The review focused on agricultural practices that can improve the hydrology and physical structure of freshwater habitats. These included restrictions on ploughing, grazing or mowing along watercourses, temporary storage of floodwater on agricultural fields, drainage bans and restrictions, hedgerows and field margins, ponds and small wetlands, wetland and peatland management, agroforestry, and soil and grassland practices intended to increase water retention. Agricultural pollution was outside the review’s direct scope, although the authors noted that restoring natural hydrological and morphological processes may also reduce pollution.

CAP funding for 2023–2027 comprises EUR 307 billion in planned public expenditure from EU and national sources, with spending scheduled through 2029. The “Green Architecture” combines conditionality, eco-schemes, Environment and Climate interventions (ENVCLIM), and investment support, alongside smaller categories such as support for Areas of Specific Disadvantage, cooperation, knowledge exchange and innovation. Regulations require at least 25% of European Agricultural Guarantee Fund direct payments to be allocated to eco-schemes and at least 35% of European Agricultural Fund for Rural Development funding to support climate, environment and animal-welfare interventions.

Approximately 29% of the annual CAP budget, equivalent to EUR 89 billion, is allocated to interventions contributing to the sustainable management of natural resources, including water, soil and air. Of that total, EUR 2 billion is exclusively dedicated to measures targeting that objective, excluding direct payments without an explicit environmental purpose. The review found that 35% of the eco-scheme budget and 66% of the ENVCLIM budget were linked to area-based payments contributing to improved water quality beyond conditionality. Funding linked to sustainable water use and water-balance measures was lower, at 14% of the eco-scheme budget and 8% of the ENVCLIM budget.

Conditionality provides the broadest baseline reach, applying to 89% of the EU’s utilised agricultural area. GAEC 2 requires Member States to ensure appropriate protection of wetlands and peatlands by 2025, while GAEC 4 establishes minimum 3-metre buffer strips along watercourses with restrictions on fertiliser and pesticide use. GAEC 8 requires retention of landscape features that can reduce runoff and increase infiltration when positioned on slopes or in riparian areas. Small ponds, streams and small wetlands are eligible under this standard but were rarely selected by Member States.

The review identified important limitations in the baseline rules. Implementation of GAEC 2 was delayed, some definitions were ambiguous, and exemptions were widely used. In the approved CSPs, every Member State exempted farms below 10 hectares from GAEC 7, representing 76% of EU farms and about 26% of arable land. Simplification packages adopted in April 2024 and May 2025 also allowed Member States to remove GAEC 2 from conditionality, align watercourse definitions with national legislation, remove the minimum landscape-feature requirement under GAEC 8, extend permanent-grassland status from five to seven years, and increase the allowable reduction in permanent grassland from 5% to 10% before triggering reconversion requirements.

National plans nevertheless contained examples of interventions with potential restoration value. Poland’s “Water retention on permanent grassland” eco-scheme has EUR 97.3 million in planned public expenditure, targets up to 315,000 hectares annually and pays EUR 62 per hectare. Ireland’s ACRES Cooperation intervention combines fixed and result-based payments, assesses drainage conditions, and gives substantial emphasis to commonages and peatlands; it has EUR 460 million in planned public expenditure for 2023–2029, targets 2 million hectares and represents 26.17% of Ireland’s ENVCLIM budget. Finland’s “management of run-off waters” intervention regulates drainage to reduce runoff and nutrient leaching, maintain groundwater levels outside active cultivation periods and recycle drainage water through storage and later irrigation.

Investment support is mixed. Twenty-four Member States planned at least one non-productive on-farm investment, while 22 planned off-farm non-productive investments. Green investments account for 62% of investment interventions and EUR 28 billion in public expenditure, while non-productive on- and off-farm investments specifically linked to environmental and climate goals account for EUR 17 billion, approximately 30% of the investment allocation. However, many water-related investments focus on technical efficiency, including irrigation, fertiliser and pesticide use, rather than habitat restoration. Support for creating or restoring drainage schemes appears in at least 11 CSPs, a practice the authors identify as potentially undermining freshwater restoration.

The authors’ overall assessment is that CAP 2023–2027 has substantial potential to support freshwater restoration, but that national flexibility has often favoured political feasibility and farmer participation over environmental ambition. The review identifies inconsistent conditionality, limited targeting of eco-schemes and ENVCLIM measures, investment focused more on “grey” infrastructure than ecosystem restoration, and a CAP budget still dominated by income support. It recommends more consistent enforcement of baseline standards, better-targeted interventions, robust monitoring, a larger role for non-productive investments and cooperation, and payments more directly tied to measurable environmental outcomes. The review did not assess whether particular restoration measures produced ecological improvements, so the findings concern the design and planned allocation of CAP interventions rather than demonstrated restoration outcomes.

Subject of Research: Evaluation of EU Common Agricultural Policy plans for freshwater ecosystem restoration

Article Title: Does the Common Agricultural Policy 2023–2027 support the restoration of freshwater ecosystems?

Article References: Rouillard, J., Meier, J., Blackstock, K. L., Matthews, K. B., & Birk, S. (2026). Does the Common Agricultural Policy 2023–2027 support the restoration of freshwater ecosystems?. Nature Conservation, 62, 337-354. https://doi.org/10.3897/natureconservation.62.148845

Image Credits: AI Generated

DOI: 10.3897/natureconservation.62.148845

Keywords: Common Agricultural Policy, freshwater restoration, EU agriculture, wetlands, peatlands, rivers and lakes, agricultural policy, environmental payments, CAP Strategic Plans, Does, Common, Agricultural

The study, published in Biogeosciences by Iuliia Burdun of Aalto University and KU Leuven, Jiabin Pu and Ranga B. Myneni of Boston University, and corresponding author Miina Rautiainen of Aalto University, tracked leaf area index (LAI) across peatland-dominated pixels north of 45 degrees North from 2001 to 2023. LAI is an Essential Climate Variable that describes the amount of green foliage above the ground, defined as one half of the total green leaf area per unit of horizontal ground surface. In simple terms, higher LAI means more green leaf area, and the team interpreted increases over time as greening and decreases as browning.

What makes the analysis technically distinctive is the data record itself. The researchers used a gap-filled, sensor-independent LAI climate data record at 500-meter resolution, which merges high-quality retrievals from MODIS Terra, MODIS Aqua, and VIIRS for each eight-day period. This sensor-independence reduces biases tied to any single satellite’s calibration and overpass time, while a spatio-temporal tensor completion model fills gaps left by clouds, aerosols, and snow. The result is a consistently processed, uncertainty-quantified time series stable enough for climate-scale analysis, a critical requirement when the goal is to detect subtle, multi-decadal canopy change.

The peatland mask was built conservatively by integrating four complementary global datasets: PEATMAP, OpenStreetMap wetland polygons, ESA WorldCover herbaceous wetlands, and the Global Peatland Map 2.0. Areas were retained only when supported by at least two of the three wetland-mapping sources and located within the Global Peatland Map 2.0, yielding roughly 535,017 square kilometers of conservatively mapped peatland. The team then kept only 500-meter pixels with at least 90 percent mapped peatland cover and excluded any pixel classified as burned between 2001 and 2023 in the MCD64A1 fire dataset, leaving 1,244,063 pixels capturing more than half of the conservative peatland mask. This pixel selection was designed to minimize mixed-pixel effects from adjacent forests, open water, and farmland, and to avoid confounding by abrupt fire disturbance and post-fire recovery.

The headline numbers are striking. More than 77 percent of the studied peatland area, about 203,269 of roughly 261,819 square kilometers, showed positive LAI trends, corresponding to a greening-to-browning ratio of 3.5:1. The strongest greening clustered in southern West Siberia, Central Europe, and southern Fennoscandia, while the largest browning pattern appeared near the Hudson Bay Lowlands in North America. Across the distribution, decadal LAI trends ranged from -1.07 to 0.78 square meters per square meter per decade, with 95 percent of values between -0.07 and 0.09. Yet here is the twist: when the researchers accounted for spatial autocorrelation across the map using a partitioned spatial generalised least squares framework, the area-weighted LAI trend at the map scale was statistically indistinguishable from zero. Widespread local greening did not add up to a significant overall increase in greenness.

