Harvesting of plantation conifers on peatlands is carried out as part of restoration and forestry operations. In particular, in the UK and Ireland, conifer plantations on drained ombrotrophic blanket ...and raised bogs are increasingly being removed (by harvesting), along with blocking of drainage ditches to help raise water tables to reinitiate and restore bog vegetation and function. However, both tree harvesting and peatland restoration operations can have significant impacts on water quality at local and catchment scales. Previous research has suggested that leaching from leftover decomposing brash (tree tops and branches, including wood and needles) is the primary cause, while other work has suggested that release from rewetted peat also contributes to water quality changes. This research investigates the relative importance of peat rewetting, needles and branches on water quality using mesocosm experiments, to help elucidate the mechanisms behind water quality changes following restoration and harvesting operations.
Peat and brash were collected from a drained afforested blanket bog in the Flow Country, Scotland. Short-term mesocosm experiments were conducted by incubating peat, peat + needles and peat + needles + branches with rainwater in quadruplicate. Brash from Sitka spruce (Picea sitchensis) and lodgepole pine (Pinus contorta) was investigated separately, while we also conducted experiments with fresh and aged (∼18 months) brash. Peat, needles and branches all significantly impacted water quality in the order of branches > needles > peat, while concentrations of DOC, PO43−, NH4+, K and Mn were most impacted. Water quality impacts of spruce brash appeared generally greater than pine, while fresh brash had larger effects than aged brash. In our mesocosms, relative contributions to water quality changes were estimated by elemental yields. On average, peat contributed 25.4% (range 0.6–72.3%), while needles and brash contributed 19.7% (range 3.0–37.0%) and 54.9% (range 22.1–70.2%) to yields, respectively. We further estimate that 267 kg C ha−1 (255.8 kg as DOC, 10.7 kg as DIC), 27.4 kg K ha−1, 5.8 kg P ha−1 (as PO43−) and 0.5 kg N ha−1 (as NH4+) could be released from brash, over nine days.
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•Relative contributions of peat, needles and branches to water quality were assessed.•DOC, PO43−, NH4+, K and Mn were collectively the variables most impacted.•Contributions to leaching were peat (25.4%), needles (19.7%) and branches (54.0%).•Removal of needles and branches could help mitigate water pollution.
•Peatland can serve as archive of local smelting activity in the Brynica River catchment.•Magnetic signal is highly correlated with Pb content along the study peat profiles.•The strongest magnetic ...signal and Pb content is related to medieval mining activity.
One of the oldest areas of ore mining in Upper Silesia (southern Poland) is Miasteczko Śląskie, which is surrounded by numerous peat bogs developed in the Brynica Valley. These can offer a good alternative to standard archaeological investigations because they are valuable archives of climatic and anthropogenic impacts. The main aim of this study was to detect traces of human activity and historical mining and smelting in the Brynica River catchment using a combination of magnetic, radiometric and geochemical methods. The research was conducted on two peat profiles: Moczydła and Żyglinek. The application of mass-specific magnetic susceptibility (χ), the determination of the content of heavy metals (Pb, Cu, Zn, Cd, Fe) and radiocarbon dating allowed for investigation into the distribution of anthropogenic pollutants in the peat profile. Additionally, the enrichment factor (EF) of selected heavy metals was calculated. The results revealed the potential mobility of Cu, Zn and Cd in peat profiles and the lack of Pb mobility. Maximum enrichment of Pb could be observed in the Moczydła profile at a depth of 17 cm (5,996 mg kg−1) and in the Żyglinek profile at a depth of 14 cm, where it amounted to 287 mg kg−1 and dated back to the period 1300–1600 AD. However, in the Żyglinek profile a noticeable increase in the value of χ could be seen from a depth of 40 cm, where peat layers corresponded to 2700 BC. The high correlation observed between anthropogenic Pb (EFPb) and magnetic parameters (χ and χ/Fe) will be useful for the further study of the tracers of ore mining and smelting and other historical human impacts on the environment. It can support archaeological studies conducted at the sites of early settlements, which in Central and Northern Europe were very often located on hills surrounded by swamps and peat bogs.
