ИСТИНА

Quantifying and understanding catchment sediment fluxes is crucial from both a scientific and an environmental management perspective. To deepen the understanding of land-use impacts and climate change on sediment dynamics, this study explores the factors controlling suspended sediment yield (SSY) in the Caucasus region during the Anthropocene. We analysed long-term SSY data from approximately 200 gauging stations, with a specific focus on the Terek and Kuban River basins. Using statistical approaches including cumulative sum (CUSUM) charts, double mass curves, and Top-Kriging interpolation, alongside repeated reservoir bathymetric surveys, we reconstructed sediment dynamics over the last century. Spatially, the most robust relationship was observed between SSY and topographic factors, specifically the normalised steepness index. Temporally, however, the collapse of the Soviet Union emerged as a definitive breakpoint. In the North Caucasus, mean annual suspended sediment discharge significantly declined following the 1988–1994 transition period. Observed cumulative sediment discharge was reduced by 11–43% compared to extrapolated pre-transition trends. Similarly, in the Western Caucasus, sedimentation rates in the Krasnodar Reservoir peaked during the early post-Soviet period before decreasing, coinciding with major alterations in cropland area. Correlation analyses suggest that while the region has experienced active deglaciation and rising summer temperatures, these hydro-climatic factors played a secondary role in recent decades. Instead, the variation in sediment flux trends is mainly explained by large-scale post-Soviet land-use transformations—specifically the abandonment of arable land and the reduction of grazing pressure in the foothills and lowlands. These findings demonstrate that anthropogenic landscape changes can override climatic signals in controlling sediment dynamics, leading to a marked decline in sediment yield despite enhanced glacial melting. This research was supported by the Ministry of Science and Higher Education of the Russian Federation (Contract No. 075-15-2025-008) under the research programme “Pollutant transport, toxic chemicals and their compounds in river catchments: technologies of studying, quantified assessment and forecast”.