In this short communication, we respond to criticisms of our previous work relating to peatland carbon balance calculations that have been raised in the current volume of Mires and Peat.
Peatlands are a major source of dissolved organic carbon (DOC) for inland waters in Western Siberia. Continuous hydrological and hydrochemical monitoring of these peatlands is essential for understanding the global carbon cycle. We investigated a pristine ombrotrophic bog in Western Siberia to determine the links between seasonal hydrological changes and DOC quantity and quality. Specifically, we analysed water table fluctuations, DOC concentrations and spectral characteristics (SUVA~254~, E2:E3 and E4:E6 ratios). Our findings indicate that each peatland ecosystem exhibits distinct seasonal hydrochemical changes. The driest ecosystems (ryams) feature water with the highest DOC concentrations, characterised by high aromaticity and large molecular size, whereas the wettest ecosystems (pools) display the opposite trend. Surprisingly, the stream, which collects water from the entire peatland catchment, exhibits unique properties in that its DOC concentration is similar to that of wet ecosystems, while its spectral features more closely resemble those of dry ecosystems. Therefore, peatland ecosystems act as complex biogeochemical systems, modulating both the concentration and quality of dissolved organic carbon (DOC) based on prevailing environmental conditions.
The reintroduction of _Sphagnum_ moss is central to the process of peatland restoration in the UK. Dominant _Juncus effusus_ is a common problem resulting from eutrophication of peatland, reducing the value of the habitat. In this article we report on the management of an area of dense _J. effusus_ to permit the reintroduction of _Sphagnum_ onto a milled peat extraction site during restoration towards lowland raised bog. Trial plots were established in a waterlogged area of shallow mineralised peat covered with tall, dense _J. effusus_. Various treatments of repeated brush-cutting together with the removal (or not) of _Juncus_ litter were applied, the plots planted with commercially produced _Sphagnum_ plugs (BeadaHumok® West Pennines 5-species Mix), and followed up over three years. The results indicate that a plausible approach to reduce _J. effusus_ where it is dominant and promote _Sphagnum_ growth is to cut and windrow _Juncus_ twice prior to _Sphagnum_ planting, then regularly cut the _Juncus_ to facilitate establishment of a _Sphagnum_ lawn within the _Juncus_ stubble. Cutting less frequently than yearly had little effect on _Juncus_ dominance. The chosen _Sphagnum_ plugs appeared suitable for this application as most of the five species were evident and thriving at the end of the trial.
Shorea balangeran (Korth.) Burck is widely distributed in Southeast Asian peat swamp forests although it is not endemic to this habitat type. This study examines the ecological and biological characteristics and interactions of S. balangeran in peat swamp forests, and in particular its interactions with co-occurring species and its capacity for adaptation to challenging environmental conditions. The study addresses key questions relating to the soil characteristics in areas where S. balangeran thrives, the nature of associations with commonly co-occurring species, and how the findings might inform peatland restoration strategies. Vegetation data, soil samples and species association records arising from field surveys conducted in a peat swamp forest in Central Kalimantan, Indonesia, were analysed. S. balangeran was found to be the second most dominant species in the area, and to show positive associations with other species such as Gonystylus bancanus and Cratoxylum arborescens, suggesting shared habitat preferences or environmental tolerances. S. balangeran was commonly found in moderately acidic soils with high organic matter and low nutrient content, indicating its adaptability to nutrient-poor conditions. These findings highlight ecological characteristics of S. balangeran that may commend it for use in peatland restoration programs. However, further research is needed to fully understand its role in ecosystem functioning and resilience.
Shifting from drainage-based agriculture to paludiculture - that is, farming on rewetted peatlands - is one of the biggest opportunities for carbon farming and achieving net zero. By maintaining productivity without draining peat soils, paludiculture significantly reduces GHG emissions through the prevention of peat oxidation. Since emerging in the 1990s, the concept has led to several innovations in crop agronomy, product development and environmental benefits. However, despite the potential, widespread adoption remains limited. In the UK, lowland peat soils were drained for arable cultivation from the beginning of the 17th century, leading to extensive peat loss and continuing high CO2 emissions. This long historical legacy of peatland drainage has shaped farmers' perceptions and attitudes towards peatlands, and influenced policy and legal frameworks. In this article we review the current UK policy landscape and identify the key barriers to adoption. We then use a capacity-building pyramid framework to identify the systemic factors necessary for scaling up paludiculture including policy reform, subsidy schemes, market development, enabling infrastructure, fostering knowledge exchange amongst stakeholders and, ultimately, shifting stakeholder perceptions of paludiculture.