The climate associations were equally counterintuitive. LAI anomalies showed a weak but predominantly positive partial correlation with air temperature anomalies and a weak, predominantly negative partial correlation with precipitation anomalies, with the strongest associations in West Siberia and the Hudson Bay Lowlands. In the best-fitting model of long-term LAI trends, multi-year mean annual precipitation, rather than air temperature, was retained. The authors argue that this negative LAI-precipitation relationship aligns with peatland hydrology: reduced precipitation lowers the water table and dries peatlands, favouring the expansion of dry-habitat vascular plants at the expense of Sphagnum mosses, the ecosystem engineers that maintain the acidic, waterlogged conditions under which peat accumulates. Greening in northern peatlands may therefore reflect vascular plant expansion rather than enhanced moss growth, a shift with potential consequences for peat-forming function and carbon sequestration.

Perhaps the most intriguing finding involves the Pacific Decadal Oscillation, a pattern of Pacific climate variability that modulates temperature and precipitation north of 40 degrees North. Most peatland pixels followed a linear LAI trend with no detected breakpoint, but where non-linear trends occurred, their breakpoints were often temporally aligned with phase shifts in the PDO. Cup-shaped trends, in which LAI first declined and then increased, were concentrated in West Siberia, with breakpoints peaking during 2005-2010. Hat-shaped trends, in which LAI first rose and then fell, were widespread across Europe, northeastern Asia, and Canada, with a later breakpoint density peak during 2012-2016. In both non-linear classes, peaks in breakpoint density occurred soon after a PDO phase change, the first observation, to the authors’ knowledge, that a PDO shift might contribute to changes in peatland vegetation trends.

Tree cover also shaped the trajectories. Greater tree cover was associated with less greening, but the effect was numerically small and varied by continent, canopy type, and precipitation regime. In Asian peatlands where the nearest surrounding trees in 2001 were evergreen needleleaf, each additional 1 percent of tree cover was associated with a mean decline of 1.06 x 10^-4 square meters per square meter per decade, and the penalty was markedly steeper in North America. Deciduous needleleaf cover, such as larch, attenuated the negative tree-cover effect, consistent with field studies showing that larch mitigates the negative association between tree mortality and greening. Higher multi-year mean annual precipitation moderated the negative slope, making it less negative in sufficiently wet sites. Counterintuitively, the largest positive LAI trends in North America occurred at high tree-cover levels, a pattern that can arise when partial conifer mortality and understory release increase vascular leaf area despite high initial canopy cover.

Permafrost thaw added another pathway of decadal non-linearity. Frozen ground acts as a hydrological dam, and thermokarst-lake drainage breaches it, reconfiguring drainage pathways and triggering land cover transitions. Pixels overlapping mapped drained lakes showed a higher prevalence of increasing LAI trends, with 94.5 percent of the 2,328 overlapping pixels trending upward, predominantly in Asian peatlands. The relative share of drained-lake overlap was highest for cup-shaped increasing trends, compatible with a vegetation shift in which initial permafrost disturbance is followed by graminoid and shrub colonisation and, locally, tree establishment after two to three decades. Because moderate-resolution LAI integrates heterogeneous peatland-lake mosaics, part of the apparent increase may reflect a decline in the open-water fraction rather than canopy change alone, and the authors caution that this exploratory pattern should not be generalised.

Protection status, notably, did not explain LAI trends once differences in climate and canopy were accounted for. About 11 percent of the studied pixels fell within protected areas, mirroring global estimates that only about 17 percent of peatlands are protected. The authors stress that a null association should not be read as evidence that protection is ineffective; benefits may occur in attributes not captured by LAI, such as biodiversity, or at magnitudes below detectability given limited protected-area coverage. Taken together, the findings suggest that recent peatland canopy change was not a uniform increase in greenness but a moisture-sensitive, tree-composition-dependent response modulated by decadal climate variability. As northern Eurasia grows more arid and Arctic heatwaves expand, the authors argue that future work should link observed LAI trends with peatland-specific land-surface models to detect moisture-driven regime shifts at the circumpolar scale, and that climate-aware management, rather than legal designation alone, will be essential for conserving these carbon-rich ecosystems.

Subject of Research: Biogeosciences

Article Title: Detecting long-term canopy change and vegetation shifts in northern peatlands using LAI and climate data

Article References: Burdun, I., Pu, J., Myneni, R. B., & Rautiainen, M. (2026). Detecting long-term canopy change and vegetation shifts in northern peatlands using LAI and climate data. Biogeosciences, 23(20), 7289-7308. https://doi.org/10.5194/bg-23-7289-2026

Image Credits: AI Generated

DOI: 10.5194/bg-23-7289-2026

Keywords: peatlands, LAI, remote sensing, climate change, Pacific Decadal Oscillation, carbon storage, permafrost, Biogeosciences, Detecting, long-term, canopy, change

The study classifies selected EU environmental and climate policies according to their impacts on wetlands and their reliance on high-quality wetlands to meet their own aims. The picture that emerges is one of supportive nature and water policies undermined by counteracting sectoral policies. The Birds Directive and Habitats Directive, collectively the cornerstone of EU biodiversity law, mandate the protection and restoration of numerous wetland habitat types — from coastal salt marshes and seagrass meadows to mires, bogs and fens — and of wetland-dependent species such as the European otter, the European sturgeon and the marsh fritillary. Where the Natura 2000 network they establish is fully implemented, it has demonstrably slowed species decline and habitat loss compared with non-protected areas. Yet the latest reporting period shows how far objectives remain unmet: only 17% of protected freshwater habitats achieve good conservation status, and 80% of protected fish and 60% of amphibians reliant on these habitats are in poor or bad condition, with freshwater migratory fish abundance down 75% since 1975.

Water management legislation tells a similar story of high ambition and weak delivery. The Water Framework Directive, adopted in 2000, aims to achieve good status for all water bodies by 2027 at the latest, promoting an integrated approach that respects entire ecosystems. Its implementation would highly benefit European wetlands, which regulate water quality and ecosystem health. Yet only 37% of Europe’s surface water bodies achieved good or high ecological status in 2021, with the main pressures being hydrological modification — dams and channelization — and agricultural pollution. The Fitness Check of the Directive identified underestimated ecological timescales, ineffective integration of sectoral policies, and excessive use of exemptions by Member States as key weaknesses, alongside a lack of comparable, centrally stored European monitoring data that delays detection of emerging stressors.

The Floods Directive recognizes wetlands’ role in natural flood management, promoting their use as natural water retention areas that absorb and slowly release floodwater, and holds potential for a paradigm shift from flood protection to integrated flood risk management. That potential has not been realized: reliance on gray infrastructure such as dams and dikes remains the norm, and neither aquatic biodiversity nor ecosystem services are directly mentioned in the Directive’s text. Climate legislation adds another layer. The LULUCF Regulation governs greenhouse gas accounting for land use, land use change and forestry, setting a union target of net removals of 310 million tonnes of CO2 equivalent by 2030. Restoring drained peatlands as nature-based solutions has high potential for emission reductions, and reporting on emissions from managed wetlands will become mandatory in 2026. Yet the overall union target is unlikely to be met, and links with EU biodiversity policy remain weak.

Counteracting these supportive policies is the EU’s Common Agricultural Policy, the biggest fund for land management in the Union. The analysis finds that the CAP needs significantly better targeting to reduce continued wetland damage. Intensive agriculture presents the most significant pressure for both surface and groundwaters in the EU, with little improvement since 2010, and hydrological modification for agricultural use, pollution and degrading management practices rank among the most severe pressures on protected wetland habitats. The newly introduced GAEC 2 standard aims to protect wetlands and peatlands by setting minimum conditions for direct payments, but it does not forbid continued drainage and ploughing of wetlands under agricultural use, and many Member States have exploited its flexibility to delay implementation until 2025 or set only weak national compliance criteria. Agri-environment-climate measures remain limited by small budgets and poor targeting, and the majority of CAP strategic plans have been assessed as insufficient for delivering biodiversity, climate and water objectives.

Renewable energy policy presents a second structural conflict. The Renewable Energy Directive pursues a binding 42.5% renewable share by 2030 and obliges Member States to designate renewable acceleration areas, while generalizing renewable energy as an overriding public interest — exempting projects from the usual Environmental Impact Assessment and subjecting them to the far less stringent Strategic Environmental Assessment. Hydropower expansion in particular can fragment rivers and disrupt wetland biodiversity, yet investments in hydropower are classified as environmentally sustainable under the EU Taxonomy Regulation, though experts suggest plants under 10 megawatts should be excluded due to their environmental impact. The analysis warns of a high potential to divert climate funds to gray infrastructure rather than nature-based solutions, locking in maladaptive practices.

