The influence of abiotic factors on overgrowth of lakes in the protective zone of the Saralinsky section of the Volga-Kama nature reserve

Abstract

The study analyzes the influence of abiotic factors on the overgrowth of higher aquatic vegetation in lakes of various origins within the protective zone of the Saralinsky section of the Volga-Kama Nature Biosphere Reserve. The work examined 94 parameters, including morphometric characteristics of the lakes, physicochemical properties of bottom sediments, and hydrochemical indicators. Statistical data processing with Spearman's correlation coefficient revealed key patterns. The proportion of the littoral zone correlates with the accumulation of nitrogen (r = 0.77, p ( 0.05) and organic matter in bottom sediments (BS), which stimulates vegetation development. The granulometric composition of the sediment affects plant distribution: cattails dominate in silty sediments (correlation with clay: r = 0.72, p ( 0.05), while reeds thrive in sandy sediments. As lake area increases, the concentration of pollutants (ammonium, nitrates, phenols, COD) decreases due to the dilution effect (r = -0.62 to -0.74, p ( 0.05). Heavy overgrowth (50-95% of the water area) is associated with eutrophication, increased pH in bottom sediments and water (r = 0.61-0.71, p ( 0.05), and phenol accumulation in water (r = 0.81, p ( 0.05)