Article

PEATMAP: Refining estimates of global peatland distribution based on a meta-analysis

January 2018
CATENA 160:134-140

DOI:10.1016/j.catena.2017.09.010

Authors:

Jiren Xu

University of Glasgow

Junguo Liu

North China University of Water Resources and Electric Power

Peatlands play important ecological, economic and cultural roles in human well-being. Although considered sensitive to climate change and anthropogenic pressures, the spatial extent of peatlands is poorly constrained. We report the development of an improved global peatland map, PEATMAP, based on a meta-analysis of geospatial information collated from a variety of sources at global, regional and national levels. We estimate total global peatland area to be 4.23 million km 2 , approximately 2.84% of the world land area. Our results suggest that previous global peatland inventories are likely to underestimate peat extent in the tropics, and to overestimate it in parts of mid-and high-latitudes of the Northern Hemisphere. Global wetland and soil datasets are poorly suited to estimating peatland distribution. For instance, tropical peatland extents are overestimated by Global Lakes and Wetlands Database – Level 3 (GLWD-3) due to the lack of ground-truthing data; and underestimated by the use of histosols to represent peatlands in the Harmonized World Soil Database (HWSD) v1.2, as large areas of swamp forest peat in the humid tropics are omitted. PEATMAP and its underlying data are freely available as a potentially useful tool for scientists and policy makers with interests in peatlands or wetlands. PEATMAP's data format and file structure are intended to allow it to be readily updated when previously undocumented peatlands are found and mapped, and when regional or national land cover maps are updated and refined.

Mapping Peatland Distribution and Quantifying Peatland Below‐Ground Carbon Stocks in Colombia's Eastern Lowlands

Article

Full-text available

Apr 2025

The extent and distribution of tropical peatlands, and their importance as a vulnerable carbon (C) store, remain poorly quantified. Although large peatland complexes in Peru, the Congo basin, and Southeast Asia have been mapped in detail, information on many other tropical areas is uncertain. In the Eastern Colombian lowlands, peatland area estimates range from 700 km² to nearly 60,000 km², leading to highly uncertain C stocks. Using new field data, high‐resolution Earth observation (EO), and a random forest approach, we mapped peatlands across Colombian territory East of the Andes below 400 m elevation. We estimated peatland extent using two approaches: a conservative method focused on medium‐to‐high peat probability areas and a more inclusive one accounting for large low‐probability areas. Multiplying these extents by below‐ground carbon density yields a conservative estimate of 0.95 (0.6–1.39 Pg C, 95% confidence interval) over 9,391 km² (7,369–11,549 km²) and up to 2.86 Pg C (1.76–4.22 Pg C) across 29,069 km² (22,429–36,238 km²). Among four potentially peat‐forming ecosystems identified, palm swamps and floodplain forests contributed most to the peat extent and C stock. We found that most peatland patches were relatively small, covering less than 100 ha. We compared our map to previously published global and pan‐tropical peat maps and found low spatial overlap among them, suggesting that peat maps uninformed by local field information may not precisely specify which landscape areas within a peatland‐rich region are actually peatlands. We further assessed the suitability of different EO and climate variables, highlighting the need for high‐resolution data to capture local heterogeneities in the landscape.

Drainage density and land cover interact to affect fire occurrence in Indonesian peatlands

Article

Full-text available

Apr 2025
ENVIRON RES LETT

Fire occurrence in tropical peatlands is closely related to both land cover (LC) type and proximity to drainage (canal) networks. However, little is known about the extent to which LC and drainage density interact to alter fire occurrence. Here, we assess the relationship between these variables in the peatlands of Sumatra and Kalimantan, Indonesia, spanning a five-year period of inter-annual climatic variability. Visible Infrared Imaging Radiometer Suite imagery was used to map active fire hotspots. Drained peatlands experienced up to 13 times greater annual mean hotspot density (number of fire hotspots per km²) when compared to peatlands without canals. The greatest difference in fire hotspot density between drained and undrained peatlands occurred in forested peatlands (by a factor of 2.6–13.3), followed by shrublands (1.1–7.6), crop lands (1.4–5.0) and plantations (1.2–2.6), where largest differences were found in El Niño Southern Oscillation (ENSO) neutral years. We found a curvilinear relationship between hotspot density and canal density, with the relationship depending on LC and ENSO status. At low to moderate drainage density, hotspot density increased with drainage density in all LC types in 2013–2017. Heavily drained plantations experienced a lower hotspot density than moderately drained plantations possibly due to factors such as management practices or impacts of previous fire history. The relationship with drainage density was strongest in 2013, an ENSO-neutral year, and weakest in the strong El Niño of 2015. Our findings support the critical need for fire management in drained tropical peat areas. Peat fire management planning and peatland restoration should be tailored to the differing responses of fire to climate variability, drainage density and LC types.

Widespread carbon-dense peatlands in the Colombian lowlands

Article

Full-text available

Apr 2025
ENVIRON RES LETT

Peatlands are some of the world’s most carbon-dense ecosystems and release substantial quantities of greenhouse gases when degraded. However, conserving peatlands in many tropical areas is challenging due to limited knowledge of their distribution. To address this, we surveyed soils and plant communities in Colombia’s eastern lowlands, where few peatlands have previously been described. We documented peat soils >40 cm thick at 51 of more than 100 surveyed wetlands. We use our data to update a regional peatland classification, which includes a new and possibly widespread peatland type, ‘the white-sand peatland,’ as well as two distinctive open-canopy sub-types. Analysis of peat bulk density and organic matter content from 39 intact peat cores indicates that the average per-area carbon densities of these sites (490–1230 Mg C ha⁻¹, depending on type) is 4–10 times the typical carbon stock of a (non-peatland) Amazonian forest. We used remote sensing to upscale our observations, generating the first data-driven peatland map for the region. The total estimated carbon stock of these peatlands of 1.91 petagrams (Pg C) (2-sigma confidence interval, 0.60–4.22) approaches that of South America’s largest known peatland complex in the northern Peruvian Amazon, indicating that substantial peat carbon stores on the continent have yet to be documented. These observations indicate that tropical peatlands may be far more diverse in form and structure and broadly distributed than is widely understood, which could have important implications for tropical peatland conservation strategies.

Half of land use carbon emissions in Southeast Asia can be mitigated through peat swamp forest and mangrove conservation and restoration

Article

Full-text available

Jan 2025

Southeast Asia (SEA) contributes approximately one-third of global land-use change carbon emissions, a substantial yet highly uncertain part of which is from anthropogenically-modified peat swamp forests (PSFs) and mangroves. Here, we report that between 2001–2022 land-use change impacting PSFs and mangroves in SEA generate approximately 691.8±97.2 teragrams of CO2 equivalent emissions annually (TgCO2eyr⁻¹) or 48% of region’s land-use change emissions, and carbon removal through secondary regrowth of −16.3 ± 2.0 TgCO2eyr⁻¹. Indonesia (73%), Malaysia (14%), Myanmar (7%), and Vietnam (2%) combined accounted for over 90% of regional emissions from these sources. Consequently, great potential exists for emissions reduction through PSFs and mangroves conservation. Moreover, restoring degraded PSFs and mangroves could provide an additional annual mitigation potential of 94.4 ± 7.4 TgCO2eyr⁻¹. Although peatlands and mangroves occupy only 5.4% of SEA land area, restoring and protecting these carbon-dense ecosystems can contribute substantially to climate change mitigation, while maintaining valuable ecosystem services, livelihoods and biodiversity.

Mismatch Between Global Importance of Peatlands and the Extent of Their Protection

Article

Full-text available

Feb 2025

Global peatlands store more carbon than all the world's forests biomass on just 3% of the planet's land surface. Failure to address mounting threats to peatland ecosystems will jeopardize critical climate targets and exacerbate biodiversity loss. Our analysis reveals that 17% of peatlands are protected globally—substantially less than many other high‐value ecosystems. Just 11% percent of boreal and 27% of temperate and tropical peatlands are protected, while Indigenous peoples' lands encompass at least another one‐quarter of peatlands globally. Peatlands in protected areas and Indigenous peoples' lands generally face lower human pressure than outside those areas. Yet, almost half of temperate and tropical peatlands in protected areas still experience medium to high human pressure. Country submissions of Nationally Determined Contributions under the Paris Agreement and National Biodiversity Strategy and Action Plans under the Kunming–Montreal Global Biodiversity Framework could help catalyze actions and secure funding for peatland conservation, including support for the Indigenous stewardship that is critical to protect many of the world's highest priority peatland areas.

Impact of Snow on Underground Smoldering Wildfire in Arctic-Boreal Peatlands

Article

Full-text available

Feb 2025
ENVIRON SCI TECHNOL

Overwintering peat fires are re-emerging in snow-covered Arctic-boreal regions, releasing unprecedented levels of carbon into the atmosphere and exacerbating climate change. Despite the critical role of fire-snow interactions in these processes, our understanding remains limited. Herein, we conducted small-scale outdoor experiments (20 × 20 × 20 cm3) at sub-zero temperatures (-5 ± 5 ℃) to investigate the impact of natural snowfall and accumulated snow layers (up to 20 cm thick) on shallow smouldering peat fires. We found that, even heavy natural snowfalls (a maximum water-equivalent snowfall intensity of 1.1 mm/h or a 24-h accumulated snowfall water-equivalent precipitation of 7.9 mm) cannot suppress a shallow smouldering peat fire. A thick snow cover on the peat surface can extract heat from the burning front underneath, and the minimum thickness of the snow layer to extinguish the peat fire was found to be 9 ± 1 cm at sub-zero temperatures, agreeing well with the theoretical analysis. Furthermore, larger-scale field demonstrations (1.5 m × 1.5 m) were conducted to validate the small-scale experimental phenomena. This work helps understand the interactions between fire and snow and reveals the persistence of smouldering wildfires under cold environments.

Peat Depth and Carbon Storage of the Hudson Bay Lowlands, Canada

Article

Full-text available

Jan 2025
GEOPHYS RES LETT

Plain Language Summary The Hudson Bay Lowlands (HBL) contain the second largest peatland complex in the world. We used spatial data sourced from satellite observations and geospatial information that are associated with peat occurrence, age, formation, and accumulation to estimate peat depth and carbon storage at 30 × 30 m spatial details for the entire HBL. We combined several machine learning models together in a way that improves their ability to work well on new data with a technique called “stacking,” to improve the accuracy of peat depth estimation. The estimated average peat depth was 184 cm while the entire HBL stores 30 billion tonnes of carbon. The peat depth and carbon storage information presented in this study will help monitor and assess the vulnerability of carbon storage to anticipated changes in climate, resource development, land use, and disturbances that are intensifying in the region. They are also crucial for managing and protecting this vital ecosystem, quantifying the carbon cost of resource development, and for developing ecologically sound land management practices in the region.

Air temperature and precipitation constraining the modelled wetland methane emissions in a boreal region in northern Europe

Article

Full-text available

Jan 2025
BG

Wetland methane responses to temperature and precipitation are studied in a boreal wetland-rich region in northern Europe using ecosystem process models. Six ecosystem models (JSBACH-HIMMELI, LPX-Bern, LPJ-GUESS, JULES, CLM4.5, and CLM5) are compared to multi-model means of ecosystem models and atmospheric inversions from the Global Carbon Project and upscaled eddy covariance flux results for their temperature and precipitation responses and seasonal cycles of the regional fluxes. Two models with contrasting response patterns, LPX-Bern and JSBACH-HIMMELI, are used as priors in atmospheric inversions with Carbon Tracker Europe–CH4 (CTE-CH4) in order to find out how the assimilation of atmospheric concentration data changes the flux estimates and how this alters the interpretation of the flux responses to temperature and precipitation. Inversion moves wetland emissions of both models towards co-limitation by temperature and precipitation. Between 2000 and 2018, periods of high temperature and/or high precipitation often resulted in increased emissions. However, the dry summer of 2018 did not result in increased emissions despite the high temperatures. The process models show strong temperature and strong precipitation responses for the region (51 %–91 % of the variance explained by both). The month with the highest emissions varies from May to September among the models. However, multi-model means, inversions, and upscaled eddy covariance flux observations agree on the month of maximum emissions and are co-limited by temperature and precipitation. The setup of different emission components (peatland emissions, mineral land fluxes) has an important role in building up the response patterns. Considering the significant differences among the models, it is essential to pay more attention to the regional representation of wet and dry mineral soils and periodic flooding which contribute to the seasonality and magnitude of methane fluxes. The realistic representation of temperature dependence of the peat soil fluxes is also important. Furthermore, it is important to use process-based descriptions for both mineral and peat soil fluxes to simulate the flux responses to climate drivers.

Plant functional type control on soil microbial activity and carbon source utilization in permafrost peatland

Article

Full-text available

Apr 2025
PLANT SOIL

Background and aims Climate warming can lead to changes in plant functional types (PFTs) in permafrost peatlands, which can subsequently affect soil properties and microbial functional structures. Although the effects of PFTs changes on soil microorganisms in various ecosystems have been documented, these effects are not well understood in permafrost peatlands. Methods This study investigated the impact of removing different PFTs (sedges, evergreen shrubs, deciduous shrubs, and mosses) on soil properties and microbial functional structures (microbial activity, microbial diversity, and carbon source utilization) in a permafrost peatland. Results Variations in PFTs lead to changes in soil properties and microbial functional structures. Removal of shrubs and mosses increased soil dissolved organic carbon (DOC) content by 26% and inorganic nitrogen content by 28%, the soil microbial activity and diversity were significantly enhanced, and microbes preferred amino acids and carboxylic acids as carbon sources compared to the natural control (N). In contrast, the moss treatment (M) with shrubs and sedge removed had 30% lower soil DOC and 50% lower inorganic nitrogen content, as well as a significant reduction in microbial activity and diversity, with microorganisms preferring to utilize polymers as a carbon source. Conclusion These results indicate that peatland microorganisms are sensitive to changes in PFTs over short time scales, with a particularly rapid response to specific plant functional groups such as sedges. These findings highlight the critical role of PFTs as drivers of microbial functional structures and suggest that future vascular plant expansion may alter peatland microbial functional structures and carbon cycling in the context of climate change.

Bioclimatic, terrain, and specific peatland composition are major drivers of woodland caribou winter habitat suitability in northern Ontario

Article

Full-text available

Mar 2025

Mapping of winter habitat suitability is important for the persistence and conservation of at-risk woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)). While well documented at the national scale for boreal woodland caribou, particularly in highly disturbed southern ranges, winter habitat suitability remains understudied in northern and intact ranges such as in northern Ontario. We used boosted regression tree species distribution modeling and environmental variables with ecological relevance to woodland caribou to predict and map suitable winter woodland caribou habitat in northeastern Ontario, Canada. The best model suggests that peatland types and the climatic effect of James and Hudson Bay may have a marked (68.8% cumulative relative influence) effect on woodland caribou habitat suitability. Based on this, a predictive model identified a large and clustered zone of winter woodland caribou habitat centered within the transition between the ecozones. By accounting for local-scale aspects of woodland caribou habitat and bioclimatic variables, our model provides comprehensive predictions of woodland caribou winter habitat suitability in this transition zone. Additional investigation of the role of peatland type in woodland caribou habitat suitability in different seasons and different regions may help further understand woodland caribou distribution and habitat use.