Against this fragmented backdrop, the EU Nature Restoration Regulation, which entered into force in August 2024, represents a legislative milestone. It is the first EU-wide law prioritizing ecosystem restoration within and beyond Natura 2000, combining an overarching target — effective restoration measures covering at least 20% of land and sea by 2030 and all ecosystems in need by 2050 — with quantitative, time-bound targets for specific ecosystem types. Article 4 commits Member States to restoring at least 30% of habitats of community interest not in good condition by 2030, 60% by 2040 and 90% by 2050, covering all wetland habitat types designated under the Habitats Directive. Article 9 targets the removal of obsolete barriers to restore at least 25,000 kilometres of free-flowing rivers by 2030, defining connectivity in longitudinal, lateral and vertical terms — going beyond the Water Framework Directive’s longitudinal focus. Article 11 sets targets for drained peatlands in agricultural use, though only a fraction of mandated measures must involve rewetting.

The Regulation’s implementation architecture is designed to avoid the failures of its predecessors. Each Member State must submit a draft National Restoration Plan by 1 September 2026, identifying areas in need of restoration, specifying measures, financial resources and means of financing, and estimating co-benefits for climate mitigation and land degradation neutrality. The plans must also demonstrate synergies with sectoral policies such as forestry, agriculture and renewable energy — and indicate subsidies that would negatively affect implementation. By requiring this detail, the NRR aims to unify existing legislation, support the Nature Directives with deadlines and tools, and promote win-win scenarios for biodiversity, climate, disaster risk reduction and water resilience. Its adoption was hard-won: the original 2022 proposal was softened to gain support, a provisional trilogue agreement in November 2023 left adoption uncertain, and decisive votes passed only in February and June 2024, partly against political opposition fuelled by misinformation.

The political climate in which implementation now commences has shifted dramatically. The Green Deal is followed by a Clean Industrial Deal focused on competitiveness, and Omnibus packages launched throughout 2025 propose delaying, restricting or weakening many recently adopted Green Deal policies. The Commission’s proposal for the 2028–2034 Multiannual Financial Framework suggests a fundamental CAP reform lacking a ringfenced budget for agri-environmental schemes and replacing binding environmental standards with a more flexible farm stewardship system. Yet the case for upholding environmental ambitions remains as urgent as ever: Europe’s environment is declining across terrestrial, freshwater and marine ecosystems, the European Climate Risk Assessment warns of ever more severe impacts on food security, health and infrastructure, and the State of Water report highlights the need to restore aquatic ecosystems and wetlands at landscape scale to buffer extremes, reduce flood risks and retain water in the landscape.

The analysis concludes that the NRR’s success hinges on political will, funding and cross-sector coherence, requiring a whole-of-government and whole-of-society approach to writing, funding and implementing National Restoration Plans. Wetlands offer a tangible example of multifunctionality — nature’s most effective water managers, as the EU Water Resilience Strategy calls them — yet their contributions are not sufficiently recognized in climate, energy and agriculture policy. To make full use of synergy potentials, prevent counteracting measures and spend resources efficiently, policy integration must be actively pursued across water management, coastal defence, spatial planning, agricultural subsidies, renewable energy and disaster risk reduction. Scaling up wetland restoration through holistic implementation of the NRR is one crucial and urgent step, but it must be complemented by systemic transformations in the sectors currently driving wetland degradation. A transformative change for wetlands is needed in Europe.

Subject of Research: Environmental policy

Article Title: Wetlands in the EU policy context

Article References: Klusmann, C., Brotherton, P., Schiller, T., Wulf, S., & Marsden, K. (2026). Wetlands in the EU policy context. Nature Conservation, 62, 317-335. https://doi.org/10.3897/natureconservation.62.163780

Image Credits: AI Generated

DOI: 10.3897/natureconservation.62.163780

Keywords: wetlands, EU policy, Nature Restoration Regulation, biodiversity, climate change, Common Agricultural Policy, water resilience, peatlands, policy, context, scientific research

The review zeroes in on soil heterotrophic respiration to carbon dioxide, the process by which microbes exhale CO2 as they digest peat. It is the main loss pathway in the peatland carbon cycle, and it is the term models must get right if they are to simulate whether tropical peatlands keep accumulating carbon or start bleeding it into the atmosphere. The problem, the authors argue, is a double bind: scientists lack consensus on which environmental drivers matter most, and empirical data from the tropics are so scarce that model development has stalled. None of the models in the latest Coupled Model Intercomparison Project phase included peatlands at all, and even the land surface schemes that have since added peat modules — JULES, ORCHIDEE and CLM5 — were built around northern peatlands, leaving tropical soil carbon cycling essentially unrepresented.

Moisture emerges as the principal control. The relationship between respiration and water content follows a bell-shaped curve: respiration collapses when peat is bone dry because microbes cannot transport solutes and slip into dormancy, and it collapses again when peat is fully saturated because oxygen becomes limiting. Between those extremes lies an optimum moisture level where microbial activity peaks. The review found that this optimum varies enormously — from twenty-five to ninety-five percent water-filled pore space across compiled studies — and that degraded, drained peatlands show significantly lower optima than intact ones, consistent with the loss of porosity that accompanies drainage. For intact peatlands globally, the mean optimum sits at sixty-eight percent saturation.

The second critical parameter on the moisture curve is what the authors call the moisture resting point: the fraction of maximum respiration that persists under saturated conditions. Here the review delivers its sharpest quantitative insight. When saturation coincides with true anoxia — waterlogged conditions flushed free of oxygen — respiration drops to a median of just 0.105 of the optimum value, with a range of 0.005 to 0.290. That ratio, the authors stress, is the single most important number for tropical peat decomposition, because it is the reason peat accumulates in the first place. Intriguingly, the analysis showed that anoxia alone, whether or not the sample was water-saturated, produced the same dramatic suppression, while saturation without oxygen limitation only slightly reduced respiration. Water, in other words, kills respiration mainly by shutting off oxygen.

Temperature comes next, and the review confronts one of the most contested questions in soil carbon science: how sensitive is peat decomposition to warming? The standard metric, Q10, expresses the proportional increase in respiration for every ten degrees Celsius of warming. The rule of thumb holds that Q10 is roughly two — respiration doubles with a ten-degree jump. The authors compiled 873 peatland Q10 estimates from forty-four incubation studies worldwide and found a median of 2.04, with ninety percent of values between 1.16 and 3.62. Tropical estimates, though far fewer in number, were not significantly different from boreal and temperate ones. Given the noise from methodological differences, incubation lengths and moisture treatments, the authors conclude that a constant Q10 of about two remains the most parsimonious assumption for models — a defensible simplification, not a settled truth.

The review does not let Q10 off without criticism. The metric has no theoretical foundation, assumes an exponential response that only holds over limited temperature ranges, and is itself temperature-dependent. The authors advocate a shift toward the Arrhenius function, which is grounded in enzyme kinetics and applies across the full range where enzymes function. Existing incubation data could be reanalyzed this way if researchers reported raw data and activation energies — a change that would require no new experiments, only better reporting.

Substrate decomposability — how easily the peat’s organic matter can be mineralized — is the third major driver, and here the review exposes a field in disarray. Studies use wildly different proxies: peat depth, age, chemistry, the lignin-to-cellulose index, labile carbon fractions. Most observe that respiration declines with increasing recalcitrance, but the absence of a unified metric makes quantitative comparison across the tropics impossible. Some studies even found no significant relationship between lignin abundance or the lignin-cellulose index and CO2 emissions in tropical peat. Adding to the complexity, labile carbon inputs from litter and root exudates can trigger a priming effect, stimulating microbes to decompose even recalcitrant material faster.

Nutrients, by contrast, appear to matter less. Nitrogen and phosphorus addition experiments in tropical peatlands produced conflicting results, but all available studies agree that nutrient limitation is a weaker control on decomposition than moisture, temperature and substrate quality. The review also examined the home-field advantage hypothesis — the idea that decomposer communities specialize on local litter and decompose it faster at home — and found mixed evidence in the tropics, with one Panamanian study reporting a clear advantage and another finding only weak support.