Field data of topography, water levels, and peat hydraulic conductivity collected over a 28‐year period have revealed the impacts of marginal drainage on uncut raised bog ecohydrology and its peat ...properties. Drainage of the regional groundwater body has induced changes in the hydraulic properties of deep peat, with peat compression decreasing hydraulic conductivity and storativity while simultaneously introducing localized secondary porosity and effective storage. Where peat has increased in hydraulic conductivity, there is a corresponding decline in vertical hydraulic gradients and significant localized increases in recharge to the underlying substrate. Repeated topographic surveys show intense localized areas of peat consolidation (>5%) where it is underlain by highly permeable (>10 m/day) glacial till deposits. More widely, continued subsidence (4–6 mm/year) of the bog surface has been measured over 900 m from the bog margin, resulting in the progressive loss of approximately 40% of actively growing raised bog since 1991. This loss has thus been shown to be attributable to changes in the underlying groundwater head due to deep‐cut drainage, rather than near‐surface peatland drainage. However, although reinstating regional hydrostatic pressures in order to restore this ombrotrophic peatland may control the rapid drainage through preferential flow pathways, this may not eliminate the ecological impacts resulting from changed surface morphology arising from subsidence. Hence, this longitudinal study provides new insights into the role that aquifer systems and groundwater bodies play in maintaining hydrogeological processes in ombrotrophic peatland systems, while highlighting the difficulty in ecological restoration where regional groundwater dependencies are significant.
Key Points
Quantification of the impact of marginal drainage on peat hydrogeological properties, groundwater heads and surface ground level
Peat consolidation (>5%) most intense where it is underlain by highly permeable (>10 m/day) glacial till deposits
New insights on the role of groundwater as an environmental supporting condition in ombrotrophic raised bog ecosystems
Aeolian sediments play an important role in the global climatic system and occur in the atmosphere due to soil and bedrock erosion. Here, we applied three different methods: geochemical (XRF), manual ...and laser-based particle size analysis to an ombrotrophic peat profile in the Carpathian Mountains to determine changes in aeolian deposition and wind/storm activity over the last 7800 years. The results show the following changes in aeolian fluxes (dust and sand) over time: 7800–4150 cal. yr BP – generally low dust fluxes with a periodic intensification of sand fluxes; 4150–2300 cal. yr BP – intense deposition of both dust and sand; 2300–150 cal. yr BP – fluctuating dust and sand fluxes; the last 200 years – the highest amplitude of both sand and dust fluxes. This study found that patterns in aeolian fluxes were influenced by a combination of climate and human impact, but with anthropogenic drivers, such as disturbance by fire, becoming more important in recent times. We also found a good agreement with other studies of dust fluxes for the earlier part of this record, but an increasing divergence over the last 3500 years. In terms of a methodological approach, we suggest that the three approaches each have both advantages and disadvantages; though overall laser-based particle size dust and sand reconstruction appears to best capture the most complex changes in both aeolian deposition rates and sources.
•Reconstruction of past aeolian fluxes using ombrotrophic mountain bog•Four major shifts in aeolian fluxes in the past 7800 years•Identify the relationship between aeolian fluxes and their controlling factors•Aeolian fluxes were primarily influenced by climate and anthropogenic drivers.•Comparison with other records of aeolian estimates from central and northwest Europe
Until the beginning of the 20th century, bog burning culture was a common cultivation system for food production on otherwise non-arable bog peat soils. Burning and preliminary drainage of the peat ...impacted the soils nutrient supply, bog morphology and soils properties. To gain insights into the long-term effects of bog burning culture on the landscape and soils, a burned and unburned area within a rewetted bog complex were comparatively analysed. It was hypothesised that bog burning had a lasting effect on the soil chemistry, that the trenches created for drainage prior to burning are still detectable in the bog morphology, and that the altered soil chemistry exhibiting enhanced nutrient supply resulted in a change of vegetation patterns. To verify this, the soil chemistry was analysed regarding pH, carbon/nitrogen (C/N) ratio, and contents of plant available phosphate (PO₄3−) and potassium (K). The morphology was examined by means of aerial imagery and vegetation patterns were assessed in the field. It was shown that while PO₄3−- contents were similar, pH values and K contents of the burned area were elevated compared with the unburned area. Accordingly, they can be used as an indicator for bog burning culture, even a century after the end of the practice. As expected, C/N ratios were narrowed in the burned area, which however cannot exclusively be attributed to bog burning, since peat mineralisation in the previously drained bog soils caused narrowing C/N ratios as well. The trench structure for drainage was still visible in aerial images and vegetation patterns were similar in the burned and unburned areas. Overall, the aftermath of bog burning was still apparent in morphology and soil chemistry, however the effect was less severe than expected, as vegetation patterns and the overall restoration success were not impacted. This provides a reasonable expectation that bogs are resilient towards bog burning and the latter is no obstacle for successful restoration.
