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Studies in recent decades have shown strong evidence of physical and biological changes in the Arctic tundra, largely in response to rapid rates of warming. Given the important implications of these changes for ecosystem services, hydrology, surface energy balance, carbon budgets, and climate feedbacks, research on the trends and patterns of these changes is becoming increasingly important and can help better constrain estimates of local, regional, and global impacts as well as inform mitigation and adaptation strategies. Despite this great need, scientific understanding of tundra ecology and change remains limited, largely due to the inaccessibility of this region and less intensive studies compared to other terrestrial biomes. A synthesis of existing datasets from past field studies can make field data more accessible and open up possibilities for collaborative research as well as for investigating and informing future studies. Here, we synthesize field datasets of vegetation and active-layer properties from the Alaskan tundra, one of the most well-studied tundra regions. Given the potentially increasing intensive fire regimes in the tundra, fire history and severity attributes have been added to data points where available. The resulting database is a resource that future investigators can employ to analyze spatial and temporal patterns in soil, vegetation, and fire disturbance-related environmental variables across the Alaskan tundra. This database, titled the Synthesized Alaskan Tundra Field Database (SATFiD), can be accessed at the Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC) for Biogeochemical Dynamics (Chen et al., 2023: 10.3334/ORNLDAAC/2177). [ABSTRACT FROM AUTHOR]

Arctic tundra largely in response to exceptionally rapid rates of warming. Given the important implications of these changes on ecosystem services, hydrology, surface energy balance, carbon budgets, and climate feedbacks, research on the trends and patterns of these changes is becoming increasingly important and can help better constrain estimates of local, regional, and global impacts as well as inform mitigation and adaptation strategies. Despite this high need, scientific understanding of tundra ecology and change remains limited largely due to the inaccessibility of this region and less intensive study compared to other terrestrial biomes. A synthesis of existing datasets from past field studies can make field data more accessible and open up possibilities for collaborative research as well as for investigating and informing future studies. Here, we synthesize field datasets of vegetation, and active layer properties from the Alaskan tundra, one of the most well-studied tundra regions. Given the potential increasingly intensive fire regimes in the tundra, fire history and severity attributes have been added to data points where available. The resulting database is a resource that future investigators can employ to analyze spatial and temporal patterns in soil, vegetation, and fire disturbance-related environmental variables across the Alaskan tundra. This database, titled Synthesized Alaskan Tundra Field Database (SATFiD), can be accessed at the Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC) for Biogeochemical Dynamics (Chen et al., 2023: https://doi.org/10.3334/ORNLDAAC/2177). [ABSTRACT FROM AUTHOR]

Boreal peatlands represent a globally important store of carbon, and disturbances such as wildfire can have a negative feedback to the climate. Understanding how carbon exchange and greenhouse gas (GHG) dynamics are impacted after a wildfire is important, especially as boreal peatlands may be vulnerable to changes in wildfire regime under a rapidly changing climate. However, given this vulnerability, there is very little in the literature on the impact such fires have on methane (CH4) emissions. This study investigated the effect of wildfire on CH4 emissions at a boreal fen near Fort McMurray, Alberta, Canada, that was partially burned by the Horse River Wildfire in 2016. We measured CH4 emissions and environmental variables (2017–2018) and CH4 production potential (2018) in two different microform types (hummocks and hollows) across a peat burn severity gradient (unburned (UB), moderately burned (MB), and severely burned (SB)). Results indicated a switch in the typical understanding of boreal peatland CH4 emissions. For example, emissions were significantly lower in the MB and SB hollows in both years compared to UB hollows. Interestingly, across the burned sites, hummocks had higher fluxes in 2017 than hollows at the MB and SB sites. We found typically higher emissions at the UB site where the water table was close to the surface. However, at the burned sites, no relationship was found between CH4 emissions and water table, even under similar hydrological conditions. There was also significantly higher CH4 production potential from the UB site than the burned sites. The reduction in CH4 emissions and production in the hollows at burned sites highlights the sensitivity of hollows to fire, removing labile organic material for potential methanogenesis. The previously demonstrated resistance of hummocks to fire also results in limited impact on CH4 emissions and likely faster recovery to pre-fire rates. Given the potential initial net cooling effect resulting from a reduction in CH4 emissions, it is important that the radiative effect of all GHGs following wildfire across peatlands is taken into account. [ABSTRACT FROM AUTHOR]

