Abstract

The article discusses the results of soil and geobotanical studies at the plots on the coastal plain of the Caspian Sea (Northern Dagestan) of different ages: 1340 ± 36 years calBP (Kaspii-1) and 293 ± 13 years calBP (Kaspii-2). Changes in the biodiversity of the vegetation cover and the soil-salinity variation over time are assessed. It is shown that the variability of soil salinity (range, quartile scale, and standard deviation) at the local level (areas of nonuniformity with linear dimensions of meters or tens of meters) has increased, while the parameters of vegetation biodiversity (floristic richness, the species number, the family number, the number of long-vegetating herbaceous perennials and ephemers, the presence of species with different salinity tolerance, and differentiation of the intracoenotic diversity) have decreased. The plot with a Tamarisk community (Kaspii-2) is characterized by a statistically significant, moderate correlation (R² = 0.29) between soil salinity and vegetation based on data on the distribution of dominant species, whereas this correlation is not significant on the older plot with a saltwort-suaeda community (Kaspii-1). The data show that, when the area dries up after sea regression, the variation in soil properties (salinity) and vegetation changes in different directions: the variation in soil salinity (functional pedodiversity) increases with age, while the variation in vegetation (phytodiversity) decreases. Moisture availability is obviously the main factor limiting the biodiversity on the older plot on the background of high salinization of soils on the both plots as evidenced with the smaller moisture reserve in the top 1-m soil layer on the older plot.

中文翻译：

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里海平原不同年龄地区土壤盐分和植物多样性的变化

摘要

本文讨论了不同年龄的里海沿岸平原（北达吉斯坦州）土地上的土壤和地质植物学研究的结果：calBP（Kaspii-1）为1340±36年； calBP（Kaspii-2）为293±13年。 。评估植被的生物多样性变化和土壤盐碱度随时间的变化。结果表明，当地水平（线性度为米或数十米的非均匀区域）的土壤盐分（范围，四分位数尺度和标准差）的变异性增加了，而植被生物多样性的参数（植物丰富度，物种数量，科数，长生草本多年生植物和表观植物的数量，具有不同盐度耐受性的物种的存在以及雌雄同体内物种多样性的减少）。基于优势种分布的数据，土壤盐分与植被之间的R ² = 0.29），而这种相关性在含盐蒿-苏打草群落（Kaspii-1）的旧样地上并不显着。数据表明，当海域回归后该区域变干时，土壤特性（盐度）和植被的变化朝不同的方向变化：土壤盐分（功能性多样性）的变化随年龄增长而增加，而植被的变化（植物多样性）减少。在两个土地上土壤高盐分化的背景下，水分供应显然是限制旧土地上生物多样性的主要因素，这可以从较旧土地上最上面的1-m土层中较小的水分储备中得到证明。