Changes in Aquatic Carbon Following Rewetting of a Nutrient‐Poor Northern Peatland

Article

Full-text available

Mar 2025

Rewetting drained peatlands by raising the groundwater table is currently suggested, and widely implemented, as an efficient measure to reduce peat soil degradation and decrease CO2 emissions. However, limited information exists regarding effects of peatland rewetting on lateral carbon export (LCE) via the aquatic pathway. Any changes in LCE are critical to consider, as they affect the overall peatland C balance, and may offset any climatic benefits from rewetting. Additionally, altered LCE could have consequences for downstream water quality and biota. Here, we monitored aquatic C content (DOC, DIC and CH4) in runoff and pore water, as well as radiocarbon content of DOC in runoff from a drained, nutrient‐poor boreal peatland that was rewetted during autumn 2020. By comparing pre‐ (2019–2020) and post‐ (2021–2022) rewetting periods, we detected changes in the aquatic C export. The results showed that the rewetting effect was site‐, season‐ and C form‐specific. Overall, one catchment showed elevated (DOC, DIC) or highly elevated (CH4) concentrations and exports post‐rewetting, whereas the other site showed only elevated DOC. Changes in runoff C concentrations after rewetting were likely driven by site‐specific factors such as expansion of open‐water areas, altered hydrological flow paths and proportion of filled in ditches of total ditch length. Finally, radiocarbon measurements indicated enhanced export of contemporary DOC via runoff following rewetting. These initial (short‐term) findings highlight the need for site‐specific before‐after assessments to better evaluate the C sequestration capacity of peatlands while undergoing rewetting operations.

Revised and updated geospatial monitoring of 21st century forest carbon fluxes

Article

Full-text available

Mar 2025

Earth observation data are increasingly used to estimate the magnitude and geographic distribution of greenhouse gas (GHG) fluxes and reduce overall uncertainty in the global carbon budget, including for forests. Here, we report on a revised and updated geospatial, Earth-observation-based modeling framework that maps GHG emissions, carbon removals, and the net balance between them globally for forests from 2001 to 2023 at roughly 30 m resolution, hereafter referred to as the Global Forest Watch (GFW) model (see the “Code and data availability” section). Revisions address some of the original model's limitations, improve model inputs, and refine the uncertainty analysis. We found that, between 2001 and 2023, global forest ecosystems were, on average, a net sink of -5.5± 8.1 Gt CO2e yr⁻¹ (gigatonnes of CO2 equivalent per year ± 1 standard deviation), which reflects the balance of 9.0 ± 2.7 Gt CO2e yr⁻¹ of GHG emissions and -14.5± 7.7 Gt CO2 yr⁻¹ of removals, with an additional -0.20 Gt CO2 yr⁻¹ transferred into harvested wood products. Uncertainty in gross removals was greatly reduced compared with the original model due to the refinement of uncertainty for carbon removal factors in temperate secondary forests. After reallocating GFW's gross CO2 fluxes into anthropogenic fluxes from forest land and deforestation categories to increase the conceptual similarity with national greenhouse gas inventories (NGHGIs), we estimated a global net anthropogenic forest sink of -3.6 Gt CO2 yr⁻¹, excluding harvested wood products, with the remaining net CO2 flux of -2.2 Gt CO2 yr⁻¹ reported by the GFW model as non-anthropogenic. Although the magnitude of GFW's translated estimates aligns relatively well with aggregated NGHGIs, the temporal trends differ. Translating Earth-observation-based flux estimates into the same reporting framework that countries use for NGHGIs helps build confidence around land use carbon fluxes and supports independent evaluation of progress towards Paris Agreement goals. The data availability is as follows: carbon removals (Gibbs et al., 2024a, https://doi.org/10.7910/DVN/V2ISRH), GHG emissions (Gibbs et al., 2024b, https://doi.org/10.7910/DVN/LNPSGP), and net flux (Gibbs et al., 2024c, https://doi.org/10.7910/DVN/TVZVBI).

The hidden carbon fluxes — unearthing root-related processes in boreal peatland forests

Article

Jan 2025

Wei He

Fine-root production (FRP) and decomposition are critical processes influencing element cycling and carbon (C) balance in boreal peatlands. The aim of this thesis was to estimate FRP across various peatland forests, examine the patterns in, and develop statistical models for estimating, the relationships between FRP and stand and site characteristics, as well as climate variables (I); and to quantify fine-root decomposition rates in various types of drained peatland forests and compare them with corresponding rates in mineral-soil forests (II). FRP was measured using ingrowth cores, covering the 0−50 cm peat profile across 28 drained peatland forest sites in Finland (I). Total site-level FRP values ranged from 30 to 473 g m−2 year−1 of dry mass, with an average of 120 g m−2 year−1, with 76–95% occurring in the 0−20 cm soil layers. Total FRP showed significant variation across different site types and generally declined with decreasing fertility, except for the most fertile site type. Additionally, total FRP tended to be higher in sites with a deeper water table (WT). Stand basal area was the best predictor of total FRP, explaining 16% of the variation at the stand-level. A model incorporating stand basal area and site type explained 47% of the variation in total FRP. Fine-root decomposition was studied using litterbags containing roots from three dominant tree species (Pinus sylvestris, Picea abies, Betula pubescens) and one fern species (Dryopteris carthusiana), covering the 0−30 cm soil profile in six drained peatland and four mineral-soil forest sites in Finland (II). Fine-root decomposition showed significant variation with soil type and nutrient regime. On nutrient-poor sites, the decomposition of fine roots was slower in peat soils compared to corresponding mineral-soil sites, while the opposite was observed in nutrient-rich sites. Consequently, fine-root decomposition was fastest in nutrient-rich peat soils. Sampling depth and root diameter also influenced decomposition rates, with slower rates in deeper soil layers and for larger diameter roots. Among the tree species, P. abies had the slowest decomposition rate. In conclusion, FRP varied significantly across site types, with higher production observed in deeper WT sites and nutrient-rich conditions, while stand basal area emerged as a key predictor. Fine-root decomposition was influenced by soil type and nutrient regime, root diameter, and sampling depth, with faster decomposition in nutrient-rich peat soils and slower rates in deeper layers and for larger roots. These findings provide valuable insights into the interactions between fine-root dynamics and site-specific characteristics, contributing to a better understanding of C cycling in drained peatland forests

Brown Forest and Organic Soils: Rich Carbon Reserves to Provide Soil Ecosystem Services

Article

Full-text available

Mar 2025

Soils’ ecosystem services, with special reference to soil carbon reserves, are immense in food production and maintaining ecosystems and biodiversity for prosterity. Among most of the soils, brown forest soils mostly formed in the forest under cooler climates or supported by soil conditioners in the humid tropics, store relatively high levels of organic carbon. Besides. organic soils mainly found under peats and marshy areas also reserve sizeable amounts of organic carbon. The role of these two types of soils in ecosystem services is discussed in this paper.

Effects of substrate quality, temperature, and water content on the decomposition of Sphagnum peat

Article

Full-text available

Mar 2025
CATENA

Peatlands, with their high water tables and anoxic conditions, have inherently low organic matter decomposition rates, making them vital carbon reservoirs. We designed a laboratory incubation experiment to investigate the interactive effects of substrate quality, temperature, and water content on the decomposition rate of Sphagnum peat. Fresh and degraded peat was collected from three different depths (0-5, 5-15, and 15-30 cm) of an Australian alpine peatland. The water contents of the peat samples were adjusted to four levels (field-moist or 50 %, 400 %, or 1500 %) and incubated at four temperatures (7, 14, 21, and 28 • C) for 70 days. Overall, fresh peat had ~ 50 % higher decomposition rate than degraded peat. Both fresh and degraded peat incubated at 7 • C had higher or similar decomposition rates to peat at 14 • C, regardless of water content, likely due to the Sphagnum peat being dominated by psychrophilic microbes that have optimal metabolism at low temperatures. Further, the duration for which peat at 7 • C had a higher decomposition rate than at 14 • C declined as water content declined in the fresh peat and as peat depth increased in degraded peat. These findings indicate that the decomposition rate of fresh peat with a high percentage of labile carbon content is determined by the availability of liquid water required for microbial metabolism, while in degraded peat, substrate availability controls the decomposition rate. Our study provides critical insights into carbon release dynamics in southern hemisphere Sphagnum peat-lands, which can inform strategies for managing and conserving these critical carbon reservoirs.

The state of drained peatlands in the Middle Urals and prospects of their use for carbon farming

Article

Full-text available

Mar 2025

The global change of the planet's climate is associated with increased concentration of greenhouse gases in the atmosphere, which is the result of irrational human economic activity. Wetlands are a natural and efficient store of carbon dioxide. It covers only about 6% of the land surface. Peatlands contain one-third of all soil carbon, or 600 billion tons, which is two times more than the entire global forest biomass pool. Only ocean sediments contain more carbon. Peatlands in the boreal zone, characterized by snowy winters and short warm summers, contain on average seven times more carbon per hectare than any other ecosystem, and ten times more in the tropics. Restoration of drained wetlands to enable their use for carbon farming is also advisable, because it reduces carbon dioxide emission caused by microbial oxidation of peat and by wildfires in the drained areas. Therefore, comprehensive research on the role of drained wetlands in capturing and storing greenhouse gases is crucial for the sustainable management of these valuable ecosystems. Identifying the most promising areas for carbon farming is an important challenge for both global and regional studies. In 2022, the Basyanovsky and Koksharovsko-Kombaevsky drained peatlands located in the Sverdlovsk region (the Middle Urals) were studied as a part of reconnaissance work aimed at finding and selecting peatlands suitable for carbon farming. These peatlands are currently not used for peat harvesting and undergo active natural restoration. The area of secondary rewetting within the Koksharovskypeatland was also studied. On the territory of the Koksharovo-Kombayevsky peatland, the species composition of vegetation in both woody and grass-shrub strata, the composition of peat deposits, and the rate of carbon accumulation were evaluated. Based on the results of this research, the most promising peatland for carbon farming and further study of greenhouse gas emissions appeared to be the Koksharovsko-Kombayevsky peatland.

Long-term ecosystem dynamics of an ice-poor permafrost peatland in eastern Eurasia: paleoecological insights into climate sensitivity

Preprint

Full-text available

Mar 2025

Northern peatlands are carbon-rich ecosystems highly sensitive to climate change, with nearly half of their carbon stocks associated with permafrost. Peat-based paleoecological records provide insights into the complex responses of permafrost peatlands to long-term climate variability, but most studies were conducted in ice-rich permafrost peatlands in Europe and North America. Here, we use multiple active-layer cores to reconstruct the ecosystem history of an ice-poor permafrost peatland in eastern Eurasia, near the southernmost limit of circumpolar permafrost but outside the circumpolar thermokarst landscape. Our results show that the peatland, which developed on a floodplain since the late Holocene cooling, underwent a major phase of lateral expansion during the Little Ice Age. A fen-to-bog transition occurred in recent decades, with dry-adapted Sphagnum mosses replacing herbaceous vegetation across the site and having rapid surficial peat accumulation. Carbon isotope ratios of Sphagnum macrofossils, a proxy for surface wetness, indicate that Sphagnum mosses initially established under very dry conditions but that their habitats have since become gradually wetter. Synthesizing these findings, we highlight that: (1) permafrost aggradation during climate cooling may promote new peatland formation over permeable mineral substrate by impeding drainage; (2) anthropogenic climate warming and active layer deepening can induce an ecosystem-scale regime shift, but ice-poor permafrost peatlands generally exhibit stability and homogeneity due to the absence of dynamic surface morphology (such as frost heave and thermokarst collapse); (3) recent wetting may result from surface adjustment–hydrology feedback and vegetation–hydrology feedback, demonstrating the internally driven resilience of ice-poor permafrost peatlands in maintaining their hydrology and carbon accumulation; and (4) ice-poor permafrost peatlands are likely to remain persistent carbon sinks under ongoing and future climate change.

Peat Water Purification using Pahae Natural Zeolite and Activated Carbon Derived from Candlenut Shell (Aleurites moluccana)

Article

Feb 2025

The escalating demand for freshwater due to the increased global population and intensified industrial activities necessitates innovative approaches to water treatment. This study explores the efficacy of a novel composite adsorbent material consisting of Pahae natural zeolite and activated carbon derived from candlenut shells for purifying peat water. This research synthesizes and evaluates the composite under varying conditions to determine its potential as an effective adsorbent material. Characterization methods included X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Brunauer-Emmett-Teller (BET) and physical properties of adsorbent. The results demonstrated that the 80:20% zeolite to activated carbon ratio exhibited the highest porosity of 56.49% and a significant water absorption capacity of 53.65%. This composition also achieved the most peat water substantial purification lowering the initial turbidity, pH, color, iron and manganese concentration from 175.4 TCU, 31.32 NTU, pH 5, 1.44 mg/L, and 0.76 mg/L to 41.7 TCU, 11.24 NTU, pH 6.8, 0.242 mg/L, and 0.020 mg/L. SEM analyses showed a more porous surface morphology at 80:20% which corroborated with the higher purification of peat water. The adsorption mechanisms involving physical adsorption due to pore size were integral as the adsorbent in capturing contaminants. The findings suggest that such adsorbent can be tailored to improve performance and provide a viable solution to the global freshwater scarcity challenge.

Harnessing iChip technology for novel antibiotic discovery from peat soil microbiomes to combat antimicrobial resistance

Article

Full-text available

Feb 2025

Climate Warming and Deglaciation Drive New Peat Formation in the Southern Alps, Aotearoa/New Zealand

Article

Full-text available

Feb 2025
GEOPHYS RES LETT

Nascent peatlands represent an emerging, nature‐based carbon sink in the global climate system. A warming climate and changing precipitation regime could drive peat initiation beyond the current latitudinal and altitudinal boundaries of the peatland bioclimatic envelope, through increases in plant productivity and moisture availability, with potential implications for global radiative forcing. However, contemporaneous observations of new peat formation remain scarce. We investigate peat initiation within the deglaciating Rob Roy valley in the Southern Alps, Aotearoa/New Zealand. We find that montane peats have developed across the head of the valley since ∼1949 C.E., coinciding with regional climate warming and glacial retreat. Further, we identify a common ecological succession, characterized by a rise in brown mosses (mainly Bryum) beginning around ∼1963 C.E. Our findings indicate the potential for wider peat expansion in increasingly warm and wet montane landscapes. However, further bioclimatic modeling is required to elucidate where future peatland developments may occur.

