## 2 Materials and Methods  
### Site Description  
Study sites are located within the Prioksko-Terrasny Nature Biosphere Reserve (Moscow region, Russia) near the integrated background monitoring of environmental pollution station (IBMon; \(54^{\circ}54.148^{\prime}\) N, \(37^{\circ}33.377^{\prime}\) E). The first site (Figure 1a) was located in the native mixed forest (>130 years; _Pinus sylvestris_, _Tilia cordata_, _Populus tremula_, _Picea abies_, _Acer platanoides_, _Betula_ spp.). The forest stand had formed during natural reforestation after pine logging in the 1930s [28]. The second site (Figure 1b) was located at a distance of 100 m on the moving grassland (>50 years developed) with a polydominant association (_Alchemilla_ sp., _Viola tricolor_ L., _Trisetum flavescens_ ([PERSON] [PERSON], _Runex acetone_ L.). The soil was classified as a weak differential Entic Podzol (Arenic) [29] on sandy alluvial-glacofluvial deposits of the Oka glacid fluvial alluvial plain (Figure 1a,b). The soil texture of topsoil (0-10 cm) is sandy loam with clay-silt content (<0.01 mm) of 8.4-9.4% and sand for the deeper soil layer (10-30 cm). The thickness of litter horizon in the forest is approximately 2-3 cm, and litter storage amounts to 550 \(\pm\) 120 g C m\({}^{-2}\). In contrast, the litter horizon in grassland is shallow and sparse, with a storage of approximately 100 \(\pm\) 17 g C m\({}^{-2}\). Soil under grassland has a well-developed sod horizon (Ah) at a depth of 0-10 cm. The soils of the two ecosystems showed no marked differences in their properties (Table 1). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Place**} & **Depth** & **pH** & **Bulk Density** & **C\({}_{\text{org}}\)** & **N\({}_{\text{tot}}\)** & **C\({}_{\text{mic}}\)** \\  & **cm** & **g cm\({}^{-3}\)** & **g kg\({}^{-1}\)** & **g kg\({}^{-1}\)** & **C/N** & **mg kg\({}^{-1}\)** \\ \hline \multirow{4}{*}{Forest} & 0-5 & 5.03 \(\pm\) 0.12 a & 0.93 \(\pm\) 0.05 a & 35.13 \(\pm\) 3.42 a & 2.23 \(\pm\) 0.15 a & 15.6 \(\pm\) 0.6 a & 150 \(\pm\) 35 ab \\  & 5-10 & 4.15 \(\pm\) 0.12 bc & 1.39 \(\pm\) 0.06 b & 16.59 \(\pm\) 0.94 c & 1.20 \(\pm\) 0.10 b & 13.9 \(\pm\) 0.8 a & 85 \(\pm\) 11 bc \\  & 10-20 & 4.01 \(\pm\) 0.11 c & 1.32 \(\pm\) 0.05 b & 7.85 \(\pm\) 0.84 de & 0.55 \(\pm\) 0.05 cd & 14.2 \(\pm\) 0.9 a & 42 \(\pm\) 9 c \\  & 20–30 & 4.06 \(\pm\) 0.15 c & 1.50 \(\pm\) 0.08 b & 4.00 \(\pm\) 0.58 e & 0.30 \(\pm\) 0.04 d & 13.4 \(\pm\) 0.2 a & 34 \(\pm\) 4 c \\ \hline \multirow{4}{*}{Grassland} & 0-5 & 4.51 \(\pm\) 0.03 b & 0.93 \(\pm\) 0.07 a & 25.34 \(\pm\) 1.25 b & 2.34 \(\pm\) 0.19 a & 10.9 \(\pm\) 0.5 b & 211 \(\pm\) 11 a \\  & 5–10 & 3.97 \(\pm\) 0.05 c & 1.39 \(\pm\) 0.12 b & 11.64 \(\pm\) 0.28 cd & 1.21 \(\pm\) 0.04 b & 9.6 \(\pm\) 0.3 b & 83 \(\pm\) 2 bc \\ \cline{1-1}  & 10–20 & 4.00 \(\pm\) 0.04 c & 1.53 \(\pm\) 0.04 b & 8.01 \(\pm\) 0.57 de & 0.84 \(\pm\) 0.06 bc & 9.5 \(\pm\) 0.1 b & 43 \(\pm\) 1 c \\ \cline{1-1}  & 20–30 & 4.10 \(\pm\) 0.05 bc & 1.56 \(\pm\) 0.06 b & 4.00 \(\pm\) 0.41 e & 0.44 \(\pm\) 0.04 cd & 9.0 \(\pm\) 0.2 b & 31 \(\pm\) 2 c \\ \hline \hline \end{tabular} \(\pm\)standard error (n = 3–4). pH was measured in KCl (1 M). Organic carbon (C\({}_{\text{org}}\)) and total nitrogen (N\({}_{\text{tot}}\)) contents were determined by the dry combustion method (LECO-932, St. Joseph, MI, USA). Microbial carbon (C\({}_{\text{mic}}\)) was analyzed by the substrate-induced respiration method [30]. Different letters indicate pairs of average values, the differences of which are detected during the multiple comparison procedure (Tukey test, \(\alpha\) = 5\(\%\)) after two-way ANOVA (Ecosystem \(\times\) Depth).  
\end{table} 
Table 1: Physicochemical soil properties of the monitoring plots in the forest and grassland. Figure 1: General view of the vegetation and soils within the native mixed forest (**a**) and mowed grassland (**b**) ecosystems, along with chambers for soil respiration measurements during warm (**b**) and cold (**c**) periods.