Upland Blanket Bog Research Articles

Post-glacial vegetation and landscape change in upland Ireland with particular reference to Mám Éan, Connemara

Holocene vegetation dynamics of mid-western Ireland are discussed with particular reference to the Galway and Mayo uplands, the development of upland blanket bog and the history of pine and yew. A detailed pollen profile from Mám Éan (Maumeen), a corrie lake, provides insights into environmental change in upland Connemara where, in recent decades, overgrazing and peat erosion have given rise to serious environmental concerns. Vegetation dynamics are broadly comparable to those in lowland Connemara and also upland sites in the Nephin Begs, Co. Mayo. The available evidence suggests corrie glaciation in the Younger Dryas. The oldest sediments show the usual early Holocene progression from open herbaceous communities to woody vegetation dominated by juniper, tree birch, and finally hazel. Tall canopy trees then spread, including pine, and elm and oak, and later alder (at ca. 7.7 ka). In the interval 10.2–4.8 ka, pine was dominant and for much of this time fires were frequent. There is a distinct mid-Holocene Elm Decline and a short Neolithic Landnam phase that is followed by woodland regeneration involving, at first, mainly pine and later yew. 14C dating of bog-pine from upland sites sheds new light on pine and upland blanket bog development in the mid-Holocene. It is shown that while blanket bog was initiated at Mám Éan by ca. 10.8 ka, the present-day treeless landscape has come about within the last 1000 years as a result of sustained human impact, that has also resulted in severe erosion of minerogenic and, more recently, peaty soils.

Empirical Modelling of Vegetation Abundance from Airborne Hyperspectral Data for Upland Peatland Restoration Monitoring

Peatlands are important terrestrial carbon stores. Restoration of degraded peatlands to restore ecosystem services is a major area of conservation effort. Monitoring is crucial to judge the success of this restoration. Remote sensing is a potential tool to provide landscape-scale information on the habitat condition. Using an empirical modelling approach, this paper aims to use airborne hyperspectral image data with ground vegetation survey data to model vegetation abundance for a degraded upland blanket bog in the United Kingdom (UK), which is undergoing restoration. A predictive model for vegetation abundance of Plant Functional Types (PFT) was produced using a Partial Least Squares Regression (PLSR) and applied to the whole restoration site. A sensitivity test on the relationships between spectral data and vegetation abundance at PFT and single species level confirmed that PFT was the correct scale for analysis. The PLSR modelling allows selection of variables based upon the weighted regression coefficient of the individual spectral bands, showing which bands have the most influence on the model. These results suggest that the SWIR has less value for monitoring peatland vegetation from hyperspectral images than initially predicted. RMSE values for the validation data range between 10% and 16% cover, indicating that the models can be used as an operational tool, considering the subjective nature of existing vegetation survey results. These predicted coverage images are the first quantitative landscape scale monitoring results to be produced for the site. High resolution hyperspectral mapping of PFTs has the potential to assess recovery of peatland systems at landscape scale for the first time.

Macroinvertebrate assemblages of small upland peatland lakes in Ireland

Blanket bogs are an important habitat in Ireland and are listed for their conservation value by the European Union. Despite this little is known about the invertebrate fauna of freshwater habitats and environmental factors that structure these in blanket bogs, particularly in small upland lakes. This study addressed this topic by sampling twelve small lakes (<0.21km2) at altitudes greater than 300 meters above sea level. Macroinvertebrates were sampled by standard kick-sweeps (five per lake) and Chironomidae were sampled by collecting foam samples, both in spring and late summer in 2005. A total of 202 taxa were identified, largely dominated by the insect orders Diptera, Trichoptera, Heteroptera and Coleoptera. Some were notable as either rare, new records for an area or typical of either upland or acidic water conditions. The chironomids alone contributed 100 species, five of which were confirmed new Irish records, one had not been recorded in the UK at the time of sampling. There were significant differences in both the macroinvertebrate and chironomid assemblages recorded in the twelve lakes. About 78% of the variation was attributed to differences in pH, elevation and nutrients (total phosphorus, nitrates and/or ammonia). Species turnover between the two seasons sampled was high for chironomids but low for the rest of the macroinvertebrates. Significant seasonal changes in the macroinvertebrate community composition occurred, particularly in lakes with a pH of less than 6. Lakes situated on either igneous or sedimentary geologies grouped together, indicating that the surrounding peaty soils usually had a greater influence on water chemistry. Small lakes in upland blanket bog have characteristic invertebrate communities, in part, similar to other aquatic peatland habitats. More such studies are required to document the species present and to determine how susceptible these lakes are to anthropogenic impacts such as climate change.

