Is bog water chemistry affected by increasing N and S deposition from oil sands development in Northern Alberta, Canada?

Nitrogen and sulfur emissions from oil sands operations in northern Alberta, Canada have resulted in increasing deposition of N and S to the region’s ecosystems. To assess whether a changing N and S deposition regime affects bog porewater chemistry, we sampled bog porewater at sites at different distances from the oil sands industrial center from 2009 to 2012 (10-cm intervals to a depth of 1 m) and from 2009 to 2019 (top of the bog water table only). We hypothesized that: (1) as atmospheric N and S deposition increases with increasing proximity to the oil sands industrial center, surface porewater concentrations of NH4+, NO3−, DON, and SO42− would increase and (2) with increasing N and S deposition, elevated porewater concentrations of NH4+, NO3−, DON, and SO42− would be manifested increasingly deeper into the peat profile. We found weak evidence that oil sands N and S emissions affect bog porewater NH4+-N, NO3−-N, or DON concentrations. We found mixed evidence that increasing SO42− deposition results in increasing porewater SO42− concentrations. Current SO42− deposition, especially at bogs closest to the oil sands industrial center, likely exceeds the ability of the Sphagnum moss layer to retain S through net primary production, such that atmospherically deposited SO42− infiltrates downward into the peat column. Increasing porewater SO42− availability may stimulate dissimilatory sulfate reduction and/or inhibit CH4 production, potentially affecting carbon cycling and gaseous fluxes in these bogs.

The ecological importance of moss ground cover in dry shrubland restoration within an irrigated agricultural landscape matrix

1. Kānuka (Kunzea serotina, Myrtaceae) dryland shrubland communities of the lowland plains of South Island (Te Wai Pounamu) New Zealand (Aoteoroa) contain a ground cover largely consisting of mosses, predominantly Hypnum cupressiforme. There has been no previous study of the role of mosses in this threatened habitat which is currently being restored within a contemporary irrigated and intensively-farmed landscape that may be incompatible with this component of the ecosystem. 2. The aim of the present study was to investigate the influence of moss ground cover on hydrology, nitrogen (N) availability and vascular plant interactions, and in relation to nutrient spillover from adjacent farmland. Experimental work was a combination of glasshouse experiments and field-based studies. 3. Extremes of soil temperature and moisture were found to be mediated by the moss carpet, which also influenced N speciation; available N declined with moss depth. The moss layer decreased the amount of germination and establishment of vascular plants but, in some cases, enhanced their growth. Spillover of mineral nitrogen and phosphate from farmland enhanced invasion of exotic grasses which may have benefited from conditions provided by the moss carpet. 4. Synthesis: We found the moss layer to be crucial to ecosystem functioning in these dry habitats with low nutrient substrate. However, when the moss layer is accompanied by nutrient spillover it has the potential to increase exotic weed encroachment. Our results emphasise the importance of non-vascular plant inclusion in restoration schemes but also highlights the importance of mitigating for nutrient spillover.

Communities with Myrica gale L. in mires of the Gulf of Finland coast (St. Petersburg and Leningrad Region)

Сommunities of Myrica gale L. (sweet gale), their ecology and geography in coastal mires of the Gulf of Finland within St. Petersburg and the Leningrad Region on the Southeastern border of their range are described based on 70 relevés, made in 1981–2018. This species is included in the Red Data Books of Russia (2008), Leningrad Region (2018), St. Petersburg (2018), and Republic of Karelia (2007). The distribution of the communities in the studied area is as follows (Fig. 1) — the Yuntolovskiy reserve (the largest population), vicinity of the Lisiy Nos ­settlement, forest-park “Gagarka”, Tarkhovskiy Mys, Yuntolovskiy fo­rest-park (within St. Petersburg); vicinity of the Pesochnoe ­settlement, the Bolshoy Berye­zovyy Isl., near the port “Primorsk” (the Nor­thern coast of the Gulf of Finland) and the vicinity of Bolshaya Izhora ­settlement (Southern coast of the latter) in the Leningrad Region area. Communities are found mainly in coastal mires of various types (raised bogs, transitional mires, fens) in the place of former lagoons and in inter-dune depressions in different trophic conditions; most diverse in the last two. Communities are assigned into 12 associations, two of which with the shrub layer formed by Myrica gale. Sphagnetum myricosum galis is the most common association in transitional mires (Table 3). The communities are two-layers: Myrica gale shrub one and closed moss layer of Sphagnum species of diffe­rent ecological groups. The association is subdivided into 3 subassociations by dominanting Sphagnum species and groups of determinant species: sphagnosum angustifolii, sphagnosum flexuosi, and sphagnosum teretis. The communities of this association are located­ in newly formed mires, and their species composition is in the process of formation. These are succession stages between the fens and transitional mires. The ass. Myricetum caricosum lasiocarpae (table 4) includes communities of fens with close (50 to 80 %) Myrica gale shrub layer. Carex lasiocarpa is the dominant of the herb layer, in some communities there is the lower herb sublayer of Comarum palustre. There is no moss layer. Association Myricetum comaroso–betulosum with sparse Betula pubescens 5–12 m high tree layer is also recorded in fens (Table 4). Communities of the ass. Salicetum myricoso–paludiherbosum with the dominance of shrub willows and Myrica gale are rather widespread in coastal fens. They have closed (up to 100 %) shrub layer formed by various willows and M. gale. The composition and cover of paludal herbaceous species is variable, the only constant, sometimes abundant, species is Comarum palustre. The association is subdivided into 3 subassociations (salicosum phylicifoliae, salicosum phylicifoliae-myrsinifoliae and salicosum rosmarinifoliae-myrsinifoliae) according to the dominating willows and mire grasses. Besides the above associations with high abundance of Myrica gale, this species occurs with low abundance in the communities of other, often widespread mire associations, as their coastal variants (Tables 2–4). The discussed community types in the Leningrad Region and St. Petersburg have regional features and differ in species composition from the sweet gale communities of Western and Northern Europe. Due to the rarity in the European part of Russia communities with both low abundance and dominance of Myrica gale need protection as well as their habitats.

