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Seismic lines are prominent linear disturbances across boreal Canada with large-scale consequences to wildlife and ecosystem function. Although seismic line restoration has been observed to improve tree growth and survival, application in peatlands has been shown to alter ecosystem functions such as hydrology and carbon storage. The most common active restoration method is called mechanical mounding, where the classic technique inverts the peat profile. New mounding methods that maintain the peat profile may provide benefits by preserving existing vegetation and reducing disturbance. To determine the effects of different mounding methods on soil quality, we collected and analyzed peat cores from two different sites for various soil properties (C/N ratios, [delta][sup.13]C, [delta][sup.15]N, and Fourier transform infrared (FTIR) spectroscopy humification indices). Vegetation surveys were also conducted. The two sites are both a collection of seismic lines crossing poor fens in Alberta. One site was treated with the classic method, while the other was treated with two new mounding methods. Classic mechanical mounding significantly increased the degree of decomposition, indicative of lower substrate quality. Mechanical mounding also greatly reduced moss cover and introduced large amounts of bare ground cover. The two newer mounding methods did not result in these changes and were largely comparable to natural peat properties and vegetation communities. Preserving the peat profile in new mounding methods may support faster return of ecosystem function. Key words: organic soil, bulk density, mechanical mounding, C/N ratio, stable isotopes Les lignes sismiques sont des perturbations lineaires importantes dans la region boreale du Canada qui ont des consequences a grande echelle sur la faune et la fonction des ecosystemes. Meme si on a observe que la restauration des lignes sismiques ameliore la croissance et la survie des arbres, on a demontre que son application dans les tourbieres modifie les fonctions de l'ecosysteme telles que l'hydrologie et le stockage du carbone. La methode de restauration active la plus courante s'appelle le buttage mecanique oU la technique classique inverse le profil de la tourbe. De nouvelles methodes de buttage qui maintiennent le profil de la tourbe peuvent presenter des avantages en preservant la vegetation existante et en reduisant les perturbations. Pour determiner les effets de differentes methodes de buttage sur la qualite du sol, on a preleve et analyse des carottes de tourbe sur deux sites differents pour confirmer diverses proprietes du sol (rapport C/N, [delta][sup.13]C, [delta][sup.15]N, indices d'humification par spectroscopie infrarouge a transformee de Fourier (FTIR)). Des etudes de la vegetation ont egalement ete menees. Les deux sites correspondent a un ensemble de lignes sismiques traversant des tourbieres pauvres en Alberta. La methode classique a ete utilisee pour traiter un site tandis que l'autre a ete traite avec deux nouvelles methodes de buttage. Le buttage mecanique classique a augmente de maniere significative le degre de decomposition, ce qui indique une qualite inferieure du substrat. Le buttage mecanique a egalement reduit considerablement la couverture de mousse et a introduit de grandes quantites de couverture de sol nu. Les deux methodes de buttage plus recentes n'ont pas entraine ces changements et etaient largement comparables aux proprietes de la tourbe naturelle et aux communautes vegetales. La preservation du profil de la tourbe dans les nouvelles methodes de buttage peut favoriser un retour plus rapide des fonctions de l'ecosysteme. [Traduit par la Redaction] Mots-cles : sol organique, densite apparente, buttage mecanique, rapport C/N, isotopes stables, Introduction An estimated 345 000 km of seismic lines covering 1910 [km.sup.2] have been created in all types of peatlands in the province of Alberta, Canada, for oil and gas [...]

