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PubMed | European Commission, James Hutton Institute, Research and Conservation Division, University of Queensland and 86 more.
Type: | Journal: Global change biology | Year: 2016

The first International Peat Congress (IPC) held in the tropics - in Kuching (Malaysia) - brought together over 1000 international peatland scientists and industrial partners from across the world (International Peat Congress with over 1000 participants!, 2016). The congress covered all aspects of peatland ecosystems and their management, with a strong focus on the environmental, societal and economic challenges associated with contemporary large-scale agricultural conversion of tropical peat. This article is protected by copyright. All rights reserved.

Wilson D.,Earthy Matters Environmental Consultants | Dixon S.D.,Durham University | Artz R.R.E.,James Hutton Institute | Smith T.E.L.,King's College London | And 4 more authors.
Biogeosciences | Year: 2015

Drained peatlands are significant hotspots of carbon dioxide (CO2) emissions and may also be more vulnerable to fire with its associated gaseous emissions. Under the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol, greenhouse gas (GHG) emissions from peatlands managed for extraction are reported on an annual basis. However, the Tier 1 (default) emission factors (EFs) provided in the IPCC 2013 Wetlands Supplement for this land use category may not be representative in all cases and countries are encouraged to move to higher-tier reporting levels with reduced uncertainty levels based on country- or regional-specific data. In this study, we quantified (1) CO2-C emissions from nine peat extraction sites in the Republic of Ireland and the United Kingdom, which were initially disaggregated by land use type (industrial versus domestic peat extraction), and (2) a range of GHGs that are released to the atmosphere with the burning of peat. Drainage-related methane (CH4) and nitrous oxide (N2O) emissions as well as CO2-C emissions associated with the off-site decomposition of horticultural peat were not included here. Our results show that net CO2-C emissions were strongly controlled by soil temperature at the industrial sites (bare peat) and by soil temperature and leaf area index at the vegetated domestic sites. Our derived EFs of 1.70 (±0.47) and 1.64 (±0.44) t CO2-C ha-1 yr-1 for the industrial and domestic sites respectively are considerably lower than the Tier 1 EF (2.8 ± 1.7 t CO2-C ha-1 yr-1) provided in the Wetlands Supplement. We propose that the difference between our derived values and the Wetlands Supplement value is due to differences in peat quality and, consequently, decomposition rates. Emissions from burning of the peat (g kg-1 dry fuel burned) were estimated to be approximately 1346 CO2, 8.35 methane (CH4), 218 carbon monoxide (CO), 1.53 ethane (C2H6), 1.74 ethylene (C2H4), 0.60 methanol (CH3OH), 2.21 hydrogen cyanide (HCN) and 0.73 ammonia (NH3), and this emphasises the importance of understanding the full suite of trace gas emissions from biomass burning. Our results highlight the importance of generating reliable Tier 2 values for different regions and land use categories. Furthermore, given that the IPCC Tier 1 EF was only based on 20 sites (all from Canada and Fennoscandia), we suggest that data from another 9 sites significantly expand the global data set, as well as adding a new region. © Author(s) 2015.

Wilson D.,Earthy Matters Environmental Consultants | Muller C.,Justus Liebig University | Muller C.,University College Dublin | Renou-Wilson F.,University College Dublin
Irish Geography | Year: 2013

In the Republic of Ireland, peatlands cover an estimated 20% of the land area and have been widely utilised over the centuries for energy production, agriculture, forestry and horticultural production. Current estimates suggest that only a small proportion of Irish peatlands are in a natural condition, and that the remainder are either moderately or severely damaged. In this paper, we reviewed carbon (C) studies for the major peatland land uses in Ireland and have estimated that at the national level, emissions from Irish peatlands and related activities (e.g. combustion, horticulture) are around 3 Mt C each year to the atmosphere. However, large uncertainties are associated with this value (1.3-4.7 Mt C yr-1) due to a paucity of field studies for some peatland land uses (particularly cutover peatlands). Mitigation measures to reduce national emissions from peatlands could include: (1) a stronger enforcement approach to protect and enhance the C store in natural peatlands, (2) the rewetting / restoration of degraded peatlands to reduce emissions and create suitable conditions for C sequestration and (3) the use of alternative non-peat sources for energy production and horticulture use. © 2013 © 2013 Geographical Society of Ireland.

Renou-Wilson F.,University College Dublin | Barry C.,Agri Food and Biosciences Institute of Northern Ireland | Muller C.,University College Dublin | Muller C.,Justus Liebig University | Wilson D.,Earthy Matters Environmental Consultants
Biogeosciences | Year: 2014

