the oil and gas industry in the northern part of Western Siberia is the formation of disturbed lands, which occur, among other reasons, during the extraction of sand and sand-gravel mixtures. The aim of this study is to conduct a remote assessment of the spatial and temporal distribution of dry sand quarries and the dynamics of their natural overgrowth over the past 40 years, using a model site in the Nadym River basin as an example. Methodology. The research objects are dry sand quarries formed during the construction of railways, highways, as well as main gas and oil pipelines. The initial data included multi-temporal satellite images from Corona (1968 and 1976), Landsat-5/7/8 (1984–2023), and Sentinel-2 (2017–2020). Calculations of the annual median NDVI values for each quarry, based on the Landsat data archive from 1985 to 2021, were performed using the Google Earth Engine platform. Methodologically, the work involved digitizing and attributing linear infrastructure objects, identifying and delineating the boundaries of the quarries, determining the degree of flooding, background landscape type, and the formation time of each quarry. Zonal statistics calculations were also performed using ArcGIS Desktop and MS Excel software. Results. A total of 343 dry sand quarries were identified, primarily located along highways and main pipelines. Based on their age, the quarries are divided into four generations, reflecting different stages of the region’s economic development. The peak of land disturbance was observed during the construction of paved roads in the second half of the 1980s. It was found that the success of quarry revegetation directly depends on their age and location type. Specifically, the highest NDVI values (0,63) were found in first-generation quarries formed more than 70 years ago in dense mossy forests, while the lowest values (0,36) were observed in younger quarries located along pipelines in lichen woodland areas. In quarries situated in dense green moss forests, the background NDVI level as of 2021 had not yet been reached, despite favorable forest growth conditions. Meanwhile, in quarries located in dry pine-lichen woodlands, NDVI values comparable to or exceeding the background level were recorded due to improved moisture conditions. Research implications. Overall, it was established that in the modern climatic conditions of the northern taiga in Western Siberia, there is a statistically stable trend of natural vegetation recovery in quarries over the past 40 years, regardless of the effectiveness of the biological stage of reclamation. The results obtained can be used to optimize and improve the efficiency of methods for restoring soil and vegetation cover on disturbed areas within the studied region.