In this short communication, we respond to criticisms of our previous work relating to peatland carbon balance calculations that have been raised in the current volume of _Mires and Peat_.
Tamanu (_Calophyllum inophyllum_ L.) has attracted increasing attention as a promising species for tropical peatland restoration in Southeast Asia. For successful restoration, it needs to survive and grow under flooded conditions, and flooding is a key factor affecting the performance of seedlings planted in tropical peatlands. To evaluate the restoration potential of tamanu, we examined the survival rate, plant height, number of leaves, root collar diameter, dry biomass and leaf area of tamanu seedlings grown in peat soil under different flooding durations, using a randomised block design. An experiment was conducted in a water tank using five flooding duration treatments and 12 tree-level replicates per treatment: F0 (non-flooding as control); F3 (3 days flooding); F5 (5 days flooding); F7 (7 days flooding); and F11 (11 days flooding). All seedlings survived across all treatments; however, their growth was inhibited as the flooding duration increased, particularly beyond one week. Of the performance indicators evaluated, number of leaves appeared to be the most sensitive to flooding stress, indicating its potential as an early indicator of plant stress. This study confirmed that even short-term flooding can cause significant growth reduction in _C. inophyllum_ seedlings planted in tropical peat soils. Further studies are needed to reflect a wider range of flooding durations and water levels that may occur in tropical peatlands in the future.
This study addresses an evidence gap on the restoration potential of climatically marginal shallow peatlands by investigating short-term (five years post-rewetting) effects of ditch blocking on runoff and water quality. Results from two sites in south-west England (UK) showed reductions in peak flows ranging from 29 % to 32 % after rewetting, indicating modifications of rainfall-runoff regime in these catchments as a consequence of rewetting. In addition, a statistically significant reduction in total rainfall-runoff event discharge was observed at one of the study sites. The findings suggest an increase in the temporary storage of flow during rainfall-runoff events and an overall attenuation of storm hydrographs. Water quality responses to rewetting did not show any significant change in either DOC or colour concentrations during rainfall-runoff events. It is likely that such behaviour is due to the spatially limited success of rewetting interventions in significantly raising water tables in these shallow peatlands, and thus to a limited reduction in decomposition of vegetation and peat. No significant changes in DOC loads (normalised by rainfall) leaving the catchments were observed either. It is possible that a longer post-rewetting period will be needed to see any change in water quality, as vegetation responds in the longer (> 5 years) term.
Swamps are treed wetlands, which account for the highest areal extent of wetland types in Southern Ontario due to the difficulties of conversion for development and agriculture. However, little is known about the environmental factors and processes that influence carbon (C) dynamics or the resulting C stocks and fluxes therein. We studied 12 swamps across Southern Ontario for 12 consecutive months to measure the exchange of carbon dioxide (CO~2~) and methane (CH~4~) between soil and atmosphere and estimate current C stocks in soil and biomass. We found mean growing season soil respiration of CO~2~ and CH~4~ across the swamps ranged from 11 g m^-2^ d^-1^ to 49 g m^-2^ d^-1^ and -3 mg m^-2^ d^-1^ to 44 mg m^-2^ d^-1^, respectively, with a water table threshold at about 20 cm where fluxes changed substantially. Biomass stored 7.92–37.0 kg m^-2^ of C across the sites, and soil stored 11.6–35.5 kg m^-2^. Over the study year, the swamps functioned as C sinks and followed similar patterns of relationships to environmental conditions as bogs and fens, with little difference between hydrogeomorphic settings or canopy types.
Due to rapid population growth, construction on peatlands is inevitable. Peat, as a compressible water-saturated and fibre-rich soil with low strength and unique microstructure, presents significant challenges for construction engineering and requires stabilisation using advanced techniques. Conventionally, piles are generally utilised in locations with thick deposits of weak soils. However, their effectiveness in peat can be limited by excessive settlement, reduced load-bearing capacity, higher construction costs, challenges in achieving lateral stability, and potential for disturbance of the peat layers during installation. To address such limitations, this study introduces the innovative concept of branched piling (BP), in which the piles have branches extending from their outer surfaces. Model scale tests were conducted on branched piles installed in large (approximately 1 m³) peat samples collected with minimal disturbance from a site at Silchar in the northeast Indian state of Assam. Extensive testing under static loads revealed a 32 % increase in vertical bearing capacity for BP compared to standard piling. Key variables that significantly influenced BP capacity included branch number (_n_), branch length (_L~b~_) and top branch inclination angle (_α_). The results showed that increasing _n_, _L~b~_ and _α_ (up to 45°) enhanced capacity, but capacity was reduced if the _α_ value (inclination) exceeded 45°. This new BP technique provides a practical and effective solution for improving stability, load-bearing capacity and durability of foundations on challenging peat deposits. By tackling the challenges of construction on peat, this method bridges the gap between research advancements and practical engineering applications.
