Testate amoebae (Protozoa: Rhizopoda) are particularly abundant in peatlands. Previous studies have used testate amoebae in palaeoenvironmental studies, but have used qualitative data only, so that results are expressed only in terms of 'wet', 'dry' or 'moist'. This study uses testate amoebae to derive quantitative reconstructions of mire surface wetness for part of the Holocene and is split into two parts. The first part of this study modelled the responses of individual testate amoebae species to environmental variables on ombrotrophic mires, since the peatland-climate link makes these habitats the one of the most useful in palaeoclimate reconstructions. 163 samples of modern testate amoebae faunas were obtained from 9 ombrotrophic mires across Britain. Environmental variables (mean annual water table, moisture content, dissolved organic carbon, pH, Ca2+ , Mg2+ , SO42- , Cl-, conductivity and host plant species) were measured. A hydrological monitoring programme on an ombrotrophic mire on Dartmoor provided a detailed record of hydrology and selected water chemistry over a year and identified the season most representative of mean annual environmental conditions. Weighted averaging regression applied to the faunas provided absolute moisture content and mean annual water table optima for 38 common testate amoebae species. In the second part of the study weighted averaging calibration was used to derive transfer functions from the modern species' optima. From these, mean annual water table and substrate moisture content were reconstructed for the top 100 cm of a selected fossil peat core from Bolton Fell Moss, Cumbria. These reconstructions were compared with those derived from plant macrofossil and peat humification analyses. Testate amoebae provided a further insight into the decline of Sphagnum imbricaturn, clarified noisy areas of the existing palaeohydrological record and suggested that hydrological changes at Bolton Fell Moss were likely to have been gradual, rather than the sudden event implied by the plant macrofossil record. This study demonstrates the future potential of testate amoebae as palaeohydrological indicators. Expansion of the modern data set in terms of species composition and geographical extent, further applications of testate amoebae into multi-proxy palaeohydrological reconstructions and taxonomic refinements are suggested to improve the technique further.

No description available.

No description available.

No description available.

Methane is a radiatively active, naturally occurring atmospheric trace gas which is thought to account for as much as 19% of the enhanced greenhouse effect. Ice core studies have shown that the atmospheric concentration has more than doubled since pre-industrial times. Wetlands are the largest natural source of atmospheric methane, contributing around 21 % of the annual global flux. The magnitude of various sources of methane is still poorly defined. Stable isotope measurements are increasingly being used to constrain global budgets of atmospheric trace gases because isotopic analysis provides a much clearer picture of global atmospheric chemistry than C~ concentration measurements alone. Conventional analytical techniques for studying dual stable isotopic composition of methane (813e and 8D) require prohibitively large quantities of CH4 for analysis. At the Planetary Sciences Research Institute of the Open University, a highly sensitive static mass spectrometer has been developed which uniquely uses CH4 as the analyte. The method requires only 8 ng ofCH4 for analysis «10 ml ambient air), making replicated measurements of the isotopic composition of CH4 emissions from wetlands feasible for the first time. Methane emissions from an ombrotrophic mire in Snowdonia have been measured over 2 years, (1995-1997) and analysed for 817M. Parallel laboratory studies have also been conducted, to constrain the effects of environmental variables such as peat temperature and water table depth. The presence of vascular plants enhanced methane flux. In the field, methane flux showed seasonal variation. Peat temperature and water table depth could account for 68% of this variation. The isotopic composition of methane flux from the ombrotrophic mire also exhibited seasonal variation, with 817M ranging from -34 to -17%0. The lowest values were observed in summer and the highest in winter. Variations in the isotopic composition of peat water are unlikely to account for more than a 2%0 shift in 817M. Although there was a strong correlation between peat temperature and methane isotopic composition in the field, peat temperature is thought to be an indirect effect, because in laboratory studies this relationship was absent. There was no relationship between water table depth and 817M. It was concluded that the seasonal variation in the isotopic composition of methane emission is linked to the plant growth cycle. Comparison of 817M values determined for methane emissions in Snowdonia with published 813C and 8D data leads to the conclusion that methane is produced mainly by C02 reduction. Contrasting terrains in a paisa mire in the Arctic region of Finland exhibited methane _ emissions with distinct 817M values: lakes, +4.8 ±1.2%0; pools, -3.9 ±O.IO/oo and hummocks, -28.6 ±5.8%0 . From these isotope data it was concluded that in pool and lake sediments the methanogenic pathway is acetate fermentation, while in hummocks methane is produced by CO2 reduction. This study is the first investigation of the stable isotopic composition of methane emissions from wetlands in the UK. The data collected in Snowdonia, and in Finland, show the need for systematic, year round isotopic analysis of methane emissions, if isotope data are to be used in constraining the global methane budget.

