The impacts of peat slides on upland blanket peatland hydrology, ecology and soil structure. A paired catchment approach.

Rainfall-induced landslides are difficult to forecast and often evolve into highly destructive flows, as such, they are one of the most dangerous natural hazards globally. While our understanding of peatland hydrology has improved greatly in the past two decades, there has been less focus on the response of peat hydrology following perturbations such as wildfires and landslides. &#160;Here we report on a new paired catchment experiment in Ireland. Our focus is to quantify the hydrological changes following peat landslides and further, to establish the short-term and longer-term impacts on local peatland hydrology, ecology and recovery.The two paired sites are located in Co. Leitrim, Ireland, in two adjacent, small upland blanket bog catchments. The first peat catchment (0.2km2) is an area of a recent (June 2020) slope failure. According to preliminary estimates ~178,000 &#8211; 188,000 tonnes of peat were transported downstream during the peat slide event, resulting in a large landslide scar section (~0.059 km2) in a special area of conservation [SAC]. Preliminary impacts are assessed to include: habitat loss, decreased slope stability, impacts on hydrology and water quality, as well as increased local erosion.This catchment is paired with an adjacent upland blanket peat catchment (0.11 km2) which is deemed to have been under the same anthropogenic pressures (grazing, upslope forestry plantation).A hydrometric suite, including weather station, piezometers, and water level recorders to evaluate the surface and subsurface hydrology has been installed at both sites. In addition, we are monitoring the response of landslide deposits (e.g. rafted peat, some with still-standing sika spruce), ecology, soil structure, permeability and shear strength in both catchments.Here we will report on the initial results of our monitoring.

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Characterisation of the 2020 Drumkeeran peat landslide: a large peat slide in Ireland.

10.5194/egusphere-egu21-13007 ◽

2021 ◽

Author(s):

John Connolly ◽

Eoghan Holohan ◽

Mary Bourke ◽

Charmaine Cruz ◽

Catherine Farrell ◽

...

Keyword(s):

Volume Ratio ◽

Thick Layer ◽

Source Area ◽

Organic Soils ◽

Topographic Slope ◽

Drainage Patterns ◽

Blanket Bog ◽

Special Area ◽

Radar Satellite ◽

Run Up

Mass movements in peatlands are poorly understood. This is because of the unusual geotechnical properties of the materials (organic soils) and a paucity of well-constrained case studies. At the end of June 2020, a large peat slide occurred on Shass mountain, several kilometres northeast of the village of Drumkeeran in Co. Leitrim, north-western Ireland. The source area of the peat slide is an area of blanket bog within a Special Area of Conservation (SAC). This area is characterised by a topographic slope of 3-5&#176;. On recently published Landslide Susceptibility Maps it was classified as &#8216;moderately low&#8217; to &#8216;low&#8217;.To understand this peat slide&#8217;s genesis and impact on the landscape, post-slide site investigations and aerial surveys were undertaken in the following days and weeks. These included: photogrammetry and LiDAR surveys via UAVs and crewed aircraft; Ground Penetrating Radar (GPR) profiling; in-situ peat depth measurements, soil coring and a vegetation survey. &#160;These data were complemented by pre-and post-slide radar satellite data (Sentinel-1) and were compared to high-resolution pre-slide aerial imagery and digital surface models (DSMs) captured in August 2017 and April 2020.Mapping and DSM differencing show a source area of 7 ha, from which ~ 171,000 m3 of peat flowed 6.6 km down a river channel. The height/run-out ratio was 0.035; the run-out/volume ratio was 0.038. Peak flow or run-up heights near the source area were >4 m. Video, field and satellite evidence indicates that the peat was highly liquified. It deposited in three zones: upstream of a small bridge, which acted as a partial dam and on two floodplain areas. About 45 ha were covered with peat up to 1-3 m thick, these deposits generally thin downstream. Radar intensity data support local accounts that most of this material failed retrogressively and redeposited within 24 hours.Data from the nearest meteorological station, 27 km to the west, show that the region experienced a relatively dry period (118 mm of precipitation) in the 2.5 months before the landslide, and a period of exceptionally high rainfall (53 mm) three days immediately beforehand. Flow pathway analysis indicates a natural drainage convergence in the upper catchment. The landslide possibly started here and regressed upslope into ~5 ha of well-drained bog, afforested in 1996, located at the head of the catchment. The areas to the south and east comprise of a mosaic flushes, wet heath, and blanket bog vegetation.The peat depth was assessed by both GPR data (calibrated by coring), which shows the base of the peat and probing. It ranged from 2-5 m. This accords with a typical 2-4 m thickness of failed peat from DSM differencing. Coring also revealed a ~50cm thick layer clay at the base of the peat. These preliminary results highlight the potential importance of local drainage patterns and localised clay layers in increasing peat-slide susceptibility on low-angle slopes. This characterization underpins further investigation into the multifarious factors causing peat slides, which may be exacerbated by climate change.

