Search

Background: Predicting fire behaviour is an ongoing challenge in temperate peatlands and heathlands, where live fuels can form the dominant fuel load for wildfire spread, and where spatial heterogeneity in fuel moisture is important but not typically represented in fuel models. Aims: We examine the impact of fuel moisture variation on simulated fire behaviour across a temperate peatland/heathland landscape. Methods: We collected field measurements of fuel moisture content in Calluna vulgaris shrub from 36 sites across the North Yorkshire Moors, United Kingdom. We used these to define fuel moisture inputs within existing shrubland fuel models to simulate fire behaviour in BehavePlus. Key results: Simulated rates of spread varied with fuel moisture content; average mean variance of 23–80% from the landscape average rate of spread. The driest sites had simulated rates of spread up to 135% above the landscape average and the wettest sites up to 86% below average. Fuel model selection dramatically impacted simulated rates of spread by a factor of five. Conclusions: We need to constrain the role of live fuel moisture within temperate fuel models to develop accurate fire behaviour predictions. Implications: Capturing cross-landscape heterogeneity in fire behaviour is important for safe and effective land and wildfire management decision-making. Predicted fire behaviour varies significantly when cross-landscape fuel moisture differences are included in simulations. In temperate fuels, where live fuel moisture is not well represented in models, this may create dangerous situations where fire behaviour is underpredicted during the typical spring fire season, which has implications for fire management decision-making. [ABSTRACT FROM AUTHOR]

To examine the relative controls of landscape and climate on spatial variability, we measured water level dynamics of shallow lakes over two decades that represent both the heterogeneity of surficial geology classifications, and thus the potential range in surface and groundwater connectivity, and the long-term weather patterns of the Boreal Plain hydrogeoclimatic setting. Large ranges in shallow lakes water levels (between 0.25 and 2 m) were observed corresponding to extremes in precipitation relative to the long-term mean precipitation over the study period. We found low concurrence in water level dynamics among four detailed study lakes that received the same meteorological weather signal, but were located in different surficial geology texture classifications that incorporated important landscape parameters associated with lake water balance and storage. Surficial geology classification alone did not, however, distinguish between different ranges in lake water level measured in a broader synoptic survey of 26 lakes across the region. Thus, simple surficial geology classifications cannot alone be applied to classify Boreal Plain lake water level dynamics and other controls, notably landscape position, must also be considered. We further show that inter-annual variability in lake water levels was significantly greater than seasonal variability in this hydrogeoclimatic setting. This emphasizes the need for studies of sufficient length to capture weather extremes that include periods of wetting and drying, and demonstrates how observed magnitudes of water level variability, and lake function, can be an artefact of study length and initiation date. These findings provide a foundation to test and calibrate conceptual understanding of the wider controls of lake water levels to form holistic frameworks to mitigate ecological and societal impacts due to hydrological changes under climate and anthropogenic disturbance within and between hydrogeoclimatic settings. [ABSTRACT FROM AUTHOR]

We examined annual runoff from 20 meso‐scale catchments over 25 years, to elucidate how interactions between physiography and long‐term weather patterns influence the magnitude of spatial–temporal thresholds in annual runoff responses in water‐limited, low‐relief, glaciated continental Boreal landscapes. Annual runoff ranged over 2 orders of magnitude (<3 to >300 mm) among catchments receiving similar annual precipitation. Threshold relationships were observed with cumulative regional moisture deficits that reflected spatial–temporal differences in effective storage and antecedent moisture among catchments with differing portions of glacial‐deposit and land‐cover types. The importance of the glacial‐deposit texture and forest‐peatland cover on runoff behavior among catchments varied with weather patterns and catchment antecedent moisture states. Dry states yielded low annual runoff that ranged by 2 orders of magnitude (0–80 mm), with higher values in catchments with predominantly coarse‐textured deposits. During near normal antecedent moisture, annual runoff remained low (<10 mm) in catchments associated with fine‐textured, hummocky landforms and deciduous forests. Annual runoff >10 mm was observed only in catchments with extensive peatlands. Infrequent wet states resulted in increased runoff in all catchments; however, ranges in maximum runoff were associated with heterogeneity in catchment landforms and land covers. Integrating cumulative precipitation with the proportion of glacial‐deposit and land‐cover types within catchments can (a) represent water cycling and regional sink‐source dynamics controlling runoff and (b) provide an effective management framework for predicting climate and land use impacts on regional runoff in water‐limited, low‐relief, glaciated landscapes such as the Boreal Plain. Key Points: Runoff threshold responses and magnitude of low and high flow vary between neighboring catchments receiving similar annual precipitationFour catchment runoff functional types are associated with contrasts in fine‐ versus coarse‐textured substrates and peatland versus forest coversThe influence of landscape heterogeneity on thresholds in annual runoff shifts dramatically with weather patterns [ABSTRACT FROM AUTHOR]