Interactions between drivers remain the murkiest territory. Does warming sensitivity rise or fall with moisture? Some studies report higher Q10 under wetter, anoxic conditions; others report the opposite. The compiled database showed that anoxic conditions led to significantly higher temperature sensitivity in tropical peat, but no significant relationship between Q10 and moisture content emerged overall. Kinetic theory predicts that recalcitrant organic matter should be more temperature-sensitive because its decomposition demands higher activation energies, and the review found weak support for this under unsaturated oxic conditions — but no evidence for peat under saturated or anoxic conditions.

From this synthesis, the authors distill three priorities for advancing tropical peatland carbon modelling: narrowing the constraint on the optimum moisture range for respiration in tropical peat, investigating how moisture and temperature sensitivity interact, and identifying the most widely applicable metric for peat decomposability that would enable quantitative comparison across the tropics. Until those gaps close, the review argues, simple assumptions — anoxia with saturation, a constant Q10 near two — remain the justifiable foundation for models. But the stakes could hardly be higher: as warming, drainage, fires and land-use change amplify across the tropics, the fate of a quarter of the planet’s soil carbon hangs on how well these equations capture the breath of the peat.

Subject of Research: Drivers of soil heterotrophic respiration in tropical peatlands

Article Title: Drivers of soil heterotrophic respiration in tropical peatlands: a review to inform peat carbon accumulation modelling

Article References: Dehaen, E. M., Burke, E. J., Chadburn, S. E., Kaduk, J., Sitch, S., Smith, N. D., & Gallego-Sala, A. V. (2025). Drivers of soil heterotrophic respiration in tropical peatlands: a review to inform peat carbon accumulation modelling. Frontiers in Geochemistry, 3, Article 1492386. https://doi.org/10.3389/fgeoc.2025.1492386

Image Credits: AI Generated

DOI: 10.3389/fgeoc.2025.1492386

Keywords: Drivers, soil, heterotrophic, respiration, tropical, peatlands, review, inform, peat, carbon, accumulation, modelling

The study, published in the journal Communications Earth & Environment, analysed 590 peatlands that were already documented on official maps in Austria, Germany and Switzerland. Rather than relying solely on those maps, the researchers built a new model that fuses multiple streams of Earth observation data. The workflow combines measurements from satellites sensing visible light with data from radar satellites, collected over the period from 2019 to 2023, and grounds the interpretation in field studies conducted on the ground. This multi-sensor strategy is crucial in mountain terrain, where clouds frequently obscure optical instruments and steep topography distorts simple satellite readings. Radar, which penetrates cloud cover and is sensitive to the moisture and structure of vegetation, complements the optical record and makes consistent monitoring possible across national borders.

When the team compared their modelled peatland extents with the official maps, a striking pattern emerged. The model repeatedly indicated that the mapped areas were significantly smaller than the boundaries shown in the national datasets. At first, the researchers suspected an error in their own method. But a closer look at the newest aerial photographs told a different story. The peatlands that appeared ‘too small’ in the model were disproportionately located in places showing clear visual evidence of disturbance, such as freshly cut drainage ditches or new paths cutting through formerly intact wet ground.

Dr Marian Schönauer of Mendel University in the Czech Republic, the study’s lead author, described the moment of realisation. The team initially believed the model was wrong, but then discovered that these undersized bogs were mostly situated in areas that had plainly been disturbed by human activity, including new drainage ditches or paths. In other words, the satellites were not failing to see the peatlands; they were accurately registering that parts of these wetlands had ceased to function as peatlands at all.

The aerial imagery revealed just how pervasive this pressure has become. Signs of disturbance were visible at almost 90 per cent of the 590 sites examined. Two categories of impact dominated. The first was the encroachment of trees and shrubs onto open peatland surfaces, a process known as scrub encroachment, which typically follows when the water table drops and the wet, acidic conditions that mosses and specialised peatland plants require begin to fade. The second was the construction of new infrastructure or drainage for agricultural use, such as drainage to improve hay production on mountain meadows. The drainage ditches dug for these purposes remain clearly visible in aerial photographs, etched into the landscape as dark linear scars.

The mechanisms behind this degradation are well understood in peatland ecology. Peatlands accumulate organic matter because waterlogged soils exclude oxygen, slowing the decomposition of dead plant material to a trickle. When ditches drain a bog or fen, air enters the peat, decomposition accelerates, and centuries of stored carbon begin to oxidise and escape as carbon dioxide. Lowered water tables also allow deeper-rooted shrubs and trees to colonise ground that was previously too wet and hostile for them, shading out the mosses and shifting the ecosystem toward ordinary forest or grassland. Once this transition takes hold, it is difficult and expensive to reverse, requiring the blocking of drains and years of rewetting to restore peat-forming conditions.

Dr Simon Drollinger of the University of Göttingen’s Bioclimatology group emphasised why these losses matter far beyond the Alps themselves. Alpine peatlands, he noted, are small habitats of great ecological importance: they store carbon in the long term, regulate the water cycle and provide habitat for specialised animal and plant species. Although individual Alpine peatlands are tiny compared with the vast boreal bogs of Scandinavia or Siberia, their combination of carbon storage, water regulation and unique biodiversity makes them disproportionately valuable per hectare. They act as natural sponges, buffering mountain valleys against both floods and droughts, and they harbour cold-adapted species, including glacial relicts, that survive nowhere else in the region.

The study’s central warning is that the condition of many bogs in the Alpine region may be more severely affected than previously thought, and that up-to-date data are crucial for planning targeted conservation and restoration interventions. Outdated official maps can mislead decision-makers in two ways. They may overstate the size and quality of peatlands that have actually been degraded, channelling protection toward habitats that no longer function, and they may miss degraded sites entirely, leaving them without any legal safeguard at all. In a policy landscape where funding for restoration is scarce and competing, accurate maps are the foundation on which every conservation decision rests.

To close that gap, the researchers are calling for a more comprehensive survey of Alpine peatlands and for better coordination of their protection and restoration across the countries that share the mountain range. Their freely available approach offers a practical path forward: it enables the regular satellite monitoring of peatlands, supports the planning of targeted field surveys where the data suggest change is occurring, and helps keep official maps continuously up to date. Because the workflow harmonises optical and radar data from multiple satellite sensors, it can be applied uniformly across political boundaries, giving Austria, Germany and Switzerland, for the first time, a shared and comparable picture of the state of their peatland heritage.

The significance of this work extends well beyond the Alpine arc. As climate change warms mountain regions faster than the global average, peatlands everywhere face intensifying pressure from drying, land-use change and infrastructure development. The demonstration that a multi-sensor satellite workflow can detect degradation signals across hundreds of small, scattered sites offers a template for monitoring remote wetlands in other mountain ranges of the world, from the Carpathians to the Andes. For the Alps, the message of the study is both sobering and actionable: with nearly nine in ten mapped peatlands already showing visible signs of disturbance, the window for protecting these carbon-rich, water-regulating, biodiversity-rich habitats is narrowing, but the tools to find and defend them are now in hand. Regular, border-crossing observation from orbit, combined with swift restoration on the ground, may be the decisive factor in whether the Alps’ tiny but mighty peatlands continue to cool the climate and shelter their rare species, or fade into drained meadows and encroaching forest.

Subject of Research: Degradation and satellite-based mapping of peatlands across the European Alps

Article Title: Alpine peatlands under pressure

Article References: Alpine peatlands under pressure. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: peatlands, Alps, satellite monitoring, remote sensing, carbon storage, wetland degradation, drainage, biodiversity, conservation, radar, aerial photography, restoration

The team cored four peatland sites along a 470-metre transect in the upper Fimba Valley, also known as Val Fenga: Lower Las Gondas, Upper Las Gondas, Marmot Mire and Lower Coffin Mire. Using a Russian corer, they extracted profiles up to 250 centimetres deep and dated them with radiocarbon measurements processed at the AMS laboratory in Poznań, Poland. Age-depth models were built with the Bayesian software Bacon and the IntCal20 calibration curve. The results reveal a strikingly asynchronous story: peat formation began between 10,450 and 9,000 calibrated years before present at the northern end of the transect, but only around 6,600 years ago at the southern end, tracing the slow retreat of the Fimba Valley glacier after the last ice age.

