The relationship between vegetation change and rehabilitation management is investigated at a severely degraded cut-over lowland raised mire on the Wales/England border, managed by Natural England and The Countryside Council for Wales. Positive responses are confirmed 11 years after rehabilitation commenced, identifying trends towards raised mire as well as bog pool vegetation and water table thresholds associated with these trends have been established. A landscape-scale vegetation survey was carried out three times over 9 years. Species abundance was correlated with average seasonal water table height, time since rehabilitation, cutting type and survey year. Key species maps for the time series confirmed positive vegetation response, but slower than stipulated in the site management plan. There was a clear increase in the target peat-forming species (Sphagnum cuspidatum, Eriophorum angustifolium and E. vaginatum) as a direct response to rehabilitation and correlating positively with a high water table. Permanent quadrat vegetation monitoring was carried out three times at five-year intervals. Uncut areas and areas of recent commercial cuttings were rehabilitated earliest having significant increases in target mire species without the loss of other mire species from excess inundation. In the recent commercial cutting areas, a successional trend was identified, from a low water table to a fluctuating water table characterised by Molinia caerulea-rich vegetation, followed by a transition to stable, inundated conditions supporting Sphagnum cuspidatum/Eriophorum spp pool vegetation. A second successional trend, associated with the achievement of a near-surface, stable water table, saw the development of raised mire vegetation including Sphagna other than S. cuspidatum. This latter trend was primarily found in the uncut areas of the site but was also found to a lesser extent in recently cut-over areas where it was preceded by a fluctuating water table with a Calluna vulgaris- Molinia caerulea vegetation. A new survey related water table residence time calculated from hydrology data with vegetation for each quadrat. Analysis identified a mire pool vegetation type correlated with shallow, above surface flooding. A diverse mire vegetation type was also found which correlated with the water table staying within the upper 10cm of peat. The minimum threshold for establishment of Sphagnum species was found to be an average water table level within the range of 5.1 to 10cm below the peat surface. Higher cover of Sphagnum species was related to shallow flooding – suggesting that these conditions would be most efficient in re-establishing mire vegetation. 3 A base-line vegetation monitoring survey on an area immediately following deforestation and damming identified a subtle but positive response of the mire vegetation to management within one year.

This dissertation presents the results of late Holocene insect fossil analysis from six raised bogs in the Irish Midlands. A distribution and taphonomic study was performed on a sequence of samples across a 1-km transect from the lagg (margin) to the dome (centre) of Ballykean Bog, County Offaly, Ireland. The purpose of this study was to detect any patterns in the taphonomy of the insect fossil assemblages, through the development of the bog and across ancient bog surfaces. This study also investigated how vegetation changes and taphonomy influence beetle assemblages from different locations across the bog surface and to test whether fossil assemblages reflect these changes. The insect faunal assemblages from the transect did not show any clear spatial or temporal patterns in fossil abundance or taxonomic diversity. However, the study demonstrated the benefit of the analysis of multiple sampling points in a bog. Multiple sampling site analysis appears to be critical in the development of a comprehensive reconstruction of key intervals of peat deposition and in providing a greater understanding of the local bog surface habitats. Insect fossil records were analysed across six raised bogs as part of a multi-proxy environmental archaeology project focusing on seven trackways, a wooden platform and a habitation structure. The archaeology dates from the early Bronze Age (1569±9 BC) at Kinnegad Bog to the Christian period (AD 900 to 1160) at Lullymore Bog. This study demonstrates that insect records associated with the minor structures, such as trackways and platforms, contained less diverse assemblages comprising of mainly generalist taxa. In comparison, the major habitation structure at Ballykean Bog had a strong anthropogenic signal. While the reasons behind the construction of the trackways and platforms remains unsolved on the basis of the multi-proxy environmental analysis, it was possible to suggest reasons for their construction based on structure directionality and historical context.