The 2018–2021 wildfire seasons were a glimpse of the future: deadly damaging fires in Mediterranean regions and high fire activity outside the typical fire season, also in temperate and boreal areas. This challenge cannot be solved with the traditional mono‐disciplinary approach of fire suppression. There is a critical need to change fire management from fire resistance to landscape resilience: Living with fire. Climate change thereby creates an urgency for understanding the integrated drivers of fire impacts and risks, and for designing creative and effective risk reduction, management and communication strategies. We argue that achieving this integrated fire management requires inter‐ and transdisciplinary research based on four axes of diversity: combining cross‐geography, cross‐risk, and cross‐sector approaches while embracing social diversity. This requires a new way of training our future experts, a broader way of defining scientific excellence, and stimulation of opportunities for people from various disciplines and sectors to meet and learn. Plain Language Summary: Because fire in the landscape is often seen as bad, management of fires in the landscape tends to be focused on putting all fires out. But fire belongs in nature and fire services around the world increasingly face the limits of firefighting. Some fires are now becoming so extreme that they cannot be controlled anymore. The way out of this challenge is to accept fire in the landscape, and work with it instead of against it. Here we argue that to live with fire, diversity is essential in four ways: to better connect knowledge and people in different countries, working on different risks, and working in science and practice, and to do this with more diverse people. We conclude by giving suggestions how to achieve this, including a new way of training our future experts. Key Points: Integrated fire management is needed to solve current fire challengesThis requires a cross‐geography, cross‐risk and cross‐sector approach embracing social diversityWe must train the next generation of inter‐ and transdisciplinary integrated fire management teams based on these four axes of diversity [ABSTRACT FROM AUTHOR]

Initiation of wetland features is integral to sustaining landscape eco-hydrological function and meeting defined goals in surface mine reclamation. Within the sub humid climate of the Athabasca Oil Sands, Canada, the water generation mechanisms (external water sources, internal feedback mechanisms) that enable wetlands to form opportunistically on recently reconstructed landscapes are currently unknown, restricting the flexibility in mine closure planning. To address this knowledge gap, we interpret site and local physical characteristics of opportunistic wetlands within the Athabasca Oil Sands through a synoptic survey. Wetlands formed in ~ 8% of the random survey transect areas designed and planted for forestlands. Wetlands had vegetation structures characteristic of woody Salix spp. swamps and narrow-leaved Carex spp. marsh wetland types, with minor coverage of open water marshes. Wetlands formed opportunistically over a range of slopes, aspects and topographic positions, across contrasting fine and coarse-textured landforms. However, different wetland establishment and maintenance controls exist on fine and coarse-textured landforms. On coarse-textured landforms with large groundwater transmissivity, wetland formation was influenced by landscape-scale factors; wetlands were restricted to the toes of slopes and areas intersecting groundwater. On fine-textured constructed landforms, small and large wetlands occurred on lower landscape elevations with the potential for the external (cumulative) water sources, and in hydrologically isolated locations with little potential for runoff contribution from adjacent forestlands (saturation and wetland formation through internal feedback mechanisms). Regardless of landscape position, wetlands formed on flat areas and in shallow inward draining endorheic pans with clay rich soils where low water storage potential promotes frequent surface saturation. These findings have important implications in landscape reclamation design, suggesting that passive techniques that support internal feedback mechanisms may offer a more cost effective reclamation approach compared to more active, expensive techniques that aim to develop wetlands with external water sources. [ABSTRACT FROM AUTHOR]