The methodological heart of the study is geochemical. The researchers measured elements such as titanium, lead, potassium, iron, strontium and rubidium using portable X-ray fluorescence spectrometry, a technique rarely applied quantitatively to peat, and cross-checked the results against 26 samples digested with hydrofluoric acid and measured by inductively coupled plasma mass spectrometry. One profile was also scanned with an XRF core scanner. The inter-calibration worked remarkably well: for peat samples, regression coefficients exceeded 0.95 for titanium and reached 0.99 for lead, meaning that field-portable instruments can deliver near-quantitative data even in these difficult, mineral-rich settings.

Titanium proved to be the key tracer of erosion. Because it arrives on the mires bound in mineral matter washed from the catchment, spikes in titanium mark episodes when glaciers upstream grew and meltwater streams delivered sediment onto the peat, interrupting peat growth. The most dramatic of these interruptions is a massive layer of coarse gravel in the Lower Las Gondas core, dated by the moss beneath it to around 8,200 calibrated years before present. This is strong evidence that the famous 8.2 ka cold event, a abrupt Northern Hemisphere cooling episode best known from Greenland ice cores, left a marked glacial fingerprint in the Silvretta Mountains, where its impact had previously been debated and even doubted.

The authors argue that only a cold and wet climate could have generated enough glacial activity to move coarse gravel into the mire, likely sourced from the Vadret da Fenga glacier field on the flank of the Fluchthorn peak. A similar gravel layer appears at the base of the Marmot Mire sequence at roughly the same age, and a silt layer in the Upper Las Gondas record also falls near 8,200 years ago. The findings align with regional evidence such as a descending treeline and the disappearance of trees near the upper mire after 8,400 years ago. Earlier, a thinner gravel layer at around 9,200 years ago points to another cold pulse, while cooler and wetter intervals follow at roughly 6,300, 5,400, 5,000 and 4,500 years before present.

From the mid-Holocene onwards, the signal becomes harder to read, because a second force begins to disturb the landscape: people. Humans have occupied the Silvretta region repeatedly over the last 11,000 years, and archaeological work has revealed dairy production in the area as early as the Early Iron Age. Mineral accumulation rates in the peat rise around 4,500 and 3,600 years before present, likely reflecting both climatic deterioration and the growing impact of Bronze Age pastoralism. Smaller increases around 3,400 and 3,200 years ago coincide with pollen evidence for agro-pastoral land use, suggesting that livestock management and associated soil disturbance were already reshaping valley slopes at high elevation.

The last 1,500 years tell an increasingly human-dominated story. Mineral accumulation rates in the Lower Las Gondas core climb from about 1 to over 120 grams per square metre per year, illustrating accelerating erosion through the Middle Ages and into modern times. Historical records show why: the village of Ischgl was first mentioned in 1104 CE, management of the Fimba alpine pasture is documented from 1163 CE, Walser settlers intensified deforestation and stocking density after the late fourteenth century, and heavy logging from the sixteenth to the late eighteenth century supplied regional mining. Layered on top of these pressures, the Little Ice Age brought strong glacial activity to the Silvretta, with the Vadret da Fenga reaching its maximum extent by the late nineteenth century.

Remarkably, the mires also preserved traces of atmospheric lead pollution despite their strongly minerotrophic, mineral-fed character, which normally complicates such signals. A distinct lead peak around 2,000 years before present coincides with the well-documented Roman-era metalworking pollution found across Europe, and a second rise after 1,500 years ago matches regional medieval and early modern mining. The authors note that erosion and decomposition in recent layers may have released some of the stored metal, yet the survival of these signals shows that even fen peatlands can archive airborne contamination, validating their age models in the process.

The implications reach beyond the history books. Peatlands store carbon and buffer floodwater, and the study warns that a millennium of grazing, trampling, erosion and drainage has suppressed peat accumulation in the Fimba Valley, undermining exactly these ecosystem services. This matters downstream: the Paznaun Valley, into which the Fimba creeks drain, is a known high-risk zone for severe flooding. The authors argue that land management in the region should explicitly account for the state of these degraded mires.

Perhaps the most encouraging conclusion is methodological. Small, dynamic, glacier-fed stream-bank mires have long been considered too noisy, too heterogeneous and too poorly dated to serve as climate archives. This study turns that weakness into an advantage: the very sediment pulses that disrupt peat growth are themselves records of glacier activity that conventional moraine-based methods often miss, because later glacier advances overprint the evidence. Read carefully, with multiple cores, radiocarbon dating, geochemistry and archaeological context combined, these humble alpine bogs turn out to be among the most complete witnesses to ten thousand years of cold, warmth, shepherds, miners and tourists in the heart of the Alps.

Subject of Research: Holocene climate and human impact recorded in alpine glaciofluvial peatlands of the Silvretta Mountains

Article Title: From the 8.2 ka event to the Little Ice Age: Holocene cold periods and human impact recorded in alpine glaciofluvial peatlands (Silvretta Mountains, Switzerland)

Article References: von Scheffer, C., De Vleeschouwer, F., Le Roux, G., & Unkel, I. (2025). From the 8.2 ka event to the Little Ice Age: Holocene cold periods and human impact recorded in alpine glaciofluvial peatlands (Silvretta Mountains, Switzerland). E&G Quaternary Science Journal, 74(2), 263-279. https://doi.org/10.5194/egqsj-74-263-2025

Image Credits: AI Generated

DOI: 10.5194/egqsj-74-263-2025

Keywords: peatlands, Holocene, 8.2 ka event, Little Ice Age, glaciers, Silvretta Mountains, pXRF, radiocarbon dating, pastoralism, lead pollution, alpine environment, flood mitigation

The research, led by Anne Y. Yusuf of RMIT University in Melbourne together with colleagues from RMIT, the University of Southern Queensland, Griffith University, and the University of Melbourne, focused on peatlands in the Bogong High Plains of the Australian Alps. The team compared three sites: one degraded peatland and two intact ones, all located within Victoria’s Alpine National Park, where soils were collected under a research permit issued by the Victorian Department of Environment, Land, Water and Planning. Alpine peatlands are rare and ecologically precious in Australia, and they face mounting pressure from historical drainage, livestock grazing, and fire — the same disturbance trifecta that threatens peatlands worldwide.

To understand how degradation reshapes the underground world, the researchers profiled the microbial communities living at different depths in the peat profile and related them to two critical environmental variables: the position of the water table and the chemical composition of the peat’s organic carbon. The carbon chemistry was characterized in terms of functional groups — the molecular building blocks such as alkyl, N-alkyl, O-alkyl, di-O-alkyl, aryl, O-aryl, and ketone structures — which together describe how labile, or easily decomposed, versus recalcitrant, or chemically stubborn, the peat’s carbon reservoir really is. This combination of microbiology and organic geochemistry allowed the team to ask not just who lives where, but why.

The results revealed a striking pattern. In the intact peatlands, microbial communities were strongly stratified: fungal and prokaryotic — bacterial and archaeal — communities differed markedly depending on depth in the profile and on their position relative to the water table. This vertical heterogeneity is exactly what one would expect in a healthy peatland, where the upper, aerated layer hosts a very different cast of organisms than the saturated, anoxic depths. The intact peats also showed strong associations between community structure and bulk indicators of carbon quality, particularly the total carbon concentration and the carbon-to-nitrogen ratio, suggesting that the microbial residents there are organized around the overall nutritional landscape of the peat.

In the degraded peatland, that orderly structure largely fell apart. The strong depth-dependent and water-table-dependent patterns in fungal and prokaryotic communities were markedly weaker or absent altogether. Instead of being arranged in coherent layers tied to oxygen availability, the microbial communities of the degraded site appeared shuffled, their organization decoupled from the hydrological architecture that normally governs it. At the same time, the chemistry signal changed: variation in the degraded peat’s microbial communities was linked more to specific carbon functional groups — the labile and recalcitrant molecular fractions — than to the bulk carbon and nitrogen measures that mattered in intact peats. In other words, degradation seems to rewrite both the physical structure of the microbial habitat and the chemical language through which microbes and organic matter interact.

Diversity itself told a story as well. The intact peats supported higher prokaryotic diversity and evenness, meaning more distinct microbial types present in more balanced proportions. Degradation, by contrast, was associated with a less diverse and less even prokaryotic community — a signature familiar from many disturbed ecosystems, where a handful of tolerant or opportunistic taxa come to dominate while specialists disappear. Because microbial diversity underpins the full suite of decomposition pathways, from slow anaerobic fermentation to methane production, losses of this kind can ripple through the entire carbon cycle of a peatland.

