Multiscale Variability and the Comparison of Ground and Satellite Radar Based Measures of Peatland Surface Motion for Peatland Monitoring

Peatland surface motion is highly diagnostic of peatland condition. Interferometric Synthetic Aperture Radar (InSAR) can measure this at the landscape scale but requires ground validation. This necessitates upscaling from point to areal measures (80 × 90 m) but is hampered by a lack of data regarding the spatial variability of peat surface motion characteristics. Using a nested precise leveling approach within two areas of upland and low-lying blanket peatland within the Flow Country, Scotland, we examine the multiscale variability of peat surface motion. We then compare this with InSAR timeseries data. We find that peat surface motion varies at multiple scales within blanket peatland with decreasing dynamism with height above the water table e.g., hummocks < lawn < hollows. This trend is dependent upon a number of factors including ecohydrology, pool size/density, peat density, and slope. At the site scale motion can be grouped into central, marginal, and upland peatlands with each showing characteristic amplitude, peak timing, and response to climate events. Ground measurements which incorporate local variability show good comparability with satellite radar derived timeseries. However, current limitations of phase unwrapping in interferometry means that during an extreme drought/event InSAR readings can only qualitatively replicate peat movement in the most dynamic parts of the peatland e.g., pool systems, quaking bog.

Loss and Recovery of Carbon in Repeatedly Burned Degraded Peatlands of Kalimantan, Indonesia

Although accurate estimates of biomass loss during peat fires, and recovery over time, are critical in understanding net peat ecosystem carbon balance, empirical data to inform carbon models are scarce. During the 2019 dry season, fires burned through 133,631 ha of degraded peatlands of Central Kalimantan. This study reports carbon loss from surface fuels and the top peat layer of 18.5 Mg C ha−1 (3.5 from surface fuels and 15.0 from root/peat layer), releasing an average of 2.5 Gg (range 1.8–3.1 Gg) carbon in these fires. Peat surface change measurements over one month, as the fires continued to smolder, indicated that about 20 cm of the surface was lost to combustion of peat and fern rhizomes, roots and recently incorporated organic residues that we sampled as the top peat layer. Time series analysis of live green vegetation (NDVI trend), combined with field observations of vegetation recovery two years after the fires, indicated that vegetation recovery equivalent to fire-released carbon is likely to occur around 3 years after fires.

Distribution of nickel (Ni) in peatland situated alongside mineral soil derived from ultrabasic rocks

<p>Detailed studies of Ni distribution in peat that is influenced by Ni-rich soil derived from ultrabasic rocks are still limited. The objective of this study was to reveal the characteristics of Ni in peat from Morowali (Central Sulawesi Province, Indonesia) at several depths and distances from the boundary of the ultrabasic mineral soil. Peat was sampled from depths of 0–30, 30–60, and 60–90 cm at distances of 100, 200, 300, 400, 500, and 600 m from the border of the ultrabasic mineral soil in March 2018. Ni characteristics were examined through their total, exchangeable, water-soluble, and adsorbed distributions. The relationships between Ni and some peat chemical properties such as pH; cation exchange capacity; macronutrient contents of K, Ca, and Mg; and micronutrient contents of Fe, Cu and Zn were also observed. The high Ni content in peat at the study transect is caused by an accumulation of Ni transported from elevated areas of mineral soil. Most Ni in peat is bonded to the soil organic exchange complexes. Accumulation of the mineral soil fraction in the peat surface is indicated at distances of 100–400 meters from the ultrabasic mineral soil. Ni distribution in peat at the study transect is mainly governed by a combination of Fe, pH, organic material, water content, peat depth, and distance from ultrabasic mineral soil.</p>

A Novel Low-Cost, High-Resolution Camera System for Measuring Peat Subsidence and Water Table Dynamics

Peatlands are highly dynamic systems, able to accumulate carbon over millennia under natural conditions, but susceptible to rapid subsidence and carbon loss when drained. Short-term, seasonal and long-term peat surface elevation changes are closely linked to key peatland attributes such as water table depth (WTD) and carbon balance, and may be measured remotely using satellite radar and LiDAR methods. However, field measurements of peat elevation change are spatially and temporally sparse, reliant on low-resolution manual subsidence pole measurements, or expensive sensor systems. Here we describe a novel, simple and low-cost image-based method for measuring peat surface motion and WTD using commercially available time-lapse cameras and image processing methods. Based on almost two years’ deployment of peat cameras across contrasting forested, burned, agricultural and oil palm plantation sites in Central Kalimantan, Indonesia, we show that the method can capture extremely high resolution (sub-mm) and high-frequency (sub-daily) changes in peat surface elevation over extended periods and under challenging environmental conditions. WTD measurements were of similar quality to commercially available pressure transducers. Results reveal dynamic peat elevation response to individual rain events, consistent with variations in WTD. Over the course of the relatively severe 2019 dry season, cameras in deep-drained peatlands recorded maximum peat shrinkage of over 8 cm, followed by partial rebound, leading to net annual subsidence of up to 5 cm. Sites with higher water tables, and where borehole irrigation was used to maintain soil moisture, had lower subsidence, suggesting potential to reduce subsidence through altered land-management. Given the established link between subsidence and CO2 emissions, these results have direct implications for the management of peatlands to reduce high current greenhouse gas (GHG) emissions. Camera-based sensors provide a simple, low-cost alternative to commercial elevation, WTD and GHG flux monitoring systems, suitable for deployment at scale, and in areas where existing approaches are impractical or unaffordable. If ground-based observations of peat motion can be linked to measured GHG fluxes and with satellite-based monitoring tools, this approach offers the potential for a large-scale peatland monitoring tool, suitable for identifying areas of active carbon loss, targeting climate change mitigation interventions, and evaluating intervention outcomes.