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Temporal turnover of the flora of lake islands: The island of Lake Pamvotis (Epirus, Greece)

Biodiversity Data Journal ◽

10.3897/bdj.7.e37023 ◽

2019 ◽

Vol 7 ◽

Cited By ~ 1

Author(s):

Maria Sarika ◽

Alexandros Papanikolaou ◽

Artemios Yannitsaros ◽

Theodoros Chitos ◽

Maria Panitsa

Keyword(s):

Species Turnover ◽

Natura 2000 ◽

Life Forms ◽

Absolute Difference ◽

Turnover Rates ◽

Ecological Value ◽

Anthropogenic Pressures ◽

Combining Data ◽

Special Area ◽

The Absolute

Lake Pamvotis is one of the Balkan "ancient" lakes, a Quaternary refugium of great environmental importance and ecological value, that is under various anthropogenic pressures. It belongs to a Natura 2000 Special Area for Conservation and Special Protection Area. Almost in the middle of the lake, there is an inhabited island - one of the two lake islands in Greece – that also attracts touristic interest. Τhe main objectives of the present study are to provide a floristic inventory of the protected island, combining data of two different sampling periods, within a 25 year interval, in order to estimate temporal beta diversity and species turnover of the island’s plant diversity. The value of the absolute and relative turnover rates of the floristic diversity of the island studied are 4.24 and 1.72, respectively and are amongst the higher rates reported for plants. The absolute difference between extinct (E) and immigrant (l) taxa is to a great extent accounted, concerning life forms, by therophytes (1.86), hemicryptophytes (1.56) and geophytes (1.04) and, for habitats, by taxa preferring agricultural and ruderal forms (2.52).

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How does wildfire impact carbon delivery to peatland drainage networks?

10.5194/egusphere-egu21-16046 ◽

2021 ◽

Author(s):

Amy Pickard ◽

Stacey Felgate ◽

Paula Fernandez Garcia ◽

Peter Gilbert ◽

Dan Mayor ◽

...

Keyword(s):

Water Quality ◽

C Sequestration ◽

Dry Period ◽

Anthropogenic Pressures ◽

Sampling Locations ◽

Drainage Networks ◽

Blanket Bog ◽

Climate Events ◽

Land Types ◽

Ecological Functioning

Peatlands are a globally important carbon (C) store, although it is well understood that anthropogenic pressures including drainage can reduce potential for C sequestration, in part due to increased losses of C via the aquatic pathway. Superimposed onto land-use pressures on peatlands are those caused by extreme climate events. Following a drought in 2018 and a subsequent dry period in spring 2019, a large wildfire burnt approximately >60 km2 of blanket bog and wet heath within the Flow Country peatlands, North Scotland in May 2019. The fire burned various peatland land types, including near-natural peatland and drained peatland areas. This event created an urgent opportunity to quantify the interacting effects of peat condition and wildfire on water quality, with a focus on dissolved organic matter (DOM) losses. An extensive water monitoring programme was established, covering 40 individual headwater stream sampling locations across the Flow Country, and monthly sampling ran from September 2019 to October 2020, with samples analysed for dissolved organic carbon (DOC), nutrients and UV-vis-based measurements to inform DOM composition. Initial data shows that samples from burned, drained areas are associated with higher DOC concentrations relative to both burned, near natural peatland areas, and unburned control sites. Furthermore the DOM from burned, drained sites is of a more aromatic nature, as indicated by elevated specific UV absorbance (SUVA), compared to unburned control sites. Such findings imply that wildfires may adversely affect water quality through changes DOM quantity and quality in areas of damaged (drained) peatland. However, more detailed compositional analyses are required to accurately predict changes in the ecological functioning of this peatland derived DOM as it enters the aquatic environment and, therefore, its likely end-fate.

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Using current hydrological conditions to better understand holocene ecohydrological dynamics in oligotrophic peatlands of north-central Quebec, Canada

10.5194/egusphere-egu2020-12278 ◽

2020 ◽

Author(s):

Michelle Garneau ◽

Marie Larocque ◽

Christelle Lambert ◽

Mylène Robitaille ◽

Andrew J. Baird ◽

...

