Hydrological controls on productivity of regenerating Sphagnum in a cutover peatland

Abstract

Recent research into the production of Sphagnum biomass in extracted peatlands, an alternative to ecological restoration as a post-industrial use of peatlands, has highlighted the need for an improved understanding of the ecohydrology of Sphagnum regenerating in these environments. Previous work suggested that limited connectivity between surficial layers and the underlying partially decomposed plant matter and peat would result in water stress and inhibited growth. This study links the soil water dynamics of regenerated layers ranging in age from 3 to 43 years and from 3 to 40 cm in thickness to the productivity of Sphagnum in order to determine the hydrological controls on productivity and the optimal range of water content for producing Sphagnum biomass. Productivity was never observed to be limited by insufficient supply of water, including during periods where water table was >40 cm below the surface and periods of 16 days without measured precipitation. While layers of different ages and thicknesses were able to sustain adequate water supply to remain productive under a range of conditions, the ability of layers to transmit water upwards differed greatly. Water content in the near-surface inhibited productivity during wetter periods, especially at newly regenerating sites where the layer was <5 cm thick. This has important implications for biomass production using the Sphagnum species studied here. Using a mixed linear modelling approach to isolate the effects of water content on variance in productivity from those of other measured variables, a volumetric water content of 0.10 is identified as optimal.

Net Ecosystem Exchange, Gross Primary Production And Ecosystem Respiration In Ridge-Hollow Complex At Mukhrino Bog

“…The rate of photosynthesis and respiration of Sphagnum mosses are well correlated with peat moisture (Molchanov and Olchev 2016;Taylor et al 2016). Changes in water table depth strongly influence GPP (Grant et al 2012;Pugh et al 2018), ER (Helfter et al 2015), and heterotrophic respiration (Eckhardt et al 2018).…”

Harvesting surface vegetation does not impede self‐recovery of Sphagnum peatlands

“…In North America, the Moss Layer Transfer Technique (MLTT; Quinty & Rochefort and Graf et al for a detailed description of the method) has been applied by the Canadian horticultural peat industry for more than 100 restoration projects for more than 1,100 ha across the country. This large‐scale mechanized restoration technique is effective for reestablishing peatland vegetation (González & Rochefort ), hydrological attributes (Taylor et al ), and restoring carbon sink function (Strack & Zuback ). The MLTT restoration approach includes the active reintroduction of typical peatland plant fragments (Graf et al ).…”

Growth characteristics of three Sphagnum species in restored extracted peatland

“…The growth of Sphagnum mosses in bogs is largely controlled by the moisture conditions determined by the combination of WTD and precipitation (Tuittila et al 2004; Nijp et al 2014; Taylor et al 2015; Kosykh et al 2017; Radu & Duval 2017). In natural bogs, there are several regulatory mechanisms on different levels from the bog micro‐topography to Sphagnum shoots' anatomy and density to maintain relatively stable moisture content of mosses regardless of precipitation and other factors (e.g.…”