Drained peatlands are a substantial contributor to global anthropogenic greenhouse gases despite the relatively small areas they occupy. In New Zealand, drained Organic Soils (former peatlands) under cropland and grazed grasslands disproportionately contribute to emissions, but outdated mapping and limited measurements result in large uncertainties. To progress our understanding of the magnitude of these emissions and potential for mitigation, we compiled existing measurements from New Zealand and default emission factors from the IPCC along with updated soil mapping to develop a comprehensive national assessment. Using the IPCC 2013 Wetland Supplement (WS), Tier 1 default emission factors, total CO~2~ equivalent (CO~2~e) drained Organic Soil emissions were 3.86 Mt yr⁻¹, equivalent to 6.5 % of the country's net emissions. This was similar to the estimate derived from the mean of New Zealand-specific annual CO~2~e emissions (3.61 Mt yr⁻¹). However, there are insufficient measurements from which to develop robust Tier 2 emission factors, and the range of CO~2~e estimates based on existing data (3.06–4.69 Mt yr⁻¹) reinforces the need for more distributed measurements. The estimated CO~2~e contribution to national emissions increased to 6.34 Mt yr⁻¹ (or 11 % of net emissions) when peaty-mineral soils were included in the calculations. Carbon-rich soils with a peaty surface horizon that do not meet the technical definition of Organic Soils are increasingly recognised as a potential source, but we have even less data quantifying their emissions to determine appropriate emission factors. We evaluated the potential for emissions mitigation through rewetting Organic Soils by running scenarios representing different areal rates of annual rewetting over the next ten years using WS default emission factors. Cumulative emissions avoided by rewetting 500–3000 hectares per year from 2026 until 2035 ranged from 0.53 to 1.25 Mt of CO~2~e. Despite the barriers to practical implementation of peatland rewetting in New Zealand, the opportunity for emissions reductions is substantial. Further work is needed to refine emission factors, improve spatial activity data, and develop operational water table management capability to realise the potential in climate mitigation.
_Shorea balangeran_ (Korth.) Burck is widely distributed in Southeast Asian peat swamp forests although it is not endemic to this habitat type. This study examines the ecological and biological characteristics and interactions of _S. balangeran_ in peat swamp forests, and in particular its interactions with co-occurring species and its capacity for adaptation to challenging environmental conditions. The study addresses key questions relating to the soil characteristics in areas where _S. balangeran_ thrives, the nature of associations with commonly co-occurring species, and how the findings might inform peatland restoration strategies. Vegetation data, soil samples and species association records arising from field surveys conducted in a peat swamp forest in Central Kalimantan, Indonesia, were analysed. _S. balangeran_ was found to be the second most dominant species in the area, and to show positive associations with other species such as _Gonystylus bancanus_ and _Cratoxylum arborescens_, suggesting shared habitat preferences or environmental tolerances. _S. balangeran_ was commonly found in moderately acidic soils with high organic matter and low nutrient content, indicating its adaptability to nutrient-poor conditions. These findings highlight ecological characteristics of _S. balangeran_ that may commend it for use in peatland restoration programs. However, further research is needed to fully understand its role in ecosystem functioning and resilience.