Complete Enclosure of Stunted Trees to Study Greenhouse Gas Fluxes in Birch-Invaded Peatland

&lt;p&gt;Ombrotrophic, naturally open peatlands are increasingly susceptible to invasion by scrub and trees due to human disturbance, N deposition and climate change. There is limited research on the effect these trees have on ecosystem functions and their removal can be costly, making decisions over best management practice challenging. The adverse growing conditions associated with many of these peatlands can result in stunted tree growth meaning that complete enclosure of a tree remains a practical possibility. In this study we aim to quantify the CH&lt;sub&gt;4&lt;/sub&gt; and CO&lt;sub&gt;2&lt;/sub&gt; fluxes from whole trees growing on a disturbed peatland and assess their significance relative to the fluxes between the vegetated peat surface and atmosphere. We also aim to identify if the establishment of trees impacts CH&lt;sub&gt;4&lt;/sub&gt; and CO&lt;sub&gt;2&lt;/sub&gt; fluxes from the vegetated peat surface, as compared to adjacent uninvaded peatland.&lt;/p&gt;&lt;p&gt;We have developed a removable chamber capable of enclosing whole trees of up to 3 metres high, making it suitable for use on juvenile or stunted trees. Being able to enclose an entire tree removes potential errors caused by estimating whole tree fluxes by upscaling measurements from a subsample of tree surfaces. The chamber is constructed with a transparent membrane and removable cover so that light and dark measurements can be taken. We use the chamber to take CH&lt;sub&gt;4&lt;/sub&gt; and CO&lt;sub&gt;2&lt;/sub&gt; flux measurements on a site with approximately 20-year-old silver birch trees (Betula pendula) of an average height of 2-3 metres. Flux measurements have been taken from the trees and ground collars at different times of year. We have also studied diurnal variation.&lt;/p&gt;&lt;p&gt;Our initial results have shown that the trees on our site are emitters of CH&lt;sub&gt;4&lt;/sub&gt;, although this emission is small in comparison to that produced by the rest of the habitat. The vegetated peat surface in the wooded area had lower CH&lt;sub&gt;4&lt;/sub&gt; emission but reduced CO&lt;sub&gt;2&lt;/sub&gt; uptake as compared to the open area. The diurnal study on one tree indicates that methane emissions increase at night. A further diurnal study is planned to explore this further. This study extends the limit on the size of vegetation that can be sampled by a manually operated flux chamber.&lt;/p&gt;

The quantification of water storage capacity of peatlands across different hydroclimatic settings using a simple rainfall event to water-table response ratio method

&lt;p&gt;In wetlands, the water budget is traditionally quantified by measuring the hydrologic components including precipitation, evapotranspiration and surface water-groundwater inflows and outflows. However, the reliability of measurements is often questioned due to the difficulty of rigorously monitoring all components of the water budget. Quantifying the rainfall event to water table response ratio is an alternative approach with minimal need for data commonly collected in peatland studies. However, the method has been used only in a limited number of biophysical settings including different microforms, hydroclimatic and hydrogeological settings. The objectives of this study are to quantify the reactivity of the water table to precipitation for different pristine peatlands located in different hydroclimatic conditions and to provide quantitative assessments of water storage of as many peatlands as possible. To do so, site-specific hourly water table and precipitation measurements was collected from northern peatlands worldwide. In total, data from more than 30 sites were retrieved from 8 research groups. For all peatlands, water-table depths varied between 80 cm below the peat surface and 10 cm above the peat surface. The results highlight that the hydrology of all peatlands is characterized by a shift from an environment that can store water to an environment that contributes to rapid outflow, and this is a uniform feature across sites. However, for peatlands with the lowest water storage capacities, this shift occurs during relatively moderate rainfall events (40 mm) or successive small rainfall events. Blanket peat bog best embodied this type of hydrological response. For peatlands with the highest water storage capacity, this shift occurs following multiple moderate to large precipitation events (40 mm &amp;#8211; 80 mm) and it is strongly enhanced by the shift from high to low evaporative periods. The peatlands with the highest storage capacity are raised bogs with deep water-table. These conditions are best observed in peatlands located in geographical settings with high evaporation rates. Among all the peatlands, maximum water storage capacity for given rainfall events was equal to &amp;#8776;150 mm. These analyses also confirm that the water table rise caused by precipitation events contain sufficient information to constrain water storage variations around monitored wells peatlands for a wide array of biophysical settings.&lt;/p&gt;