Abstract: The Boreal Plains (BP) of Western Canada have been exposed to increasing disturbance by wildfire and host a mixture of upland‐wetland‐pond complexes with substantial quantities of trembling aspen (Populus tremuloides Michx.) throughout the terrestrial areas. The ability of these tree species to regenerate within both upland and wetland areas of the BP following wildfire is unclear. The purpose of this study was to investigate the influence of fire on nutrient dynamics in soil and water in peatlands and forested landscapes in the BP and relate this to aspen regeneration. Nutrient concentrations, nutrient supply rates, and net nutrient mineralization rates were determined in burned and unburned sections of a peatland and forest and compared with the regeneration of aspen. NO3−, NH4+, and P varied spatially throughout the landscape, and differences were observed between peatland and upland areas. In general, differences in nutrient dynamics were not observed between burned and unburned areas, with the exception of P. Nutrient and growth data suggest that aspen do not require nutrient‐rich conditions for regeneration and instead relied on forest litter to satisfy nutrient demands. Although the peatlands contained high nutrients, aspen did not flourish in the combination of anoxic and aerobic organic‐rich soils present in this area. Although aspen may use peat water and nutrients through their rooting zones, peatlands are unsuitable for aspen re‐establishment in the long‐term. However, the combination of abundant nutrients in surface mineral soils in peat margins may indicate the vulnerability of margins to upland transformations in later successional stages. [ABSTRACT FROM AUTHOR]

Abstract: Northern peatlands are important global carbon stores, but there is concern that these boreal peat reserves are at risk due to increased fire frequency and severity as predicted by climate change models. In a subhumid climate, hydrogeological position is an important control on peatland hydrology and wildfire vulnerability. Consequently, we hypothesized that in a coarse‐textured glaciofluvial outwash, isolated peatlands lacking the moderating effect of large‐scale groundwater flow would have greater water table (WT) variability and would also be more vulnerable to deep WT drawdown and wildfire during dry climate cycles. A holistic approach was taken to evaluate 3 well‐accepted factors that are associated with smouldering in boreal peatlands: hollow microform coverage, peatland margin morphometry, and gravimetric water content. Using a combination of field measurements (bulk density, humification, WT position, hummock–hollow distribution, and margin width) and modelling (1‐D vertical unsaturated flow coupled with a simple peat–fuel energy balance equation), we assessed the vulnerability of peat to smouldering. We found that a peatland in the regionally intermediate topographic position is the most vulnerable to smouldering due to the interaction of variable connectivity to large‐scale groundwater flow and the absence of mineral stratigraphy for limiting WT declines during dry conditions. Our findings represent a novel assessment framework and tool for fire managers by providing a priori knowledge of potential peat smouldering hot spot locations in the landscape to efficiently allocate resources and reduce emergency response time to smouldering events. [ABSTRACT FROM AUTHOR]

Abstract: Soil‐surface temperature acts as a master variable driving nonlinear terrestrial ecohydrological, biogeochemical, and micrometeorological processes, inducing short‐lived or spatially isolated extremes across heterogeneous landscape surfaces. However, subcanopy soil‐surface temperatures have been, to date, characterized through isolated, spatially discrete measurements. Using spatially complex forested northern peatlands as an exemplar ecosystem, we explore the high‐resolution spatiotemporal thermal behavior of this critical interface and its response to disturbances by using Fiber‐Optic Distributed Temperature Sensing. Soil‐surface thermal patterning was identified from 1.9 million temperature measurements under undisturbed, trees removed and vascular subcanopy removed conditions. Removing layers of the structurally diverse vegetation canopy not only increased mean temperatures but it shifted the spatial and temporal distribution, range, and longevity of thermal hot spots and hot moments. We argue that linking hot spots and/or hot moments with spatially variable ecosystem processes and feedbacks is key for predicting ecosystem function and resilience. [ABSTRACT FROM AUTHOR]

Boreal peatlands may be vulnerable to projected changes in the wildfire regime under future climates. Extreme drying during the sensitive postfire period may exceed peatland ecohydrological resilience, triggering long-term degradation of these globally significant carbon stocks. Despite these concerns, we show low peatland evapotranspiration at both the plot- and landscape-scale postfire, in water-limited peatlands dominated by feather moss that are ubiquitous across continental western Canada. Low postfire evapotranspiration enhances the resilience of carbon stocks in such peatlands to wildfire disturbance and reinforces their function as a regional source of water. Near-surface water repellency may provide an important, previously unexplored, regulator of peatland evapotranspiration that can induce low evapotranspiration in the initial postfire years by restricting the supply of water to the peat surface. [ABSTRACT FROM AUTHOR]