Keyword(s):

Large Scale ◽

Testate Amoeba ◽

Anthropogenic Pressures ◽

Eastern Canada ◽

Northeast Section ◽

Groundwater Levels ◽

Growing Seasons ◽

Peatland Hydrology ◽

Hydraulic Gradients ◽

Current Water

The biogeographic limit of the peatlands in the central-north Quebec region (53&#176;80&#8217;-53&#176;85&#8217;N) corresponds to the ecotone between the open boreal forest and the forest-tundra.&#160; At this latitude, peatlands are mainly represented by patterned fens that developed in topographic depressions of the Precambrian Shield. They are characterized by mildly minerotrophic conditions with &#160;surface patterning similar to that observed in western Labrador, central Sweden and the aapa mires of northern Finland. &#160;In eastern Canada, &#160;patterned peatlands have shown &#160;ecohydrologic disequilibrium during the last centuries expressed by a general water table rise with degradation of strings and expansion and coalescence of pools. It has been shown that peatlands in this region present a similar pattern of ecohydrological disequilibrium to those documented in the northeast section of the La Grande River watershed, subarctic Quebec (54&#176;00&#8217;N-54&#176;05&#8217;N) and this confirms the importance of investigating their ecohydrological vulnerability to natural and anthropogenic pressures in terms of hydrology and carbon balance. A multidisciplinary project was initiated to quantify the hydroclimatic changes that may have influenced the ecohydrologic disequilibrium phenomenon using two peatlands control sites. The results presented here focus on the current water budget of the peatlands and aim at identifying the parameters that influence most significantly peatland hydrology and its connection to the surrounding aquifer. The two peatlands were instrumented with 15 piezometers (in the peat and in the aquifer) where groundwater levels were measured during two growing seasons. Peatland characterization included peat depths, peat hydraulic conductivities (six cores, Modified Cube Method), hydraulic gradients and surface outflow rates. Preliminary results from time series analyses and water budgets show indications of groundwater inflows at each site. If confirmed, these results would comfort the hypothesis that the peatlands are sensitive to hydro-climatic variations with more precipitation inducing higher groundwater levels and thus increased groundwater inflow to the peatlands. Using quantitative paleoclimate reconstructions (pollen, macrofossils and testate amoeba), it has been shown that the two peatlands have registered hydroclimatic periods with potential groundwater input sufficient to induce a shift from bog to fen in these ecosystems. Inversely, a recent shift from fen to bog during &#160;the 20th century suggest that enhanced plant productivity with the lengthening of the growing season duration might influence a decrease of groundwater input in the peatlands The warmer climate shift under way is expected to induce even more of these changes, thus increasing further the large-scale phenomenon as observed in peatlands of northeastern Canada.

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Sibbald Research Wetland: Mountain peatland form and ecohydrologic function as influenced by beaver

The Forestry Chronicle ◽

10.5558/tfc2016-011 ◽

2016 ◽

Vol 92 (01) ◽

pp. 37-38 ◽

Cited By ~ 5

Author(s):

Cherie J. Westbrook ◽

Angela Bedard-Haughn

Keyword(s):

Climate Change ◽

Rocky Mountains ◽

Primary Research ◽

Potential Influence ◽

Beaver Ponds ◽

Peatland Hydrology ◽

Initial Results

Sibbald Research Wetland is a 1.3 km2 peatland in the foothills of the Rocky Mountains. The primary research foci are 1) the influence of beaver ponds on mountain peatland hydrology and 2) the potential influence of climate change on these beaver-impacted peatlands. This paper summarizes initial results and implications of the research.

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Electron Probe Analysis of Vertebrate Smooth Muscle: Distribution of Ca and Ci

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100091652 ◽

1976 ◽

Vol 34 ◽

pp. 334-335 ◽

Cited By ~ 1

Author(s):

Avril V. Somlyo ◽

H. Shuman ◽

A.P. Somlyo

Keyword(s):

Smooth Muscle ◽

Electron Probe ◽

Preliminary Report ◽

Cell Damage ◽

Electron Probe Analysis ◽

Perinuclear Space ◽

Probe Analysis ◽

High K ◽

Low K ◽

Initial Results

This is a preliminary report of electron probe analysis of rabbit portal-anterior mesenteric vein (PAMV) smooth muscle cryosectioned without fixation or cryoprotection. The instrumentation and method of electron probe quantitation used (1) and our initial results with cardiac (2) and skeletal (3) muscle have been presented elsewhere.In preparations depolarized with high K (K2SO4) solution, significant calcium peaks were detected over the sarcoplasmic reticulum (Fig 1 and 2) and the continuous perinuclear space. In some of the fibers there were also significant (up to 200 mM/kg dry wt) calcium peaks over the mitochondria. However, in smooth muscle that was not depolarized, high mitochondrial Ca was found in fibers that also contained elevated Na and low K (Fig 3). Therefore, the possibility that these Ca-loaded mitochondria are indicative of cell damage remains to be ruled out.

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