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Globally, major efforts are being made to restore peatlands to maximise their resilience to anthropogenic climate change, which puts continuous pressure on peatland ecosystems and modifies the geography of the environmental envelope that underpins peatland functioning. A probable effect of climate change is reduction in the waterlogged conditions that are key to peatland formation and continued accumulation of carbon (C) in peat. C sequestration in peatlands arises from a delicate imbalance between primary production and decomposition, and microbial processes are potentially pivotal in regulating feedbacks between environmental change and the peatland C cycle. Increased soil temperature, caused by climate warming or disturbance of the natural vegetation cover and drainage, may result in reductions of long-term C storage via changes in microbial community composition and metabolic rates. Moreover, changes in water table depth alter the redox state and hence have broad consequences for microbial functions, including effects on fungal and bacterial communities especially methanogens and methanotrophs. This article is a perspective review of the effects of climate change and ecosystem restoration on peatland microbial communities and the implications for C sequestration and climate regulation. It is authored by peatland scientists, microbial ecologists, land managers and non-governmental organisations who were attendees at a series of three workshops held at The University of Manchester (UK) in 2019–2020. Our review suggests that the increase in methane flux sometimes observed when water tables are restored is predicated on the availability of labile carbon from vegetation and the absence of alternative terminal electron acceptors. Peatland microbial communities respond relatively rapidly to shifts in vegetation induced by climate change and subsequent changes in the quantity and quality of below-ground C substrate inputs. Other consequences of climate change that affect peatland microbial communities and C cycling include alterations in snow cover and permafrost thaw. In the face of rapid climate change, restoration of a resilient microbiome is essential to sustaining the climate regulation functions of peatland systems. Technological developments enabling faster characterisation of microbial communities and functions support progress towards this goal, which will require a strongly interdisciplinary approach.

Additional file 1: Fig. S1. Geographical distribution of the serpentine soils sampled in 10 locations of the SEP within the maps of the geology (a), soil taxonomy (b) and vegetation (c). Fig. S2. Bulk elemental correlations in serpentinized rocks from the SEP for Fe2O3, Mn, Co, Ni, Cr, MgO, Al2O3, and SiO2, all of them analyzed by XRF. Table S1. Linear correlations and probabilities associated for Fe2O3, Mn, Co, Ni, Cr, MgO, Al2O3, and SiO2 found in serpentinized rocks from the SEP, all of them analyzed by XRF. Fig. S3. Bulk mineralogy of rock clasts from the soils (10 cm depth) of the SEP. Fig. S4. Elemental distribution determined on a polished thin section of a serpentinite clast from 10 cm depth (Lowland site MAN), defined by EPMA. Fig. S5. Elemental distribution determined on a polished thin section of a serpentinized peridotite from an outcrop close to Mountain CEI location, defined by EPMA. Fig. S6. Elemental distribution determined on a polished thin section of a serpentinized peridotite from an outcrop close to Lowland BES location, defined by EPMA. Table S2. Water content, total carbon content and pH of the soils sampled. Table S3. Elemental geochemical composition of the lateritic/serpentine soils from 10 locations of the SEP, analyzed by XRF majors (%) and traces (ppm). Fig. S7. Bulk elemental correlations in the serpentine soils from the SEP for Fe2O3, Mn, Co, Ni, Cr, MgO, Al2O3, and SiO2, all of them analyzed by XRF. Table S3. Linear correlations and probabilities associated for the Fe2O3, Mn, Co, Ni, Cr, MgO, Al2O3, and SiO2, found in serpentine soils from the SEP, all of them analyzed by XRF. Fig. S8. Principal components analysis (PCA) for the geochemistry of the serpentine soils and the score of each variable within each component. Fig. S9. Altitude correlation of the concentration of Fe (a), Mn (b), Ni (c) and Co (d) in the mountain serpentine soils and of Mn (e), Cr (f) and Co (g) in the inner ophiolite lowland serpentine soils. Fig. S10. Rarefaction curves for the prokaryotic communities in the serpentine soils overall the locations sampled in the SEP per observed species (a) and Fisher Alpha (b) after sequencing the V4 region of 16S rRNA. Fig. S11. Abundance of sequences per prokaryotic metabolic function assigned to phylogenetic clades after sequencing the V4 region of 16S rRNA in the serpentine soils overall the locations from the SEP. Fig. S12. Rarefaction curves for the fungal communities in the serpentine soils overall the locations sampled in the SEP per observed species (top) and Fisher Alpha (bottom) after sequencing the ITS2 region of nuclear ribosomal DNA. Fig. S13. Principal components analysis (PCA) for microbial-geochemical associations in the serpentine soils from the SEP and the score of each variable within each component.

