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- PublicationModeling relevant factors and covariates of carbon stock changes in peatlands using a hierarchical linear mixed modeling approachWhile peatlands constitute the largest soil carbon stock in Ireland with 75% of soil carbon stored in an area covering an estimated 20% of the land surface, carbon stocks of peatlands are affected by past and present disturbances related to various land uses. Afforestation, grazing and peat extraction for energy and horticultural use often are major drivers of peatland soil degradation. A comparative assessment of the impact of land disturbance on peatland soil carbon stocks on a national scale has been lacking so far. Current research, funded by the Irish Environmental Protection Agency (EPA), addresses this issue with the goal to fill various gaps related to mapping and modeling changes of soil carbon stock in Irish peatlands. Data from the first nationwide peatland survey forms the basis for this study, in which the influence of different factors and covariates on soil carbon distribution in peatlands is examined. After data exploratory analysis, a mixed linear modeling approach is tested for its suitability to explain peatland soil carbon distribution within the Republic of Ireland. Parameters are identified which are responsible for changes across the country. In addition, model performance to map peat soil carbon stock within a three-dimensional space is evaluated.
- PublicationOptimising Water Quality Returns from Peatland Management while Delivering Co-Benefits for Climate and BiodiversityIrish peatlands are of national and international importance. Half of the blanket bogs considered to be of conservation importance in the European Atlantic Biogeographic Region are found on this island, along with some of the last Oceanic raised bog remaining in the EU. Irish peatlands are also a significant carbon store, containing ¾ of the total soil carbon stock in the Republic of Ireland. Healthy peatlands help provide natural filtration processes to clean water and reduce the quantity of water entering rivers and lakes; they help regulate the global climate and mitigate climate change; they support unique flora and fauna; and provide multiple social and cultural services to society.
- PublicationImplementation of an Emissions Inventory for UK PeatlandsThis report summarises work undertaken on behalf of the Department for Business, Energy and Industrial Strategy (BEIS) to develop and implement a new method for reporting greenhouse gas (GHG) emissions from peatlands in the UK’s emissions inventory. The work builds on the Intergovernmental Panel on Climate Change (IPCC) 2013 Wetlands Supplement, by providing empirically-based and UK-specific ‘Tier 2’ estimates of emissions from a representative range of peat land-use and condition categories. It collates consistent spatial information on peat extent and condition from each of the four UK administrations, as well as the most peat-rich Crown Dependencies and Overseas Territories (Isle of Man and Falkland Islands respectively). These data were used to assess the overall extent and condition of UK peatlands; to estimate change in condition over the period from 1990 to 2013; to implement the first UK-wide inventory of peatland GHG emissions over this period; and to project future peat-derived GHG emissions through to 2050 based on a set of five illustrative scenarios.
- PublicationThe bogs of Ireland: an introduction to the natural, cultural and industrial heritage of Irish peatlandsThe bogs were the last wilderness to take shape in the Irish landscape in the wake of the Ice Age. As they expanded, they forced back the tide of farming, and then kept the fields at bay along their inhospitable frontiers. During the first farming millennia little could be done to reclaim these barren, wet deserts and replace them with friendly fields as had been done with most of the forest wilderness. Only rarely were the bogs resorted to – to bury butter, to take a short cut, to hide the bodies of the murdered. This outlook on the bog changed for two related reasons. One was the disappearance of woodland, and the increasing scarcity of wood as a domestic fuel; the second was the increasing population. Since the publication of The Bogs of Ireland in 1996, research on Irish peatlands has been concentrated on two main areas: carbon sequestration and a re-evaluation of the prospects for afforestation of the cutaway. Apart from some minor corrections, the text of this digital version is essentially that of the original printed edition of 1996, with the exception of Chapters 5, 7 and 16, which have been expanded and rewritten to take account of recent and ongoing research and developments in these two areas.