Peatlands are unique habitats that have absorbed large amounts of carbon dioxide and locked it away as carbon buried in peat for millennia. In the UK, blanket peatlands form one of the largest terrestrial stores of carbon (Milne and Brown, 1997). Recent research suggests that the carbon sequestering potential and carbon stores of UK blanket peatlands are at risk from changes in land use practices and climate. Although, to date, little research has considered blanket peatland at a landscape scale and a comprehensive understanding of land use and degradation impact upon carbon sequestration has not been gained. This thesis presents a study of Dartmoor, a blanket peatland in south west England vulnerable to climate change (Clark et al, 2010). A landscape scale carbon inventory, using a methodology designed for blanket peatlands is presented. Nearly 1000 peat depths and 30 cores were taken using stratified sampling across Dartmoor’s landscape. Functional relationships between peat depth, bulk density and carbon content and topographic parameters were found. In arc GIS 9.3 these were used to model landscape scale carbon, this estimates that Dartmoor contained 9.7 (-2.91 + 2.97) Mt of carbon, a value similar to that of the national inventory (Bradley et al, 2005). The thesis then considers the impact of drainage and degradation on carbon accumulation. Fifteen cores were dated from a drained, degraded site with a history of burning and control site using Spheroidal Carbonaceous Particles (SCPs) and radionuclide techniques. Previous studies have raised concern surrounding accuracy dating recent peats. Results indicate that although dating was largely successful, some discrepancies existed related to poor calibration of SCPs and mobility of radionuclides. To avoid error in dating, it was concluded that multiple dates should be used per core. With consideration of this, carbon accumulation was found to be active but significantly lower in the degraded site and unchanged in the drained site. Further analysis suggested that this outcome may vary with changing management and topographic situations. Future carbon accumulation at a landscape scale was calculated under different scenarios. This found degradation could potentially reduce carbon sequestration on Dartmoor by up to 32%. Economic valuation of accumulation values was used to demonstrate how this data could be used to inform management. This thesis provides an insight into the carbon storage and threats to Dartmoor, an under investigated, yet threatened blanket peatland environment. This helps broaden the spatial

It is estimated that peatlands cover around 20% of Scotland’s land area. Scotland’s peatlands are important ecosystems in terms of the services they provide; carbon sequestration, water chemistry and flow regulation, biodiversity, as well as for the homes and livelihoods they offer to their inhabitants. Due to historical management practices over 70% of Scotland’s peatlands are damaged to some degree, and are now in need of restoration. The remaining peat bogs need to be conserved. Peatlands are complex landscapes that require good governance in order to be managed fairly and effectively. This thesis sets out to explore the issues surrounding peatland management and offer some recommendations. Workshops were carried out in Dumfries, The Cairngorms, Thurso and Shetland in order to explore how landowners and managers perceived peatlands and peatland restoration and the potential to fund restoration through the Peatland Code Payment for Ecosystem Services Scheme. The main findings were; there was confusion over the policy concerning peatlands, landowners and managers felt uncertain of the potential carbon benefits and methods to predict them, the Peatland Code focuses on carbon benefits and landowners and managers cared more about water and wildlife. These findings prompted a more in depth study of the objectives, priorities and values of landowners and managers through the use of qualitative interviews, and a policy analysis to clarify funding options and regulations and to identify potential barriers. Sixty-seven semi-structured interviews were carried out with landowners and managers from the four regions around Scotland. These were analysed in order to find common themes. Many of the interviewees had social and environmental aims for their land, as well as financial aims. There was a very strong sense of care and responsibility for the land, which was linked to heritage, legacy and identity. Communication was poor between different groups (landowners vs crofters, locals vs incomers, landowners and managers vs NGOs, Scientists, Politicians), fostering a sense of discord or antagonism. This lead to a lack of trust and a reluctance to engage with other groups, exacerbating communication issues. Poor communication means that the good environmental intensions of evident from the interviews did not always translate into action. Exceptions to this always involved face-to-face communication, site visits, and a long term relationship allowing the build-up of trust. Policy documents relating to peatlands were reviewed. Findings were presented at a workshop attended by peatland policy experts, in order to identify gaps or misconceptions, which were then addressed. Peatlands do not have their own policy area, but are mentioned in policy related to agriculture, forestry, fresh water and biodiversity. Peatlands are most often mentioned in terms of their carbon sequestration potential. They are poorly integrated in fresh water policy. This shows a mismatch between the interests of policy-makers, and the interests of practitioners, as identified in the workshops. Funding for peatland restoration is limited, restrictive in terms of activities that will be funded, and the application process is onerous. The regulations are poorly communicated leading many to fear they will be penalised for undertaking management that is beneficial to peatlands. There are few policies with the intention of building capacity through information provision or training. The uncertainty surrounding funding options for peatland restoration may discourage contractors from diversifying in this area, leading to a shortage of people with the skills necessary to carry out the work. In all three chapters there is a common thread that the various policies and schemes created in order to facilitate conservation and restoration of peatlands do not adequately harness the feelings of care and responsibility towards the environment that are present in the landowning and managing communities. This is due to poor communication and a misunderstanding of the various perspectives of groups in these areas, leading to sometimes obstructive policies which fall short of their ambitions.