Linear disturbances are widespread in the boreal region of Alberta, Canada. Despite their ubiquitous nature, little is known about their influence on over‐winter meteorological conditions and if and how they alter the snowpack and soil temperature profiles through altered energy and water balances in the wintertime. The presence of seismic lines could affect hydrological processes in both the wintertime and warm months. This will then affect plant communities and carbon cycling on these disturbances. Thus, understanding the effect of seismic lines on meteorological conditions during cold weather conditions will be important to better understand how they alter ecosystem function. Accordingly, this study aims to assess the effect of two seismic lines with different orientations created for petroleum resource exploration on energy and meteorological variables by comparing them with the near surface conditions in the adjacent wooded peatland area from October 2022 to April 2023. We observed 1.8 times higher photon flux density of photosynthetically active radiation on the linear disturbances than in the understory of the undisturbed locations and a greater negative net radiation on the seismic lines compared with that observed off the lines. Furthermore, the average wind speed on the seismic lines were eight and seven times higher at the east–west and south–north oriented seismic lines than the adjacent wooded peatland, respectively. Together, these changes resulted in a denser snowpack on the seismic line and overall higher snow water equivalent in the pre‐melt snowpack. This provided insulation for the soil, and soil temperature on the lines stayed above freezing 7 days longer at the east–west oriented site or retained non‐freezing condition at the south–north oriented site in the upper 15 cm. This would result in more microbial activity and potential higher over‐winter carbon releases. [ABSTRACT FROM AUTHOR]

Northern peatlands are sinks for atmospheric carbon (C), but peat extraction converts these ecosystems to C sources. Due to a dry regional climate, undisturbed bog peatlands in western Canada often have a tree cover of Picea mariana (Mill.) B.S.P. Thus, a coniferous forest plantation may be an appropriate land use for cutover peatlands. This study determined the effect of a 7-year-old P. mariana plantation on C balance of a cutover peatland. We measured C stored in P. mariana biomass and carbon dioxide (C[O.sub.2]) and methane (C[H.sub.4]) fluxes from bare peat at each of four fertilizer doses. Carbon stored in biomass of Betula papyrifera (Marsh.) that had spontaneously colonized the postfertilized site was also determined. Given that the water table remained very deep and that the sphagnum moss--ericaceous shrub peat- accumulating vegetation was not present, the site remained a source of C when only the planted P. mariana trees were considered, primarily in the form of C[O.sub.2] emissions by soil respiration. However, C accumulation in trees, including B. papyrifera biomass, resulted in a net C sink in fertilized plots. Results from this study indicate that tree plantations on cutover peatland may be a suitable land-management strategy on sites difficult to effectively rewet. Key words: carbon dioxide, peatland restoration, forest plantation, methane, soil organic matter. Les tourbieres nordiques sont des puits de carbone (C) atmospherique mais l'extraction de la tourbe convertit ces ecosystemes en source de C. A cause d'un climat regional sec, les tourbieres ombrotrophes non perturbees de l'ouest du Canada ont souvent un couvert arborescent de Picea mariana (Mill.) B.S.P. Par consequent, la plantation de forets de conifere peut constituer une utilisation appropriee des terres dans le cas des tourbieres qui ont subi une coupe. Cette etude a examine l'effet d'une plantation de P. mariana agee de 7 ans sur le bilan du C dans une tourbiere qui a ete coupee. Nous avons mesure le C emmagasine dans la biomasse de P. mariana ainsi que les flux de dioxyde de carbone (C[O.sub.2]) et de methane (C[H.sub.4]) dans la tourbe denudee pour chacune de quatre doses de fertilisant. Le carbone emmagasine dans la biomasse de Betula papyrifera Marsh., qui avait spontanement colonise le site apres une fertilisation, a egalement ete mesure. Etant donne que la nappe phreatique est demeuree tres profonde, et qu'il n'y avait pas de vegetation, mousse de sphaigne et ericacees arbustifs, qui permettait d'accumuler de la tourbe, le site est demeure une source de C lorsqu'on tenait compte seulement des tiges de P. mariana, surtout sous forme d'emissions de C[O.sub.2] provenant de la respiration du sol. Cependant, l'accumulation du C dans les arbres, incluant la biomasse de B. papyrifera, se traduisait par un puits net de C dans les places echantillons fertilisees. Les resultats de cette etude indiquent que la plantation d'arbres dans les tourbieres qui ont ete coupees peut constituer une strategie d'amenagement appropriee des terres pour les sites qui sont effectivement difficiles a rehumidifier. [Traduit par la Redaction] Mots-cles: dioxyde de carbone, restauration des tourbieres, plantation forestiere, methane, matiere organique du sol., Introduction When a peatland is used for commercial peat extraction, vegetation is removed and open ditches are installed to dry the land. Drainage of peatland and extraction of peat leads [...]

