Sphagnum establishment in alkaline fens: Importance of weather and water chemistry

Vicherová, Eliška; Hájek, Michal; Šmilauer, Petr; Hájek, Tomáš

doi:10.1016/j.scitotenv.2016.12.109

Cited by 32 publications

(41 citation statements)

References 47 publications

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“…Granath et al 2010;Vicherová et al 2015). Sphagna can establish and survive thanks to their high water retention capacity; the pH and ion concentration of the water can be reduced by the buffering action of the cell-wall carboxyls (here enumerated as CEC; Vicherová et al (2017)). Furthermore, the typical bog hummock species S. fuscum can expand as its decay-resistant litter gives an ability to form high hummocks, thereby avoiding the influence of the fen water ions.…”

Section: Discussionmentioning

confidence: 99%

Biochemical determinants of litter quality in 15 species of Sphagnum

2018

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Background and aims Sphagnum mosses are ecosystem engineers that create and maintain boreal peatlands. With unique biochemistry, waterlogging and acidifying capacities, they build up meters-thick layers of peat, reducing competition and impeding decomposition. We quantify within-genus differences in biochemical composition to make inferences about decay rates, related to hummock-hollow and fen-bog gradients and to phylogeny. Methods We sampled litter from 15 Sphagnum species, abundant over the whole northern hemisphere. We used regression and Principal Components Analysis (PCA) to evaluate general relationships between litter quality parameters and decay rates measured under laboratory and field conditions. Results Both concentrations of the polysaccharide sphagnan and the soluble phenolics were positively correlated with intrinsic decay resistance, however, so were the previously understudied lignin-like phenolics. More resistant litter had more of all the important metabolites; consequently, PC1 scores were related to lab mass loss (R 2 = 0.57). There was no such relationship with field mass loss, which is also affected by the environment. PCA also revealed that metabolites clearly group Sphagnum sections (subgenera). Conclusions We suggest that the commonly stated growth-decomposition trade-off is largely due to litter quality. We show a strong phylogenetic control on Sphagnum metabolites, but their effects on decay are affected by nutrient availability in the habitat.

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Section: Discussionmentioning

confidence: 99%

Biochemical determinants of litter quality in 15 species of Sphagnum

2018

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“…The secondary changes we observed as a result of biological interaction following canopy development show that the initiation of tree cover is a likely turning point in the successional trajectory of drying fens; the presence of these trees may be sufficient to maintain a lowered WT even during wet years (Laine et al., ; Minkkinen et al., ). The responses of rich and calcareous fens, which our study did not encompass, involve changes in dominant functional group of bryophytes (i.e., brown mosses versus Sphagna) and may be more complex (Vicherová, Hájek, Šmilauer, & Hájek, ).…”

Section: Discussionmentioning

confidence: 85%

Responses of peatland vegetation to 15‐year water level drawdown as mediated by fertility level

Kokkonen

Laine

et al. 2019

J Vegetation Science

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Questions Peatland ecosystems are a globally important carbon storage that is predicted to turn into a carbon source due to water level drawdown (WLD) associated with climate change. The predictions assume stable plant communities but how realistic is this assumption? If the vegetation is not stable, what are the nature and rate of changes? Location Peatland complex in Southern Finland. Methods We conducted a water level drawdown (WLD of ~10 cm) experiment over 17 years in three peatland types differing in their fertility. On each peatland type, we included an adjacent forestry drained (FD, with water table ca. 40 cm lower than in control) area for comparison. Results Peatland type had a clear impact on the response to WLD: at the ecosystem level, the two minerotrophic fens underwent rapid species turnover, while the vegetation in nutrient‐poor bog was more resilient to change. In nutrient‐rich sites, WLD initiated tree canopy development and created understorey conditions that strengthened impact of WLD. In nutrient‐poor site, tree establishment was seen only in the FD area. In addition to high nutrient level, high wetness accelerated change at the plant community level, where we found three types of responses: accelerating change, decelerating change, and stability. Succession resulted in an overall loss of community heterogeneity. Conclusions Interaction between hydrology, nutrient availability, and biological factors in boreal peatlands is important: the drop in water table required to achieve the shift from open peatland to forested system is inversely proportional to the nutrient level of the system. The results suggest that predictive models of peatland functions under climate change should consider compositional change for fens and their diverse plant communities but are more realistic for bogs. The response of bog vegetation to climate change may, however, be more dependent on changes in rainfall regime and therefore needs to be further addressed.