Macroinvertebrate assemblages of small upland peatland lakes in Ireland

Blanket bogs are an important habitat in Ireland and are listed for their conservation value by the European Union. Despite this little is known about the invertebrate fauna of freshwater habitats and environmental factors that structure these in blanket bogs, particularly in small upland lakes. This study addressed this topic by sampling twelve small lakes (<0.21km2) at altitudes greater than 300 meters above sea level. Macroinvertebrates were sampled by standard kick-sweeps (five per lake) and Chironomidae were sampled by collecting foam samples, both in spring and late summer in 2005. A total of 202 taxa were identified, largely dominated by the insect orders Diptera, Trichoptera, Heteroptera and Coleoptera. Some were notable as either rare, new records for an area or typical of either upland or acidic water conditions. The chironomids alone contributed 100 species, five of which were confirmed new Irish records, one had not been recorded in the UK at the time of sampling. There were significant differences in both the macroinvertebrate and chironomid assemblages recorded in the twelve lakes. About 78% of the variation was attributed to differences in pH, elevation and nutrients (total phosphorus, nitrates and/or ammonia). Species turnover between the two seasons sampled was high for chironomids but low for the rest of the macroinvertebrates. Significant seasonal changes in the macroinvertebrate community composition occurred, particularly in lakes with a pH of less than 6. Lakes situated on either igneous or sedimentary geologies grouped together, indicating that the surrounding peaty soils usually had a greater influence on water chemistry. Small lakes in upland blanket bog have characteristic invertebrate communities, in part, similar to other aquatic peatland habitats. More such studies are required to document the species present and to determine how susceptible these lakes are to anthropogenic impacts such as climate change.

Temporal variations in dissolved organic carbon concentrations in upland and lowland lakes in North Wales

AbstractOver a period of 18 months, the dissolved organic carbon (DOC) concentration of a series of four lakes in North Wales was measured monthly. The lake catchment profiles consisted of an upland thin peat/soil (Llyn Cwellyn), an upland thin peat/soil associated with an adjacent area of small bog (Llyn Teyrn), an upland blanket bog (Llyn Conwy), and large lowland fen and fertile agricultural area (Llyn Cefni). The results examine the indirect effect of temperature and precipitation on the DOC concentrations found in the lakes fed by the catchments. The lowest DOC of the four sites was observed for Llyn Teyrn, varying from 1.2 to 3.30 mg/L, and with the highest being recorded for Llyn Cefni (5.45–10.83 mg/L). Temperature and rainfall data were both collected. Correlations with the DOC exhibited significant relationships with temperature for three of the sampled lakes Cwellyn (r 0.490), Teyrn (r 0.640) and Cefni (r 0.472). Recomputation versus 30‐ and 60‐day temperature lag times improved the correlation coefficients. The data showed weak and insignificant correlations for DOC versus rainfall for the three lakes, but the upland lake, Llyn Conwy, with its blanket bog catchment, did not demonstrate any statistical correlation with temperature, although it did show a significant correlation for DOC versus rainfall (r 0.553, P &lt; 0.05). Over the sampling period, although tentative relationships were found among temperature, rainfall and DOC levels, an indirect association tempered by site hydrology is suggested.

