Climate-driven “greening” of the kurum landscape in the valley of the lower reaches of the Podkamennaya Tunguska river

Abstract

The paper considers changes in the biological productivity of the landscapes recorded in the Yenisei Siberian taiga kurums associated with climate warming of mid-1970s to early 1980s. Specifically, changes in NDVI (as an indicator of plant-mass productivity) from 1992 to 2018 were assessed within representative sites of the key study area located in the west of the Central Siberian Plateau. To study the bioproductivity dynamics and the current state of kurum landscapes, 30-meter resolution satellite images—Landsat 4.5 (TM), 7 (ETM+), and 8 (OLI) series—with atmospheric correction (Landsat Surface Reflectance) were used. Refinement of data on individual kurums was carried out with the help of WorldView-1 (2.4 m) and PlanetScope (3 m) multi-zone images. From the end of the first decade of the 21st century to 2019, NDVI increased by 0.38 units, on average. This is manifested in a larger area under moss cover, spread of shrubs and small-leaved species undergrowth, and emergence of sparse stands. The data calculated from processing of the 30-meter resolution satellite images (Landsat) exhibit a high-degree correlation with the results obtained by using higher-resolution analogous images (WorldView-1 and PlanetScope). It appeared that the cold-exposure slopes covered with block accumulations were more responsive to the growth of plant-mass. The results of remote-sensing data processing allow for a field-based extrapolation within a large and genetically unified territory. It was revealed that the intensity of kurums “greening” in the considered middle taiga area is comparable with the increase in NDVI in even higher latitude regions (north taiga, forest-tundra, and tundra) of Central Siberia.