Satellite-based modeling of wetland methane emissions on a global scale (SatWetCH4 1.0)

Article

Full-text available

Feb 2025
GMD

Wetlands are major contributors to global methane emissions. However, their budget and temporal variability remain subject to large uncertainties. This study develops the Satellite-based Wetland CH4 model (SatWetCH4), which simulates global wetland methane emissions at 0.25° × 0.25° and monthly temporal resolution, relying mainly on remote-sensing products. In particular, a new approach is derived to assess the substrate availability, based on Moderate-Resolution Imaging Spectroradiometer (MODIS) data. The model is calibrated using eddy covariance flux data from 58 sites, allowing for independence from other estimates. At the site level, the model effectively reproduces the magnitude and seasonality of the fluxes in the boreal and temperate regions but shows limitations in capturing the seasonality of tropical sites. Despite its simplicity, the model provides global simulations over decades and produces consistent spatial patterns and seasonal variations comparable to more complex land surface models (LSMs). Such an independent data-driven approach based on remote-sensing products is intended to allow for future studies of intra-annual variations in wetland methane emissions. In addition, our study highlights uncertainties and issues in wetland extent datasets and the need for new seamless satellite-based wetland extent products. In the future, there is potential to integrate this one-step model into atmospheric inversion frameworks, thereby allowing for the optimization of the model parameters using atmospheric methane concentrations as constraints and hopefully better estimates of wetland emissions.

Mid-term (5 years) impacts of wildfire on soil chemical and biological properties in a UK peatland

Article

Full-text available

Feb 2025
APPL SOIL ECOL

Peat degradation due to human activities and global change exposes peatlands to increasing fire risk. Given their key ecological role in carbon storage and water filtration, studying fire impacts on a UK peatland is significant in a global context. This study aimed to assess the medium-term impacts of the 2018 wildfire on peatland soil within the Roaches Nature Reserve (UK). To test whether fire effects were still evident five years after the event and whether marginally affected areas exhibited greater soil recovery, several peat characteristics were evaluated in 2023 at increasing distances from the unburnt control area toward the fire's ignition point, in the order S1, S2, S3 and S4. Results confirmed that the fire effect was still evident after five years, showing a significant increase in pH from 3.59 ± 0.04 in control to 3.85 ± 0.03 in burnt peat, a 60 and 70 % reduction in water and organic carbon content compared to control (65.2 ± 1.33 % and 42.9 ± 1.80 %, respectively), up to 85 % reductions in microbial carbon and nitrogen relative to control (2.48 ± 0.12 and 0.17 ± 0.01 g kg − 1 , respectively). The observed spatial gradient of fire impact was: S4 ≫ S3 = S1 ≥ S2, only partially confirming the second hypothesis. As expected, S4 site, farther from the unburnt area, exhibited the worst recovery, but S1 site, proximal to the unburnt area, did not show the highest recovery. This is probably due to the variable nature of peatland fire dynamics and post-fire recovery, highlighting the need for more detailed analyses in future studies.

Peatlands as Geo-Archives for Atmospheric Micro- and Nano-Plastics: A Perspective Review

Article

Full-text available

Feb 2025

Since commercial manufacture of plastics started around 1950, plastics have grown more and more important to human society. The ubiquity of plastic particles in the environment and Inefficient waste management have led to the presence of tiny plastic particles in a wide range of natural matrices. Nowadays, finding natural environments with the most potential to archive the past deposition of airborne microplastics is among the hot research topics while investigating plastic pollution across the globe. The capability of peatlands as the most widespread type of wetlands throughout the earth to illustrate natural and anthropogenic deposition of different contaminants has drawn the attention of researchers in recent years. A number of studies have been conducted on the presence and distribution of various pollutants in peatland areas. However, there is still limited information on the presence of microplastics in peatlands. The purpose of this study is to gather the existing data on the occurrence, deposition and distribution of microplastics in peatland areas. We have tried to examine the potential of peatlands as natural archives of atmospheric micro and nano plastics. The research indicates that peatlands serve as a reliable (with some uncertainties) geo-archive for atmospheric micro(nano)plastics. It thoroughly assesses various methods, from sampling to final analyses, to empower researchers in selecting the most effective approach.

Historical Variation in Carbon Fractions in Permafrost Peatland and Its Effects on Peatland Carbon Pool

Article

Feb 2025
LAND DEGRAD DEV

Permafrost peatlands store high amount of soil carbon. These developed on permafrost layers, which are being endangered increasingly by climate change and wildfires. However, limited data exist on the variation in carbon fractions and their effects on the stability of permafrost peatland carbon pools, despite that carbon fractions are widely used in other ecosystems. Here, we considered that peat soils consist of undecomposed plant litter and separated these into five carbon fractions: macro plant residue carbon (MPRC), coarse particulate organic carbon (cPOC), free particulate organic carbon (fPOC), occluded particulate organic carbon (oPOC), and mineral‐associated organic carbon (MAOC). We analyzed the historical variation in these fractions over the past 700 years and their effects on the carbon pool in the Hongtu peatland (HT, northern Great Khingan Mountains, China). Our results showed that MPRC comprised 66.7% ± 7.6% of the carbon pool, whereas oPOC and MAOC accounted for less than 1%. Notably, fPOC, which represented 15.6% ± 6.5% of the total carbon, had a high aromatic content. It may serve as an important stable carbon fraction for the peatland carbon pool. Over the past 700 years, the decrease in proportion of MPRC and increase in proportions of cPOC and fPOC have resulted in significant increases in both carbon content and aromaticity. Warm/dry conditions and high‐intensity fires reduced the accumulation rates (ARs) of MPRC while increasing those of fPOC and cPOC. The high organic carbon content in the HT peatland limited the availability of mineral elements and resulted in MAOC ARs of approximately 0.01 g m ⁻² yr ⁻¹ . This was strongly influenced by the regional dust deposition. Cold climates and intense fires caused an increase in dust deposition, which also increased the MAOC ARs.

High-resolution mapping of peatland CO2 fluxes using drone multispectral images

Article

Full-text available

May 2025
ECOL INFORM

Climate change impacts on blanket peatland in Great Britain

Article

Full-text available

Jan 2025
J APPL ECOL

Peatland restoration has been suggested as a key method for the UK to meet national, legally binding climate targets. This can involve blocking up drainage ditches or erosion features, as well as encouraging regeneration of peatland vegetation through Sphagnum reintroduction or removal of scrub or trees. It is unclear, however, how suitable future conditions will be for both peat accumulation and Sphagnum survival. We applied three bioclimatic envelope models for blanket bogs in Britain to assess how future climate is likely to deviate from current conditions, focussing on four national parks with significant peatland area (Dartmoor, the Flow Country, the Peak District and Snowdonia). We also assessed the likelihood of thresholds being passed at which irreversible desiccation of Sphagnum moss may occur. Our bioclimatic envelope models use updated climate projections (bias‐corrected UKCP18 projections under Representative Concentration Pathways (RCP) 2.6, 4.5 and 8.5) that are more accurate in the upland regions in which blanket bogs can occur, and use thresholds of blanket bog occurrence which are tailored to Britain. This gives us higher confidence in the results as compared to previous models. Our results show substantial losses in areas suitable for peatland by 2061–2080 under all RCPs. Under RCP8.5 there is virtually no peatland within its current bioclimatic envelope in our case study areas and only limited areas in Snowdonia under RCP4.5, suggesting these regions will be outside the ideal conditions that lead to peat accumulation. Only western Scotland retains substantial areas suitable for peat. The frequency of Sphagnum desiccation events is projected to increase by between 44% and 82% which will likely result in decreased success of hummock forming species, particularly at easterly sites where rainfall is lower, though wetter microsites will likely allow more drought‐tolerant species to persist. Policy implications. Action should be taken to raise water tables at degraded sites to limit the impact of future drought conditions. However, climatic conditions being outside the current bioclimatic envelope may make full restoration challenging. Sphagnum reintroduction programmes may have greater success utilising drought‐tolerant species as hummock forming species are at greater risk of die off during desiccation events.

Water quality impacts from post-fire erosional events: A case study from a peatland within the Greater Blue Mountains World Heritage Area

Conference Paper

Full-text available

Aug 2024

Key Points • Peatlands are recognised fragile ecosystems that cover approximately 0.40% of the Greater Blue Mountains World Heritage Area. • Extreme climatic events result in pulses of nutrients downstream. • Loss of peatlands reduces water storage capacity in upper catchments. Abstract Peatlands occur globally and are known to store significant amounts of water and key nutrients such as carbon, nitrogen, and phosphorus. Extensive research has been conducted on peat in the Northern Hemisphere, however, research is limited for Australian peatlands. A peatland at Kings Tableland within the Greater Blue Mountains World Heritage Area was assessed after a period of drought (2017-2019), severe bushfires and a high rainfall event (which occurred within a six-week period in 2020) to explore the export of nutrients, including carbon, nitrogen, and phosphorus into downstream waterways. The entire study site (4.74 ha) was burnt (at high to extreme severity) in 2019-2020, and a subsequent heavy rainfall event resulted in an estimated export of 3.46 t of carbon, 0.14 t of nitrogen, and 0.03 kg of phosphorus from the site. The total loss of peat material across the site during this event was estimated at 58 t. This equates to a water storage loss of approximately 0.03 ML from this peatland in less than six weeks. Peatlands are a precious resource, however, peat loss due to desiccation, fire, and erosion can significantly impact water storage and nutrient export. This has implications for downstream water quality, including higher sediment loads, the export of key nutrients which may lead to eutrophication, and increased flows contributing to erosion. The protection of natural hydrology is important for reducing degradation of peatlands and potential impacts to downstream environments.

Water quality impacts from post-fire erosional events: A case study from a peatland within the Greater Blue Mountains World Heritage Area

Presentation

Full-text available

Aug 2024

Particles emitted from smouldering peat: size-resolved composition and emission factors

Article

Full-text available

Jan 2025

Peat fires emit large quantities of particles and gases, which cause extensive haze events. Epidemiological studies have correlated wildfire smoke inhalation with increased morbidity and mortality. Despite this, uncertainties surrounding particle properties and their impact on human health and the climate remain. To expand on the limited understanding this laboratory study investigated the physicochemical characteristics of particles emitted from smouldering Irish peat. Properties investigated included number and mass emission factors (EFs), size distribution, morphology, and chemical composition. Fine particles with a diameter less than 2.5 μm (PM2.5), accounted for 91 ± 2% of the total particle mass and the associated mass EF was 12.52 ± 1.40 g kg⁻¹. Transmission electron microscopy imaging revealed irregular shaped metal particles, spherical sulfate particles, and carbonaceous particles with clusters of internal particles. Extracted particle-bound metals accounted for 3.1 ± 0.5% of the total particle mass, with 86% of the quantified metals residing in the fraction with a diameter less than 1 μm. Redox active and carcinogenic metals were detected in the particles, which have been correlated with adverse health effects if inhaled. This study improves the understanding of size-resolved particle characteristics relevant to near-source human exposure and will provide a basis for comparison to other controlled and natural peatland fires.

Mountain Bogs of Costa Rica: Ecological Dynamics, Biogeography, Diversity, and Conservation

Chapter

Jan 2025

High-altitude mountain bogs, located in the Central and Talamanca Mountain Ranges of Costa Rica (1200–3100 m a.s.l.), remain one of the least explored inland aquatic ecosystems and potentially one of the most geographically restricted. These unique wetlands are confined to topographic depressions with limited drainage, rely solely on rainfall for the maintenance of their water bodies, and can dry up entirely during prolonged dry spells. Since they are limited to specific topographic and soil conditions and maintain a characteristic biota with many endemic species, mountain bogs deserve urgent conservation attention. Unfortunately, human activities have significantly impacted these fragile ecosystems (e.g. soil drainage for agricultural purposes, illicit extraction of plant species, fragmentation, pollution, and fire). Concentrated predominantly in Talamanca, mountain bogs represent discrete biomes embedded within oak forests and páramos, reflecting a complex interplay between the parent material, the topography, and climatic factors. Here, we discuss the ecological traits, biogeographic significance, limnological characteristics, representative organisms, and climate change vulnerability of mountain bogs and propose key research areas to enhance the management and conservation of this ecosystem. We compiled a list of 108 vascular plant species (27% endemics), analyzed the bird species composition, and listed representative amphibians and reptiles, particularly the endemic Bolitoglossa salamanders. We present a preliminary list of expected mammals (57 species, 18 endemics, and 3 bat genera). Aquatic insects and crustaceans are just beginning to be explored, but several new reports and new species were reported. Mountain bogs are particularly diverse and are characterized by high levels of endemism. They are important carbon reservoirs and serve as a comprehensive paleobotanical pollen record showing fluctuations in the location of the tree line and the extension of páramos in the geologic past. Climate change may cause significant species turnover and elevational shifts due to decreasing rainfall and increasing temperatures, further compounded by the risk of biological invasions and habitat loss mediated by human activities such as road construction and powerline installation. Urgent scientific research and comprehensive conservation strategies are imperative to safeguard the endangered mountain bog ecosystem, ensuring its continued existence and resilience amidst escalating environmental pressures and anthropogenic disturbances.

Fluctuations of Water Table Level in a Subtropical Peatland, Central China

Article

Apr 2025
J EARTH SCI-CHINA

Water level is the overriding control on carbon cycles in peatlands, which are important for global carbon cycles and ecosystem services. To date, our knowledge of the pattern of water level fluctuations in peatlands and the influence of precipitation and air temperature on them in the subtropical remains poor. In this study, we conducted continuous high-resolution monitoring of water levels from 2014 to 2021 in the Dajiuhu peatland, a typically subtropical peatland in central China. Monitoring results showed that the water level had strong annual (370 days) and seasonal (130 days) oscillations in the Dajiuhu peatland. The annual oscillation is associated with both precipitation and temperature, while the seasonal oscillation is mainly controlled by precipitation. In addition, the depth of peat surface to the water table (DWT) has weak but significant correlations with precipitation and temperature on the daily and weekly scales (r = 0.1–0.21, p < 0.01). Once replacing DWT with water table fluctuation cumulation, the correlation coefficients increase apparently (r = 0.47–0.69, p < 0.01), especially on the monthly scale. These findings highlight a more important role of the fluctuation than the mean position of water level and have the potential to improve the interpretation of water-level related paleoenvironmental proxies and the understanding of the relationship between water level and biogeochemical processes.

Towards Resilient Peatlands: Integrating Ecosystem-Based Strategies, Policy Frameworks, and Management Approaches for Sustainable Transformation

Article

Apr 2025

This paper examines the critical importance of peatlands in climate regulation, biodiversity conservation, and the provision of essential ecosystem services, emphasizing the urgent need for their preservation and restoration. Although peatlands cover just 3% of global land, they store 30% of the world’s terrestrial carbon, making them vital for mitigating climate change. However, activities such as agriculture, forestry, and peat extraction have caused significant degradation, compromising their ecological integrity and climate functions. This review makes a unique contribution by applying a systems thinking approach to synthesize the interconnected technical, environmental, and socioeconomic dimensions of peatland management, an often underrepresented perspective in existing literature. By offering a holistic and integrative analysis, it identifies key leverage points for effective and sustainable conservation and restoration strategies. This paper also explores the European Union’s policy response, including the EU Restoration Law and sustainability initiatives aimed at peatland recovery. It highlights the shift from peat use in energy production to its application in horticulture, reflecting growing demand for sustainable alternatives and eco-friendly restoration practices across Europe. Furthermore, this review addresses the environmental consequences of peat extraction, such as increased greenhouse gas emissions and biodiversity loss and emphasizes the need for robust EU legislation aligned with climate neutrality and biodiversity enhancement goals. It concludes by advocating for comprehensive research and proactive, policy-driven measures to ensure the long-term protection and sustainable use of these vital ecosystems.