Why does this matter for the climate? The mechanism is rooted in redox chemistry. When a peatland’s water table is high, the deep peat stays anoxic, and decomposition proceeds slowly through anaerobic pathways, allowing carbon to accumulate faster than it is released. When drainage or degradation lowers the water table, oxygen floods into previously sealed layers, aerobic microbes switch on, and ancient carbon begins to oxidize into carbon dioxide. The new findings suggest that degradation does not merely flip this switch; it dismantles the entire regulatory apparatus. If the tight coupling between water table position and microbial community structure is lost, the ecosystem may lose a key buffer that would otherwise restrain decomposition when conditions fluctuate. A degraded peatland, in effect, may have fewer microbial safeguards standing between its carbon store and the atmosphere.

The shift in which chemical variables best explain microbial community structure is equally significant. Bulk carbon concentration and carbon-to-nitrogen ratio are coarse-grained descriptors; carbon functional groups are fine-grained ones. A community whose composition tracks specific functional groups such as O-alkyl carbohydrates or aryl aromatic structures is one that is responding to the molecular availability of its substrate — potentially indicating that decomposition in the degraded peat is being driven by which compounds are chemically accessible rather than by the broad nutritional context. Such a regime could favor the rapid consumption of labile carbon pools while leaving recalcitrant fractions exposed to slower attack, a dynamic that would progressively erode the peat’s capacity to hold carbon over centuries.

The study also carries a geographic wake-up call. Much of what the world knows about peat microbiology comes from the vast boreal and tropical peat domes of the Northern Hemisphere and Southeast Asia. Alpine peatlands in Australia are small by comparison, but they perform outsized functions: they act as alpine sponges, regulating water flow into major river systems, and they harbor distinctive Sphagnum-associated microbiomes. The Bogong High Plains sites, sampled with support from Australian Government and Parks Victoria scholarships, show that the microbial signatures of degradation are not unique to any one continent. Wherever drainage, grazing, and fire intersect with peat, the same architectural collapse of the microbial–carbon–water table relationship appears to follow.

For conservationists and land managers, the implications point toward restoration with a microbial lens. Rewetting drained peatlands is the flagship intervention, and this study adds a mechanistic rationale: restoring the water table may do more than slow aerobic decay — it may allow the depth-stratified microbial communities that regulate carbon storage to reassemble. Whether that reassembly is possible after severe degradation, and how long it takes, remains an open question that the authors’ framework is well suited to test. What is already clear is that peatland carbon storage is not a passive geological accident but an actively maintained biological system, one that depends on an intricate interplay of water, chemistry, and life. Degrade that interplay, and the planet’s most carbon-rich soils begin, microbe by microbe, to give back what they have spent thousands of years keeping out of the air.

Subject of Research: The effects of peatland degradation on microbial community composition, carbon chemistry, and water table interactions regulating soil carbon storage in alpine peatlands

Article Title: Peatland Degradation Alters the Microbial–carbon–water Table Interactions that Regulate Carbon Storage

Article References: Yusuf, A. Y., Krohn, C., Birnbaum, C., Hearn, K., Treby, S., Ball, A. S., Chapman, J., & Grover, S. (2026). Peatland Degradation Alters the Microbial–carbon–water Table Interactions that Regulate Carbon Storage. Microbial Ecology. https://doi.org/10.1007/s00248-026-02891-3

Image Credits: AI Generated

DOI: 10.1007/s00248-026-02891-3

Keywords: peatlands, microbial ecology, carbon storage, water table, soil carbon, fungal communities, prokaryotes, carbon functional groups, Australian Alps, peatland degradation, Sphagnum, climate

The stakes are higher than they might first appear. Evapotranspiration, the combined flux of transpiration from vegetation and evaporation from soil, water, and other surfaces, is the dominant way water leaves a wetland. Separating it into its two components matters because transpiration is tightly linked to photosynthesis, the process by which ecosystems pull carbon dioxide out of the air. Wetlands, especially peatlands, are among the planet’s most important carbon sinks and play an outsized role in regulating regional hydrology and climate. If scientists cannot reliably say how much water moves through plants versus straight off the surface, they cannot accurately model how these ecosystems will respond to drought, warming, or changes in water management.

The difficulty in wetlands stems largely from the moss itself. Mosses photosynthesize and contribute to ecosystem carbon uptake, yet they contribute nothing to transpiration, which is by definition a vascular-plant process. That decoupling violates a core assumption of several popular partitioning methods, which presume that photosynthesis and transpiration share identical sources and sinks. Mosses also behave unlike vascular plants in other ways: they cannot actively regulate water transport, relying instead on passive capillary rise, and they can store water equivalent to 300 to 500 percent of their dry weight. When dry conditions limit capillary supply, moss cells rapidly equilibrate with the surrounding air, suppressing both evaporation and photosynthesis even while the atmosphere’s evaporative demand remains high. These traits can scramble the environmental relationships that partitioning algorithms depend on.

To find out how badly these violations matter, the team assembled data from four moss-covered wetlands: three sites in the Canadian Rocky Mountains, named Sibbald, Burstall, and Bonsai, measured during the 2021 growing season, and a forested peatland near Fort McMurray, Alberta, called Poplar, measured in 2013. The sites spanned a remarkable range of conditions. Canopy heights ranged from 0.8 meters at Bonsai to 4.2 meters at Poplar, leaf area indices varied more than threefold, and hydrology differed sharply: Sibbald and Bonsai stayed non-flooded throughout, Burstall transitioned to flooded conditions in mid-August 2021, and Poplar remained flooded for nearly the entire study period.

The ten methods evaluated fell into three methodological groups. The first exploits high-frequency eddy covariance data, using rapid fluctuations in carbon dioxide and water vapor to statistically separate ground-level and canopy-level fluxes. The second group relies on ecosystem carbon-water coupling, inferring transpiration from the relationship between photosynthesis and water use, often built on theories of optimal stomatal behavior. The third group applies machine learning, training models to predict evaporation from nighttime measurements, when transpiration is assumed negligible, and then subtracting that estimate from total evapotranspiration. Each group carries its own vulnerabilities in a mossy wetland, from the possibility that moss photosynthesis flips the surface carbon signal to the fact that nighttime transpiration, though often small, is not always zero.

Against what benchmark should the methods be judged? The researchers compiled independent, measurement-based estimates of the transpiration-to-evapotranspiration ratio using micro-lysimeters, leaf porometers, flux chambers, and sap flow sensors, reconstructed into continuous daily time series with a site-calibrated Shuttleworth-Wallace model that explicitly accounted for moss and litter effects on ground evaporation. The calibrated model reproduced measured latent heat flux and ground evaporation closely, with coefficients of determination of 0.83 and 0.85 respectively. Because even careful field reconstructions carry uncertainty, the team also evaluated every method against the ensemble mean of all ten approaches, a second reference that averages out method-specific errors.

The results dismantled any hope of a universal winner. No single method outperformed the others across all four sites, and no methodological group demonstrated a clear overall advantage. Most methods performed no better than simply predicting the observed mean, as reflected in predominantly negative or near-zero Nash-Sutcliffe efficiency values. Among the high-frequency methods, mean transpiration estimates exceeded the measurement-based values by 18.4 percent on average, with individual methods diverging by more than 26 percent. The carbon-water coupling ensemble came closest in magnitude, exceeding the measurement-based mean by just 0.32 percent, yet its individual members swung wildly, with one method underestimating the ratio by nearly 168 percent relative to measurements.

Flooding proved especially revealing. When Burstall transitioned to flooded conditions in August 2021, the measurement-based transpiration ratio dropped sharply, but most methods barely registered the change. The single exception was the TEA algorithm, which estimates a temporally varying water-use efficiency with a random forest model, allowing it to adapt as the relationship between carbon uptake and water flux shifted after inundation. The machine learning framework of Eichelmann and colleagues, which had performed well in California freshwater marshes, failed to capture the transition here, likely because its models were trained under non-flooded conditions and the environmental relationships they learned no longer applied once the site was inundated. Yet at Poplar, continuously flooded and densely forested, the machine learning estimates stayed close to the references, hinting that sparse, waterlogged vegetation poses particular difficulties.

Perhaps the most unsettling finding concerned the benchmarks themselves. The measurement-based time series and the all-method ensemble showed markedly different correlation patterns with the evaluated methods, and the two references were not significantly correlated with each other at any site. In other words, the verdict on any given method depends heavily on which reference you trust, exposing deep uncertainty in how partitioning performance is benchmarked. The authors also found that ecosystem heterogeneity mattered: at Sibbald, with its multi-layered shrub canopy, large gaps, and hummock-hollow microtopography, methods agreed least with one another, while at the structurally homogeneous Poplar forest they agreed most.

