Stages of Restoration of the Components of Postagrogenic Pine Forest Ecosystems in the Smolenskoye Poozerye National Park

摘要

The rural depopulation of Russia was accompanied by the abandonment of arable lands and natural reforestation. The aim of our work was to study soils and phytocenoses of six stages of pine forests restoration on the coarse-textured parent materials in the northwest of the Smolensk region. Data on the 18 key sites characterizing these stages in triplicate were obtained. We found agrozems (Arenosols (Aric)) with a thick arable horizon and a minimum abundance and biomass of macrofauna represented mostly by phytophages and saprophages under agrocenoses and a 1-year-old fallows. At the second stage of a fallow meadow, gray-humus soils (Arenosols) and postagrogenic soddy podzols (Entic Podzols) were identified. Their morphological features did not differ much from those in the postagrogenic soils at the first stage. However, the biomass of macrofauna gained maximum due to intense colonization of the open meadow biotopes by insects. Young (up to 30 years) pine forests characterized the third stage of a postagrogenic succession. At this stage, in ten years old forests, litter and protohumus horizons were formed in the soils. Under the middle-aged (70-80 years) pine forests, the soils displayed clear signs of eluviation processes and were classified as postagrogenic soddy podburs. In their macrofauna, the share of litter-dwelling animals somewhat decreased. Spruce eventually replaced pine with the formation of complex spruce forests older than 80 years. At this stage, the smooth lower boundary of the former plow horizon completely disappeared from the soils, though the podzolized (albic) horizon was not formed yet. The maximum biomass of macrofauna was found in the litter. The final sixth stage corresponded to the dwarf shrub (cowberry)-green moss pine forests of older than 90 years developing on podzols (Albic Podzols) with degrading remains of the former plow horizon. Litter macrofauna predominated in these soils, but its biomass was less than that at the previous stage. The soils of the fifth and sixth stages developed under forests of the similar age and differed in the degree of manifestation of Al-Fe-humus podzolization in the soil profile with the appearance of eluvial (albic) horizon at the sixth stage.