- PublicationInsights into CO2 simulations from the Irish Blackwater peatland using ECOSSE modelNon-degraded peatlands are known to be important carbon sink; however, if they are exposed to anthropogenic changes they can act as carbon source. This study forms a part of the larger AUGER project (http://www.ucd.ie/auger). It uses the ECOSSE process-based model to predict CO2 emissions [heterotrophic respiration (Rh)] associated with different peatland management (Smith et al., 2010). The work aims to provide preliminary insights into CO2 modelling procedures for drained and rewetted sites from Blackwater, the former Irish raised bog. After drainage in 1950’s (due to peat-extraction) and cessation of draining in 1999, the landscape developed drained ‘Bare Peat’ (BP), and rewetted ‘Reeds’ (R) and ‘Sedges’ (S) sites (Renou-Wilson et al., 2019). Modelling of CO2 from these sites was done using ECOSSE-v.6.2b model (‘site-specific’ mode) with water-table (WT) module (Smith et al., 2010), and default peatland vegetation parameters. The other model-input parameters (including soil respiration, WT and other soil parameters) were obtained from measurements reported in Renou-Wilson et al. (2019). Simulations on drained BP site were run starting from 1950 and on rewetted R and S sites starting from 1999 (which is the year of cessation of drainage). The climate data inputs (2010-2017) were obtained from ICHEC (EPA_Climate-WRF, 2019). The long-term average climate data for model spin-up were obtained from Met Éireann (2012) with potential evapotranspiration estimated by Thornthwaite (1948) method. Daily ecosystem respiration (Reco) data for May/June 2011 to Aug 2011 obtained from raw CO2 flux measurements (Renou-Wilson et al., 2019) were used. For vegetated sites Rh was estimated from Reco using method explained in Abdalla et al. (2014). Daily CO2 simulations were compared to Reco for BP site (r2 =0.20) and to Rh for R site (r2 = 0.35) and S site (r2 = 0.55). The preliminary results showed some underestimation of simulated CO2 indicating the need for further modelling refinements for satisfactory results. The results from BP site further indicated on the importance of including long-term drainage period (i.e. from 1950 on) because avoiding this step resulted in a large overestimation of predicted CO2.
- PublicationPeatland Properties Influencing Greenhouse Gas Emissions and RemovalA nationwide peatland survey was conducted across 50 ombrotrophic peatlands (bogs) in Ireland to ascertain a wide range of peat properties. In addition to natural (relatively intact) sites, we surveyed the most prevalent peatland land use categories (LUCs): grassland, forestry and peat extraction (both industrial and domestic), as well as management options (deep drained; shallow drained; rewetting). Furthermore, the entirety of the peat profile (down to the sub-peat mineral soil/bedrock) was sampled. Our results demonstrate that Irish bogs have been drastically altered by human activities and that the sampled peat properties reflect the nature and magnitude of the impact of the land use and management.
- PublicationImpacts of a mature forestry plantation on blanket peatland runoff regime and water qualityA lack of information concerning the hydrology and hydrogeology of intact blanket bogs limits current understanding of how their alteration to mature forestry plantations impacts stream flow and associated water quality. An integrated hydrological/hydrogeological monitoring programme compared processes operating in a relatively intact blanket peat-covered catchment with conditions encountered in an adjacent area under closed canopy plantation forestry. Groundwater monitoring revealed contrasting water level regimes and deeper summer water tables in the afforested area, with forest groundwater also having more elevated specific electrical conductance (SEC) and containing higher concentrations of dissolved organic carbon (DOC). Near-simultaneous pairwise runoff sampling at the relatively intact catchment and afforested catchment outlets demonstrated no significant difference in DOC concentration. Conversely, water samples from the afforested catchment outlet displayed significantly greater SEC; this arose in part because of higher concentrations of dissolved calcium and magnesium, discharging via artificial drainage. Comparison of base flow runoff SEC with peat groundwater samples reflected in significant contrasts in ionic signature and greater levels of mineralisation in surface water, pointing to contributions of deeper water, derived from inorganic substrate materials. Study findings indicate that disturbance to the ground in that part of the catchment under plantation forestry has led to greater variations in stream flow and water quality for aquatic ecosystems. Comparable conditions have been observed instreams flowing through plantation forestry in similar physical settings elsewhere. Study findings suggest that plantations on deep peat can adversely affect stream ecosystems and this may impact on a water body's legal status.
