|Thursday, April 07|
Where next for restoration in Canada?
* Eric Higgs, School of Environmental Studies, University of Victoria, Canada
These are exciting times for restoration practitioners and scientists in Canada. Initial efforts to develop national guidelines in the mid-2000s propelled restoration activity and resulted in significant leadership at a global scale. The launch of the UN Decade of Ecosystem Restoration in 2021 signalled that restoration is a priority action to address ecological and social crises resulting from climate change, land degradation, urbanization, and resource extraction. The pressure is on, but how well prepared are we as Canadians to mobilize effective, efficient, and engaging restoration? In this presentation I will describe recent work to synthesize knowledge on restoration in Canada, and address emerging challenges and opportunities for restoration, including Indigenous resurgence, ecological novelty ,and appropriate guidance.
10 years of research on peatland restoration techniques following in situ well pad disturbances in the Oil Sands regions
* Meike Lemmer, Université Laval, Canada
In the Oil Sands region of Alberta, Canada, boreal peatlands experience disturbances by the vast infrastructure of the in situ oil and gas industry. Besides numerous access roads, pipelines, and processing facilities, thousands of in situ well pads are constructed to extract bitumen from oil deposits at great depth. Oftentimes these well pads are constructed within pristine peatland ecosystems, disturbing their functionality. Well pads consist of a mix of mineral soils of 1 to 4 m in thickness and sized approximately 1 to 4 ha installed on the surface of the targeted peatland. A well pad’s lifespan is approximately 20 years. Since 2015, the energy operators are obliged to restore peatlands, following the disturbance. As of November 2021, there were more than 42 500 active wells in Alberta, of which more than 11 700 have been abandoned. The restoration aim is the reestablishment of important peatland functions, such as wildlife habitat, peat accumulation, and carbon sequestration. Since the late 2000’s, several peatland restoration approaches have been tested in the Oil Sands regions. The approaches include 1) the partial removal of the mineral fill to 15 cm above the water table level and 4 to 6 cm above the water table level, and planting of specific fen species seedlings (Carex aquatilis, Larix laricina, and Salix lutea), 2) the partial removal of the mineral fill to the water table level and spontaneous revegetation, 3) the partial removal of the mineral fill to the water table level in combination with an adjusted moss layer transfer technique (MLTT), 4) the complete removal of a well pad’s mineral fill and spontaneous revegetation via natural ingress, 5) the complete removal of a well pad’s mineral fill in combination with the MLTT, and 6) the inversion of the mineral fill and the underlying compressed peat, in combination with the MLTT. The relative success of the different restoration approaches considering the return of characteristic vegetation and carbon sequestration will be discussed.
Disentangling competition from water and salt stress for Carex aquatilis and Juncus balticus during oil sands fen reclamation
* Ellie Goud, University of Waterloo, Canada
Maria Strack, University of Waterloo, Canada
Fen reclamation projects after oil sands mining are designed with the goal of recreating self-sustaining, biodiverse fens that accumulate carbon over time. Environmental stress from water table fluctuations and sodium (Na) and sulphate-containing salts left over from the bitumen extraction process can impede fen reclamation due to adverse impacts on plant biodiversity and function. In 2013, a fen reclamation project was initiated in northern Alberta, which included planting freshwater and saline species water sedge (Carex aquatilis) and Baltic rush (Juncus balticus), respectively, to account for changes in water chemistry over time. However, only two years after planting, the fen was dominated by Carex while Juncus declined. Currently, Carex remains dominant although both species show signs of plateau. Meanwhile, salinity has increased substantially, and water table varies across space and time. Variation in plant cover could be caused by competition or environmental stress. We tested these hypotheses in a greenhouse experiment that manipulated diversity, water availability, and salinity and determined the relative roles of inter and intraspecific competition and stress responses. To identify mechanisms underlying variation in growth across treatments, we measured leaf and root stable isotopes of carbon (δ13C), oxygen (δ18O), and sulphur (δ34S) to integrate physiology, as well as salt concentrations (e.g., Na) and morphological traits (e.g., height, leaf density). We found species-specific responses, with Carex growing best under wet, low salt conditions and displayed strong intraspecific competition. Juncus grew best in dry, low salt conditions where it was able to outcompete Carex. Juncus maintained similar growth across variable treatments, except under wet, low salt conditions where Carex had the largest growth. Both species had the lowest growth under high salt conditions, regardless of water availability. Variation in growth was driven by metabolic tradeoffs related to water use and salt tolerance, as measured by stable isotopes, and salt avoidance traits measured by tissue chemistry. Carex adjusted leaf physiology to limit water loss while Juncus adjusted allocation to root biomass and salt sequestration. Although Carex may be a superior competitor under favorable conditions, increasing salinity and water limitation reduce its growth and competitive ability. High salt concentrations may continue to limit productivity at constructed fens, although Juncus is likely to persist and possibly increase over time. Our results highlight the important of species choice and competitive interactions in restoration outcomes in the face of dynamic environmental stress.