The ecohydrological impact of tree-canopy removal on moss and peat, which provide a principal carbon store, is just starting to be understood. Different mosses have contrasting contributions to carbon and water fluxes (e.g., Sphagnum fuscum, Pleurozium schreberi) and are strongly influenced by tree-canopy cover. Changes in tree-canopy cover may therefore lead to long-term shifts in species composition and associated ecohydrological function. However, the medium-term response to such disturbance, the associated lag in this transition to a new ecohydrological and biogeochemical regime, is not understood in detail. We investigate this medium-term (4 years) ecohydrological, biogeochemical, and species compositional response to tree-canopy removal using a randomized plot design within a northern peatland. This is the only study to test for the influence of increased light alone. We demonstrate that changes in treatment plots 4 years after tree-canopy removal were not significant. Notably, P. schreberi and S. fuscum remained within their respective plots post treatment, and there was no significant difference in plot resistance to evapotranspiration or carbon exchange. Results show that tree-canopy removal alone has little impact on bryophyte ecohydrology in the short or medium-term. This resistance to disturbance contrasts strongly with short-term changes observed within mineral soils, suggesting that concurrent shifts in the large scale hydrology induced within such disturbances are necessary to cause rapid ecohydrological transitions. Understanding this lagged response is critical to determine the strength of medium to long-term negative ecohydrological feedbacks within peatlands in addition to carbon and water fluxes on a decadal timescale in response to disturbance. [ABSTRACT FROM AUTHOR]