Abiotic drivers and their interactive effect on the flux and carbon isotope ( 14C and δ 13C) composition of peat-respired CO 2

Feedbacks to global warming may cause terrestrial ecosystems to add to anthropogenic CO 2 emissions, thus exacerbating climate change. The contribution that soil respiration makes to these terrestrial emissions, particularly from carbon-rich soils such as peatlands, is of significant importance and its response to changing climatic conditions is of considerable debate. We collected intact soil cores from an upland blanket bog situated within the northern Pennines, England, UK and investigated the individual and interactive effects of three primary controls on soil organic matter decomposition: (i) temperature (5, 10 and 15 °C); (ii) moisture (50 and 100% field capacity – FC); and (iii) substrate quality, using increasing depth from the surface (0–10, 10–20 and 20–30 cm) as an analogue for increased recalcitrance of soil organic material. Statistical analysis of the results showed that temperature, moisture and substrate quality all significantly affected rates of peat decomposition. Q 10 values indicated that the temperature sensitivity of older/more recalcitrant soil organic matter significantly increased (relative to more labile peat) under reduced soil moisture (50% FC) conditions, but not under 100% FC, suggesting that soil microorganisms decomposing the more recalcitrant soil material preferred more aerated conditions. Radiocarbon analyses revealed that soil decomposers were able to respire older, more recalcitrant soil organic matter and that the source of the material (deduced from the δ 13C analyses) subject to decomposition, changed depending on depth in the peat profile.

The impact of drain blocking on an upland blanket bog during storm and drought events, and the importance of sampling-scale

► Restoring peatlands by drain blocking leads to more stable water tables during drought periods. ► These higher water tables led to higher and more stable discharge during droughts. ► Restoration reduces the severity of peak flow responses. ► Restoration reduces the loss of fluvial organic carbon both during and after drought periods. Organic carbon solution and transport processes which occur during periods of heavy rainfall and periods or little or no rainfall, can exert a significant control over a systems’ annual organic carbon budget. In addition, either or both extremes can be key contributors to contaminant release, water discolouration, flood risk or vegetation growth. Although there is an increasing body of work studying hydrological responses to peatland restoration, there are very little available data on the performance of restored peatlands during these key periods. This study builds on previous work from an upland peatland in Wales that has been restored through drain-blocking, and presents evidence from a landscape scale experimental study at the site. A comparison of sampling scales within the study demonstrates the necessity of larger spatial scales, in combination with high resolution datasets, in assessing catchment level responses. Our results suggest that drain blocking leads to higher and more stable water tables that are able to better resist drought periods, and thus lead to more stable discharge from the system. The shallower water tables and pooling in drains also appear to reduce the production and transport of fluvial organic carbon, and thus less organic material is available to be released as during peak flow or dry periods. Despite restoration apparently reducing the available water storage within the peat, the increase in overland flow and in pooling within blocked drains appears to have led to a less flashy system. Peak flow responses in both drains and upland streams are less severe, with more rainfall being retained within the bog. We suggest that restoration leads to a more buffered system, with more moderate responses to extreme events, and reduced release of both dissolved and particulate organic carbon. We discuss the implications of this for fluxes of fluvial organic carbon and sediment loss.

Ditch blocking, water chemistry and organic carbon flux: Evidence that blanket bog restoration reduces erosion and fluvial carbon loss

The potential for restoration of peatlands to deliver benefits beyond habitat restoration is poorly understood. There may be impacts on discharge water quality, peat erosion, flow rates and flood risk, and nutrient fluxes. This study aimed to assess the impact of drain blocking, as a form of peatland restoration, on an upland blanket bog, by measuring water chemistry and colour, and loss of both dissolved (DOC) and particulate organic carbon (POC). The restoration work was designed to permit the collection of a robust experimental dataset over a landscape scale, with data covering up to 3 years pre-restoration and up to 3 years post-restoration. An information theoretic approach to data analyses provided evidence of a recovery of water chemistry towards more ‘natural’ conditions, and showed strong declines in the production of water colour. Drain blocking led to increases in the E4:E6 ratio, and declines in specific absorbance, suggesting that DOC released from blocked drains consisted of lighter, less humic and less decomposed carbon. Whilst concentrations of DOC showed slight increases in drains and streams after blocking, instantaneous yields of both DOC and POC declined markedly in streams over the first year post-restoration. Attempts were made to estimate total annual fluvial organic carbon fluxes for the study site, and although errors around these estimates remain considerable, there is strong evidence of a large reduction in aquatic organic carbon flux from the peatland following drain-blocking. Potential mechanisms for the observed changes in water chemistry and organic carbon release are discussed, and we highlight the need for more detailed information, from more sites, to better understand the full impacts of peatland restoration on carbon storage and release.