Temperate grasslands on organic soils are diverse due to edaphic properties but also to regional management practices and this heterogeneity is reflected in the wide range of greenhouse gas (GHG) flux values reported in the literature. In Ireland, most grasslands on organic soils were drained several decades ago and are managed as extensive pastures with little or no fertilisation. This study describes a 2-year study of the net ecosystem carbon balance (NECB) of two such sites. We determined GHG fluxes and waterborne carbon (C) emissions in a nutrient-rich grassland and compared it with values measured from two nutrient-poor organic soils: a deep-drained and a shallow-drained site. Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes were determined using the chamber technique, and fluvial C fluxes were estimated by combining drainage water concentrations and flows. The nutrient-rich site was an annual source of CO2 (233 g C m-2 yr-1), CH4 neutral, and a small source of N2O (0.16 g N2O-N m-2 yr-1). Net ecosystem exchange (NEE) at the shallow-drained nutrient-poor site was -89 and -99 g C m-2 yr-1 in Years 1 and 2 respectively, and NEE at the deep-drained nutrient-poor site was 85 and -26 g C m-2 yr -1 respectively. Low CH4 emissions (1.3 g C m-2 yr-1) were recorded at the shallow-drained nutrient-poor site. Fluvial exports from the nutrient-rich site totalled 69.8 g C m-2 yr-1 with 54% as dissolved organic C. Waterborne C losses from the nutrient-poor site reflected differences in annual runoff totalling 44 g C m-2 yr-1 in Year 1 and 30.8 g C m-2 yr -1 in Year 2. The NECB of the nutrient-rich grassland was 663 g C m-2 yr-1 with biomass exports being the major component accounting for 53%. The NECB of the nutrient-poor deep-drained site was less than half of the nutrient-rich site (2-year mean 267 g C m-2 yr -1). Although NEE at the nutrient-poor shallow-drained site was negative in both years, high biomass export meant it was a net C source (2-year mean NECB 103 g C m-2 yr-1). While the impacts of the nutrient and drainage status on NEE, biomass exports and fluvial C losses were confirmed, inter-regional differences in management practice and climate were also significant factors which impacted on the overall NECB of these ecosystems. Contrary to expectation, the NECB of nutrient-poor drained organic soils under grasslands is not necessarily a large C source and this has implications for Ireland's choice of national GHG inventory reporting methodologies. This study can also aid the development of strategies to deliver reduced emissions tailored to local grassland types. © Author(s) 2014.

Laine A.M.,University of Oulu | Wilson D.,Earthy Matters Environmental Consultants | Alm J.,Finnish Forest Research Institute | Schneider J.,University of Koblenz-Landau | Tuittila E.-S.,University of Eastern Finland
Journal of Vegetation Science | Year: 2016

Question: Measurements of ecosystem carbon (C) exchange are usually labour-intensive and expensive. In peatlands, these temporally and spatially limited measurements are often up-scaled over comparable ecosystems, such as ombrotrophic bogs, to provide an estimate for ecosystem level carbon dioxide (CO2) fluxes. Peatlands typically have moisture variations reflected in the presence of microforms (e.g. hummocks and hollows), each with characteristic plant life forms. However, so far the applicability of peatland type (e.g. bog, fen) or microforms for up-scaling has not been assessed. Does the vegetation composition or function of associated species differ so greatly between the same types of peatland that up-scaling is impossible? Location: Five ombrotrophic bogs in Northern Europe; in Ireland, Finland and western Russia. Methods: We described the variation in vegetation of microforms within and between ombrotrophic bogs using multivariate analyses. Thereafter, we measured CO2 exchange at different microforms and evaluated the relationship between vegetation structure and the light response of photosynthesis. Results: Our results show that the community composition of hummocks, lawns and hollows was rather uniform at the plant life-form level. The photosynthetic capacity per leaf area unit was quite similar within microform classes over the different bogs. The observed differences between sites in capacity were mainly related to variation in leaf area. Conclusions: A reliable estimate of ecosystem-level photosynthesis requires knowledge of the proportion of different microforms in an area and the leaf area characteristics for each microform in the year(s) in question. Assessments of ecosystem-level photosynthesis are important with regard to current and future changes in climate, as the most dramatic changes in peatlands involve water level drawdown, which in turn is likely to lead to changes in the relative proportions of microforms within peatlands. © 2016 International Association for Vegetation Science.

Renou-Wilson F.,University College Dublin | Muller C.,University College Dublin | Muller C.,Justus Liebig University | Moser G.,Justus Liebig University | Wilson D.,Earthy Matters Environmental Consultants
Agriculture, Ecosystems and Environment | Year: 2016

Nutrient-poor organic soils under maritime grassland are often located in remote wet locations in the landscape. Leaving these soils without drainage maintenance often raise the water table but continuous management (grazing) means they could remain a source of carbon dioxide (CO2) while also turning into a small source of methane (CH4). Due to geographical and socio-economic reasons, removing these sites from agricultural production may be an option to mitigate greenhouse gas (GHG) emissions. To test this hypothesis we measured GHG fluxes over a four year period, at a drained and a rewetted organic soil under grassland, which were both grazed for the first two years and not grazed for the following two years. Statistical response functions estimated for gross primary production (GPP) and ecosystem respiration (Reco) were used to reconstruct annual CO2-C balances using site-specific models driven by soil temperature, solar radiation, soil water table (WT) and leaf area index (LAI). Annually, soil CO2 emissions were comparable when grazed, although the rewetted site had a lower net ecosystem carbon balance (NECB) despite displaying higher CH4 emissions. Both sites have lower CO2 emissions than typical drained organic soils due to management practices: extensive grazing, no fertilisation and mean annual water tables above -25 cm. When grazing stopped, GPP and Reco increased dramatically driven by vigorous growth of vegetation at both sites. The shallow drained site remained a source of CO2 and small source of CH4 while the rewetted site became either neutral or a small sink of CO2 with decreased CH4 emissions compared to the grazing period. Nitrous oxide (N2O) emissions were negligible at either site. Removing grazing significantly reduced the NECB at both sites but in terms of global warming potential (GWP), the greatest GHG mitigation was in the rewetted site which exerted a cooling effect in the second year after the management shift. © 2016 Elsevier B.V.

PubMed | Earthy Matters Environmental Consultants, Justus Liebig University, Bord na Mona and University College Dublin
Type: Journal Article | Journal: Global change biology | Year: 2016

Drained peat soils are a significant source of greenhouse gas (GHG) emissions to the atmosphere. Rewetting these soils is considered an important climate change mitigation tool to reduce emissions and create suitable conditions for carbon sequestration. Long-term monitoring is essential to capture interannual variations in GHG emissions and associated environmental variables and to reduce the uncertainty linked with GHG emission factor calculations. In this study, we present GHG balances: carbon dioxide (CO

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