Evaluation of the Extinguishing Efficiency of Eco-Friendly Soap-Based Media Against Prolonged Simulated Peat Fires

Article

Apr 2025

Peat fires generate significant greenhouse gas emissions, thereby posing considerable environmental challenges arising from smoke pollution, health hazards, and ecological impacts. Water alone is inefficient for extinguishing peat fires because it cannot immediately penetrate the soil. Therefore, firefighting agents with high penetrative capabilities are used. This study evaluated an environmentally friendly soap-based firefighting agent against peat fires in Palangka Raya, Indonesia. A 1.5 m × 1.5 m peat area was burned for 24 h to simulate a peat fire. The fire was then extinguished either with groundwater or a 1 vol.% soap-based firefighting agent solution. With groundwater, the volumes required to extinguish the fire were 16.0 and 23.9 L/m2, whereas with the soap-based solution, the volumes used were 3.8 and 7.4 L/m2. Furthermore, the time to extinguish the fire with the soap-based solution was approximately one-third of the requirement when using water alone. The soap-based firefighting agent was proven to be more effective against peat fires than water alone, reducing both the amount of agent used and the time required for extinguishing the fire. Given the increased severity of fires in recent years, this agent can facilitate the efficient management of peat fires.

A case study of the effect of permafrost peat on fires in the Arctic using Sentinel-5P data

Article

Apr 2025

Characterization of DOC in riparian wetland pore water and its interference in stable water isotope analysis of δ2H and δ18O

Article

Apr 2025
J HYDROL

Assessing the SMAP Level-4 Carbon Product Over the Arctic and Subarctic Zones

Article

Full-text available

Jan 2025
IEEE J-STARS

The Soil Moisture Active Passive (SMAP) satellite mission distributes a product of CO

_{2}

flux estimates (SPL4CMDL) derived from a terrestrial carbon flux model in which SMAP brightness temperatures are assimilated to update soil moisture (SM) and constrain the carbon cycle modeling. While the SPL4CMDL product has demonstrated promising performance across the continental USA and Australia, a detailed assessment over the Arctic and Subarctic zones (ASZ) is still missing. In this study, SPL4CMDL net ecosystem exchange (NEE), gross primary production (GPP), and ecosystem respiration (R

_{\text{E}}

) are evaluated against measurements from 37 eddy covariance towers deployed over the ASZ, spanning from 2015 to 2022. The assessment indicates that the NEE unbiased root mean square error (ubRMSE) falls within the targeted accuracy of 1.6 gC.m

^{-2}

^{-1}

, as defined for the SPL4CMDL product. However, modeled GPP and R

_{\text{E}}

are overestimated at the beginning of the growing season over evergreen needleleaf forests and shrublands, while being underestimated over grasslands. Discrepancies are also found in the annual net CO

_{2}

budgets. SM appears to have a minimal influence on the GPP and R

_{\text{E}}

modeling, suggesting that ASZ vegetation is rarely subjected to hydric stress, which contradicts some recent studies. These results highlight the need for further carbon cycle process understanding and model refinements to improve the SPL4CMDL CO

_{2}

flux estimates over the ASZ.

Terrain is a stronger predictor of peat depth than airborne radiometrics in Norwegian landscapes

Preprint

Full-text available

Mar 2025

Peatlands are Earth's most carbon-dense terrestrial ecosystems and their carbon density varies with the depth of the peat layer. Accurate mapping of peat depth is crucial for carbon accounting and land management, yet existing maps lack the resolution and accuracy needed for these applications. This study evaluates whether digital soil mapping using remotely sensed data can improve existing maps of peat depth in western and southeastern Norway. Specifically, we assessed the predictive value of LiDAR-derived terrain variables and airborne radiometric data across two, >10 km2 sites. We measured peat depth by probing and ground-penetrating radar at 372 and 1878 locations at the two sites, respectively. Then we trained Random Forest models using radiometric and terrain variables, plus the national map of peat depth, to predict peat depth at 10 m resolution. The two best models achieved mean absolute errors of 60 and 56 cm, explaining one-third of the variation in peat depth. Terrain variables were better predictors than radiometric variables, with elevation and valley bottom flatness showing the strongest relationships to depth. Radiometric variables showed inconsistent predictive value – improving performance at one site while degrading it at the other. The accuracy of the national map of peat depth did not measure up to any of our remote sensing models, even though it was calibrated to the same data. Still, weak relationships with remotely sensed variables made peat depth hard to predict overall. Based on these findings, we conclude that digital soil mapping can improve existing, broad-scale maps of peat depth in Norway, but highly localized carbon stock assessments are best made from field measurements. Furthermore, the inability of models to identify peat presence outside known peatlands highlights the need for integrated mapping of peat lateral extent and depth. Together, these pathways promise more accurate landscape-scale carbon stock assessments and better-informed land management policies.

Remote Sensing for Identification and Mapping of Thermokarst Landforms: A Review

Article

Mar 2025
PERMAFROST PERIGLAC

Permafrost is deeply involved in a series of geophysical processes, and it plays an important role in the hydrology cycle, vegetation evolution, and greenhouse gas emission. As one of the most sensitive indicators of global climate warming, the dynamic changes in permafrost distribution and its thermal state have been the focus of cryospheric change research. The highly developed remote sensing technology can provide abundant earth observation data over a wide spatiotemporal range, and it has become a powerful approach to detecting permafrost variations and their related landforms. In this review, we summarize the applications of remote sensing technologies in identifying and mapping typical thermokarst landforms that are closely related to permafrost degradation, namely, thermokarst lakes, thaw slumps, and thermokarst bogs. We emphasize the great potential of using automated methods on high‐resolution optical images and the extraction of multi‐temporal kinematic information from laser scanning and interferometric synthetic aperture radar (InSAR). We not only show the usefulness of remote sensing in the identification and mapping of thermokarst landforms, but we also point out several limitations and future directions for further improvement.

Potential of rhizospheric bacteria isolated from ferns ( Nephrolepis sp) growing in peatlands of West Kalimantan as biofertilizers

Article

Mar 2025

Peatlands are critical ecosystems known for their carbon sequestration capabilities and unique plant biodiversity. However, their acidic and nutrient-poor conditions pose challenges for plant growth and soil fertility. This study investigated the potential of bacteria isolated from rhizosphere of fern ( Nephrolepis sp) in peatlands to act as biofertilizers, enhancing soil fertility and plant growth. The research was carried out on peatlands at three distinct locations in Pontianak, West Kalimantan. Ferns, due to their high survival ability, dominate these peatlands and their rhizosphere is a potential source of beneficial bacteria. Eleven bacterial strains were successfully isolated from NA medium. The bacteria isolated on NA medium were then examined for their ability to solubilize phosphorus (P), fix nitrogen (N), and produce indole-3-acetic acid (IAA). Results showed that 5 isolates could solubilize P, 6 isolates could fix N, and 3 isolates were positive for IAA production. Additionally, 2 bacteria were found to have no ability to solubilize P, fix N, or produce IAA. This study highlights the potential of utilizing beneficial rhizobacteria from peatland ecosystems as biofertilizers, contributing to sustainable agricultural practices and the conservation of these sensitive environments.

Change in Particle Density and Other Hydrophysical Properties With Depth in a Northern Boreal Bog Peatland

Article

Mar 2025
WETLANDS

Advances in peatland ecohydrological modelling require higher resolution depth profiles of important soil physical properties, which exist as a continuum from Sphagnum-dominated surface cover to highly decomposed peat at depth. We determined the bulk and particle density, porosity, saturated hydraulic conductivity (Ksat ), and von Post score at 5 locations in a northern bog to a depth of ~ 200 cm in 5-cm intervals. The bulk and particle densities and von Post scores increased, and porosity decreased with depth. The particle density had a relatively abrupt shift near ~ 75 cm changing from ~ 0.8 g cm− 3 to a relatively consistent ~ 1.4 g cm− 3. The variability measured was small in the upper ~ 25 cm, larger at depths of ~ 25–125 cm, and became more moderate at depths > ~ 125 cm (but not particle density). The variability of bulk density at the deeper depths results in the observed variability of porosity. The larger variability in physical properties roughly coincides with the abrupt shift in the magnitude of measured properties suggesting that contemporary processes and/or past events (e.g., wildfire, or vegetation succession and peat botanical type) could be responsible for this pattern. Bulk and particle density and porosity exhibited a relationship with the von Post score with a shift in values between von Post scores of 3 and 4. Detailed examination of peatland soil properties, in particular particle densities which are not commonly reported, will improve the robustness and reliability of models and may reveal additional information on the history and processes of formation.

Integrating Environmental Conservation and Cultural Values in Peatland泥炭地の環境保全と文化的価値の統合: A Literature Review of World Heritage Designation and the Scottish Whisky Industry世界遺産登録とウィスキー産業の関係に関する文献研究

Article

Mar 2025

This study examined the relationship between peatland conservation, World Heritage designation, and the whisky industry in Scotland through literature review. Analysis of 1,332 papers revealed a significant increase in peatland conservation research since 2020, particularly during the year of Flow Country's World Heritage designation in 2024. While conservation and whisky industry research have been developing independently, studies integrating cultural landscape perspectives remain limited. This study highlights the necessity of understanding peatland conservation not just as an environmental issue, but also from the perspective of preserving cultural landscapes that encompass regional identity and traditional industries.

Mapping the distribution and condition of mountain peatlands in Colombia for sustainable ecosystem management

Article

Mar 2025
J ENVIRON MANAGE

High mountain peatlands in Colombia play a crucial role in water regulation, store significant carbon, and yet remain poorly studied and threatened. The lack of a comprehensive national peatland map hinders effective management. Our objectives were to create a national mountain peatland map for Colombia, assess peatland distribution, quantify degraded pasture peatlands, and evaluate soil carbon percentages and bulk density in the top 40 cm of mountain peatlands soils. We developed and compared three national-scale maps using field validation, Sentinel-2 imagery, SAR data, and topographic variables as inputs to a Random Forest classifier, each reflecting a different grouping of the study area. The Subregional map classifies four smaller subregions individually and merges them, the Regional groups two larger regions, and the National classifies the entire study area. Mapping 4.8 million hectares, we found peatlands occupy approximately 225,000 to 250,000 ha. About 13–15% are pasture peatlands, even within protected areas, 7–8% have been disturbed. Soil analyses up to 40 cm show consistently high carbon percentage in undisturbed peatlands, whereas pasture peatlands exhibit lower carbon and higher bulk density, revealing detrimental effects caused by drainage and livestock. These findings underscore the urgent need for targeted conservation and restoration to reduce greenhouse gas emissions, protect water resources, and strengthen climate mitigation strategies. Future research should refine peatland depth estimates to enhance the accuracy of peatland carbon stock assessments, leverage all three maps to improve training data in areas with substantial discrepancies, and use emerging technologies to better detect unaccounted peatland degradation.

Recovery of Soil Organic Matter Dynamics in Fen Peatlands after Rewetting

Preprint

Jan 2025

Spikes in UK wildfire emissions driven by peatland fires in dry years

Article

Full-text available

Feb 2025
ENVIRON RES LETT

Wildfires on peatlands can nearly double global fire-driven carbon emissions, requiring centuries to re-sequester carbon (C) losses. Peatland fires require sufficiently hot, dry conditions and/or drainage for the peat to burn. Although these conditions have historically been infrequent, the warming and drying climate could increase the potential for wildfires and subsequent emissions. Here, we evaluate how climate change impacts peatland fire emissions by using the United Kingdom as a case study—where peatlands store an estimated 3.2 PgC. We use a fire emission model to quantify fire-driven C emissions using high-resolution land-surface data and fire-weather indices. Between 2001 and 2021, we estimate 0.8 TgC has been emitted from fires on peatlands, which can contribute up to 90% of total annual UK fire-driven C emissions. Consequently, protecting peatlands from fires in the UK would be a cost-effective way to slow climate change by avoiding future emissions. Peatland emissions spike during prominent dry years, implicating the inter-annual climate as a dominant driver of year-to-year variability. Integrating future climate projections suggests that a 2 °C global warming level could increase fire-driven C emissions in peatlands by over 60% solely via increased burn depths. Our findings are likely a bellwether for other temperate peatlands where climate change is leading to drier conditions, which increase burn depths and C emissions.

Process-based modelling of multi-decade carbon dynamics of a cool temperate swamp

Preprint

Full-text available

Feb 2025

Swamps are important wetlands globally, but temperate swamps have been understudied even though they store substantial quantity of carbon (C) in their biomass and can accumulate peat. This stored C supports their role as nature-based solutions in climate change mitigation efforts. In particular, Southern Ontario swamps are estimated to store ~1.1 Pg C under distinct hydroclimatic conditions. Previous studies on temperate swamp C fluxes are mostly based on short-term (<5 years) field measurements that limit our understanding of the multi-decadal dynamics that exist between this ecosystem’s C flux and biophysical conditions. To elucidate the long-term interactions and feedbacks that are important to temperate swamp C dynamics, we adopted a process-based model (CoupModel) to simulate daily plant processes, energy, water and C fluxes in one of the most well-preserved swamps in Southern Ontario over a 40-year period (1983–2023). CoupModel reasonably simulated the C flux and controlling variables with coefficient of determination (R2) values of 0.60, 0.95 & 0.61 for soil respiration, surface soil temperature (0–5cm) and water table level respectively when validated with field measurements. Over the simulation period, the swamp’s C uptake capacity as net ecosystem exchange declined but it maintained a net C sink in most years. This declining trend can be attributed to a consistent rise in soil respiration (11 % per decade) that is likely to continue with future climate change predictions. Overall, the study shows that processed-based models are effective tools for improving our understanding of long-term C dynamics of temperate swamps.