- PublicationCarbon and climate implications of rewetting a raised bog in IrelandPeatland rewetting has been proposed as a vital climate change mitigation tool to reduce greenhouse gas emissions and to generate suitable conditions for the return of carbon (C) sequestration. In this study, we present annual C balances for a 5-year period at a rewetted peatland in Ireland (rewetted at the start of the study) and compare the results with an adjacent drained area (represents business-as-usual). Hydrological modelling of the 230-hectare site was carried out to determine the likely ecotopes (vegetation communities) that will develop post-rewetting and was used to inform a radiative forcing modelling exercise to determine the climate impacts of rewetting this peatland under five high-priority scenarios (SSP1-1.9, SS1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5). The drained area (marginal ecotope) was a net C source throughout the study and emitted 157 ± 25.5 g C m−2 year−1. In contrast, the rewetted area (sub-central ecotope) was a net C sink of 78.0 ± 37.6 g C m−2 year−1, despite relatively large annual methane emissions post-rewetting (average 19.3 ± 5.2 g C m−2 year−1). Hydrological modelling predicted the development of three key ecotopes at the site, with the sub-central ecotope predicted to cover 24% of the site, the sub-marginal predicted to cover 59% and the marginal predicted to cover 16%. Using these areal estimates, our radiative forcing modelling projects that under the SSP1-1.9 scenario, the site will have a warming effect on the climate until 2085 but will then have a strong cooling impact. In contrast, our modelling exercise shows that the site will never have a cooling impact under the SSP5-8.5 scenario. Our results confirm the importance of rapid rewetting of drained peatland sites to (a) achieve strong C emissions reductions, (b) establish optimal conditions for C sequestration and (c) set the site on a climate cooling trajectory.
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- PublicationRewetting degraded peatlands for climate and biodiversity benefits: Results from two raised bogsGlobally, peatlands are under threat from a range of land use related factors that have a significant impact on the provision of ecosystem services, such as biodiversity and carbon (C) sequestration/storage. In Ireland, approximately 84% of raised bogs (a priority habitat listed in Annex I of the EU Habitats Directive) have been affected by peat extraction. While restoration implies the return of ecosystem services that were characteristic of the pre-disturbed ecosystem, achieving this goal is often a challenge in degraded peatlands as post-drainage conditions vary considerably between sites. Here, we present multi-year greenhouse gas (GHG) and vegetation dynamics data from two former raised bogs in Ireland that were drained and either industrially extracted (milled) or cut on the margins for domestic use and subsequently rewetted (with no further management). When upscaled to the ecosystem level, the rewetted nutrient poor domestic cutover peatland was a net sink of carbon dioxide (CO 2 ) (−49 ± 66 g C m −2 yr −1 ) and a source of methane (CH 4 ) (19.7 ± 5 g C m −2 yr −1 ), while the nutrient rich industrial cutaway was a net source of CO 2 (0.66 ± 168 g C m −2 yr −1 ) and CH 4 (5.0 ± 2.2 g C m −2 yr −1 ). The rewetted domestic cutover site exhibited the expected range of micro-habitats and species composition found in natural (non-degraded) counterparts. In contrast, despite successful rewetting, the industrially extracted peatland did not exhibit typical raised bog flora. This study demonstrated that environmental and management variables can influence species composition and, therefore, the regeneration of species typical of natural sites, and has highlighted the climate benefits from rewetting degraded peatlands in terms of reduced GHG emissions. However, rewetting of degraded peatlands is a major challenge and in some cases reintroduction of bryophytes typical of natural raised bogs may be more difficult than the achievement of proper GHG emission savings.
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- PublicationAssessing the impact of long-term soil phosphorus on N-transformation pathways using 15N tracingA laboratory incubation study was conducted on a temperate grassland soil to quantify the main mineral nitrogen (N) transformation rates and pathways via a15N tracing approach. Soil samples were taken from a long-term phosphorus (P) trial to investigate the effects on gross N-transformations under high and low phosphorus amendment. The soils were incubated over a 2-week period and treated with ammonium-nitrate (NH4NO3) which was applied to the soil both with and without a glucose amendment and labelled with 15N either on the ammonium (NH4+) or nitrate (NO3−) moiety at 50% atom enrichment. The results showed immobilisation to greatly outweigh mineralisation and that NO3− was predominantly produced via heterotrophic nitrification. Individual pathways for NO3− production were quantified including oxidation of NH4+, recalcitrant and labile organic N. Oxidation of labile organic N to NO3−, a newly considered pathway, accounted for between 63 and 83% of total NO3− production across the various treatments and P levels. This process was significantly higher in the low-P rather than the high-P soils (p < 0.05), highlighting the effect of soil P on the microbial community.
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