The practical takeaway is not that existing methods are useless, but that none should be trusted alone. The authors recommend applying multiple approaches from all three groups concurrently wherever possible, using disagreement among methods to diagnose uncertainty, and paying particular attention to how water-use efficiency is parameterized, which emerged as a major source of inter-method conflict. More fundamentally, the study makes a case for developing wetland-specific partitioning approaches that explicitly represent moss-mediated carbon uptake, dynamic carbon-water coupling, and the transitions between unsaturated and flooded states that define so many of these ecosystems. As climate change alters wetland hydrology worldwide, the humble moss carpet, it turns out, is a harder scientific problem than anyone’s equations anticipated.

Subject of Research: Evaluation of eddy covariance-based evapotranspiration partitioning methods in moss-covered wetland ecosystems

Article Title: Technical note: How well do evapotranspiration partitioning approaches perform in moss-covered wetlands?

Article References: Wang, Y., Petrone, R. M., & Zhang, L. (2026). Technical note: How well do evapotranspiration partitioning approaches perform in moss-covered wetlands?. Biogeosciences, 23(19), 7067-7090. https://doi.org/10.5194/bg-23-7067-2026

Image Credits: AI Generated

DOI: 10.5194/bg-23-7067-2026

Keywords: evapotranspiration, wetlands, peatlands, moss, eddy covariance, transpiration, evaporation, machine learning, carbon-water coupling, hydrology, biogeosciences, water-use efficiency

The problem the researchers set out to solve is a stubborn one. Peatlands are among the largest terrestrial carbon reservoirs on the planet, and their expansion after the last ice age helped shape the concentration of methane and carbon dioxide in the Holocene atmosphere. Yet peat is perishable. Radiocarbon dating, the workhorse of peatland science, reaches back less than 50,000 years, and in formerly glaciated northern landscapes, ice sheets destroyed nearly all peat that formed before the Last Glacial Maximum. In old, undisturbed bogs, decomposition eventually balances the input of fresh plant litter, so the modern peat column no longer records the full history of peat on the landscape. Everything scientists believe about peatlands before the last glacial cycle therefore rests on a handful of exceptionally well-preserved deposits and on computer models.

The Belgian team’s solution exploits a property of quartz that has become one of geomorphology’s most powerful tools. Cosmic rays striking the uppermost meters of the Earth’s surface produce rare isotopes, including beryllium-10 and aluminum-26, inside mineral grains. The deeper a grain sits beneath overlying material, the fewer cosmic rays reach it, so the concentration of these cosmogenic nuclides in a sample carries a memory of how much mass, in this case peat, shielded it over its exposure history. Crucially, the two isotopes decay at different rates: aluminum-26 has a half-life of about 717,000 years while beryllium-10 persists for about 1.39 million years. When a landscape erodes slowly enough, the mismatch between these clocks becomes measurable, and the ratio of the two isotopes can be unpicked to yield both the rate of landscape lowering and the average thickness of the blanket above it simultaneously.

The Hautes Fagnes turned out to be an almost ideal natural laboratory. Perched on the highest ground in the Belgian Ardennes, the plateau receives about 1,440 millimeters of rain per year while mean annual temperatures hover near 6.7 degrees Celsius, and persistent orographic cloud keeps evapotranspiration low, conditions that favor peat accumulation. The study hillslope sits upstream of a mid-Pleistocene knickzone on the Hoëgne river, in a landscape so sluggish that it has barely responded to the uplift that rejuvenated rivers elsewhere in the Ardennes. The team cored through the modern peat blanket, which ranges from 0.2 to 2.1 meters deep along the transect, to collect saprolite, the rotted bedrock beneath, at six positions from the interfluve down to the channel. They also gathered stream sediment at the base of the slope and spent a full year gauging discharge and sampling stream water for dissolved silicon.

The measurements delivered a surprise. In quartz formed at the surface, aluminum-26 and beryllium-10 accumulate in a characteristic production ratio, about 7.2 at this site. Every sample the team analyzed fell below that ratio, from 3.29 at the summit to 6.06 at the toe-slope, and all plotted below the steady-state denudation line on a two-nuclide diagram by more than the modern peat cover could explain. Because the site sits near a local topographic high in a region never overridden by ice, deep burial by sediment or glaciers could not account for the deficit. The only plausible interpretation was that the samples had spent their exposure histories under substantially more shielding than the present-day peat provides, in other words, that the peat used to be much thicker.

To turn that qualitative signal into numbers, the researchers built a sophisticated inverse model. They accounted for the fact that saturated peat, which is roughly 90 percent water, attenuates cosmic radiation differently from mineral rock, adopting a shorter absorption mean free path of about 110 grams per square centimeter in peat compared with 160 in saprolite. They also modeled muon-induced production, which matters greatly under thick cover because muons penetrate far deeper than ordinary cosmic-ray nucleons. A Markov Chain Monte Carlo inversion then explored millions of parameter combinations to find those consistent with the measured isotope concentrations, yielding probability distributions rather than single answers. The results were cross-checked against an entirely independent estimate of the watershed-scale denudation rate, about 7.2 tons per square kilometer per year, derived from dissolved silicon fluxes and the weathering intensity of the regolith, which agreed in order of magnitude with the cosmogenic values.

The modeled denudation rates were astonishingly low, between 0.3 and 4.9 tons per square kilometer per year, equivalent to a landscape lowering of roughly 0.1 to 1.9 meters per million years, placing the Ardennes plateau among the slowest-eroding landscapes on Earth, comparable to ancient surfaces in Brazil, Australia, and South Africa. Because erosion is so slow, the isotope signal integrates over 0.7 to 1.8 million years, spanning every glacial-interglacial cycle since the mid-Pleistocene. Against that long baseline, the median long-term overburden thicknesses exceeded modern values by 190 to 350 grams per square centimeter along the transect, equivalent to roughly 1.8 to 3.4 meters of saturated peat. The inferred thicknesses, between about 2.5 and 4.2 meters, are physically sensible: they fall below the roughly 8.5-meter maximum observed in plateau raised bogs such as Misten, and their relationship to hillslope gradient obeys the classic groundwater-mound physics that governs steady-state bog morphology.

So where did the missing meters of peat go? The team systematically ruled out alternatives. Snow cover, even at persistent winter maxima, would add only a few grams per square centimeter of shielding on average, two orders of magnitude too little. A continuous loess blanket thick enough to explain the signal would have to exceed a meter and a half, yet no loess survives at the site and the geochemistry of the saprolite shows it formed in place from the underlying bedrock. Ground ice during periglacial episodes was too local and too short-lived. That leaves human activity. Peat cutting for fuel is documented in the Hautes Fagnes since the sixteenth century and intensified dramatically in the nineteenth, when records show nearly 200,000 cubic meters extracted annually. Medieval mowing, grazing, slash-and-burn cultivation, and wildfires shifted the bogs into negative mass balance, and drainage ditches plus spruce plantations in the early twentieth century accelerated subsidence at rates of one to two centimeters per year reported for comparable bogs. Together, the authors calculate, these pressures could account for more than two meters of peat loss, explaining most of the gap between the long-term average and today’s thin blanket.

The summit sample held one final revelation. Its model clearly resolved a step-change in overburden thickness, a thickening event with peak probability between 0.8 and 1.4 million years ago, which the authors interpret as the onset of the peat blanket itself. Remarkably, that timing coincides with a well-documented pulse of tectonic uplift in the Ardennes, recorded by the abandonment of the Younger main terrace of the Meuse and Rhine rivers around 0.7 million years ago. Before that uplift, the summit stood near 530 meters elevation, just below the threshold where orographic cooling and cloudiness begin to create the cool, wet conditions peat requires. As the massif rose roughly 100 meters, the site crossed into peat-forming territory, tying the birth of this carbon-rich ecosystem directly to the slow breathing of the Earth’s crust.