The Extent of Anthropogenic Disturbance on Wetland Area in the Oil Sands Region of Alberta, Canada Between 2000 and 2018

Article

Full-text available

Feb 2025

Wetlands globally have and continue to undergo modification from anthropogenic and natural environmental factors. To bridge this gap, this study utilised a GIS-based approach to quantify the areal extent of human footprint disturbances to wetlands over time. This approach attributed wetland disturbance by wetlands class, disturbance type and sector during two notable disturbance transitions, from 2000 to 2010 and from 2010 to 2018, in the oil sands region (OSR) of northern Alberta, Canada. The wetland disturbance area was calculated using a physical disturbance dataset intersected with the Alberta Merged Wetland Inventory. Results indicate that 3284 km² (2616 km² between 2000 and 2010, 668 km² between 2010 and 2018) of wetlands have undergone disturbance in the OSR. Examination of disturbance by the industrial sector between 2010 and 2018 indicates that the oil and gas and forestry sectors are the greatest sources of disturbance (402 km² and 179 km², respectively). Monetary assessment of wetland ecosystem services per year results in a minimum yearly loss of USD 30.05 million for peatlands and USD 197.86 million for marshes and swamps in USD (2007). This analysis is valuable for quantifying the impact of human footprint on wetlands, which is critical for ensuring sustainable development in wetland-rich areas.

A 20 m spatial resolution peatland extent map of Alaska

Article

Full-text available

Feb 2025

Peatlands are prevalent across northern regions, including bogs, fens, marshes, meadows, and select tundra wetlands that all vary in size (e.g., 0.01 s to 10 s km²) and shape (e.g., circular to elongated). However, our best remotely sensed products describing the regional-scale distribution of peatland extents are constrained to 1 km² pixels, often representing notable sub-pixel heterogeneity and local-scale uncertainties. Here we develop a new 20 m spatial resolution wall-to-wall ~1.5 million km² peatland map of Alaska, using peat cores, ground observations, and sub-meter resolution image interpretation. Ground-data were used to train machine learning classifiers to detect peatlands using a fusion of Sentinel-1 (Dual-polarized Synthetic Aperture Radar), Sentinel-2 (Multi-Spectral Imager), and derivatives from the Arctic Digital Elevation Model (ArcticDEM), that were spatially constrained by a peatland suitability model. Statewide peatland mapping (overall agreement:85%) identified peatlands to cover 4.6, 10.4, and 5.3% of polar, boreal, and maritime ecoregions, respectively, and 7.3% of the total terrestrial land area. This new dataset will improve the representation of peatland carbon, nutrient, and fire dynamics across Alaska.

Testate amoebae as paleohydrological indicators in the boreal and subarctic permafrost mires in the western part of the central Siberian Plateau

Article

Feb 2025
QUATERNARY SCI REV

Protist ecology in Patagonian peatlands: pH, organic phosphorus, and sulfate as key drivers of testate amoeba diversity in undisturbed ecosystems

Preprint

Full-text available

Jan 2025

Peatlands in southern Chile, particularly in the remote Aysén region, provide unique ecosystems that remain understudied despite their ecological significance. Testate amoebae, a group of shelled protists, are important components of these ecosystems due to their roles in nutrient cycling and their sensitivity to environmental changes, which make them valuable bioindicators. However, research on the ecological drivers shaping their diversity and community composition in Chilean peatlands remains scarce. This study investigates the spatial distribution and diversity of testate amoebae across five peatlands in the Aysén region. By analyzing environmental variables such as pH, dissolved organic carbon, and sulfate, we identify key factors influencing community structure. Our findings highlight significant spatial turnover in testate amoeba communities, suggesting that local environmental gradients strongly shape their distribution. Notably, the Sphagnum -dominated peatlands exhibit higher diversity compared to mixed vegetation peatlands. The redundancy analysis reveals that organic phosphorus, pH, and sulfate are the most influential variables affecting testate amoeba communities. This study fills a critical gap in the understanding of microbial biodiversity in Chilean peatlands and underscores the importance of conserving these near-pristine ecosystems as reservoirs of microbial diversity and natural archives of environmental change.

Impacts of different intensities of commercial Sphagnum moss extraction on CO2 fluxes in a northern Patagonia peatland

Article

Jan 2025

An expert system model for mapping tropical wetlands and peatlands reveals South America as the largest contributor

Article

Full-text available

Mar 2017
GLOBAL CHANGE BIOL

Wetlands are important providers of ecosystem services and key regulators of climate change. They positively contribute to global warming through their greenhouse gas emissions, and negatively through the accumulation of organic material in histosols, particularly in peatlands. Our understanding of wetlands' services is currently constrained by limited knowledge on their distribution, extent, volume, inter-annual flood variability, and disturbance levels. We present an expert system approach to estimate wetland and peatland areas, depths and volumes, which relies on three biophysical indices related to wetland and peat formation: 1. Long-term water supply exceeding atmospheric water demand; 2. Annually or seasonally water-logged soils; 3. A geomorphological position where water is supplied and retained. Tropical and subtropical wetlands estimates reach 4.7 million km(2) . In line with current understanding, the American continent is the major contributor (45%) and Brazil, with its Amazonian inter-fluvial region, contains the largest tropical wetland area (800,720 km(2) ). Our model suggests, however, unprecedented extents and volumes of peatland in the tropics (1.7 million km(2) and 7,268 (6,076-7,368) km(3) ), which more than three-fold current estimates. Unlike current understanding, our estimates suggest that South America and not Asia contributes the most to tropical peatland area and volume (ca. 44% for both) partly related to some yet unaccounted extended deep deposits but mainly to extended but shallow peat in the Amazon Basin. Brazil leads the peatland area and volume contribution. Asia hosts 38% of both tropical peat area and volume with Indonesia as the main regional contributor and still the holder of the deepest and most extended peat areas in the tropics. Africa hosts more peat than previously reported but climatic and topographic contexts leave it as the least peat forming continent. Our results suggest large biases in our current understanding of the distribution, area, and volumes of tropical peat and their continental contributions. This article is protected by copyright. All rights reserved.

Peatland Restoration and Ecosystem Services: Science, Policy and Practice

Book

Full-text available

Aug 2016

www.cambridge.org/9781107619708 Peatlands provide globally important ecosystem services through climate and water regulation or biodiversity conservation. While covering only 3% of the earth's surface, degrading peatlands are responsible for nearly a quarter of carbon emissions from the land use sector. Bringing together world-class experts from science, policy and practice to highlight and debate the importance of peatlands from an ecological, social and economic perspective, this book focuses on how peatland restoration can foster climate change mitigation. Featuring a range of global case studies, opportunities for reclamation and sustainable management are illustrated throughout against the challenges faced by conservation biologists. Written for a global audience of environmental scientists, practitioners and policy makers, as well as graduate students from natural and social sciences, this interdisciplinary book provides vital pointers towards managing peatland conservation in a changing environment.

World reference base for soil resources: 2006: a framework for international classification, correlation and communication

Book

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Jan 2006

The impact of land-cover change on flood peaks in peatland basins

Article

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Apr 2016

In headwater peatlands, saturation-excess overland flow is a dominant source of river discharge. Human modifications to headwater peatlands result in vegetation cover change but there is a lack of understanding about how the spatial distribution of such change impacts flood peaks. A fully distributed version of TOPMODEL with an overland flow velocity module was used to simulate flood response for three upland peat basins. Bare peat strips adjacent to channels resulted in a higher and faster flow peak; for a 20 mm h-1 rainfall event, with bare riparian zones covering 10% of the basin area, peaks were increased, compared to the current hydrograph, by 12.8%, 1.8%, and 19.6% in the three basins. High density Sphagnum ground cover over the same riparian zones reduced flow peaks (e.g., by 10.1%, 1.8%, and 13.4% for the 20 mm h-1 event) compared to the current hydrograph. With similar total areas of land-cover change, the size of randomly located patches of changed cover had no effect on peak flow for patch sizes up to 40,000 m2. However, cover changes on gentle slope areas generally resulted in a larger change in peak flow when compared with the same changes on steeper slopes. Considering all results for the same proportion of catchment area that undergoes change, land-cover change along narrow riparian buffer strips had the highest impact on river flow. Thus, the protection and revegetation of damaged riparian areas in upland peat catchments may be highly beneficial for flood management.

Peatlands – guidance for climate changes mitigation through conservation, rehabilitation and sustainable use

Article

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Jan 2012

Global Change Pressures on Soils from Land Use and Management

Article

Full-text available

Mar 2016
GLOBAL CHANGE BIOL

Soils are subject to varying degrees of direct or indirect human disturbance, constituting a major global change driver. Factoring out natural from direct and indirect human influence is not always straightforward, but some human activities have clear impacts. These include land use change, land management, and land degradation (erosion, compaction, sealing and salinization). The intensity of land use also exerts a great impact on soils, and soils are also subject to indirect impacts arising from human activity, such as acid deposition (sulphur and nitrogen) and heavy metal pollution. In this critical review, we report the state-of-the-art understanding of these global change pressures on soils, identify knowledge gaps and research challenges, and highlight actions and policies to minimise adverse environmental impacts arising from these global change drivers. Soils are central to considerations of what constitutes sustainable intensification. Therefore, ensuring that vulnerable and high environmental value soils are considered when protecting important habitats and ecosystems, will help to reduce the pressure on land from global change drivers. To ensure that soils are protected as part of wider environmental efforts, a global soil resilience programme should be considered, to monitor, recover or sustain soil fertility and function, and to enhance the ecosystem services provided by soils. Soils cannot, and should not, be considered in isolation of the ecosystems that they underpin and vice versa. The role of soils in supporting ecosystems and natural capital needs greater recognition. The lasting legacy of the International Year of Soils in 2015 should be to put soils at the centre of policy supporting environmental protection and sustainable development. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Hydrologically driven ecosystem processes determine the distribution and persistence of ecosystem-specialist predators under climate change

Article

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Aug 2015

Climate change has the capacity to alter physical and biological ecosystem processes, jeopardizing the survival of associated species. This is a particular concern in cool, wet northern peatlands that could experience warmer, drier conditions. Here we show that climate, ecosystem processes and food chains combine to influence the population performance of species in British blanket bogs. Our peatland process model accurately predicts water-table depth, which predicts abundance of craneflies (keystone invertebrates), which in turn predicts observed abundances and population persistence of three ecosystem-specialist bird species that feed on craneflies during the breeding season. Climate change projections suggest that falling water tables could cause 56–81% declines in cranefly abundance and, hence, 15–51% reductions in the abundances of these birds by 2051–2080. We conclude that physical (precipitation, temperature and topography), biophysical (evapotranspiration and desiccation of invertebrates) and ecological (food chains) processes combine to determine the distributions and survival of ecosystem-specialist predators.

Global distribution of soil organic carbon - Part 1: Masses and frequency distributions of SOC stocks for the tropics, permafrost regions, wetlands, and the world

Article

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Apr 2015

The global soil organic carbon (SOC) mass is relevant for the carbon cycle budget and thus atmospheric carbon concentrations. We review current estimates of SOC stocks and mass (stock * area) in wetlands, permafrost and tropical regions and the world in the upper 1 m of soil. The Harmonized World Soil Database (HWSD) v.1.2 provides one of the most recent and coherent global data sets of SOC, giving a total mass of 2476 Pg when using the original values for bulk density. Adjusting the HWSD's bulk density (BD) of soil high in organic carbon results in a mass of 1230 Pg, and additionally setting the BD of Histosols to 0.1 g cm-3 (typical of peat soils), results in a mass of 1062 Pg. The uncertainty in BD of Histosols alone introduces a range of -56 to +180 Pg C into the estimate of global SOC mass in the top 1 m, larger than estimates of global soil respiration. We report the spatial distribution of SOC stocks per 0.5 arcminutes; the areal masses of SOC; and the quantiles of SOC stocks by continents, wetland types, and permafrost types. Depending on the definition of "wetland", wetland soils contain between 82 and 158 Pg SOC. With more detailed estimates for permafrost from the Northern Circumpolar Soil Carbon Database (496 Pg SOC) and tropical peatland carbon incorporated, global soils contain 1325 Pg SOC in the upper 1 m, including 421 Pg in tropical soils, whereof 40 Pg occurs in tropical wetlands. Global SOC amounts to just under 3000 Pg when estimates for deeper soil layers are included. Variability in estimates is due to variation in definitions of soil units, differences in soil property databases, scarcity of information about soil carbon at depths > 1 m in peatlands, and variation in definitions of "peatland". Open access, available from http://www.soil-journal.net/1/351/2015/soil-1-351-2015.html

Improving estimates of tropical peatland area, carbon storage, and greenhouse gas fluxes

Article

Full-text available

Jan 2014

Our limited knowledge of the size of the carbon pool and exchange fluxes in forested lowland tropical peatlands represents a major gap in our understanding of the global carbon cycle. Peat deposits in several regions (e.g. the Congo Basin, much of Amazonia) are only just beginning to be mapped and characterised. Here we consider the extent to which methodological improvements and improved coordination between researchers could help to fill this gap. We review the literature on measurement of the key parameters required to calculate carbon pools and fluxes, including peatland area, peat bulk density, carbon concentration, above-ground carbon stocks, litter inputs to the peat, gaseous carbon exchange, and waterborne carbon fluxes. We identify areas where further research and better coordination are particularly needed in order to reduce the uncertainties in estimates of tropical peatland carbon pools and fluxes, thereby facilitating better-informed management of these exceptionally carbon-rich ecosystems.

How much wetland has the world lost? Long-term and recent trends in global wetland area

Article

Full-text available

Sep 2014

Nick C Davidson

It has been frequently stated, but without provision of supporting evidence, that the world has lost 50% of its wetlands (or 50% since 1900 AD). This review of 189 reports of change in wetland area finds that the reported long-term loss of natural wetlands averages between 54–57% but loss may have been as high as 87% since 1700 AD. There has been a much (3.7 times) faster rate of wetland loss during the 20th and early 21st centuries, with a loss of 64–71% of wetlands since 1900 AD. Losses have been larger and faster for inland than coastal natural wetlands. Although the rate of wetland loss in Europe has slowed, and in North America has remained low since the 1980s, the rate has remained high in Asia, where large-scale and rapid conversion of coastal and inland natural wetlands is continuing. It is unclear whether the investment by national governments in the Ramsar Convention on Wetlands has influenced these rates of loss. There is a need to improve the knowledge of change in wetland areas worldwide, particularly for Africa, the Neotropics and Oceania, and to improve the consistency of data on change in wetland areas in published papers and reports.

Biodiversity and Conservation of Tropical Peat Swamp Forests

Article

Full-text available

Apr 2011

Tropical peat swamp forest is a unique ecosystem that is most extensive in Southeast Asia, where it is under enormous threat from logging, fire, and land conversion. Recent research has shown this ecosystem's significance as a global carbon store, but its value for biodiversity remains poorly understood. We review the current status and biological knowledge of tropical peat swamp forests, as well as the impacts of human disturbances. We demonstrate that these forests have distinct floral compositions, provide habitat for a considerable proportion of the region's fauna, and are important for the conservation of threatened taxa, particularly specialized freshwater fishes. However, we estimate that only 36% of the historical peat swamp forest area remains, with only 9% currently in designated protected areas. Given that peat swamp forests are more vulnerable to synergies between human disturbances than other forest ecosystems, their protection and restoration are conservation priorities that require urgent action.