Bis zum Beginn des 20. Jahrhunderts war die Moorbrandkultur eine gängige Kultivierungspraxis zur landwirtschaftlichen Nutzbarmachung von Hochmoorböden. Die Nährstoffzufuhr durch das Moorbrennen sowie die vorherige Trockenlegung veränderten die Morphologie und Bodeneigenschaften. Um die Langzeitfolgen der Moorbrandkultur auf die Bodeneigenschaften und Vegetationsentwicklung zu untersuchen, wurden eine gebrannte und eine ungebrannte Fläche eines wiedervernässten Hochmoores vergleichend analysiert. Die Haupthypothese lautete, dass das Moorbrennen den Bodenchemismus nachhaltig beeinflusst hat. Eine zweite Hypothese war, dass die vor dem Moorbrennen zur Drainage angelegte Grüppenstruktur in der Hochmoor Morphologie noch zu erkennen ist. Außerdem wurde angenommen, dass die Nährstoffzufuhr durch das Moorbrennen zur Ausbildung eines veränderten Vegetationsmusters geführt hat. Um dies zu untersuchen wurde der Bodenchemismus hinsichtlich pH-Werten, Kohlenstoff/Stickstoff (C/N) Verhältnis sowie Gehalt an pflanzenverfügbarem Phosphat (PO₄3−) und Kalium (K) untersucht, die Oberflächenmorphologie wurden anhand von Luftbildmaterial untersucht und die Vegetationstypen wurden im Gelände bestimmt. Es konnte gezeigt werden, dass während sich die PO₄3− Gehalte ähnelten, die pH-Werte und Gehalte an pflanzenverfügbarem K in der gebrannten Fläche im Vergleich mit der ungebrannten Fläche erhöht waren und somit noch ein Jahrhundert nach Ende der Methode als ein Indikator für die frühere Moorbrandkultur dienen. Wie erwartet waren die C/N Verhältnisse in der gebrannten Fläche verengt, was jedoch nicht ausschließlich auf das Torfbrennen zurückgeführt werden kann, da die C/N Verhältnisse durch die vorangegangene Trockenlegung zusätzlich stark durch Mineralisierung beeinflusst wurden. Die charakteristische Grüppenstruktur für die Drainage war in den Luftbildern deutlich zu erkennen. Die Vegetationsstrukturen der gebrannten und ungebrannten Flächen ähnelten sich weitgehend. Die Nachwirkungen der Moorbrandkultur können also noch heute in der Oberflächenmorphologie und im Bodenchemismus nachgewiesen werden. Letztere fielen weniger stark aus als erwartet, da sie sich offenbar nicht maßgeblich auf die Vegetationsentwicklung auswirkten. Daher besteht Grund zur Annahme, dass Hochmoore resilient auf Moorbrandkultur reagieren und dass Moorbrandkultur kein Hindernis für den Erfolg einer Renaturierung darstellt.