Microbial nitrogen (N2) fixation supplies important nitrogen inputs to boreal peatlands, extremely oligotrophic ecosystems dominated by Sphagnum mosses. In this study, we coupled major and trace nutrient analyses and rate measurements to characterize interactions between N2 fixation and CH4 cycling at the S1 peat bog in Marcell Experimental Forest and the Zim bog (Minnesota, USA). Total dissolved inorganic nitrogen (NO3-+NO2-+NH4+) and phosphate were both consistently < 2 μM in the porewater of surface peat, indicating severe nutrient limitation. While dissolved Fe was fairly abundant (18-35 mM), Mo, V and Cu were scarce (2-40 nM), suggesting that alternative metalloenzymes containing Fe in place of other metals may be favored. Rates of diazotrophy measured by both 15N2 incorporation and the acetylene (C2H2) reduction assay (ARA) were 7-fold higher under anoxic vs. oxic incubations conducted at both 4°C and 25°C. No significant difference in N2 fixation rates measured by either method was observed with or without the amendment of 1% CH4 at 25 °C; however, a significant inhibitory effect by methane was seen at 4°C in material from the S1 bog hollows. Anoxic 15N2 incorporation was 3-4x higher in treatments lacking acetylene, suggesting that the ARA likely underestimates N2 fixation by inhibiting diazotrophs sensitive to C2H2. Aerobic methanotrophy was also inhibited by 1% C2H2 when incubated under oxic conditions. No observations for the production of ethane (C2H6) were detected during the ARA, a biomarker for alternative nitrogenase activity. Major differences in ARA rates were observed to vary locally within microhabitats and between two bogs. In June 2014, peat sampled from hollows incubated under anoxic conditions showed the highest ARA rates (94.9 ± 11.0 nmol C2H4 g-1 moss dry mass hr-1), while the lowest rates were observed in ix hummock samples incubated under oxic conditions (5.1 ± 0.8 nmol C2H4 g-1 moss dry mass hr-1) in the S1 bog (T3 site). Observed rates have the potential to be a function of oxygen concentrations and or water content. ARA rates in all microcosm treatments were significantly lower at Zim bog compared to the S1 bog. The developed conversion factor between the regression of 15N2 and ARA in this study was 3.9 and agrees with the theoretical conversion factor as well as previous studies of soils and forest mosses.

No description available.

The wet zone – the lagg – that tends to form at the edge of ombrotrophic peatlands is believed to play an important role in promoting and maintaining the health of bog systems. The lagg is well-recognized by peatland scientists, yet empirical knowledge is surprisingly limited, and most of the characteristics associated with this ecotone come from qualitative observations. Understanding the role played by the lagg, and the potential impact its disturbance might have on the integrity of a raised bog system, is valuable for sustainable land management and peatland restoration science alike. This thesis explores and documents the basic ecohydrological characteristics of the lagg in the context of the neighbouring natural landscapes, and discusses the spatial properties of various types of laggs by exploring airborne LiDAR datasets to detect and position the ecotone. The specific objectives are 1) to describe the form and abiotic controls of the laggs and margins of bog peatlands, 2) to propose a conceptual model in cross-section of the “bog-lagg-mineral land” transition, 3) to explore the potential of data derived from aerial LiDAR (Light Detection And Ranging) to detect and locate laggs and lagg boundaries, and 4) to consider the spatial distribution of laggs around raised bog peatlands. Data were collected along 10 transects located within 6 relatively undisturbed bogs of the New Brunswick eastern lowlands, Canada. Each transect consisted of 4-6 wells, straddling the ombrotrophic bog and the adjacent mineral land, and of 3 nested piezometers in the center of each lagg. These instruments were used to monitor the position of the water table, to measure hydraulic gradient, hydraulic conductivity, and for water sampling. Dissimilarity analysis (edge-detection, split moving window) and similarity analysis (cluster, k-means) were used to test the delineation capacity of five variables derived from the LiDAR dataset; ground elevation (topography), vegetation height, topographic wetness index, and spatial frequency of both vegetation and ground LiDAR returns. The major abiotic control of the lagg appears to be topography. Two geomorphological categories were identified; confined and unconfined. The importance of topography is through the affect it has on water flow rates and direction, which in turn affect water chemistry, and most likely nutrient transport and availability, hence vegetation characteristics. Dissimilarity analysis of the five variables derived from LiDAR data revealed that some indicators were better at predicting the bog-lagg boundary (e.g. vegetation height), and others at finding the lagg-mineral land boundary (e.g. topography). In contrast, the similarity analysis gave more decisive influence to the topographic wetness index. When the lagg was confined between the bog and the adjacent upland, it took a linear form, parallel to the peatland’s edge. However, when the adjacent mineral land was flat or even sloping away, the lagg spatial distribution was discontinuous and intermittent around the bog. Our results confirms that laggs can take many forms, while suggesting two broad geomorphological categories from which they can more easily be studied and understood and highlight the potential offered by LiDAR technology in predicting their likely location around a raised bog. The results and conclusion from this research further our understanding of the goals to be achieved for ecological restoration, and favor sustainable management inclusive of the margins or bog peatlands.