Boreal peatlands represent a globally important store of carbon, and disturbances such as wildfire can have a negative feedback to the climate. Understanding how carbon exchange and greenhouse gas (GHG) dynamics are impacted after a wildfire is important, especially as boreal peatlands may be vulnerable to changes in wildfire regime under a rapidly changing climate. Yet, given this vulnerability, there is very little in the literature on the impact such fires have on methane (CH4) emissions. This study investigated the effect of wildfire on CH4 emissions at a boreal fen near Fort McMurray, AB, Canada, that was partially burned by the Horse River Wildfire in 2016. We measured CH4 emissions and environmental variables (2017-2018) and CH4 production potential (2018) in two different microform types (hummocks and hollows) across a burn severity gradient (unburned (UB), moderately burned (MB) and severely burned (SB)). Results indicated a switch in the typical understanding of boreal peatland CH4 emissions. For example, emissions were much lower in the MB and SB hollows in both years compared to UB hollows. Interestingly, across the burned sites, hummocks had higher fluxes in 2017 than hollows at the MB and SB sites. We found typically higher emissions at the UB site where the water table was close to the surface. However, at the burned sites, no relationship was found between CH4 emissions and water table, even under similar hydrological conditions. This further strengthens the argument on the overriding influence of fire. There was also significantly higher CH4 production potential from the UB site than the burned sites. The reduction in CH4 emissions and production in the hollows at burned sites highlights the sensitivity of hollows to fire, removing labile organic material for potential methanogenesis. The previously demonstrated resistance of hummocks to fire also results in limited impact to CH4 emissions and likely faster recovery to pre-fire rates. Given the potential initial net cooling effect resulting from a reduction in CH4 emissions, it is important that the radiative effect of all GHG following wildfire across peatlands is taken into account. [ABSTRACT FROM AUTHOR]

Boreal peatlands represent a globally important store of carbon, and disturbances such aswildfire can have a significant positive feedback to the climate. Understanding how carboncycling and greenhouse gas (GHG) dynamics are impacted after a wildfire is important,especially as boreal peatlands may be vulnerable to changes in wildfire regime under arapidly changing climate. Yet given this vulnerability, there is very little in the literature onthe impact such fires have on methane (CH4) emissions. This study investigated the effect of wildfire on CH4 emissions at a boreal fen near FortMcMurray, AB, Canada, partially burned by the Horse River Wildfire in 2016. We measuredCH4 emissions and environmental variables (2017-2018) and CH4 production potential(2018) in two different microform types (hummocks and hollows) across a burnseverity gradient (unburned (UB), moderately burned (MB) and severely burned(SB)). The average CH4 flux at the UB hollows was 96.5 and 66.6 mg CH4 m−2 d−1in 2017 and2018, respectively. Methane emissions were much lower in the MB and SB hollows in bothyears, with the average flux being 0.25 and 0.06 mg CH4 m−2d−1 in 2017 and 1.93 and 1.38mg CH4m−2 d−1, respectively. Interestingly, across the burned sites, hummocks had higherfluxes in 2017 than hollows with the average flux being 1.82 and 5.83 mg CH4m−2 d−1 at theMB and SB sites, respectively. Results of a linear mixed effects model (LMM) illustrate thereis a significant effect of burn severity on CH4 flux, although no significant difference betweenmicroform or year. Another LMM found a significant interaction between burnseverity and both soil temperature at 30 cm depth and water table. There was alsosignificantly higher CH4 production potential from the UB site than the burnedsites. The reduction in CH4 emissions and production in the hollows at burned sites highlightsthe sensitivity of hollows to fire, removing labile organic material for potentialmethanogenesis. The previously demonstrated resilience of hummocks to fire also results inlimited impact to methane emissions and likely faster recovery to pre-fire rates. [ABSTRACT FROM AUTHOR]