A comparative study of forest clear-cut logging effects on daily growing season (May to October) net ecosystem CO2 exchange (NEE) of adjacent peatlands was conducted in two neighbouring forest upland-peatland complexes over 4 years (2005 to 2008) on the Boreal Plains (BP) of Alberta, Canada. Higher vapour pressure deficit at the harvested-upland (H-U) peatland, reflecting increased turbulent mixing after adjacent upland forest removal (2007 and 2008), resulted in increased peatland evapotranspiration rates that contributed to a seasonal decline in soil moisture (volumetric moisture content) influencing NEE. Overall, a significant change in mid-season NEE occurred at the H-U peatland 1 year post-harvesting, greater than NEE changes at the neighbouring intact-upland peatland. However, 2 years post-harvesting, mid-season NEE returned to within range of pre-harvesting variability (−0.54 to 1.34 g CO2-C m−2 day−1). Results of this study demonstrate that BP peatland NEE is largely regulated by site-specific water availability, which, in turn, may be influenced in the short term by shifting microclimate and soil moisture patterns because of clear-cut logging. As such, predicting long-term carbon storage function of BP peatlands will require careful consideration of changing hydroclimatic conditions because of rapid expansion of BP deforestation, given that these ecosystems already exist in a state of hydrologic risk in this moisture deficit eco-region. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Peatland ecosystems are globally important carbon and terrestrial surface water stores that have formed over millennia. These ecosystems have likely optimized their ecohydrological function over the long-term development of their soil hydraulic properties. The optimization of peat hydraulic properties is examined to determine which of the following conditions peatland ecosystems target during this development: (i) maximize carbon accumulation, (ii) maximize water storage, or (iii) balance carbon profit across hydrological disturbances. To identify this control, the short-term hydrological response of a 0.5-m-deep peat profile was simulated during a 50-day rain-free period. A total of 5000 Monte-Carlo model realizations were conducted, with peat hydraulic properties differing between each realization (values derived from known probability distributions). Saturated hydraulic conductivity ( Ks) and empirical van Genuchten water retention parameter α were shown to provide a first order control on simulated water tensions. For hypothetical combinations of Ks and α, the probability that water tension exceeds the ecologically important threshold of 100 mb within 24 h showed a bimodal distribution. A peak at high probabilities was associated with profiles of high Ks and low α. Such a profile is optimized for water storage. A peak at low probabilities is associated with low Ks, high α, and is optimized for carbon accumulation. Actual hydraulic properties from five northern peatlands fall between this binominal distribution, balancing the competing demands of carbon accumulation and water storage. We argue that peat hydraulic properties are thus optimized to maximize water use efficiency and that this optimization occurs over a centennial to millennial timescale. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Wildfire is the largest disturbance affecting peatland ecosystems and can typically result in the combustion of 2-3 kg C m−2 of near-surface peat. We hypothesized that organic soil burn severity, as well as the associated carbon emissions, varies significantly as a function of hydrogeological setting due to groundwater impacts on peat bulk density and moisture content. We measured depth of burn (DOB) in three peatlands located along a hydrogeological and topographic gradient in Alberta's Boreal Plains. Peatland margins across all hydrogeological settings burned significantly deeper (0.245 ± 0.018 m) than peatland middles (0.057 ± 0.002 m). Further, hydrogeological setting strongly impacted DOB. A bog with an ephemeral groundwater connection in a coarse-textured glaciofluvial outwash experienced the greatest DOB at its margins (0.514 ± 0.018 m) due to large water table fluctuations, while a low-lying oligotrophic groundwater flow-through bog in a coarse-textured glaciofluvial outwash experienced limited water table fluctuations and had the lowest margin burn severity (0.072 ± 0.002 m). In an expansive peatland in a lacustrine clay plain, DOB at the margins bordering an isolated domed bog portion (0.186 ± 0.003 m, range: 0.0-0.748 m) was considerably greater than the DOB observed at fen margins with a longer groundwater flow path (<0.05 m). Our research indicates that groundwater connectivity can have a dominant control on soil carbon combustion across and within hydrogeological settings. We suggest that hydrogeological setting be used to identify potential deep burning 'hotspots' on the landscape to increase the efficacy of wildfire management and mitigation strategies. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Wildfire is the largest disturbance affecting northern peatlands; however, little is known about how burn severity (organic soil depth of burn) alters post-fire hydrological conditions that control the recovery of keystone peatland mosses (i.e. Sphagnum). For this reason, we assessed the impact of burn severity on moss water availability by measuring soil tension ( Ψ) and surface volumetric moisture content ( θ) in burned and unburned portions of a peatland complex 2 years after fire. We found that both high and low burn severity decreased post-fire water availability by altering peat hydrophysical properties (moisture retention and water repellency). Locations covered by Sphagnum fuscum prior to fire exhibited a decreasing post-fire water availability with an increasing burn severity. In contrast, the lowest water availability ( Ψ > 400 cm, θ < 0·02) was observed in feather mosses that underwent low burn severity (residual branches identifiable). Deep burning (>0·20 m) in peatland margins and burn depths >0·05 m in the middle of the peatland exhibited the highest water availability ( Ψ < 60 cm). Locations with low surface θ and high Ψ, notably feather mosses undergoing low burn severity, exhibited minimal moss recolonization. Such areas dominate post-fire surface cover (~40%) within late successional (mature) peatlands or peatlands located in dry hydrological settings. We argue that such environments are under-represented in conceptual models of post-fire recovery. A new conceptual model is proposed in which (1) deep burning is counterbalanced by rapid recolonization and (2) pre-fire species interact with burn severity to produce substantial lags in post-fire moss recovery. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Northern peatlands provide important global and regional ecosystem services (carbon storage, water storage, and biodiversity). However, these ecosystems face increases in the severity, areal extent and frequency of climate-mediated (e.g. wildfire and drought) and land-use change (e.g. drainage, flooding and mining) disturbances that are placing the future security of these critical ecosystem services in doubt. Here, we provide the first detailed synthesis of autogenic hydrological feedbacks that operate within northern peatlands to regulate their response to changes in seasonal water deficit and varying disturbances. We review, synthesize and critique the current process-based understanding and qualitatively assess the relative strengths of these feedbacks for different peatland types within different climate regions. We suggest that understanding the role of hydrological feedbacks in regulating changes in precipitation and temperature are essential for understanding the resistance, resilience and vulnerability of northern peatlands to a changing climate. Finally, we propose that these hydrological feedbacks also represent the foundation of developing an ecohydrological understanding of coupled hydrological, biogeochemical and ecological feedbacks. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Consecutive multiple disturbances to northern peatlands can dramatically impact peat hydrophysical properties. We examine the impact of a double disturbance (drainage and wildfire) on the hydrophysical and moisture retention properties of peat, a key regulator of peatland ecohydrological resilience, and compare this with the impact to each individual disturbance (drainage and wildfire). The compound effect of drainage and wildfire resulted in a shift of the surface datum down the peat profile, revealing denser peat. Less-dense near-surface peats that regulate water-table position and near-surface moisture content, both favourable to Sphagnum recolonization, were lost. At a drained peatland that was then subject to wildfire, peat bulk density increased by 14.1%, von Post humification class increased by two categories and water retention increased by 15.6%, compared with an adjacent burned but undrained (single disturbance) portion of the fen. We discuss the key hydrophysical metrics of peatland vulnerability and outline how they are affected by the isolated impacts of drainage and wildfire, as well as their combined effects. We demonstrate that multiple peatland disturbances have likely led to an increase in hydrological limitations to Sphagnum recovery, which may impact peatland ecohydrological resilience. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Methane emissions from northern peatlands are strongly dependent on soil temperatures. Therefore, to predict methane emissions from northern peatlands under future climatic conditions, it is important to simulate the effect of these changing climatic conditions on peat temperatures. This article reports on the development and testing of two one-dimensional (1D) models used to simulate soil temperatures at shallow depths in a northern peatland. First, the HIP-Dlet (Heat in Peat – Dirichlet) model applies measured temperatures to the surface boundary of a conduction-based temperature model. Secondly, the HIP-Nmann (Heat in Peat – von Neumann) model simulates the surface boundary from standard meteorological measurements. The HIP-Dlet model provides a reasonable to good approximation of measured temperatures showing that heat transport processes within the soil are adequately simulated. The model does not simulate an advective liquid heat flux. However, only substantial rainfall events (> 70 mm over 3 days) during the study period had any significant effect on model error. Errors in the HIP-Nmann model were of a similar magnitude to the HIP-Dlet model. Errors in the HIP-Dlet model resulted predominantly from errors in the measured soil temperatures. Errors in the HIP-Nmann were due to errors in the measured soil temperatures and the inaccurate simulation of the surface boundary condition. The development of future peatland temperature models should, therefore, focus on the simulation of the surface boundary condition, particularly the parameterisation of the surface resistance that is shown here to produce significant errors in the modelled soil temperatures. [ABSTRACT FROM AUTHOR]