The Characteristic of Groundwater Table and Subsidence of Degraded Peatland in Ex ICCTF Plot Central Kalimantan

Degraded peatlands typically have been cultivated by communities for agriculture. Ex ICCTF plot in Jabiren is considered as a degraded peatland since the area has been cultivated and drained for smallholder plantation. This study aimed to characterise the groundwater level and peat subsidence periodically over seven months of observation. It has been found that the groundwater level fluctuated from 50 cm to 150 cm below the peat surface, implying the deterioration of peat ecosystem. Based on the transect observation, the groundwater table seems to form a dome shape with the deeper level existed adjacent to the canal. The average peat subsidence was around 27 to 39 cm in cumulative since the subsidence stick installation. However, in the range of ten-month of observation, the peat subsidence was around 8.5 cm. The subsidence was higher on the location adjacent to the canal (25 m) compared to the farther one (100 m). The subsidence also fluctuated, notably in the wet season, indicating the influence of rain event to peat subsidence. Rewetting peatland was likely to result in reducing peat subsidence suggesting the importance of water management in peatland to recover degraded peatland.

Simultaneous direct ex vitro rooting and adaptation of the blue honeysuckle micro-sprouts (Lonicera Caerulea L. var. Kamtschatica)

Direct rooting of regenerative plants under ex vitro conditions is of great importance in agricultural biotechnology, as it leads to acceleration of micropropagation process by eliminating the stage of in vitro rooting and reduces the costs for obtaining healthy planting material of fruit and small-fruit crops. Possibility of direct ex vitro rooting and adaptation of blue honeysuckle microshoots at one stage with no stage of in vitro rooting has been determined. For ex vitro rooting and adaptation of honeysuckle microshoots, it is required to use non-sterile substrate: Sphagnum L. moss with a surface layer of peat (0.5 cm). The rate of rooted microshoots on this substrate makes 72-84 % during summer-autumn period and not less than 60 % during winter period. Thermal treatment of the peat surface layer and the use of aqueous IBA solutions at ex vitro rooting stage will be economically justified during propagation of individual varieties characterized by low proliferation activity in in vitro culture or low ex vitro rhizogenic activity, as well as breeding novelties requiring rapid propagation and obtaining of large amount of planting material. Thermal treatment of the peat surface layer allows increasing the rate of rooted microshoots of Volkhov variety by 10.7 %, Krupnoplodnaya variety by 13.2 %, Pavlovskaya variety by 3.8 % when rooting during spring period. Use of aqueous solutions of IBA increases the rate of rooted plants by 6.2-6.7 % in Vostorg and Krupnoplodnaya varieties when rooting during summer period. Carrying out of one cutting of ex vitro rooted microshoots and further cuttings of obtained material can be used to increase the yield of planting material of blue honeysuckle varieties. Ex vitro rooting and adaptation of blue honeysuckle microshoots at one stage with further ex vitro cutting increases production profitability by 3.5 and 12.9 times in comparison with conventional method of clonal micropropagation of blue honeysuckle.

First Evidence of Peat Domes in the Congo Basin using LiDAR from a Fixed-Wing Drone

The world’s most extensive tropical peatlands occur in the Cuvette Centrale depression in the Congo Basin, which stores 30.6 petagrams of carbon (95% CI, 6.3–46.8). Improving our understanding of the genesis, development and functioning of these under-studied peatlands requires knowledge of their topography and, in particular, whether the peat surface is domed, as this implies a rain-fed system. Here we use a laser altimeter mounted on an unmanned airborne vehicle (UAV) to measure peat surface elevation along two transects at the edges of a peatland, in the northern Republic of Congo, to centimetre accuracy and compare the results with an analysis of nearby satellite LiDAR data (ICESat and ICESat-2). The LiDAR elevations on both transects show an upward slope from the peatland edge, suggesting a surface elevation peak of around 1.8 m over ~20 km. While modest, this domed shape is consistent with the peatland being rainfed. In-situ peat depth measurements and our LiDAR results indicate that this peatland likely formed at least 10,000 years BP in a large shallow basin ~40 km wide and ~3 m deep.