Drainage of peatlands for agriculture reverses their natural carbon sink function and leads to substantial CO~2~ emissions. However, the relative contributions of topsoil and subsoil layers to these emissions remain poorly quantified, limiting the accuracy of CO~2~ flux models in national greenhouse gas inventories. In this incubation study, we quantified CO~2~, N~2~O and CH~4~ fluxes from intact peat cores collected at 5–13 cm (topsoil) and 25–33 cm (subsoil) depth from arable and permanent grassland sites at a cultivated Danish bog. Fluxes were measured at five temperatures (2.5–23.4 °C) and across four soil water tensions ranging from full rewetting to pF 2.5. Topsoil consistently showed higher CO~2~ fluxes than subsoil, averaging a threefold difference. Temperature exerted a strong exponential control on emissions, with Q~10~ values ranging from 1.7 to 4.0 depending on depth, site and moisture status. Rewetting reduced CO~2~ fluxes from the topsoil at elevated temperatures but had little effect on the subsoil, which showed weaker temperature sensitivity and lower microbial activity. These findings align with asymptotic depth–flux relationships indicating that topsoil dominates the short-term response of CO~2~ fluxes to rewetting. Fluxes of N~2~O were negligible except in rewetted arable subsoil, where high fluxes suggested incomplete denitrification under micro-oxic and acidic conditions. Fluxes of CH~4~ were also negligible, indicating insufficiently anaerobic conditions for methanogenesis during the short-term incubation. Our results emphasise the importance of incorporating depth-specific CO~2~ dynamics in emission models and indicate that rewetting strategies must target the near-surface peat to optimise mitigation outcomes.
Forest logging operations have negatively affected the populations of orangutans and other wildlife species in Sebangau National Park, Indonesia. Understanding these changes is critical for effective conservation efforts. While techniques for mapping vegetation at landscape scale have advanced significantly, detailed assessments of forest profiles and orangutan habitats at local scale are lacking. To address this gap, data were collected from four forest zones with distinct tree composition, located in two different areas: the Natural Laboratory Peat Swamp Forest (NLPSF) and Punggualas (PA). Sixteen 20 m × 20 m plots were used to collect data on vegetation, soil and water quality, and to construct tree species profiles using the Oldeman method. Physico-chemical factors were measured on-site and laboratory analyses of soil samples were carried out. Canonical correspondence analysis was employed to examine site – species relationships in three dimensions. The analysis revealed that forest regrowth is in progress at both the NLPSF and PA, with significant potential for replacement of the previously logged trees by saplings. Continuous habitat restoration is essential to foster the natural regeneration of tree seedlings that will contribute to future forest recovery. The study also identified spatial heterogeneity in the NLPSF and PA forest habitats, reflecting the disturbed forest structure and the responses of trees to altered patterns of light intensity and water table depth. Nonetheless, the combination of tree species at both locations provided abundant dietary resources for orangutans. Ongoing efforts to enhance recovery of the Sebangau forest ecosystem, involving community participation, have further supported orangutan habitat conservation.
In 2022, the United Nations Environment Programme (UNEP) Global Peatlands Initiative (GPI) published the first Global Peatland Assessment (GPA) examining current knowledge on the state of a newly approximated total extent (500 million hectares) of peatlands across all seven continents. The GPA launch at United Nations Framework Convention on Climate Change (UNFCCC) COP 27 in Sharm-el-Sheikh (Egypt) was a landmark moment for collaborative efforts to provide evidence on the roles of policymakers, academic research and community-led initiatives in supporting global peatland conservation and restoration. Following an assessment of key geographic regions, and of the policy and governance in place to protect, preserve and restore national peatlands, the GPA concluded that policy and governance on peatlands in their current (2022) state offered limited scope to address international agendas without a unilateral national policy approach. This article employs a narrative review methodology to draw together findings from the GPA and information from peer reviewed and grey literature to enable a more comprehensive systematic analysis, interpretation and contextualisation of evidence towards achieving an integration of peatland policy and governance worldwide. Although no new empirical results are presented, the process reveals three consistent challenges, namely: (i) contradictory and fragmented policy frameworks; (ii) insufficient and poorly structured finance for restoration; and (iii) limited inclusion of communities and rights holders. These challenges form the basis for three recommendations to guide the formulation of policy for global and national frameworks. The recommendations are: 1) a commitment to establish national policies that protect, preserve and restore peatlands and align with globally established policy; 2) to develop and provide transparent market policy and mechanisms that allow international financial investment to support gaps in national public funding for restoration, conservation and stewardship of intact and high-integrity peatlands; and 3) to develop and integrate a mechanism for public consultation on peatland conservation and restoration programmes to ensure that agency and concerns for local community, culture and economy are formally recognised at global level. We discuss the rationale for each recommendation in the context of the GPA, to demonstrate how each will contribute to ensuring sustainable peatland governance along with the protection and conservation of peatlands, as a part of future global efforts supported by the UNEP GPI.
This short article is an introduction to a new open-source program that enables the production of quality plots of Troels-Smith data predominantly for peatlands. Here the potential of the program and the distinct general concept behind it is described. The strengths and potential for development are explored. Functionality is demonstrated using real and fictional data.