Peatland ecosystem restoration following oil mining activities in Alberta, Canada, aims at reestablishing crucial peatland functions, such as wildlife habitat, water storage and filtration, peat accumulation, and carbon sequestration. To reinstate peatland functions, characteristic hydrological conditions are necessary to support the establishment and growth of characteristic wetland vegetation. Following in situ oil sands well pad disturbances in the Peace River and Cold Lake Oil Sands regions in Alberta, we evaluated the efficiency of peatland restoration approaches including different groundwork and revegetation techniques. Groundwork techniques included the complete removal (CR) or partial removal (PR) of the former in situ well pads' mineral fill and revegetation included the spontaneous revegetation via natural ingress of diaspores from nearby peatlands, or managed revegetation via planting of Carex aquatilis, Larix laricina, and Salix lutea. We assessed the plant species composition, biochemical and hydrological properties of all study areas, including restored peatland areas, an unrestored area, and reference areas (REF) for comparison. Ten years post‐restoration, in the restored areas the mean total plant cover was 57% with an average of 35 vascular plant and bryophyte species, while in REF 68% mean total plant cover and an average of 64 plant species were recorded. Respectively, characteristic peatland species contributed to 61 and 100% of the species composition. PR and hydrological connection to the adjacent peatland resulted in near surface water table and the highest peatland plant species diversity, while CR promoted the formation of a shallow open water area. [ABSTRACT FROM AUTHOR]

Draining and extracting peat alters the conditions that control CO 2 and CH 4 emissions. Carbon (C) emissions from peatlands undergoing horticultural peat extraction are not well constrained due to a lack of measurements. We determine the effect that production duration (years of extraction) has on the CO 2 and CH 4 emissions from an actively extracted peatland over 3 years of measurements (2018–2020). We studied five sectors identified by the year when extraction began (1987, 2007, 2010, 2013, 2016). Greater average CO 2 and CH 4 emissions were measured from the drainage ditches (CO 2 : 2.05 ± 0.12 g C m -2 d -1 ; CH 4 : 72.0 ± 18.0 mg C m -2 d -1) compared to the field surface (CO 2 : 0.9 ± 0.06 g C m -2 d -1 ; CH 4 : 9.2 ± 4.0 mg C m -2 d -1) regardless of sector. For peat fields, CO 2 fluxes were highest in the youngest sector, which opened in 2016 (1.5 ± 0.2 g C m -2 d -1). The four older sectors all had similar mean CO 2 fluxes (∼ 0.65 g C m -2 d -1) that were statistically different from the mean 2016 CO 2 flux. A spatial effect on CO 2 fluxes was observed solely within the 2016 sector, where CO 2 emissions were highest from the centre of the peat field and declined towards the drainage ditches. These observations occur due to operators contouring surfaces to facilitate drainage. The domed shape and subsequent peat removal resulted in a difference in surface peat age hence different humification and lability. In addition, 14 C dating confirmed that the peat contained within the 2016 sector was younger than peat within the 2007 sector and that peat age is younger toward the centre of the field in both sectors. Humification indices derived from mid-infrared spectrometry (MIRS) (1630/1090 cm -1) indicated that peat humification increases with increasing years of extraction. Laboratory incubation experiments showed that CO 2 production potentials of surface peat samples from the 2016 sector increased toward the centre of the field and were greater than for samples taken from the 1987 and 2007 sectors. Our results indicate that peatlands under extraction are a net source of C, where emissions are high in the first few years after opening a field for extraction and then decline to about half the initial value and remain at this level for several decades, and the ditches remain a 2 to 3 times greater source than the fields but represent <3.5 % of the total area of a field. [ABSTRACT FROM AUTHOR]