Spatial and temporal dynamics of gully erosion in anthropogenically modified forest and forest‐steppe landscapes of the European part of Russia

Abstract

AbstractGully erosion is a major soil degradation process on arable land. Therefore, it is important to better understand the spatial and temporal patterns of this linear erosion process, considering the impacts of land use and climate change. The main objective of this study was to analyse the spatial and temporal patterns of permanent gully development in a study area of 123 300 km2 located in the eastern periphery of the European boreal zone (southern taiga, mixed and deciduous forests and forest‐steppe). In this study, visual interpretation of remote sensing data is used to detect changes in permanent gully channel length and density for each river basin between 1950/1970 and 2017/2021. Currently, 22 688 permanent gullies have been identified in the study area, their average length being 64 m, with the total gully network length reaching 1450.3 km. The average density of the gully network for 2017/2021 is 16 m km−2; the maximum value reaching 471 m km−2. During the period under study (c. 50 years), there was a widespread reduction in gully density by 184 m km−2 on average (i.e. from 100–500 m km−2 in 1950/1970 to <10 m km−2 in 2017/2021). Linear and areal channel changes were determined for 304 active gullies over the 2009/2016 period. The average linear gully growth rate during this period is 0.6 m year−1, whereas the areal growth rate is 28 m2 year−1. There is a clear reduction of gully erosion in the study area. Analysis of the gully network density in relation to land use changes (i.e. cultivated, forest and pasture area) did not reveal any significant relationship. It is concluded that the reduction of gully density in the study area is caused by the natural evolution of these linear erosion forms and their transformation into balkas (i.e. small, dry, flat‐bottomed valleys).