Modelling the habitat preference of two key <i>Sphagnum</i> species in a poor fen as controlled by capitulum water content

Current peatland models generally treat vegetation as static, although plant community structure is known to alter as a response to environmental change. Because the vegetation structure and ecosystem functioning are tightly linked, realistic projections of peatland response to climate change require the inclusion of vegetation dynamics in ecosystem models. In peatlands, Sphagnum mosses are key engineers. Moss community composition primarily follows habitat moisture conditions. The known species habitat preference along the prevailing moisture gradient might not directly serve as a reliable predictor for future species compositions, as water table fluctuation is likely to increase. Hence, modelling the mechanisms that control the habitat preference of Sphagna is a good first step for modelling community dynamics in peatlands. In this study, we developed the Peatland Moss Simulator (PMS), which simulates the community dynamics of the peatland moss layer. PMS is a process-based model that employs a stochastic, individual-based approach for simulating competition within the peatland moss layer based on species differences in functional traits. At the shoot-level, growth and competition were driven by net photosynthesis, which was regulated by hydrological processes via the capitulum water content. The model was tested by predicting the habitat preferences of Sphagnum magellanicum and Sphagnum fallax – two key species representing dry (hummock) and wet (lawn) habitats in a poor fen peatland (Lakkasuo, Finland). PMS successfully captured the habitat preferences of the two Sphagnum species based on observed variations in trait properties. Our model simulation further showed that the validity of PMS depended on the interspecific differences in the capitulum water content being correctly specified. Neglecting the water content differences led to the failure of PMS to predict the habitat preferences of the species in stochastic simulations. Our work highlights the importance of the capitulum water content with respect to the dynamics and carbon functioning of Sphagnum communities in peatland ecosystems. Thus, studies of peatland responses to changing environmental conditions need to include capitulum water processes as a control on moss community dynamics. Our PMS model could be used as an elemental design for the future development of dynamic vegetation models for peatland ecosystems.

Conditions for the Compost Bomb Instability

&lt;p&gt;Under global warming, soil temperatures are expected to rise. This increases the specific rate of microbial respiration in the soils which in turn warms the soil, creating a positive feedback process. This leads to the possibility of an instability, known as the compost bomb, in which rapidly warming soils release their soil carbon as CO2 to the atmosphere, accelerating global warming. Models of the compost bomb have exhibited interesting dynamical phenomena: excitability, rate induced tipping and bifurcation induced tipping. We examine models with increasing degrees of sophistication, to help understand the conditions that give rise to the compost bomb. We clarify the role an insulating moss layer plays and demonstrate that it has a 'most dangerous' thickness. We also use JULES, a land surface model, to examine where a compost bomb might occur and what affect other processes such as hydrology might have on the compost bomb.&lt;/p&gt;

Dynamics of vegetation changes in oil and salt-contaminated oligotrophic ridge-hollow mire complexes after reclamation (Middle Pre-Ob region, Khanty-Mansi Autonomous Okrug – Yugra)

Oligotrophic ridge-hollow and ridge-hollow-pool complex mires are widely distributed in the central part of West Siberia, including many oil fields of the Middle Pre-Ob region. The article considers the dynamics of re-vegetation of oil and salt-contaminated areas of these mire types subjected to reclamation. Survey materials for 2–3 years and 15 years after reclamation allow to identify the main trends in vegetation restoration in the short and medium term. The reversible oligotrophication of ridges manifests in a relative decrease in the participation of the meso-eutrophic species on contaminated mire sites. In the hollows, however, the similar trend can be traced only in relation to oil-contaminated sites, whereas in the salt-contaminated hollows, the strong eutrophic conditions last. In the medium-term perspective, most typical oligotrophic hollow species, with the exception of Eriophorum russeolum and Oxycoccus palustris, were unable to recover. In the course of dynamic changes in the vegetation, the leading role in recovery successions gradually passes to mesotrophic and eutrophic species possessing massive root systems and aerenchyma – Eriophorum angustifolium, Phragmites australis, Carex rostrata, etc. Restoration of the moss layer is several years behind that of the grass layer, and due to the lack of competition, the participation of liverworts in it is of great importance, especially in salt spills. At the same time, among mosses as in the case of vascular species mesotrophic components are the main dominant ones15 years after reclamation.

A pilot study on improve the functioning of extensive green roofs in city centers using mosses

Most of environmental benefits of green roofs results from the presence of a vegetation layer. However vascular plants quickly die in harsh urban conditions. This paper presents research involving moss species appearing spontaneously on green roofs in cities to test whether we can create a vegetation layer with simplifi ed structure introducing that moss. It was checked using two transplant methods and three models of such roofs. Research evidenced that moss Ceratodon purpureus Hedw. is able to survive on green roofs in cities with high efficiency and can develop after transplant on roofs with a simple structure. Maximum weight of the moss layer during the year did not exceed 7.0 kg·m–2.