Impact of gully erosion on carbon sequestration in blanket peatlands

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 45:31-41 (2010) - DOI: https://doi.org/10.3354/cr00887 Impact of gully erosion on carbon sequestration in blanket peatlands Martin Evans1,*, John Lindsay2 1Upland Environments Research Unit, School of Environment and Development, University of Manchester, Manchester M19 3PL, UK 2Department of Geography, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada *Email: martin.evans@manchester.ac.uk ABSTRACT: Over 50% of UK soil carbon is stored in peatland systems and 75% of these peatlands are upland blanket bog. The upland blanket bogs of the UK have suffered severe erosion over the last millennium so that they are widely dissected by gully systems. Gully erosion entails primary removal of particulate carbon from the peatland system but also has secondary effects in that it enhances drainage and lowers water tables, potentially enhancing decomposition of surface peats. This paper exploits recent high resolution mapping of the gully erosion on the Bleaklow Plateau in the southern Pennines and existing data on peat growth rates in the area to assess the impact of gully erosion on peatland carbon balance and the relative importance of primary and secondary impacts of gullying on carbon sequestration. The results indicate that gully erosion during the last millennium has shifted the Bleaklow Plateau from being a net sink of carbon (–20.3 gC m–2 yr–1) to a net source (29.4 gC m–2 yr–1). The relative importance of gullying impacts can be expressed as follows: particulate organic carbon (POC) flux > change in gully net ecosystem exchange >> loss of gully margin carbon sequestration. The implication of these findings is that the magnitude of the potentially reversible impacts of gully erosion (reduced carbon fixation due to vegetation loss and ongoing erosional loss of POC) far exceed the effects associated with irreversible morphological change (enhanced peat decomposition in gully margin locations). KEY WORDS: Blanket peat · Gully erosion · Carbon balance · Carbon sequestration Full text in pdf format PreviousNextCite this article as: Evans M, Lindsay J (2010) Impact of gully erosion on carbon sequestration in blanket peatlands. Clim Res 45:31-41. https://doi.org/10.3354/cr00887 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 45. Online publication date: December 30, 2010 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2010 Inter-Research.

Carbon budgets of an upland blanket bog managed by prescribed fire

This study presents the carbon budget of a blanket bog, North Pennines, UK, subject to grazing and prescribed burning for vegetation management. The budget considers both fluvial and gaseous carbon fluxes and the following uptake and release pathways: dissolved organic carbon, particulate organic carbon, excess dissolved CO2, release of methane (CH4), net ecosystem respiration of CO2, and uptake of CO2 through primary productivity. Measurements of CH4 were not directly measured as part of this study but were estimated from hydroclimatic variables measured within the study. The results show that, if management combinations were extrapolated across the catchment, then over a 3 year period, the catchment would be a net source of carbon of between 62 and 206 gC m−2 yr−1. The action of both burning and grazing was to significantly decrease the magnitude of the carbon source relative to unburnt controls. Over the study period burnt sites were a mean source of approximately 117.8 gC m−2 yr−1 compared to unburnt sites with a mean source of 156.7 gC m−2 yr−1. Even when including the loss of carbon during the vegetation combustion, there are conditions under which the long‐term loss of carbon is less than if no burning had occurred. If total combustion of vegetation occurs, provided burning occurs at cycles longer than 32 years, then less carbon is predicted to be lost than in a no‐burn scenario.