Burns Bog covers approximately 3,000 hectares between the Fraser River and Boundary Bay in Delta, BC. An ecologically unique ecosystem, its hydrology and ecology have been widely disturbed. Hydrology strongly shapes the character and distribution of vegetation and Sphagnum growth. This study investigated measures of hydrology, including water table residence times and cumulative moisture deficits, to quantify intuitive relationships between moisture stress and ecological zones. Regression analysis of quantitative field observations reveal statistically significant relationships between cumulative moisture deficits and several key bog plant species and Lodgepole pine (Pinus contorta) diameter at breast height, signifying that these relationships can be used to predict the potential for vegetation recovery. Sphagnum height measurements reveal the unexpected observation that most growth occurs during the cool moist winter and early spring. This study contributes to the hydrological management of Burns Bog and will help to guide the location and mechanisms of restoration efforts.

Northern peatlands are an important component of the global carbon (C) cycle and have been a net sink of atmospheric C during the Holocene. Under current climate warming conditions, the future sink-source balance of these peatlands is uncertain. In particular, peatlands near the southern limit of permafrost are likely to be sensitive to changes in topography as well as climate. In order to predict how the sink-source balance may change, this thesis focuses on determining the generality of observed patterns of C accumulation in Northeastern Canada. The methodological approach in this thesis is unique. A total of 30 cores were taken from 9 peatlands located in 3 ecoclimatic regions along the North Shore of the Gulf of St Lawrence. This replication of records allows for climate-scale (allogenic) signals to be separated from the internal or local factors (autogenic), and for statistical testing of differences between regions and within sites over time. Trends in carbon accumulation rates (CAR) were analysed on three levels: (1) within individual sites along a hydrological or microtopography gradient, (2) between overall regions located along a climatic or permafrost gradient, and (3) over time on a multi-centennial scale. Lead-210 (210Pb) dating was used throughout the analysis to increase temporal resolution for the last 150-200 years of C accumulation. The method was thoroughly tested from preparation to analysis and found to produce reliable results, comparable with other dating methods. These dates were then used to develop combined age-depth models for longer-term context. Replicated records of 210Pb inventories and fallout rates were also used to address questions of deposition patterns and post-depositional mobility in peat profiles. Total inventories decreased with water table depth, with lichen hummocks having significantly higher inventories. One site also received significantly higher 210Pb deposition than the other two, as it is more sheltered from the Gulf influence. Recent carbon accumulation rates for the 150-year period for all microforms across all regions was 62.1 ± 4.4 g C m-2 a-1, and were highest for Sphagnum hummocks (79.9 ± 8.9 g C m-2 a-1) and lowest for dry lichen hummocks (42.7 ± 6.2 g C m-2 a-1). Patterns and trends at this scale were mainly driven by autogenic processes, including incomplete decomposition in the acrotelm peat. Models of peat accumulation related to acrotelm thickness were found to be overly simplistic, as carbon accumulation for intermediate microforms showed large natural variability driven by changing ecohydrological feedbacks, in part due to permafrost degradation at one of the sites. Over a multi-centennial scale, carbon accumulation rates were driven by a combination of climatic changes and ecohydrological feedbacks due to shifts in the microform configuration in response to permafrost degradation. Changes in carbon accumulation rates were detected and coincided with Little Ice Age temperature/solar minima (including the Spörer, Maunder and Dalton Minima), permafrost degradation since the 1950s, and recent climatic changes in the mid-1990s. Snow cover and exposure of sites and microforms were found to play an important role, rather than solely climatic variables. Rapid Sphagnum re-establishment in post-permafrost degraded features and increasing temperatures meant that carbon accumulation was highest for the northernmost site in the transect. Age-depth models using a combination of lead-210 and radiocarbon dates allowed for the calculation of carbon accumulation rates at a decadal resolution. While peat carbon sequestration is projected to increase in northern regions, the fate of peatland C near the southern limit of permafrost is complex. Future studies seeking to interpret recent changes should include multiple cores and consider both regional climatic and local ecohydrological drivers.

Spontaneous vegetation succession in mined peatlands in the Czech Republic was studied using the space-for-time substitution approach. The study focused on the variability of vegetation in traditionally mined (block-cut) and industrially mined (milled) peatlands. The influences of age, abiotic site factors, as well as landscape factors were analysed. The thesis summarizes also the state of current knowledge on various groups of organisms (plant, algae, fungi, and animals) in the extracted peatlands in the Czech Republic. The recomendations for the ecological restoration of mined peatlands are given.