Clay Minerals in the Loose Substrate of Quarries Affected by Vegetation in the Cold Environment (Siberia, Russia)

Pioneer plant communities play an important role in the process of parent substrate colonization by biota and a successful restoration of ecosystem as well, especially in the first stages of recovery successions. The aim of the present research is to study the influence of plant communities of the initial stages of primary succession on the mineral composition of substrates from sandy quarries situated in the forest-tundra zone to understand the specificity of substrate transformation initiated by vegetation, Western Siberia close to the town of Labytnangi. Sandy substrate was quarried here in former open woodlands, in communities with spruce, larch, and birch in the overstory and dwarf shrubs, mosses, and lichens in the ground layer. The time of vegetation development in quarries varies from 15 to 40 years. In substrates, pH values decrease simultaneously with the rise of moistening as well as plant canopy closure, which also influences the moistening. Clay size fraction of all samples is characterized by the same mineral association, as follows: highly smectitic clay, minerals of the mica group, chlorite, and kaolinite. In addition, traces of quartz were also identified. According to our findings, the changes in substrate mineralogy affected by the plant community decrease from mosses (reduced proportion of highly smectitic clay and transformation of chlorite into random mixed-layer chlorite-smectite), lichens (reduced proportion of highly smectitic clay), and vascular plants (absence of changes).