The effect of blanket bog drainage on habitat condition and on sheep grazing, evidence from a Welsh upland bog

There has been increasing interest in potential benefits to be gained by restoring damaged peatlands, with the majority of funding currently being driven by the recovery of protected habitats. However, few data are available linking vegetation community declines with peatland drainage, and so the potential for recovery remains difficult to predict. Surprisingly, there is a similar paucity of research demonstrating the extent of drainage impacts on grazing conditions for livestock, despite this being a priority amongst land managers. We attempt to address these two knowledge gaps, first by investigating whether ditches in blanket bog habitat have improved or increased grazing for sheep, and second by assessing the impact of ditches on the condition of vegetation communities. At an extensively drained upland blanket bog in Wales, currently undergoing ditch blocking restoration, we collected vegetation and sheep occurrence data across five catchments and over 2 years. We present evidence that drained areas had remained relatively wet and were less preferred by sheep. Furthermore, our results show that while sheep preferred graminoid-rich areas, drainage did not increase the abundance of this species group. Drainage at the site has, however, resulted in some degradation in blanket bog vegetation adjacent to ditches; although at the landscape scale, historic high grazing levels appear to explain much of the current poor ecological condition of the site. We conclude that drain-blocking restoration should not reduce sheep grazing conditions beyond their current relatively poor state, and thus in this respect may not represent a threat to hill farming productivity.

Recovery of water tables in Welsh blanket bog after drain blocking: Discharge rates, time scales and the influence of local conditions

Peatland practitioners and scientists have increasingly recognised the damage resulting from various management methods, and the need to restore peatlands to achieve several potential benefits. Many of the hoped-for benefits of peatland restoration, such as Carbon storage, biodiversity conservation and water quality improvements, are thought to depend on a reinstatement of high water tables that had been reduced by drainage. Despite the current emphasis on restoring drained peatlands, many of the predicted responses to restoration are still not adequately proven and the mechanisms behind them still uncertain. This study reports on water table and discharge responses to drain blocking restoration of a degraded Welsh upland blanket bog. Restoration work and monitoring were designed to permit a novel catchment scale control-intervention experimental design. An information theoretic approach to examining the data provided evidence of increases in water retention and water tables within the bog after restoration. But the study also demonstrated the importance of small and large scale topography in determining the degree of these responses. The increases in water storage after restoration produced lower discharge rates observable at the level of both drains and hill streams; as well as greater water table stability, reduction in peak flows and increases in water residency after rainfall. Crucially, this study showed strong catchment scale differences in response, and a very gradual recovery of water tables, both of which highlight the need for more studies to be carried out at the landscape scale and over longer time periods.

Compositional changes in soil water and runoff water following managed burning on a UK upland blanket bog

Summary This study examines the effect managed rotational burning has on soil water and runoff water compositions at the end of a 10 year burning cycle and into the year following a managed burn. This study includes aluminium, iron, calcium, sodium, magnesium, potassium, sulphate, chloride, bromide, fluoride, phosphate and nitrate along with pH, conductivity and DOC. The main findings of this study are: 1. The presence of burning leads to lower concentrations of species associated with deep water sources in both soil and runoff waters. 2. Following burning, soil water has increased concentrations in shallow soil water components (i.e. Al, Fe). Conversely runoff water shows a decrease in the concentration of shallow water components 3. Principal component analysis shows that in the post-burn period, soil water is less mixed with rainwater and runoff water becomes more rainwater-like in composition, i.e. compositions of soil and runoff have diverged as a result of the burn.