Beyond its local story, the study carries a warning for anyone estimating erosion rates in peatland terrain. If the beryllium-10 concentration in the stream sediment were interpreted the conventional way, assuming the modern peat cover represents long-term steady state, the resulting erosion rate would overestimate landscape lowering by an order of magnitude, because depressed aluminum-26 to beryllium-10 ratios masquerade as deep burial rather than thick organic cover. The paired-nuclide approach demonstrated here should work in any slowly eroding, unglaciated landscape with peat, from the moorlands of southwestern Britain to tropical cratonic peatlands in Amazonia and the Congo basin. And pairing beryllium-10 with cosmogenic carbon-14, whose short half-life suits faster-eroding and formerly glaciated terrain, could soon extend the method to peatlands worldwide. At a moment when drained and degraded peatlands are recognized as ticking carbon bombs, the Hautes Fagnes offer a sobering baseline: what we see today is not what these landscapes once were, and the atmosphere remembers the difference.

Subject of Research: Using paired cosmogenic 26Al and 10Be nuclides to reconstruct long-term peat thickness and denudation rates in the Hautes Fagnes upland peatland, Belgian Ardennes

Article Title: Long-term peat thickness from cosmogenic 26Al and 10Be, Hautes Fagnes, Belgian Ardennes

Article References: Moore, A., Henrion, M., Li, Y., du Bois d'Aische, E., Gautschi, P., Christl, M., Jonard, F., Lambot, S., Van Oost, K., Opfergelt, S., & Vanacker, V. (2026). Long-term peat thickness from cosmogenic 26 Al and 10 Be, Hautes Fagnes, Belgian Ardennes. Earth Surface Dynamics, 14(5), 763-780. https://doi.org/10.5194/esurf-14-763-2026

Image Credits: AI Generated

DOI: 10.5194/esurf-14-763-2026

Keywords: cosmogenic nuclides, peatlands, beryllium-10, aluminum-26, Hautes Fagnes, Belgian Ardennes, denudation rates, carbon cycle, peat degradation, land use history, mid-Pleistocene uplift, Earth Surface Dynamics

The story begins with a sediment core recovered from the Amundsen Sea during an expedition of the research icebreaker Polarstern. In 2020, the same international team, led by marine geologist Dr Johann Klages of the Alfred Wegener Institute, stunned the scientific community when they announced in the journal Nature that the core contained an extraordinarily well-preserved forest soil dating back roughly 90 million years, complete with abundant pollen, spores and a dense network of fossil roots. During the Cretaceous, tectonic conditions placed this temperate rainforest even farther south than the drill site itself, a mere 900 kilometres from the geographic South Pole. Today, average annual temperatures at that location hover around minus 30 degrees Celsius, and the entire region lies beneath an ice sheet several kilometres thick.

The climate that supported such a forest was shaped by greenhouse conditions unlike anything in the recent geological past. Atmospheric carbon dioxide concentrations during the warmest interval of the Cretaceous were four to six times higher than preindustrial modern levels, and the average annual temperature in the West Antarctic rainforest reached around 12 degrees Celsius, roughly two degrees warmer than present-day Germany. Rainfall was plentiful but strongly seasonal: dry periods regularly gave way to monsoon-like rainy seasons. For about four months of each year, the forest endured the continuous darkness of the polar night, yet conifers and tree ferns thrived, and dinosaurs roamed through the misty swamplands. It was this combination of warmth, abundant moisture and pronounced seasonality that set the stage for the fires the team has now documented.

In the new study, the researchers re-examined the same core using a broader suite of analytical methods, and the evidence of fire proved unmistakable. Throughout the Late Cretaceous section of the sediment sequence, the team identified microscopic charcoal particles, the diagnostic residue of vegetation burned in situ or transported short distances by water and wind. Critically, the abundance of these charcoal particles increased steadily in the younger sediments, indicating that fires became more frequent as the ecosystem evolved. The particles themselves carried chemical and structural signatures showing that the fuel was mainly soft conifer wood burned at relatively low temperatures, a pattern typical of surface fires that creep through undergrowth and ground litter without climbing into the forest canopy.

Fire left its mark in more than charcoal. The sediments also yielded amber, the fossilised form of tree resin, appearing in a configuration that suggests the resin flowed over fire-damaged areas of tree trunks and hardened into a protective seal, much as living conifers today exude resin to wall off wounds. Together, the charcoal and amber record a forest that was burned and healed, burned and healed again, over an extended stretch of Late Cretaceous time. Because volcanically active areas lay at least 400 kilometres away from the site during that period, the researchers conclude that the most plausible ignition source was not lava or volcanic ash flows but lightning strikes from thunderstorms, a conclusion consistent with the strongly seasonal, storm-prone climate inferred from the broader sedimentological and palaeontological evidence.

Perhaps the most consequential discovery in the core concerns what grew back after the fires. The sediments contain countless spores of peat moss of the genus Sphagnum, the same group of plants that dominates raised bogs across the modern Northern Hemisphere. These spores provide evidence of some of the earliest raised bogs known, and their rise was closely intertwined with the recurrence of fire. According to the scenario the researchers developed from their data, the temperate and very swampy Antarctic rainforest, with its alternating dry and monsoon seasons, gradually silted up and transitioned into a peatland dominated by peat mosses. Wildfires, growing ever more frequent, played a decisive role in that transition by keeping the vegetation open, preventing the re-establishment of dense forest, and creating the conditions under which waterlogged, moss-dominated ground could persist and expand.

Once the peat bog had formed, fire did not disappear from the system. Instead, it changed character. Ground-level smouldering fires occurred repeatedly within the peat itself, burning slowly through damp, carbon-rich material rather than racing through standing forest. Co-first author Prof. Dr Ulrich Salzmann of Northumbria University draws a direct line from that ancient process to the present day, noting that such smouldering ground fires resemble those that have become increasingly common in German peatlands in recent years, where prolonged drought has lowered water tables and left once-saturated peat vulnerable to slow, persistent combustion. The Antarctic core thus preserves a complete natural experiment in how fire, hydrology and vegetation interact during the birth and maturation of a peatland, conducted under greenhouse conditions far warmer than today’s.

The climate significance of that experiment is difficult to overstate. Peatlands are among the most effective long-term carbon stores on Earth, accumulating partially decomposed plant material over thousands to millions of years because waterlogged conditions slow decay to a crawl. Co-first author Prof. Dr Thorsten Bauersachs of RWTH Aachen University emphasises that peatlands played a key role in the climate system then as now, precisely because of this capacity to lock away carbon over long periods. Paradoxically, the Cretaceous record suggests that in a warm climate, where wetlands dry out more quickly and fires that suppress forest development occur more frequently, conditions can actually favour the formation of new peatlands, allowing carbon-rich plant matter to accumulate even as the world warms. Fire, in other words, was not merely a destructive force in this ancient ecosystem but an architect of one of the planet’s most durable carbon sinks.

For the research team, the parallels between the Cretaceous Antarctic and today’s high latitudes were among the most surprising findings of the study. Dr Johann Klages, co-first author of the paper, describes the team’s astonishment at finding evidence in the core of an early Antarctic ecosystem that, in many respects, resembled today’s Arctic raised bogs and also experienced regular fires. Modern raised bogs in Arctic and boreal regions face acute threats from climate change and increasing drought, and the fate of the carbon they store is a major uncertainty in projections of future warming. The West Antarctic record demonstrates that peat formation and fire can coexist and even reinforce one another under greenhouse conditions, but it also shows how sensitive these systems are to the balance between moisture and burning, a balance that human-driven warming is now shifting across the northern peatlands.

The study also underscores how much remains hidden beneath the Antarctic ice. A single sediment core, drilled through the seafloor of the Amengen Sea region, has now yielded a rainforest soil, a fire history and the trace of the earliest polar peatlands, all from a time when the South Pole itself was green. As analytical methods grow more sensitive, existing cores continue to surrender new secrets, and each one refines the picture of how Earth’s most extreme greenhouse intervals functioned. Ninety million years ago, lightning-lit fires crackled through swampy conifer forests under a polar night, and from those ashes rose the bogs that would bury carbon for geological time. Understanding that ancient dance between flame and moss may prove essential to anticipating what a warming world will do to the peatlands that still guard vast reservoirs of carbon today.

Subject of Research: Cretaceous wildfires and early Sphagnum peatland formation near the South Pole

Article Title: Evidence of ancient wildfires near the South Pole

Article References: Evidence of ancient wildfires near the South Pole. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Antarctica, wildfires, Cretaceous, peatlands, Sphagnum, paleoclimate, charcoal, amber, carbon storage, West Antarctica, sediment core, climate change