Recovery of Smelter Impacted Peatlands in Sudbury, Ontario
* James Seward, Laurentian University , Canada
Peter Beckett, Laurentian University , Canada
Suzanna Bräuer, Appalachian State University, United States
Pascale Roy-Leveillee, Université Laval, Canada
Nathan Basiliko, Laurentian University , Canada
Erik Emilson, Great Lakes Forestry Centre, Canada
Shaun Watmough, Trent University, Canada
A century of Ni and Cu smelting has damaged poor fens before the start of pollution controls in 1972. There has been a re-establishment of Sphagnum, as demonstrated by a recent re-survey compared to a 1986 report. In addition, microbial communities are controlled by pH as well as Ni and Cu concentrations. This assessment could assist in future restoration of the peatlands.
Restauration des zones dénudées dans les bleuetières sauvages
* Nadler Simon, VALORES, Canada
Jolaine Arseneau, VALORES, Canada
Marion Tétégan Simon, VALORES, Canada
Plusieurs techniques utilisées (mécanisation, pesticides, etc) pour la mise en place de champs de bleuets sauvages (Vaccinium angustifolium) ont favorisé le développement de nombreuses zones dénudées – i.e. sans couvert végétal – au sein de ces derniers. Le phénomène des zones dénudées pose un problème critique auquel les producteurs n'ont pas encore trouvé de solution. Quelques études aléatoires infructueuses ont été menées sans succès par des producteurs qui espéraient que les zones dénudées seraient éventuellement recolonisées par les rhizomes de Vaccinium angustifolium. Ainsi, depuis de nombreuses années, les zones dénudées sont une préoccupation croissante, car elles ont un impact sur le rendement des cultures et la valeur de vente des champs. La propagation en serre de semences de bleuets sauvages apparaît comme une alternative intéressante pour traiter les zones dénudées des bleuetières sauvages. Des essais ont été effectués au Nouveau-Brunswick sur différents substrats de croissance et traitements de semences sur la germination de Vaccinium angustifolium. Des expérimentations ont été réalisées en conditions contrôlées (température ambiante et humidité de 22±1°C et 30±2% respectivement, seize heures de lumière/jour, arrosage : 25,5 ml/jour, etc.) sur 44 cas d'étude considérant 11 substrats et 4 traitements de semences avec 9 répétitions (pots) par traitement. Les graines de Vaccinium angustifolium ont été initialement congelées à -18°C pendant plus de 90 jours, trempées de 12 à 24 heures dans des traitements liquides (5 ml) avant d'être plantées dans chaque substrat à un taux de semis de 0,31×10-3g.cm-2. Les observations 12 semaines après l'ensemencement ont montré une nette influence des substrats à base de sphaigne ou de tourbe sur l'augmentation du taux de germination par rapport aux substrats à base de compost, suggérant qu'un pH élevé du compost inhiberait le processus de germination et la densité des germes de bleuets.