Recent warming at high-latitudes has accelerated permafrost thaw in northern peatlands, and thaw can have profound effects on local hydrology and ecosystem carbon balance. To assess the impact of ...permafrost thaw on soil organic carbon (OC) dynamics, we measured soil hydrologic and thermal dynamics and soil OC stocks across a collapse-scar bog chronosequence in interior Alaska. We observed dramatic changes in the distribution of soil water associated with thawing of ice-rich frozen peat. The impoundment of warm water in collapse-scar bogs initiated talik formation and the lateral expansion of bogs over time. On average, Permafrost Plateaus stored 137 ± 37 kg C m⁻², whereas OC storage in Young Bogs and Old Bogs averaged 84 ± db 13 kg C m⁻². Based on our reconstructions, the accumulation of OC in near-surface bog peat continued for nearly 1,000 years following permafrost thaw, at which point accumulation rates slowed. Rapid decomposition of thawed forest peat reduced deep OC stocks by nearly half during the first 100 years following thaw. Using a simple mass-balance model, we show that accumulation rates at the bog surface were not sufficient to balance deep OC losses, resulting in a net loss of OC from the entire peat column. An uncertainty analysis also revealed that the magnitude and timing of soil OC loss from thawed forest peat depends substantially on variation in OC input rates to bog peat and variation in decay constants for shallow and deep OC stocks. These findings suggest that permafrost thaw and the subsequent release of OC from thawed peat will likely reduce the strength of northern permafrost-affected peatlands as a carbon dioxide sink, and consequently, will likely accelerate rates of atmospheric warming.
Owning to the high radiotoxicity in high concentrations, as well as the irreplaceability in quantifying soil erosion rates, demarcating the Anthropocene, and dating of sediment, anthropogenic ...239,240Pu have drawn high attention. However, the source in specific areas, preservation characteristics in different environment media, and re-distribution process after the cessation of atmospheric nuclear weapons tests, have not been fully understood, which obscures the exact start year, temporal variation, and deposition flux of 239,240Pu in sedimentary records, and hinders the wide application of 239,240Pu in environment study. A sediment core from the Yiwu peat bog with dominance of atmospheric deposition in the source material, simple sedimentary environment, and high dust deposition flux, was collected to examine the 239,240Pu, and explore the source, preservation, and re-distribution process. The double peaks of 239,240Pu in 1952 CE and 1963 CE, as well as 240Pu/239Pu ratios of 0.163–0.190 with an average of 0.177 ± 0.010 confirmed that the 239,240Pu source originated predominantly from global fallout. The minimal vertical migration of plutonium in the Yiwu peat core was attributed to the near-neutral pH condition. The high inventory of 128 ± 7 Bq m−2, as well as the atypical negative correlation between 239,240Pu concentrations and organic matter content (r = − 0.79, P < 0.01), was attributed to the contribution of 239,240Pu re-suspended with dust from the neighboring Gobi Desert, particularly in the cold and dry years. The total re-suspended 239,240Pu was estimated to be 77 Bq m−2, exceeding the direct fallout level of 51 Bq m−2 during 1945–2016 CE. In this study, the specified deposition pattern of 239,240Pu after the cessation of atmospheric nuclear weapons was established, providing an important standard for multiple environmental studies, and the re-suspended amount of 239,240Pu in a typical arid area was quantified for the first time.
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•239,240Pu re-suspended with dust in arid areas was firstly quantified.•The 239,240Pu re-suspended with dust exceeds the direct fallout amount.•Minimal vertical migration of Pu in the near-neutral pH peat core.
Mires or peatlands host unique biodiversity and provide many valuable ecosystem services. Mires often undergo different development phases during their evolution. Two mire phases that have clearly ...divergent hydrological regimes and characteristic biotas are minerotrophic fen and ombrotrophic bog. Open mires can be overgrown by trees and develop into peatland forests. Mire development trajectories are expected to be associated with three major factors—post‐glacial isostatic uplift, autogenic succession and climate‐induced changes. Understanding long‐term mire development is important for the conservation planning of these threatened habitats.
We use data from modern pollen samples to characterize differences between the pollen signal and to identify indicator pollen taxa for three mire development phases—open fens, forested fens and bogs. The modern reference samples are then used to support the interpretation of the sediment records in terms of mire development phases and related biodiversity changes in six mires within a 20 × 30 km area in western Saaremaa, Estonia. Palynological richness and phylogenetic diversity (PD) as well as Ellenberg indicator values are compared throughout the 10,000‐year history of the Saaremaa mires.
Pollen of herbaceous taxa discriminates between open fens, forested fens and bogs, and indicator pollen taxa can be associated with each mire phase. In general, the fen phases of the mires show higher richness and PD than the bog phases but there is considerable variation between the sites. The mire diversity peaks are often associated with transitional periods when high local community heterogeneity allows the coexistence of high numbers of taxa from different phylogenetic lineages.
