Forest Litter in Middle-Taiga Pine Stands of Eastern Fennoscandia: Chemical Composition and Its Spatial Heterogeneity.

Forest litter is an important component of taiga ecosystems. Transformations of its parameters, including changes in chemical composition, are of utmost scientific interest due to the high spatial variability of litter even within the same forest type. The purpose of this study is to examine concentrations of macro- and microelements in forest litter and identify patterns in their changes at two levels: (1) the elementary geochemical landscape (EGCL) and (2) the plant microgroup (PMG). The field studies are conducted in the Kivach State Nature Reserve located in the middle taiga subzone of eastern Fennoscandia (Republic of Karelia). A landscape–geochemical catena is established on a smooth slope of an esker ridge in a pine habitat formed on sandy fluvioglacial deposits. The total content of mobile forms of macro- (K, Mg, and Ca) and microelements (Mn, Zn, and Cu) in forest litter subhorizons is analyzed. The results indicate that concentrations of K, Mn, Zn, and Cu vary significantly at all studied structural–functional levels of territorial organization. Concentrations of Mg and Ca vary less significantly. An analysis of variance applied to the data show that the effect of the selected factors (EGCL and PMG) on changes in concentrations of most macro- and microelements is statistically significant (p ≤ 0.05). The dynamics of most of the studied elements can be described with a high degree of reliability (R²) by a second-order polynomial curve. An inverse linear correlation between the concentration and location in the EGCL system is identified only for potassium. On watersheds (eluvial EGCLs) and upper slopes (transeluvial EGCLs), the forest litter is distinguished by the accumulation of potassium, magnesium, zinc, and copper compared to subordinate (transaccumulative and accumulative) EGCLs. A different pattern is identified for calcium and manganese: their maximum concentrations are typical for forest litter underlain by soils formed on slopes under transit conditions, and the high content of these elements is determined primarily by their high concentrations in the predominant plant species: European blueberry. [ABSTRACT FROM AUTHOR]