We report a previously undescribed member of the Helotiales that is superabundant in soils at two maritime Antarctic islands under Antarctic Hairgrass (Deschampsia antarctica Desv.). Pyrosequencing showed that up to 92% of DNA reads, and 68% of RNA reads, in soils from the islands were accounted for by the fungus. Sequencing of the large subunit region of ribosomal (r)DNA places the fungus in the Pezizellaceae or Porodiplodiaceae, with analyses of internal transcribed spacer regions of rDNA indicating that it has affinities to previously unnamed soil and root fungi from alpine, cool temperate and Low Arctic regions. The fungus was found to be most frequent in soils containing C aged to 1,000–1,200 years before present. The relative abundances of its DNA and RNA reads were positively associated with soil carbon and nitrogen concentrations and δ13C values, with the relative abundance of its DNA being negatively associated with soil pH value. An isolate of the fungus produces flask-shaped phialides with a pronounced venter bearing masses of conidia measuring 4.5–6(7) × 1.8–2.5 µm, suggestive of anamorphic Chalara. Enzymatic studies indicate that the isolate strongly synthesizes the extracellular enzyme acid phosphatase, and also exhibits alkaline phosphatase and naphthol-AS-BI-phosphohydrolase activities. Ecophysiological measurements indicate optimal hyphal growth of the isolate at a pH of 4.2–4.5 and a water potential of -0.66 MPa. The isolate is a psychrotroph, exhibiting measureable hyphal growth at -2 °C, optimal hyphal extension rate at 15 °C and negligible growth at 25 °C. It is proposed that the rising temperatures that are predicted to occur in maritime Antarctica later this century will increase the growth rate of the fungus, with the potential loss of ancient C from soils. Analyses using the GlobalFungi Database indicate that the fungus is present in cold, acidic soils on all continents. We advocate further studies to identify whether it is superabundant in soils under D. antarctica elsewhere in maritime Antarctica, and for further isolates to be obtained so that the species can be formally described.

Temporal stability of ecosystem functioning increases the predictability and reliability of ecosystem services, and understanding the drivers of stability across spatial scales is important for land management and policy decisions. We used species-level abundance data from 62 plant communities across five continents to assess mechanisms of temporal stability across spatial scales. Weassessed how asynchrony (i.e. different units responding dissimilarly through time) of species and local communities stabilised metacommunity ecosystem function. Asynchrony of species increased stability of local communities, and asynchrony among local communities enhanced metacommunity stability by a wide range of magnitudes (1–315%); this range was positively correlated withthe size of the metacommunity. Additionally, asynchronous responses among local communities were linked with species’ populations fluctuating asynchronously across space, perhaps stemming from physical and/or competitive differences among local communities. Accordingly, we suggestspatial heterogeneity should be a major focus for maintaining the stability of ecosystem services at larger spatial scales.

We have examined organismic responses of Dryas octopetala to simulated changes in the summer climate at four tundra sites as part of the International Tundra Experiment (ITEX). Our study sites are located in the High Arctic, on Svalbard, Norway, in the Low Arctic at Abisko, Sweden, and at Toolik Lake, Alaska, USA and our temperate alpine site is at Niwot Ridge, Colorado, USA. These sites represent a range of tundra temperature and precipitation regimes, being generally cold and dry in the High Arctic and warmer and wetter at Toolik Lake and Niwot Ridge. Results from our studies indicate organismic attributes such as flowering shoot length varies by 30% between low and high arctic populations and that experimental warming results in significant increases in shoot height at three of four sites. We find that phenological development of Dryas is accelerated under experimentally warmed conditions which corresponds with a lengthening of the growing season in autumn, greater degrees of seed set and a higher likelihood of colonization of bare ground. We also observe that Dryas dominated ecosystems which are exposed to experimental manipulations are capable of exhibiting net carbon sequestration in late autumn, and that Dryas photosynthesis and green leaf biomass is significantly greater under warmer as opposed to ambient temperature conditions. Dryas leaf nitrogen is also significantly lowered under warmer conditions resulting in senescent leaves having a higher C:N ratio than those under ambient conditions. Together these findings indicate that Dryas phenology and carbon flux may be altered to the greatest degree in spring and again in autumn by higher summer temperatures and that simultaneously both positive and negative feedback effects may result from changes in plant and ecosystem performance. © 1997 Blackwell Science Ltd.

Impacts of climate change were simulated in two contrasting European arctic ecosys tems, a high arctic polar semi-desert and a subarctic dwarf shrub heath, by increasing temperature (using polythene tents), precipitation and soil nutrient (NPK) availability. The effects of these treatments and their interactions on plant litter decomposition and soil nutrient fluxes were assessed. Polythene tents increased air, litter and soil temper atures but reduced litter and soil moisture contents. At both sites, litter decomposition was significantly retarded in the tent treatments due probably to reduced litter mois ture contents. The tent treatment had no effect on extractable soil N pools or net total N mineralisation at either site, although the treatment significantly reduced net sea sonal nitrification values at the subarctic site. The additional precipitation treatment significantly increased litter decomposition at the dwarf shrub heath site and the net amount of N mineralised at the polar semi-desert site. Litter decomposition was in creased, as was net N mineralisation, by the application of nutrients. The results sug gest that soil temperature increases of up to 1VC, which may occur by the end of the next century as an effect of a predicted 4VC rise in air temperature, have only small ef fects on total N mineralisation in the short term in arctic soils.