Synthesis. When the initiation of mires in isostatic land uplift areas is closely related to water‐level changes and the position of the sites in relation to the sea, the development of mires and their biodiversity in the late Holocene is associated with local conditions but mediated by climate. The ongoing rapid climate change is likely to accelerate changes in existing mires, and while the transitional periods are characterized by high diversity, these periods are temporary, and the overall diversity of mires can be expected to decrease.
When the initiation of mires in isostatic land uplift areas is closely related to water‐level changes and the position of the sites in relation to the sea, the development of mires and their biodiversity in the late Holocene is associated with local conditions but mediated by climate. The ongoing rapid climate change is likely to accelerate changes in existing mires, and while the transitional periods are characterized by high diversity, these periods are temporary, and the overall diversity of mires can be expected to decrease.
The Late Devensian Lateglacial to early Holocene transition across north-west Europe was characterized by a rapid shift in climate from the cold, harsh conditions of the Loch Lomond Stadial to the ...warmer climate of the early Postglacial. However, our knowledge of this transition in south-east England has been hampered by the paucity of mires with sedimentary records spanning this period. We present two new high-resolution paleoenvironmental records from Langshot Bog and Elstead Bog B (Surrey, UK), which provide a clear signature of vegetation succession and fire history. Organic sedimentation at Langshot Bog commenced prior to 12,640–12,410 cal. BP (95% probability) and continued until 8430–8350 cal. BP (95% probability). Providing a robust chronology for Elstead Bog B proved to be problematic, although available dates suggest sediment accumulation commenced prior to 11,820–11,400 cal. BP (WM-168, 2σ). The sites are characterized by similar vegetation records, indicating a regional signal from locations over 20 km apart. Scrubby tundra-style vegetation is characteristic of cold conditions associated with the Lateglacial. The identification of Alnus and Corylus, taxa not normally associated with this period, indicates that microclimates may have permitted the survival of these species. Expansion of Betula followed by Pinus dates to the onset of the Holocene, forming mixed coniferous-deciduous woodland, during a period which is punctuated by short climatic events identified from stable isotope analysis. Subsequent expansion of thermophilous taxa Corylus, Ulmus and Quercus results in the formation of deciduous woodland. A rise in micro-charcoal, heathland and herbaceous taxa indicates development of heathy-scrubby clearings within this Holocene landscape.
•New lowland, inland wetland records develop understanding of vegetation succession.•Pinus, Alnus and Corylus were components of Late Glacial vegetation in SE England.•Stable isotope records provide evidence for short-term Early Holocene climate events.•Early Holocene rapid climate events were too short to impact vegetation composition.
Minerotrophic fens and ombrotrophic bogs differ in their nutrient status, hydrology, vegetation and carbon dynamics, and their geographical distribution is linked to various climate parameters. ...Currently, bogs dominate the northern temperate and southern boreal zones but climate warming may cause a northwards shift in the distribution of the bog zone. To more profoundly understand the sensitivity of peatlands to changes in climate, we first used the plant macrofossil method to identify plant communities that are characteristic of past fen–bog transitions. These transitions were radiocarbon dated, to be linked to Holocene climate phases. Subsequently, palaeoecological data were combined with an extensive vegetation survey dataset collected along the current fen–bog ecotone in Finland where we studied how the distribution of the key plant species identified from peat records is currently related to the most important environmental variables. The fossil plant records revealed clear successional phases: an initial Carex-dominated fen phase, an Eriophorum vaginatum–dominated oligotrophic fen phase followed by an early bog phase with wet bog Sphagna. This was occasionally followed by a dry ombrotrophic bog phase. Timing of initiation and phase transitions, and duration of succession phases varied between three sites studied. However, the final ombrotrophication occurred during 2000–3000 cal. BP corresponding to the neoglacial cooling phase. Dry mid-Holocene seems to have facilitated initiation of Eriophorum fens. The peatlands surveyed in the fen–bog ecotone were classified into succession phases based on the key species distribution. In 33% of the studied peatlands, Sphagnum had taken over and we interpret they are going through a final transition from fen to bog. In addition to autogenic processes and direct climate impact, our results showed that ecosystem shifts are also driven by allogenic disturbances, such as fires, suggesting that climate change can indirectly assist the ombrotrophication process in the southern border of the fen–bog ecotone.
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