The potential of high severity wildfires to increase global terrestrial carbon emissions and exacerbate future climatic warming is of international concern. Nowhere is this more prevalent than within high latitude regions where peatlands have, over millennia, accumulated legacy carbon stocks comparable to all human CO2 emissions since the beginning of the industrial revolution. Drying increases rates of peat decomposition and associated atmospheric and aquatic carbon emissions. The degree to which severe wildfires enhance drying under future climates and induce instability in peatland ecological communities and carbon stocks is unknown. Here we show that high burn severities increased post-fire evapotranspiration by 410% within a feather moss peatland by burning through the protective capping layer that restricts evaporative drying in response to low severity burns. High burn severities projected under future climates will therefore leave peatlands that dominate dry sub-humid regions across the boreal, on the edge of their climatic envelopes, more vulnerable to intense post-fire drying, inducing high rates of carbon loss to the atmosphere that amplify the direct combustion emissions. [ABSTRACT FROM AUTHOR]

Northern and tropical peatlands represent a globally significant carbon reserve accumulated over thousands of years of waterlogged conditions. It is unclear whether moderate drying predicted for northern peatlands will stimulate burning and carbon losses as has occurred in their smaller tropical counterparts where the carbon legacy has been destabilized due to severe drainage and deep peat fires. Capitalizing on a unique long-term experiment, we quantify the post-wildfire recovery of a northern peatland subjected to decadal drainage. We show that the moderate drop in water table position predicted for most northern regions triggers a shift in vegetation composition previously observed within only severely disturbed tropical peatlands. The combined impact of moderate drainage followed by wildfire converted the low productivity, moss-dominated peatland to a non-carbon accumulating shrub-grass ecosystem. This new ecosystem is likely to experience a low intensity, high frequency wildfire regime, which will further deplete the legacy of stored peat carbon. [ABSTRACT FROM AUTHOR]