Meta-discoveries from a synthesis of satellite-based land-cover mapping research

Article

Full-text available

Jul 2014

Since the launch of the first land-observation satellite (Landsat-1) in 1972, land-cover mapping has accumulated a wide range of knowledge in the peer-reviewed literature. However, this knowledge has never been comprehensively analysed for new discoveries. Here, we developed the first spatialized database of scientific literature in English about land-cover mapping. Using this database, we tried to identify the spatial temporal patterns and spatial hotspots of land-cover mapping research around the world. Among other findings, we observed (1) a significant mismatch between hotspot areas of land-cover mapping and areas that are either hard to map or rich in biodiversity; (2) mapping frequency is positively related to economic conditions; (3) there is no obvious temporal trend showing improvement in mapping accuracy; (4) images with more spectral bands or a combination of data types resulted in increased mapping accuracies; (5) accuracy differences due to algorithm differences are not as large as those due to various types of data used; and (6) the complexity of a classification system decreases its mapping accuracy. We recommend that one way to improve our understanding of the challenges, advances, and applications of previous land-cover mapping is for journals to require area-based information at the time of manuscript submission. In addition, building a standard protocol for systematic assessment of land-cover mapping efforts at the global scale through international collaboration is badly needed.

Assessing and valuing peatland ecosystem services for sustainable management

Article

Full-text available

Sep 2014

Mapping global land cover in 2001 and 2010 with spatial-temporal consistency at 250 m resolution

Article

Full-text available

Apr 2014
ISPRS J PHOTOGRAMM

Global land cover types in 2001 and 2010 were mapped at 250 m resolution with multiple year time series Moderate Resolution Imaging Spectrometer (MODIS) data. The map for each single year was produced not only from data of that particular year but also from data acquired in the preceding and subsequent years as temporal context. Slope data and geographical coordinates of pixels were also used. The classification system was derived from the finer resolution observation and monitoring of global land cover (FROM-GLC) project. Samples were based on the 2010 FROM-GLC project and samples for other years were obtained by excluding those changed from 2010. A random forest classifier was used to obtain original class labels and to estimate class probabilities for 2000–2002, and 2009–2011. The overall accuracies estimated from cross validation of samples are 74.93% for 2001 and 75.17% for 2010. The classification results were further improved through post processing. A spatial-temporal consistency model, Maximum a Posteriori Markov Random Fields (MAP-MRF), was first applied to improve land cover classification for each 3 consecutive years. The MRF outputs for 2001 and 2010 were then processed with a rule-based label adjustment method with MOD44B, slope and composited EVI series as auxiliary data. The label adjustment process relabeled the over-classified forests, water bodies and barren lands to alternative classes with maximum probabilities.

Global soil carbon: Understanding and managing the largest terrestrial carbon pool

Article

Full-text available

Feb 2014

Carbon stored in soils worldwide exceeds the amount of carbon stored in phytomass and the atmosphere. Despite the large quantity of carbon stored as soil organic carbon (SOC), consensus is lacking on the size of global SOC stocks, their spatial distribution, and the carbon emissions from soils due to changes in land use and land cover. This article summarizes published estimates of global SOC stocks through time and provides an overview of the likely impacts of management options on SOC stocks. We then discuss the implications of existing knowledge of SOC stocks, their geographical distribution and the emissions due to management regimes on policy decisions, and the need for better soil carbon science to mitigate losses and enhance soil carbon stocks.

Northern peatland carbon stocks and dynamics: A review

Article

Full-text available

Oct 2012
BG

Z. C. Yu

Peatlands contain a large belowground carbon (C) stock in the biosphere, and their dynamics have important implications for the global carbon cycle. However, there are still large uncertainties in C stock estimates and poor understanding of C dynamics across timescales. Here I review different approaches and associated uncertainties of C stock estimates in the literature, and on the basis of the literature review my best estimate of C stocks and uncertainty is 500 ± 100 (approximate range) gigatons of C (Gt C) in northern peatlands. The greatest source of uncertainty for all the approaches is the lack or insufficient representation of data, including depth, bulk density and carbon accumulation data, especially from the world's large peatlands. Several ways to improve estimates of peat carbon stocks are also discussed in this paper, including the estimates of C stocks by regions and further utilizations of widely available basal peat ages. Changes in peatland carbon stocks over time, estimated using Sphagnum (peat moss) spore data and down-core peat accumulation records, show different patterns during the Holocene, and I argue that spore-based approach underestimates the abundance of peatlands in their early histories. Considering long-term peat decomposition using peat accumulation data allows estimates of net carbon sequestration rates by peatlands, or net (ecosystem) carbon balance (NECB), which indicates more than half of peat carbon (> 270 Gt C) was sequestrated before 7000 yr ago during the Holocene. Contemporary carbon flux studies at 5 peatland sites show much larger NECB during the last decade (32 ± 7.8 (S.E.) g C m⁻² yr^–1) than during the last 7000 yr (∼ 11 g C m⁻² yr^–1), as modeled from peat records across northern peatlands. This discrepancy highlights the urgent need for carbon accumulation data and process understanding, especially at decadal and centennial timescales, that would bridge current knowledge gaps and facilitate comparisons of NECB across all timescales.

Current systematic carbon cycle observations and needs for implementing a policy-relevant carbon observing system

Article

Full-text available

Jul 2013

A globally integrated carbon observation and analysis system is needed to improve the fundamental understanding of the global carbon cycle, to improve our ability to project future changes, and to verify the effectiveness of policies aiming to reduce greenhouse gas emissions and increase carbon sequestration. Building an integrated carbon observation system requires transformational advances from the existing sparse, exploratory framework towards a dense, robust, and sustained system in all components: anthropogenic emissions, the atmosphere, the ocean, and the terrestrial biosphere. The paper is addressed to scientists, policymakers, and funding agencies who need to have a global picture of the current state of the (diverse) carbon observations. We identify the current state of carbon observations, and the needs and notional requirements for a global integrated carbon observation system that can be built in the next decade. A key conclusion is the substantial expansion of the ground-based observation networks required to reach the high spatial resolution for CO2 and CH4 fluxes, and for carbon stocks for addressing policy-relevant objectives, and attributing flux changes to underlying processes in each region. In order to establish flux and stock diagnostics over areas such as the southern oceans, tropical forests, and the Arctic, in situ observations will have to be complemented with remote-sensing measurements. Remote sensing offers the advantage of dense spatial coverage and frequent revisit. A key challenge is to bring remote-sensing measurements to a level of long-term consistency and accuracy so that they can be efficiently combined in models to reduce uncertainties, in synergy with ground-based data. Bringing tight observational constraints on fossil fuel and land use change emissions will be the biggest challenge for deployment of a policy-relevant integrated carbon observation system. This will require in situ and remotely sensed data at much higher resolution and density than currently achieved for natural fluxes, although over a small land area (cities, industrial sites, power plants), as well as the inclusion of fossil fuel CO2 proxy measurements such as radiocarbon in CO2 and carbon-fuel combustion tracers. Additionally, a policy-relevant carbon monitoring system should also provide mechanisms for reconciling regional top-down (atmosphere-based) and bottom-up (surface-based) flux estimates across the range of spatial and temporal scales relevant to mitigation policies. In addition, uncertainties for each observation data-stream should be assessed. The success of the system will rely on long-term commitments to monitoring, on improved international collaboration to fill gaps in the current observations, on sustained efforts to improve access to the different data streams and make databases interoperable, and on the calibration of each component of the system to agreed-upon international scales.

Peatlands in the Earth’s 21st century climate system

Article

Full-text available

Sep 2011
ENVIRON REV

Peatlands occupy a relatively small fraction of the Earth’s land area, but they are a globally important carbon store because of their high carbon density. Undisturbed peatlands are currently a weak carbon sink (~0.1 Pg C y–1), a moderate source of methane (CH4; ~0.03 Pg CH4 y–1), and a very weak source of nitrous oxide (N2O; ~0.00002 Pg N2O–N y–1). Anthropogenic disturbance, primarily agriculture and forestry drainage (10%–20% of global peatlands), results in net CO2 emissions, reduced CH4 emissions, and increased N2O emissions. This likely changes the global peatland greenhouse gas balance to a C source (~0.1 Pg C y–1), a 10% smaller CH4 source, and a larger (but still small) N2O source (~0.0004 Pg N2O–N y–1). There is no strong evidence that peatlands significantly contributed to 20th century changes in the atmospheric burden of CO2, CH4, or N2O; will this picture change in the 21st century? A review of experimental and observational studies of peatland dynamics indicates that the main global change impacts on peatlands that may have significant climate impacts are (1) drainage, especially in the tropics; (2) widespread permafrost thaw; and (3) increased fire intensity and frequency as a result of drier climatic conditions and (or) drainage. Quantitative estimates of global change impacts are limited by the sparse field data (particularly in the tropics), the large variability present in existing data, uncertainties in the future trajectory of peatland use, interactive effects of individual impacts, and the unprecedented rates of climate change expected in the 21st century.

Global land cover classi cation at 1km spatial resolution using a classification tree approach

Article

Full-text available

Apr 2000
INT J REMOTE SENS

This paper on reports the production of a 1 km spatial resolution land cover classification using data for 1992-1993 from the Advanced Very High Resolution Radiometer (AVHRR). This map will be included as an at-launch product of the Moderate Resolution Imaging Spectroradiometer (MODIS) to serve as an input for several algorithms requiring knowledge of land cover type. The methodology was derived from a similar effort to create a product at 8 km spatial resolution, where high resolution data sets were interpreted in order to derive a coarse-resolution training data set. A set of 37 294 x 1 km pixels was used within a hierarchical tree structure to classify the AVHRR data into 12 classes. The approach taken involved a hierarchy of pair-wise class trees where a logic based on vegetation form was applied until all classes were depicted. Multitemporal AVHRR metrics were used to predict class memberships. Minimum annual red reflectance, peak annual Normalized Difference Vegetation Index (NDVI), and minimum channel three brightness temperature were among the most used metrics. Depictions of forests and woodlands, and areas of mechanized agriculture are in general agreement with other sources of information, while classes such as low biomass agriculture and high-latitude broadleaf forest are not. Comparisons of the final product with regional digital land cover maps derived from high-resolution remotely sensed data reveal general agreement, except for apparently poor depictions of temperate pastures within areas of agriculture. Distinguishing between forest and non-forest was achieved with agreements ranging from 81 to 92% for these regional subsets. The agreements for all classes varied from an average of 65% when viewing all pixels to an average of 82% when viewing only those 1 km pixels consisting of greater than 90% one class within the high-resolution data sets.

Development of a global land characteristics database and IGBP DISCover from 1 km AVHRR data

Article

Full-text available

Apr 2000

This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or

Carbon emissions from forest conversion by Kalimantan oil palm plantations

Article

Full-text available

Oct 2012

Oil palm supplies >30% of world vegetable oil production1. Plantation expansion is occurring throughout the tropics, predominantly in Indonesia, where forests with heterogeneous carbon stocks undergo high conversion rates2, 3, 4. Quantifying oil palm’s contribution to global carbon budgets therefore requires refined spatio-temporal assessments of land cover converted to plantations5, 6. Here, we report oil palm development across Kalimantan (538,346 km2) from 1990 to 2010, and project expansion to 2020 within government-allocated leases. Using Landsat satellite analyses to discern multiple land covers, coupled with above- and below-ground carbon accounting, we develop the first high-resolution carbon flux estimates from Kalimantan plantations. From 1990 to 2010, 90% of lands converted to oil palm were forested (47% intact, 22% logged, 21% agroforests). By 2010, 87% of total oil palm area (31,640 km2) occurred on mineral soils, and these plantations contributed 61–73% of 1990–2010 net oil palm emissions (0.020–0.024 GtC yr−1). Although oil palm expanded 278% from 2000 to 2010, 79% of allocated leases remained undeveloped. By 2020, full lease development would convert 93,844 km2 (~ 90% forested lands, including 41% intact forests). Oil palm would then occupy 34% of lowlands outside protected areas. Plantation expansion in Kalimantan alone is projected to contribute 18–22% (0.12–0.15 GtC yr−1) of Indonesia’s 2020 CO2-equivalent emissions. Allocated oil palm leases represent a critical yet undocumented source of deforestation and carbon emissions.

Subsidence and carbon loss in drained tropical peatlands

Article

Full-text available

Mar 2012

Conversion of tropical peatlands to agriculture leads to a release of carbon from previously stable, long-term storage, resulting in land subsidence that can be a surrogate measure of CO2 emissions to the atmosphere. We present an analysis of recent large-scale subsidence monitoring studies in Acacia and oil palm plantations on peatland in SE Asia, and compare the findings with previous studies. Subsidence in the first 5 yr after drainage was found to be 142 cm, of which 75 cm occurred in the first year. After 5 yr, the subsidence rate in both plantation types, at average water table depths of 0.7 m, remained constant at around 5 cm yr-1. The results confirm that primary consolidation contributed substantially to total subsidence only in the first year after drainage, that secondary consolidation was negligible, and that the amount of compaction was also much reduced within 5 yr. Over 5 yr after drainage, 75 % of cumulative subsidence was caused by peat oxidation, and after 18 yr this was 92 %. The average rate of carbon loss over the first 5 yr was 178 t CO2eq ha-1 yr-1, which reduced to 73 t CO2eq ha-1 yr-1 over subsequent years, potentially resulting in an average loss of 100 t CO2eq ha-1 yr-1 over 25 yr. Part of the observed range in subsidence and carbon loss values is explained by differences in water table depth, but vegetation cover and other factors such as addition of fertilizers also influence peat oxidation. A relationship with groundwater table depth shows that subsidence and carbon loss are still considerable even at the highest water levels theoretically possible in plantations. This implies that improved plantation water management will reduce these impacts by 20 % at most, relative to current conditions, and that high rates of carbon loss and land subsidence are inevitable consequences of conversion of forested tropical peatlands to other land uses.

Drought-induced C loss in peatlands

Article

Full-text available

Nov 2011

Peatlands store vast amounts of organic carbon, amounting to approximately 455 Pg. Carbon builds up in these water-saturated environments owing to the presence of phenolic compounds-which inhibit microbial activity and therefore prevent the breakdown of organic matter. Anoxic conditions limit the activity of phenol oxidase, the enzyme responsible for the breakdown of phenolic compounds. Droughts introduce oxygen into these systems, and the frequency of these events is rising. Here, we combine in vitro manipulations, mesocosm experiments and field observations to examine the impact of drought on peatland carbon loss. We show that drought stimulates bacterial growth and phenol oxidase activity, resulting in a reduction in the concentration of phenolic compounds in peat. This further stimulates microbial growth, causing the breakdown of organic matter and the release of carbon dioxide in a biogeochemical cascade. We further show that re-wetting the peat accelerates carbon losses to the atmosphere and receiving waters, owing to drought-induced increases in nutrient and labile carbon levels, which raise pH and stimulate anaerobic decomposition. We suggest that severe drought, and subsequent re-wetting, could destabilize peatland carbon stocks; understanding this process could aid understanding of interactions between peatlands and other environmental trends, and lead to the development of strategies for increasing carbon stocks.