Hydrological responses to managed burning and grazing in an upland blanket bog

The management of the UK uplands by rotational burning and grazing is a widespread practice that aims to control the development of vegetation in order to create suitable habitats for grouse and sheep. By modifying the above ground biomass it is possible that above and/or below ground hydrological regimes may be altered. This study investigates the effect burning has on various hydrological parameters of an upland blanket bog. The study was conducted on a long-term experimental site examining different combinations of managed burning and grazing intensities. The study has found that: (1) Although depth to water table shows strong seasonal trends, the shallowest water tables were found on those sites that were burnt every 20 years and grazed by sheep. The deepest water tables were found on those sites that had never been burnt. (2) In the year following a managed burn, water tables on those sites that were burnt were significantly shallower than before the burn. (3) Hydraulic conductivity, as determined by dipwell slug tests, was found to be significantly lower on those plots that were burnt every 20 years. (4) Runoff occurrence was recorded and occurred at a significantly greater frequency on those sites that had recently been burnt. (5) By using antecedent weather conditions, significant parameters were found that could be used to model runoff generation. This paper demonstrates how the use of managed burning in upland settings can affect various hydrological responses of the peatland. These variations in hydrological response will have important consequences on DOC export through changes in water table and the partitioning of precipitation into runoff.

WATER ANALYSES FROM SOME IRISH BOGS AND FENS, WITH THOUGHTS ON 'THE &lt;i&gt;SCHOENUS&lt;/i&gt; PROBLEM'

WATER ANALYSES FROM SOME IRISH BOGS AND FENS, WITH THOUGHTS ON 'THE &lt;i&gt;SCHOENUS&lt;/i&gt; PROBLEM'

Temporal variation in the surface‐water chemistry of a blanket bog on Dartmoor, southwest England: analysis of 5 years' data

SummaryBlanket‐bog peats, mapped as the Winter Hill and Crowdy associations by the Soil Survey of England and Wales, are an oceanic manifestation of the ombrotrophic ‘raised‐bog’ (Hochmoor) peats that cover large tracts in the boreal zone of the northern hemisphere. This paper examines monthly analyses from 1992 to 1997 of major ions and other variables from an upland blanket bog in southwest England in relation to seasonality, rainfall, and the chemical composition of rainwater. Average ionic composition of surface water (and peat) integrates variable atmospheric solute inputs over the years. The dominant ions in the surface water, Na+ and Cl–, showed only weak seasonality, but divalent cations a stronger seasonal pattern with a summer maximum. Mean pH ranged from c. 4.4 in February to c. 4.2 in August. Changes in concentration of different cations were closely interlinked by cation exchange. The anion deficit, accounted for by anionic groups on the dissolved organic matter, was strongly seasonal with a summer maximum, as was optical absorbance at 320 nm. Nitrate and NH4+ were both at much smaller concentrations than in rain. Nitrate exceeded 1 μmol l−1 only during cold periods in winter, mainly following drought in the summer of 1995; NH4+ reached a few μmol l−1 only in summer. There was evidence of net retention of S by the peat in wet sites and during wet periods, and of net release of SO42– (and acidity) under dry conditions. The 1995 summer drought and ensuing dry year in 1996 had marked and persistent effects on pH, apparent ion deficit (DEF), SO42–, the divalent cations and Fe.

Short-term impact of sheep and cattle grazing on upland wet heath vegetation

The UK Biodiversity Action Plan identifies upland heath and blanket bog as priorities for conservation. Heavy grazing by livestock has damaged these habitats in many parts of the UK. Agri-environment schemes have partly addressed the problem by encouraging farmers to reduce sheep stocking levels on degraded moorland. This can prevent further loss of dwarf shrub cover, but the increased biomass of moorland grasses can inhibit regeneration of dwarf shrubs and other desirable species. The objectives of this system-scale study are to assess the impact on plant species composition and animal performance, of sheep-only and mixed grazing regimes with both cattle and sheep on degraded wet heath vegetation. It is being carried out as part of a wider project to determine environmentally sustainable and economically viable grazing systems for heather moorland.

The application of multivariate land classification to vegetation survey in the Wicklow Mountains, Ireland

Multivariate land classification and land cover mapping by aerial photographic interpretation were used to model spatial variation of land cover in the Wicklow Mountains, Ireland and to structure a stratified random sampling programme of upland blanket bog vegetation. The total area of blanket bog with gully-erosion features was estimated as 33% of the area studied. Vegetation with hand peat-cutting patterns was estimated at 5%, and there was 35% undissected (intact) vegetation. There were differences between land classes in the estimated area of land cover with gully-erosion features or hand peat-cutting patterns.