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“…It has been shown that acidic conditions decrease germination of rich fen vegetation, specifically Schoenus nigricans , though the exact mechanism remains unclear (Boatman, ; Clymo & Hayward, ). Inversely, abiotic conditions that favor rich fen vegetation growth, such as a high pH, high alkalinity and high

{HCO}_{3}^{-}

concentrations (Tyler, ), negatively affect poor fen vegetation performance (Harpenslager, van den Elzen, et al, ; Vicherová, Hájek, & Hájek, ; Vicherová, Hájek, Šmilauer, & Hájek, ). Additionally, dense rich fen vegetation tussocks reduce light and water accessibility to the moss layer, thereby impeding generally sparsely and lower growing poor fen vegetation growth (Berendse et al, ; Lamers et al, ; Malmer et al, ; Pouliot et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…Base‐rich conditions originating from the influence of calcareous groundwater in upper fen layers previously explained the occurrence of Schoenus nigricans in a similar peatland ecosystem (Grootjans et al, ). The observed mosaic of rich and poor fen vegetation could originate from a short period of alleviating environmental stressors: a window of opportunity (sensu Balke, Herman, & Bouma, ), as generally poor fen vegetation is unable to establish in areas influenced by upwelling and inundation of

{HCO}_{3}^{-}

‐rich groundwater (Lamers, Smolders, & Roelofs, ; Vicherová et al, , ). Therefore, we expect that a period of drought resulted in lower groundwater levels, which temporarily alleviated stress enabling establishment of poor fen vegetation inside rich fen vegetation.…”

Section: Discussionmentioning

confidence: 99%

Self‐facilitation and negative species interactions could drive microscale vegetation mosaic in a floating fen

Bergen

Temmink

Tweel‐Groot

et al. 2020

J Vegetation Science

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Aim The formation of a local vegetation mosaic may be attributed to local variation in abiotic environmental conditions. Recent research, however, indicates that self‐facilitating organisms and negative species interactions may be a driving factor. In this study, we explore whether heterogeneous geohydrological conditions or vegetation feedbacks and interactions could be responsible for a vegetation mosaic of rich and poor fen species. Location Lake Aturtaun, Roundstone Bog, Ireland. Methods In a floating fen, transects were set out to analyze the relation between vegetation type and rock–peat distance and porewater electrical conductivity. Furthermore, three distinct vegetation types were studied: rich fen, poor fen and patches of poor fen within rich fen vegetation. Biogeochemical measurements were conducted in a vertical profile to distinguish abiotic conditions of distinct vegetation types. Results Geohydrological conditions may drive the distribution of poor and rich fen species at a larger scale in the floating fen, due to the supply of minerotrophic groundwater. Interestingly, both rich and poor fen vegetation occurred in a mosaic, when electrical conductivity values at 50 cm depth were between 300 µS/cm and 450 µS/cm. Although environmental conditions were homogeneous at 50 cm, they differed markedly between rich and poor fen vegetation at 10 cm depth. Specifically, our measurements indicate that poor fen vegetation lowered porewater alkalinity, bicarbonate concentrations and pH. No effects of rich fen vegetation at 10 cm depth on biogeochemistry was measured. However, rich fen litter had a higher mineralization rate than poor fen litter, which increases the influence of minerotrophic water in rich fen habitat. Conclusions These results strengthen our hypothesis that species can drive formation of vegetation mosaics under environmentally homogeneous conditions in a floating fen. Positive intraspecific self‐facilitating mechanisms and negative species interactions could be responsible for a stable coexistence of species, even leading to local ecosystem engineering by the species, explaining the local vegetation mosaic at the microscale level in a floating fen.

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Sphagnum establishment in alkaline fens: Importance of weather and water chemistry

Cited by 32 publications

References 47 publications

Biochemical determinants of litter quality in 15 species of Sphagnum

Biochemical determinants of litter quality in 15 species of Sphagnum

Responses of peatland vegetation to 15‐year water level drawdown as mediated by fertility level

Self‐facilitation and negative species interactions could drive microscale vegetation mosaic in a floating fen

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