A Classification of Major Naturally-Occurring Amazonian Lowland Wetlands

Article

Full-text available

Aug 2011

Our estimates indicate that about 30% of the seven million square kilometers that make up the Amazon basin comply with international criteria for wetland definition. Most countries sharing the Amazon basin have signed the Ramsar Convention on Wetlands of International Importance but still lack complete wetland inventories, classification systems, and management plans. Amazonian wetlands vary considerably with respect to hydrology, water and soil fertility, vegetation cover, diversity of plant and animal species, and primary and secondary productivity. They also play important roles in the hydrology and biogeochemical cycles of the basin. Here, we propose a classification system for large Amazonian wetland types based on climatic, hydrological, hydrochemical, and botanical parameters. The classification scheme divides natural wetlands into one group with rather stable water levels and another with oscillating water levels. These groups are subdivided into 14 major wetland types. The types are characterized and their distributions and extents are mapped. KeywordsAmazon basin–Higher vegetation–Hydrology–Water types

Peatland biodiversity and ecosystem services: nature-based solutions for societal goals

Chapter

Full-text available

Sep 2016

Peatlands provide globally important ecosystem services through climate and water regulation or biodiversity conservation. While covering only 3% of the earth's surface, degrading peatlands are responsible for nearly a quarter of carbon emissions from the land use sector. Bringing together world-class experts from science, policy and practice to highlight and debate the importance of peatlands from an ecological, social and economic perspective, this book focuses on how peatland restoration can foster climate change mitigation. Featuring a range of global case studies, opportunities for reclamation and sustainable management are illustrated throughout against the challenges faced by conservation biologists. Written for a global audience of environmental scientists, practitioners and policy makers, as well as graduate students from natural and social sciences, this interdisciplinary book provides vital pointers towards managing peatland conservation in a changing environment.

Development and Validation of a Global Database of Lakes, Reservoirs and Wetlands

Article

Full-text available

Aug 2004
J HYDROL

Drawing upon a variety of existing maps, data and information, a new Global Lakes and Wetlands Database (GLWD) has been created. The combination of best available sources for lakes and wetlands on a global scale (1:1 to 1:3 million resolution), and the application of Geographic Information System (GIS) functionality enabled the generation of a database which focuses in three coordinated levels on (1) large lakes and reservoirs, (2) smaller water bodies, and (3) wetlands. Level 1 comprises the shoreline polygons of the 3067 largest lakes (surface area ≥50 km2) and 654 largest reservoirs (storage capacity ≥0.5 km3) worldwide, and offers extensive attribute data. Level 2 contains the shoreline polygons of approx. 250,000 smaller lakes, reservoirs and rivers (surface area ≥0.1 km2), excluding all water bodies of level 1. Finally, level 3 represents lakes, reservoirs, rivers, and different wetland types in the form of a global raster map at 30-second resolution, including all water bodies of levels 1 and 2.In a validation against documented data, GLWD proved to represent a comprehensive database of global lakes ≥1 km2 and to provide a good representation of the maximum global wetland extent. GLWD-1 and GLWD-2 establish two global polygon maps to which existing lake registers, compilations or remote sensing data can be linked in order to allow for further analyses in a GIS environment. GLWD-3 may serve as an estimate of wetland extents for global hydrology and climatology models, or to identify large-scale wetland distributions and important wetland complexes.

MODIS Collection 5 Global Land Cover: Algorithm Refinements and Characterization of new Datasets

Article

Full-text available

Jan 2010
REMOTE SENS ENVIRON

Information related to land cover is immensely important to global change science. In the past decade, data sources and methodologies for creating global land cover maps from remote sensing have evolved rapidly. Here we describe the datasets and algorithms used to create the Collection 5 MODIS Global Land Cover Type product, which is substantially changed relative to Collection 4. In addition to using updated input data, the algorithm and ancillary datasets used to produce the product have been refined. Most importantly, the Collection 5 product is generated at 500-m spatial resolution, providing a four-fold increase in spatial resolution relative to the previous version. In addition, many components of the classification algorithm have been changed. The training site database has been revised, land surface temperature is now included as an input feature, and ancillary datasets used in post-processing of ensemble decision tree results have been updated. Further, methods used to correct classifier results for bias imposed by training data properties have been refined, techniques used to fuse ancillary data based on spatially varying prior probabilities have been revised, and a variety of methods have been developed to address limitations of the algorithm for the urban, wetland, and deciduous needleleaf classes. Finally, techniques used to stabilize classification results across years have been developed and implemented to reduce year-to-year variation in land cover labels not associated with land cover change. Results from a cross-validation analysis indicate that the overall accuracy of the product is about 75% correctly classified, but that the range in class-specific accuracies is large. Comparison of Collection 5 maps with Collection 4 results show substantial differences arising from increased spatial resolution and changes in the input data and classification algorithm.

High sensitiviy of peat decomposition to climate change through water-table feedback

Article

Full-text available

Nov 2008

Historically, northern peatlands have functioned as a carbon sink, sequestering large amounts of soil organic carbon, mainly due to low decomposition in cold, largely waterlogged soils. The water table, an essential determinant of soil-organic-carbon dynamics interacts with soil organic carbon. Because of the high water-holding capacity of peat and its low hydraulic conductivity, accumulation of soil organic carbon raises the water table, which lowers decomposition rates of soil organic carbon in a positive feedback loop. This two-way interaction between hydrology and biogeochemistry has been noted but is not reproduced in process-based simulations. Here we present simulations with a coupled physical–biogeochemical soil model with peat depths that are continuously updated from the dynamic balance of soil organic carbon. Our model reproduces dynamics of shallow and deep peatlands in northern Manitoba, Canada, on both short and longer timescales. We find that the feedback between the water table and peat depth increases the sensitivity of peat decomposition to temperature, and intensifies the loss of soil organic carbon in a changing climate. In our long-term simulation, an experimental warming of 4 °C causes a 40% loss of soil organic carbon from the shallow peat and 86% from the deep peat. We conclude that peatlands will quickly respond to the expected warming in this century by losing labile soil organic carbon during dry periods. Earth and Planetary Sciences Organismic and Evolutionary Biology Version of Record

Artificial drainage of peatlands: Hydrological and hydrochemical process and wetland restoration

Article

Full-text available

Mar 2003
PROG PHYS GEOG

Peatlands have been subject to artificial drainage for centuries. This drainage has been in response to agricultural demand, forestry, horticultural and energy properties of peat and alleviation of flood risk. However, the are several environmental problems associated with drainage of peatlands. This paper describes the nature of these problems and examines the evidence for changes in hydrological and hydrochemical processes associated with these changes. Traditional black-box water balance approaches demonstrate little about wetland dynamics and therefore the science of catchment response to peat drainage is poorly understood. It is crucial that a more process-based approach be adopted within peatland ecosystems. The environmental problems associated with peat drainage have led, in part, to a recent reversal in attitudes to peatlands and we have seen a move towards wetland restoration. However, a detailed understanding of hydrological, hydrochemical and ecological process-interactions will be fundamental if we are to adequately restore degraded peatlands, preserve those that are still intact and understand the impacts of such management actions at the catchment scale.

Climate regulation of fire emissions and deforestation in equatorial Asia

Article

Full-text available

Jan 2009
P NATL ACAD SCI USA

Drainage of peatlands and deforestation have led to large-scale fires in equatorial Asia, affecting regional air quality and global concentrations of greenhouse gases. Here we used several sources of satellite data with biogeochemical and atmospheric modeling to better understand and constrain fire emissions from Indonesia, Malaysia, and Papua New Guinea during 2000-2006. We found that average fire emissions from this region [128 +/- 51 (1sigma) Tg carbon (C) year(-1), T = 10(12)] were comparable to fossil fuel emissions. In Borneo, carbon emissions from fires were highly variable, fluxes during the moderate 2006 El Niño more than 30 times greater than those during the 2000 La Niña (and with a 2000-2006 mean of 74 +/- 33 Tg C yr(-1)). Higher rates of forest loss and larger areas of peatland becoming vulnerable to fire in drought years caused a strong nonlinear relation between drought and fire emissions in southern Borneo. Fire emissions from Sumatra showed a positive linear trend, increasing at a rate of 8 Tg C year(-2) (approximately doubling during 2000-2006). These results highlight the importance of including deforestation in future climate agreements. They also imply that land manager responses to expected shifts in tropical precipitation may critically determine the strength of climate-carbon cycle feedbacks during the 21st century.

The Amount of Carbon Released from Peat and Forest Fires in Indonesia During 1997

Article

Full-text available

Dec 2002

Tropical peatlands are one of the largest near-surface reserves of terrestrial organic carbon, and hence their stability has important implications for climate change. In their natural state, lowland tropical peatlands support a luxuriant growth of peat swamp forest overlying peat deposits up to 20 metres thick. Persistent environmental change-in particular, drainage and forest clearing-threatens their stability, and makes them susceptible to fire. This was demonstrated by the occurrence of widespread fires throughout the forested peatlands of Indonesia during the 1997 El Niño event. Here, using satellite images of a 2.5 million hectare study area in Central Kalimantan, Borneo, from before and after the 1997 fires, we calculate that 32% (0.79 Mha) of the area had burned, of which peatland accounted for 91.5% (0.73 Mha). Using ground measurements of the burn depth of peat, we estimate that 0.19-0.23 gigatonnes (Gt) of carbon were released to the atmosphere through peat combustion, with a further 0.05 Gt released from burning of the overlying vegetation. Extrapolating these estimates to Indonesia as a whole, we estimate that between 0.81 and 2.57 Gt of carbon were released to the atmosphere in 1997 as a result of burning peat and vegetation in Indonesia. This is equivalent to 13-40% of the mean annual global carbon emissions from fossil fuels, and contributed greatly to the largest annual increase in atmospheric CO(2) concentration detected since records began in 1957 (ref. 1).

Peatland hydrology and carbon release: Why small-scale process matters

Article

Full-text available

Oct 2005
PHILOS T R SOC A

Joseph Holden

Peatlands cover over 400 million hectares of the Earth's surface and store between one-third and one-half of the world's soil carbon pool. The long-term ability of peatlands to absorb carbon dioxide from the atmosphere means that they play a major role in moderating global climate. Peatlands can also either attenuate or accentuate flooding. Changing climate or management can alter peatland hydrological processes and pathways for water movement across and below the peat surface. It is the movement of water in peats that drives carbon storage and flux. These small-scale processes can have global impacts through exacerbated terrestrial carbon release. This paper will describe advances in understanding environmental processes operating in peatlands. Recent (and future) advances in high-resolution topographic data collection and hydrological modelling provide an insight into the spatial impacts of land management and climate change in peatlands. Nevertheless, there are still some major challenges for future research. These include the problem that impacts of disturbance in peat can be irreversible, at least on human time-scales. This has implications for the perceived success and understanding of peatland restoration strategies. In some circumstances, peatland restoration may lead to exacerbated carbon loss. This will also be important if we decide to start to create peatlands in order to counter the threat from enhanced atmospheric carbon.

Age, extent and carbon storage of the central Congo Basin peatland complex

Article

Jan 2017

Peatlands are carbon-rich ecosystems that cover just three per cent of Earth's land surface, but store one-third of soil carbon. Peat soils are formed by the build-up of partially decomposed organic matter under waterlogged anoxic conditions. Most peat is found in cool climatic regions where unimpeded decomposition is slower, but deposits are also found under some tropical swamp forests. Here we present field measurements from one of the world's most extensive regions of swamp forest, the Cuvette Centrale depression in the central Congo Basin. We find extensive peat deposits beneath the swamp forest vegetation (peat defined as material with an organic matter content of at least 65 per cent to a depth of at least 0.3 metres). Radiocarbon dates indicate that peat began accumulating from about 10,600 years ago, coincident with the onset of more humid conditions in central Africa at the beginning of the Holocene. The peatlands occupy large interfluvial basins, and seem to be largely rain-fed and ombrotrophic-like (of low nutrient status) systems. Although the peat layer is relatively shallow (with a maximum depth of 5.9 metres and a median depth of 2.0 metres), by combining in situ and remotely sensed data, we estimate the area of peat to be approximately 145,500 square kilometres (95 per cent confidence interval of 131,900-156,400 square kilometres), making the Cuvette Centrale the most extensive peatland complex in the tropics. This area is more than five times the maximum possible area reported for the Congo Basin in a recent synthesis of pantropical peat extent. We estimate that the peatlands store approximately 30.6 petagrams (30.6 × 10(15) grams) of carbon belowground (95 per cent confidence interval of 6.3-46.8 petagrams of carbon)-a quantity that is similar to the above-ground carbon stocks of the tropical forests of the entire Congo Basin. Our result for the Cuvette Centrale increases the best estimate of global tropical peatland carbon stocks by 36 per cent, to 104.7 petagrams of carbon (minimum estimate of 69.6 petagrams of carbon; maximum estimate of 129.8 petagrams of carbon). This stored carbon is vulnerable to land-use change and any future reduction in precipitation.

Worldwide peatland degradations and the related carbon dioxide emissions: the importance of policy regulations

Article

Mar 2017
ENVIRON SCI POLICY

Peatlands cover cca 3% of the planet‘s surface, yet have disproportional role in carbon stocking. Our goal is to understand the world peatland degradation and it’s possible CO2 emissions for two time periods: 2025 and 2050. First we modeled the future degradation of peatlands and the associated carbon emissions. Second, a conceptual representation was developed to understand the most important socio-political factors behind the observed peatland degradation. We found an increase of the degraded peatland surfaces by 17% till in the period of 2008–2025 (summing cca 559,519 km2) and 26% till 2050 (summing 626,048 km2). The highest degradation levels expected for Asia (about 472,197 km2 until 2050). The global carbon emission resulting from peatland degradation was 1,052.79 Mtone in 1990 and 1298 Mtone in 2008, the differences being largely related to the Asian emissions (47.8% increase from 345 Mtone in 1990 to 722 Mtone in 2008). We expect an increase of carbon emission due to peatland degradation from 2008 to 1582 Mtone until 2025 and to 2118 Mtone until 2050. The model shows that 25% of the current peatlands will be degraded until 2050 and will be responsible for about 8% of the global anthropogenic carbon dioxide emissions.

