The relative importance of global versus local environmental factors for growth and thus carbon uptake of the bryophyte genus Sphagnum—the main peat‐former and ecosystem engineer in northern peatlands—remains unclear. We measured length growth and net primary production (NPP) of two abundant Sphagnum species across 99 Holarctic peatlands. We tested the importance of previously proposed abiotic and biotic drivers for peatland carbon uptake (climate, N deposition, water table depth and vascular plant cover) on these two responses. Employing structural equation models (SEMs), we explored both indirect and direct effects of drivers on Sphagnum growth. Variation in growth was large, but similar within and between peatlands. Length growth showed a stronger response to predictors than NPP. Moreover, the smaller and denser Sphagnum fuscum growing on hummocks had weaker responses to climatic variation than the larger and looser Sphagnum magellanicum growing in the wetter conditions. Growth decreased with increasing vascular plant cover within a site. Between sites, precipitation and temperature increased growth for S. magellanicum. The SEMs indicate that indirect effects are important. For example, vascular plant cover increased with a deeper water table, increased nitrogen deposition, precipitation and temperature. These factors also influenced Sphagnum growth indirectly by affecting moss shoot density. Synthesis. Our results imply that in a warmer climate, S. magellanicum will increase length growth as long as precipitation is not reduced, while S. fuscum is more resistant to decreased precipitation, but also less able to take advantage of increased precipitation and temperature. Such species‐specific sensitivity to climate may affect competitive outcomes in a changing environment, and potentially the future carbon sink function of peatlands.

Rain-fed peatlands are dominated by peat mosses (Sphagnum sp.), which for their growth depend on nutrients, water and CO₂ uptake from the atmosphere. As the isotopic composition of carbon (^12,13C) and oxygen (^16,18O) of these Sphagnum mosses are affected by environmental conditions, Sphagnum tissue accumulated in peat constitutes a potential long-term archive that can be used for climate reconstruction. However, there is inadequate understanding of how isotope values are influenced by environmental conditions, which restricts their current use as environmental and palaeoenvironmental indicators. Here we tested (i) to what extent C and O isotopic variation in living tissue of Sphagnum is species-specific and associated with local hydrological gradients, climatic gradients (evapotranspiration, temperature, precipitation) and elevation; (ii) whether the C isotopic signature can be a proxy for net primary productivity (NPP) of Sphagnum; and (iii) to what extent Sphagnum tissue δ¹⁸O tracks the δ¹⁸O isotope signature of precipitation. In total, we analysed 337 samples from 93 sites across North America and Eurasia using two important peat-forming Sphagnum species (S. magellanicum, S. fuscum) common to the Holarctic realm. There were differences in δ¹³C values between species. For S. magellanicum δ¹³C decreased with increasing height above the water table (HWT, R² = 17 %) and was positively correlated to productivity (R² = 7 %). Together these two variables explained 46 % of the between-site variation in δ¹³C values. For S. fuscum, productivity was the only significant predictor of δ¹³C but had low explanatory power (total R² = 6 %). For δ¹⁸O values, approximately 90 % of the variation was found between sites. Globally modelled annual δ¹⁸O values in precipitation explained 69 % of the between-site variation in tissue δ¹⁸O. S. magellanicum showed lower δ¹⁸O enrichment than S. fuscum (−0.83 ‰ lower). Elevation and climatic variables were weak predictors of tissue δ¹⁸O values after controlling for δ¹⁸O values of the precipitation. To summarize, our study provides evidence for (a) good predictability of tissue δ¹⁸O values from modelled annual δ¹⁸O values in precipitation, and (b) the possibility of relating tissue δ¹³C values to HWT and NPP, but this appears to be species-dependent. These results suggest that isotope composition can be used on a large scale for climatic reconstructions but that such models should be species-specific.

The study investigated changes in plant communities in sand and sandy loam quarries of various revegetational age in the northern taiga of West Siberia over the recent 13 years. Species composition of pioneer communities is determined by substrate texture; the communities are dominated by either herbaceous or woody species. The vegetation changes culminate in a zonal or secondary forest community. The beginning of a forest community is determined by chance factors.

The aim of this research is to carry out an assessment of pyrogenic load after the fire event in 2016 within the drained site of Great Vasyugan mire (Bakchar bog, North-East part of The Great Vasyugan mire). Specifically, the objectives of this study were to: 1) perform a retrospective analysis of the water-thermal regime of the area under study according to monitoring data on the nearby site for estimation of development emergence of a fire-dangerous situation conditions; 2) determine the quantitative characteristics of vegetation and microtopography fire transformation based on field data; 3) estimate zone of contamination by combustion products and 4) estimate the hydrocarbons composition of mire and river water, peat and typical plants of the pyrogenic disturbed bog. The water-thermal retrospective analysis confirmed that in August 2016, the most favourable conditions for the emergence of a fire-dangerous situation were developed. The area of fire spread was 5.54 km², including within the mire of 4.44 km². The area of Zn and Pb pollution covers an area of 8 km, which is consistent with the prevailing wind direction and atmospheric deposition data for 2016. The zone of extreme pollution of heavy metal peat deposits is limited mainly by the zone of intensive burning of the surface, however, and beyond it, there was also a significant (2 times) Zn, Cd and Pb concentration (except Cu) increase, mainly due to the migration of elements with water flow. Carbon losses for the burned area of 1 square metre to a depth of 30 cm were about 3,800 gC/m². Against the background of a decrease in the content of n-alkanes, their share in the composition of peat lipids of the burnt area increases slightly, and among them the content of homologues C23–C25 increases, C29–C33 decreases and the CPI value decreases.