Hydrology is the fundamental control of peatland ecosystems. The spatial pattern of isotopic variability in peatland water provides insights into the site-scale heterogeneity of water sources, turnover and flow patterns. However, we still lack comprehensive documentation of spatial isotope datasets across different peatland types and climates, and no study has presented an interpretative framework for such spatial data or related them to quantitative models of isotopic fractionation. Here we investigate the spatial distribution of isotope ratios in water at the peatland surface within temperate peatlands of three different types (sloping poor fen, drainage-affected poor fen on a flat platform, steeply sloping bog with strong pool patterning) in Northeast China and develop a mechanistic model of isotopic fractionation for a generalised understanding of relevant mechanisms. Our data show an evaporation-induced increasing trend in peatland water δ^18^O towards the downslope direction in the sloping poor fen. This pattern can be reproduced by the model simulation but is not observed in the drainage-affected poor fen or in the patterned bog. The latter two sites show isotopic heterogeneities that directly indicate poor surface water connectivity due to topographic, hydraulic and hydrological factors, as supported by the model sensitivity analysis and constraints from river isotope data. Additionally, all three sites have notably narrow ranges of variability in peatland water δ^18^O compared to previously investigated European and North American peatlands. This may result from the high transpiration fraction of herbaceous vegetation and accelerated turnover of the surface water reservoir under a wet monsoon climate, which together prevent the development of strongly enriched isotopic signatures in regional peatlands. This study underscores the potential for using the spatial distribution of water isotope ratios as a simple and efficient method to distinguish surface hydrology among different hydrogenetic types of peatlands, with scope for making quantitative inferences by developing isotope-based hydrological models.
Peatlands play an important role in carbon and nitrogen cycles, functioning as either sinks or sources of greenhouse gases (GHGs) depending on environmental and management conditions. While extensive research has been conducted on peatlands in northern latitudes and the tropics, there is limited knowledge of GHG flux dynamics in southern African peatlands. This study examined methane (CH4) and nitrous oxide (N2O) fluxes from two differently managed peatlands in Eswatini over 12 months using the opaque static chamber technique. The Motjane peatland, under community management, functioned as a slight net sink for CH4-C (-2.92 mg m(-2) hr(-1)) but was a slight net source for N2O-N (0.11 mu g m(-2) hr(-1)). The Malolotja peatland, located in a nature reserve, was a slight source for N2O-N (0.26 mu g m(-2) hr(-1)) and neither a source nor a sink for CH4-C (0.06 mg m(-2) hr(-1)). CH4-C flux was positively correlated with temperature (below-ground, surface and air), while N2O-N fluxes showed a negative relationship with rainfall. Seasonal environmental factors and land use management influenced CH4-C and N2O-N fluxes. Differences between CH4-C and N2O-N fluxes in the two peatlands were linked to variations in the degree of human disturbance, vegetation communities, climatic factors and soil properties. The findings highlight the importance of targeted intervention measures that are informed by continuous ecological monitoring. Sustainable peatland management strategies should focus on restoring indigenous vegetation and stabilising water levels to minimise CH4 and N2O emissions and enhance carbon sequestration. Future assessments of the overall GHG balance and carbon sequestration potential should consider the combined effects of all three major greenhouse gases, including CO2.
This unpublished manuscript from 1966 by Hugo Sjörs and Eville Gorham was found in the archives at Uppsala University. It is published here to make their data available as historical reference material. Floristic data on higher plants, bryophytes, lichens and microalgae were obtained from ombrotrophic bogs in Ireland with and without _Schoenus nigricans_. Analyses were made for Na, K, Ca, Mg, Cl, SO~4~, dissolved organic carbon, optical density and pH in the free superficial waters; for Na, K, Ca, Mg and pH in waters expressed from the bog peats; and for ash, P, pH, and the exchangeable cations Na, K, Ca, Mg and H in the peats themselves. The richness of the ombrotrophic flora in western Ireland is confirmed by this study, which demonstrates that bogs there contain many species of microalgae as well as higher plants which are restricted to minerotrophic fens in Sweden. Marine influence upon ion supply is very strong, with the Irish bog waters uncommonly high in Na, Mg and Cl. Exchangeable Na and Mg are also unusually abundant in the peats. Associated with marine influence are higher pH values than are normal in more continental sites, and a higher degree of adsorptive neutralisation of the peats. Total P is low by comparison with ombrotrophic peats in Sweden. Expressed waters are much higher than free superficial waters in K, and to a lesser extent in Ca, but they are much lower than free waters in H ions.