Hybrid Mapping of Pantropical Wetlands from Optical Satellite Images, Hydrology, and Geomorphology

Chapter

Mar 2015

Thomas Gumbricht

Global and regional importance of the tropical peatland carbon pool

Article

Jun 2010
GLOBAL CHANGE BIOL

11% of global peatland area) of which 247 778 km 2 (56%) is in Southeast Asia. We estimate the volume of tropical peat to be 1758 Gm 3 (

18–25% of global peat volume) with 1359 Gm 3 in Southeast Asia (77% of all tropical peat). This new assessment reveals a larger tropical peatland carbon pool than previous estimates, with a best estimate of 88.6 Gt (range 81.7–91.9 Gt) equal to 15–19% of the global peat carbon pool. Of this, 68.5 Gt (77%) is in Southeast Asia, equal to 11–14% of global peat carbon. A single country, Indonesia, has the largest share of tropical peat carbon (57.4 Gt, 65%), followed by Malaysia (9.1 Gt, 10%). These data are used to provide revised estimates for Indonesian and Malaysian forest soil carbon pools of 77 and 15 Gt, respectively, and total forest carbon pools (biomass plus soil) of 97 and 19 Gt. Peat carbon contributes 60% to the total forest soil carbon pool in Malaysia and 74% in Indonesia. These results emphasize the prominent global and regional roles played by the tropical peat carbon pool and the importance of including this pool in national and regional assessments of terrestrial carbon stocks and the prediction of peat-derived greenhouse gas emissions.

Global vulnerability of peatlands to fire and carbon loss

Article

Dec 2014

Globally, the amount of carbon stored in peats exceeds that stored in vegetation and is similar in size to the current atmospheric carbon pool. Fire is a threat to many peat-rich biomes and has the potential to disturb these carbon stocks. Peat fires are dominated by smouldering combustion, which is ignited more readily than flaming combustion and can persist in wet conditions. In undisturbed peatlands, most of the peat carbon stock typically is protected from smouldering, and resistance to fire has led to a build-up of peat carbon storage in boreal and tropical regions over long timescales. But drying as a result of climate change and human activity lowers the water table in peatlands and increases the frequency and extent of peat fires. The combustion of deep peat affects older soil carbon that has not been part of the active carbon cycle for centuries to millennia, and thus will dictate the importance of peat fire emissions to the carbon cycle and feedbacks to the climate.

Does prescribed burning on peat soils influence DOC concentrations in soil and runoff waters? Results from a 10 year chronosequence

Article

Jul 2012
J HYDROL

Prescribed burning of moorland, heathland and blanket bog vegetation on peatlands in the UK is a contentious issue. Given the large carbon store in these peatlands, concern ha:; been raised over land management and its effect on the carbon dynamics of peat ecosystems. In particular the spatial and temporal link between burning and concentrations of dissolved organic carbon (DOC) in waters draining these catchments has received particular attention. This study investigates water colour and DOC concentrations in soil pore water and runoff water at the plot-scale over a chronosequence of burn ages. Results from this study show that there is an elevated water colour in the few years immediately following burning but that this is not matched by a rise in DOC concentration. Therefore we propose that burning appears to affect the composition of the DOC rather than the absolute DOC concentration. This study also highlights that in some cases the use of water colour as a proxy for DOC concentration should be treated with caution.

Peatlands and Their Role in the Global Carbon Cycle

Article

Mar 2011
Eos Trans. AGU

Global peatlands store a very large carbon (C) pool located within a few meters of the atmosphere. Thus, peatland-atmosphere C exchange should be a major concern to global change scientists: Will large amounts of respired belowground C be released in a warmer climate, causing the climate to further warm (a positive climate feedback)? Will more C be sequestered due to increased plant growth in a warmer climate? How will land use change, fires, and permafrost thaw affect the magnitude and direction of carbon dioxide (CO2) and methane (CH4) exchange with the atmosphere? These questions remain challenging, but some significant progress has been made recently.

Methane emission from natural wetlands: Global distribution, area, and environmental characteristics of sources

Article

Mar 1987

A global data base of wetlands at 1 degree resolution was developed from the integration of three independent global, digital sources: (1) vegetation, (2) soil properties and (3) fractional inundation in each 1 degree cell. The integration yielded a global distribution of wetland sites identified with in situ ecological and environmental characteristics. The wetland sites were classified into five major groups on the basis of environmental characteristics governing methane emissions. The global wetland area derived in this study is 5.3 trillion sq m, approximately twice the wetland area previously used in methane emission studies. Methane emission was calculated using methane fluxes for the major wetland groups, and simple assumptions about the duration of the methane production season. The annual methane emission from wetlands is about 110 Tg, well within the range of previous estimates. Tropical/subtropical peat-poor swamps from 20 degrees N to 30 degrees S account from 30% of the global wetland area and 25% of the total methane emission. About 60% of the total emission comes from peat-rich bogs concentrated from 50-70 degrees N, suggesting that the highly seasonal emission from these ecosystems is the major contributor to the large annual oscillations observed in atmospheric methane concentrations at these latitudes. 78 refs., 6 figs., 5 tabs.

Harmonized World Soil Database (HWSD), version 1.1

Book

Jan 2012

The large Amazonian peatland carbon sink in the subsiding Pastaza‐Marañón foreland basin, Peru

Article

Sep 2011
GLOBAL CHANGE BIOL

The carbon (C) dynamics of tropical peatlands can be of global importance, because, particularly in Southeast Asia, they are the source of considerable amounts of C released to the atmosphere as a result of land-use change and fire. In contrast, the existence of tropical peatlands in Amazonia has been documented only recently. According to a recent study, the 120 000 km2 subsiding Pastaza-Marañón foreland basin in Peruvian Amazonia harbours previously unstudied and up to 7.5 m thick peat deposits. We studied the role of these peat deposits as a C reserve and sink by measuring peat depth, radiocarbon age and peat and C accumulation rates at 5–13 sites. The basal ages varied from 1975 to 8870 cal yr bp, peat accumulation rates from 0.46 to 9.31 mm yr−1 and C accumulation rates from 28 to 108 g m−2 yr−1. The total peatland area and current peat C stock within the area of two studied satellite images were 21 929 km2 and 3.116 Gt (with a range of 0.837–9.461 Gt). The C stock is 32% (with a range of 8.7–98%) of the best estimate of the South American tropical peatland C stock and 3.5% (with a range of 0.9–10.7%) of the best estimate of the global tropical peatland C stock. The whole Pastaza-Marañón basin probably supports about twice this peatland area and peat C stock. In addition to their contemporary geographical extent, these peatlands probably also have a large historical (vertical) extension because of their location in a foreland basin characterized by extensive river sedimentation, peat burial and subsidence for most of the Quaternary period. Burial of peat layers in deposits of up to 1 km thick Quaternary river sediments removes C from the short-term C cycle between the biosphere and atmosphere, generating a long-term C sink.

DOC budgets of drained peat catchments: Implications for DOC production in peat soils

Article

Jun 2009
HYDROL PROCESS

The blocking of drainage ditches in peat has been proposed as a possible mitigation strategy for the widely observed increases in dissolved organic carbon (DOC) concentrations from northern peatlands. This study tested the hypothesis that drain-blocking could lead to lower DOC concentrations by measuring the DOC export from a series of small peat-covered catchments over a period of 2 years. Six catchments were chosen: two were pristine that had never been drained; three where drains had been blocked (one in 1995, and two in 2003); and a control peat drain catchment where the drain was left unblocked throughout the study. In the case where drains were blocked as part of thus study, the drains were observed for 2 months before blocking and 2 years after blocking. The results show that: (i) high concentrations of DOC can come from water ponded in the drain; (ii) the DOC export (flux of DOC per area of catchment) from the six study catchments shows a high degree of positive correlation with both catchment size and water yield; (iii) distinctly lower DOC export with water yield was observed for the catchments containing higher-order channels (>27 500 m2) as opposed to single drain catchments (>7500 m2); (iv) drain-blocking resulted in a statistically significant decrease in DOC export (average was 39%) but the effect upon DOC concentration explained only 1% of the variance in the data. The results suggest that drain blocking works by decreasing the flow from the drain, not by changing the production of DOC in the peat. The change in export with catchment size implies a considerable removal of DOC from large catchments. Copyright © 2009 John Wiley & Sons, Ltd.

Page SE, Rieley JO, and Banks CJ. Global and regional importance of the tropical peatland carbon pool. Glob Change Biol

Article

Feb 2011
GLOBAL CHANGE BIOL

Accurate inventory of tropical peatland is important in order to (a) determine the magnitude of the carbon pool; (b) estimate the scale of transfers of peat-derived greenhouse gases to the atmosphere resulting from land use change; and (c) support carbon emissions reduction policies. We review available information on tropical peatland area and thickness and calculate peat volume and carbon content in order to determine their best estimates and ranges of variation. Our best estimate of tropical peatland area is 441 025 km2 (∼11% of global peatland area) of which 247 778 km2 (56%) is in Southeast Asia. We estimate the volume of tropical peat to be 1758 Gm3 (∼18–25% of global peat volume) with 1359 Gm3 in Southeast Asia (77% of all tropical peat). This new assessment reveals a larger tropical peatland carbon pool than previous estimates, with a best estimate of 88.6 Gt (range 81.7–91.9 Gt) equal to 15–19% of the global peat carbon pool. Of this, 68.5 Gt (77%) is in Southeast Asia, equal to 11–14% of global peat carbon. A single country, Indonesia, has the largest share of tropical peat carbon (57.4 Gt, 65%), followed by Malaysia (9.1 Gt, 10%). These data are used to provide revised estimates for Indonesian and Malaysian forest soil carbon pools of 77 and 15 Gt, respectively, and total forest carbon pools (biomass plus soil) of 97 and 19 Gt. Peat carbon contributes 60% to the total forest soil carbon pool in Malaysia and 74% in Indonesia. These results emphasize the prominent global and regional roles played by the tropical peat carbon pool and the importance of including this pool in national and regional assessments of terrestrial carbon stocks and the prediction of peat-derived greenhouse gas emissions.

Contemporary carbon accumulation in a boreal oligotrophic minerogenic mire - A significant sink after accounting for all C-fluxes

Article

Oct 2008
GLOBAL CHANGE BIOL

Based on theories of mire development and responses to a changing climate, the current role of mires as a net carbon sink has been questioned. A rigorous evaluation of the current net C-exchange in mires requires measurements of all relevant fluxes. Estimates of annual total carbon budgets in mires are still very limited. Here, we present a full carbon budget over 2 years for a boreal minerogenic oligotrophic mire in northern Sweden (64°11′N, 19°33′E). Data on the following fluxes were collected: land–atmosphere CO2 exchange (continuous Eddy covariance measurements) and CH4 exchange (static chambers during the snow free period); TOC (total organic carbon) in precipitation; loss of TOC, dissolved inorganic carbon (DIC) and CH4 through stream water runoff (continuous discharge measurements and regular C-concentration measurements). The mire constituted a net sink of 27±3.4 (±SD) g C m−2 yr−1 during 2004 and 20±3.4 g C m−2 yr−1 during 2005. This could be partitioned into an annual surface–atmosphere CO2 net uptake of 55±1.9 g C m−2 yr−1 during 2004 and 48±1.6 g C m−2 yr−1 during 2005. The annual NEE was further separated into a net uptake season, with an uptake of 92 g C m−2 yr−1 during 2004 and 86 g C m−2 yr−1 during 2005, and a net loss season with a loss of 37 g C m−2 yr−1 during 2004 and 38 g C m−2 yr−1 during 2005. Of the annual net CO2-C uptake, 37% and 31% was lost through runoff (with runoff TOC>DIC≫CH4) and 16% and 29% through methane emission during 2004 and 2005, respectively. This mire is still a significant C-sink, with carbon accumulation rates comparable to the long-term Holocene C-accumulation, and higher than the C-accumulation during the late Holocene in the region.

Global Distribution of Natural Freshwater Wetlands and Rice Paddies, Their Net Primary Productivity, Seasonality and Possible Methane Emissions

Article

May 1989

A global data set on the geographic distribution and seasonality of freshwater wetlands and rice paddies has been compiled, comprising information at a spatial resolution of 2.5 by latitude and 5 by longitude. Global coverage of these wetlands total 5.7106 km2 and 1.3106 km2, respectively. Natural wetlands have been grouped into six categories following common terminology, i.e. bog, fen, swamp, marsh, floodplain, and shallow lake. Net primary productivity (NPP) of natural wetlands is estimated to be in the range of 4–91015 g dry matter per year. Rice paddies have an NPP of about 1.41015 g y–1. Extrapolation of measured CH4 emissions in individual ecosystems lead to global methane emission estimates of 40–160 Teragram (1 Tg=1012 g) from natural wetlands and 60–140 Tg from rice paddies per year. The mean emission of 170–200 Tg may come in about equal proportions from natural wetlands and paddies. Major source regions are located in the subtropics between 20 and 30 N, the tropics between 0 and 10 S, and the temperate-boreal region between 50 and 70 N. Emissions are highly seasonal, maximizing during summer in both hemispheres. The wide range of possible CH4 emissions shows the large uncertainties associated with the extrapolation of measured flux rates to global scale. More investigations into ecophysiological principals of methane emissions is warranted to arrive at better source estimates.

Land management as a factor controlling dissolved organic carbon release from upland peat soils 1: Spatial variation in DOC productivity

Article

May 2009
SCI TOTAL ENVIRON

The importance of soil storage in global carbon cycling is well recognised and factors leading to increased losses from this pool may act as a positive feedback mechanism in global warming. Upland peat soils are usually assumed to serve as carbon sinks, there is however increasing evidence of carbon loss from upland peat soils, and DOC concentrations in UK rivers have increased markedly over the past three decades. A number of drivers for increasing DOC release from peat soils have been proposed although many of these would not explain fine-scale variations in DOC release observed in many catchments. We examined the effect of land use and management on DOC production in upland peat catchments at two spatial scales within the UK. DOC concentration was measured in streams draining 50 small-scale catchments (b3 km2) in three discrete regions of the south Pennines and one area in the North Yorkshire Moors. Annual mean DOC concentration was also derived from water colour data recorded at water treatment works for seven larger scale catchments (1.5-20 km2) in the south Pennines. Soil type and land use/management in all catchments were characterised from NSRI digital soil data and ortho-corrected colour aerial imagery. Of the factors assessed, representing all combinations of soil type and land use together with catchment slope and area, the proportion of exposed peat surface resulting from new heather burning was consistently identified as the most significant predictor of variation in DOC concentration. This relationship held across all blanket peat catchments and scales. We propose that management activities are driving changes in edaphic conditions in upland peat to those more favourable for aerobic microbial activity and thus enhance peat decomposition leading to increased losses of carbon from these environments.

World Bank Technical Paper No. 41. The World Bank

Jan 1984

Móna Bord Na

Bord na Móna, 1984. Fuel Peat in Developing Countries. World Bank Technical Paper No. 41. The World Bank, Washington, DC.

DiGMapGB data at 1:625 000 scale, surficial deposits V1

Jan 2013

British Geological Survey, 2013. DiGMapGB data at 1:625 000 scale, surficial deposits V1.0. http://www.bgs.ac.uk/products/digitalmaps/dataInfo.html#_625.

Lowland Peat in England and Wales

Jan 1987

R G O Burton
J M Hodgson

Burton, R.G.O., Hodgson, J.M., 1987. Lowland Peat in England and Wales. Soil Survey Technical Monograph No. 15, Harpenden, UK.

PEATMAP: Refining estimates of global peatland distribution based on a meta-analysis

Abstract

No full-text available

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