Capture success for pygmy and common shrews (Sorex minutus and S. araneus) in Longworth and pitfall traps on upland blanket bog

Journal of ZoologyVolume 237, Issue 4 p. 657-662 Capture success for pygmy and common shrews (Sorex minutus and S. araneus) in Longworth and pitfall traps on upland blanket bog R. F. Shore, R. F. Shore Institute of Terrestrial Ecology, Monks Wood, Abbots, Ripton, Huntingdon, Cambridgeshire PE 17 2LSSearch for more papers by this authorD. G. Myhill, D. G. Myhill Institute of Terrestrial Ecology, Monks Wood, Abbots, Ripton, Huntingdon, Cambridgeshire PE 17 2LSSearch for more papers by this authorR. Lhotsky, R. Lhotsky Institute of Terrestrial Ecology, Monks Wood, Abbots, Ripton, Huntingdon, Cambridgeshire PE 17 2LSSearch for more papers by this authorS. Mackenzie, S. Mackenzie School of Biological Sciences, University of Manchester, Manchester M13 9PLSearch for more papers by this author R. F. Shore, R. F. Shore Institute of Terrestrial Ecology, Monks Wood, Abbots, Ripton, Huntingdon, Cambridgeshire PE 17 2LSSearch for more papers by this authorD. G. Myhill, D. G. Myhill Institute of Terrestrial Ecology, Monks Wood, Abbots, Ripton, Huntingdon, Cambridgeshire PE 17 2LSSearch for more papers by this authorR. Lhotsky, R. Lhotsky Institute of Terrestrial Ecology, Monks Wood, Abbots, Ripton, Huntingdon, Cambridgeshire PE 17 2LSSearch for more papers by this authorS. Mackenzie, S. Mackenzie School of Biological Sciences, University of Manchester, Manchester M13 9PLSearch for more papers by this author First published: December 1995 https://doi.org/10.1111/j.1469-7998.1995.tb05022.xCitations: 9AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume237, Issue4December 1995Pages 657-662 RelatedInformation

Limiting Nutrients in Acid-Mire Vegetation: Peat and Plant Analyses and Experiments on Plant Responses to Added Nutrients

(1) In pot experiments on a wet-heath peat from east Devon, Cirsium dissectum showed a strong positive response to lime but not to CaCl2, and to added P but not to N. Carex echinata responded strongly to lime, N and P. Neither species responded significantly to added K. (2) Peat samples were analysed from six sites in Devon: two lowland wet heaths (Ericion tetralicis), an upland blanket bog (Calluno-Sphagnion papillosilOxycoccoEricion), and three upland poor-fens (Caricion nigrae). (3) Extractable amounts of the major cations were similar at the six sites, with somewhat higher levels of K in the wet heaths, Mg and Na in the blanket bog, and Ca in the poor-fens. The wet-heath sites were lowest in extractable NH4-N and P; the highest NH4-N values were in the poor-fens. (4) Total P was highest in the poor-fens; total Mn and Al were lowest in the blanket peat. C-N and C-P ratios were highest in the wet heath and blanket bog, and lowest in the poor-fens. (5) Plant analyses suggested greater availability of Fe and Mn in the wet heath and poor-fen sites, but otherwise did not closely reflect the peat analyses. (6) A factorial nutrient-addition experiment with Carex echinata grown on peats from the six sites showed that N and P were limiting growth on all six. N was more strongly limiting on the wet heath peats and P on the blanket bog. Both N and P appeared more freely available in the poor-fen peats. (7) K appeared to be in at least adequate supply in all but the blanket-bog peat; it showed no significant main-effect response, but there were significant interactions with N, P and Site. These suggest differences in processes of N supply and uptake in the wet heaths and blanket bog on the one hand, and the poor-fens on the other.