As a consequence to climate change and resulting severe weather events such as prolonged hot and dry periods, wildfire frequency increases globally. Progressively, these effects are noticeable in high latitude countries such as Sweden where a megafire burned 13 100 ha of managed coniferous forest in 2014. While the effect of fire on species communities has been much studied, species surveys often only collect data opportunistically after a wildfire, making inferences about the fire effect uncertain. In this study my aim was to examine the response of peatland dwelling beetles (Coleoptera) to fire by comparing beetle communities of burned drained Swedish peatlands and adjacent non-burned (reference) areas. The first beetle survey took place in 2009, the second was carried out in 2020, 6 years after the fire occurred. Both surveys used pitfall traps in a burned and un-burned area, which were divided into two types of mires, fen and bog, respectively. As a result of the post-fire recovery, dead wood accumulated in the burned area and shrubs and young trees replaced the original vegetation. The reference area did not show significant changes in vegetation. Over all 188 species were found in 2009 and 256 in 2020. In 2009 most species were found in the pre-fire area while in 2020 most species were found in the reference area. Further, two red-listed species (conservation category NT) were found in the fire area as well as two new species for Västmanland country. As expected, the fire had a large impact on the beetle community, where once dominant species declines and got replaced by more dispersive or more moisture striving species. In contrast to my expectations, not only the fire area showed notable changes in the beetle community regarding diversity and composition, also the reference area showed changes in species dominance and a high species turnover. Although the before-after-control-impact study design illustrates the independence of the fire impact to the changes in species composition over time, the results suggest that the time between the surveys (10 years) was the main factor for the community change.

Ce mémoire poursuit deux objectifs. Le premier objectif est d'examiner les liens entre les dispositions d'attachement et le fait d'accepter d'être mentor ou protégé dans un programme de mentorat formel en milieu scolaire. Le second objectif vise à vérifier si la qualité de la relation développée entre le mentor et le protégé est influencée par leurs dispositions d'attachement respectives. Les participants sont des étudiants collégiaux et universitaires sollicités pour participer au programme MIRES (Mentorat pour l'Intégration et la Réussite des Étudiants de Sciences). Les dispositions d'attachement ont été mesurées avant d'inviter les étudiants à participer au programme MIRES alors que la qualité de la relation de mentorat a été évaluée en deux temps, après deux mois et six mois d'intervention. Les résultats suggèrent que les dispositions d'attachement des étudiants universitaires influencent leur intérêt à devenir mentor. De plus, la qualité de la relation est évaluée moins positivement par les mentors anxieux et perçue plus positivement lorsque le protégé présente une sécurité d'attachement. Certains effets d'interaction des dispositions d'attachement ont également été notés. Les dyades sécurisant-sécurisant démontrent une plus grande satisfaction de la qualité de la relation que les autres dyades.

Zehn unerforschte und natürliche Moore entlang der Flüsse Baker und Pascua in der Region Aysén, im chilenischen Patagonien, wurde untersucht, um Informationen über ihre Entstehung, Hydrologie, Geomorphologie, Stratigraphie, Ökologie und Wasser- und Kohlenstoffspeichervermögen zu gewinnen. Es wurden acht verschiedene ökologische Moortypen identifiziert und fünf Moortypen unterscheidbar durch ihr geohydromorphologisches Setting mit insgesamt elf verschiedenen organischen Moorsubstraten. Die gesammelten Information erlauben erste Abschätzungen der Torf-, Süßwasser- und Kohlenstoffmengen, die in den Mooren Ayséns gespeichert sind, sowie der jährlichen Torfakkumulationsraten. Die Moortypen und die in ihnen vorkommenden organischen Substrate wurden in einem geohydromorphologischen Klassifizierungssystem zusammengefasst, welches wichtige hydrologische, geomorphologische, ökologische, bodenkundliche und landschaftliche Parameter integriert. Forschung und Kommunikation über die chilenischen Moore sollen durch diese Arbeit unterstützt werden, um angemessene Monitoring Tools und partizipative Naturschutzstrategien zu entwickeln, die für die Erhaltung dieser Ökosysteme und ihrer Kreisläufe anwendbar sind. / Ten unexplored and pristine mires along the Baker and Pascua River Basins in Aysén, Chilean Patagonia, were examined, generating information about their origin, hydrology, geomorphology, stratigraphy, ecology, and carbon and water storage capacities. Eight mire types ecologically differentiable, associated with five main mire types separable by their hydrology and geomorphology were detected, as well as eleven organic substrate types forming mire soils. The information gathered allows for a first estimation of the peat, fresh water and carbon content stored in the mires of Aysén, as well as for an average growth and annual accumulation rate of the peat. Mire types and their associated substrates are systematized in a hydrogeomorphic classification system, integrating important landscape, hydrological, geomorphical, ecological and pedological components. Research and communication about mires in the Chilean Patagonia should be further supported to generate accurate monitoring tools and participative conservation strategies that are replicable for the preservation of these ecosystems and its balance.

<p>Since the start of the industrialisation, the deposition of nitrogen and sulphur and the atmospheric concentrations of greenhouse gases have increased. The main objectives of this study were to find how these changes in climate and deposition can change the vegetation of mire ecosystems and the growth of <i>Sphagnum</i>species. Two main approaches were applied: re-investigated of two mires previously investigated 40-50 years ago and experiment manipulations. </p><p>The plant species diversity had decreased on one of the two re-investigated mires (Skattlösbergs Stormosse; central Sweden), but the total number of species was unchanged on the other (Åkhultmyren; southern Sweden). On Skattlösbergs Stormosse, an acidification was found in the high pH areas, coinciding with reduction in rich fen species. At Åkhultmyren, there was a similar reduction in pH, but the changes in the plant composition also indicated increased nutrient levels and a drier mire surface. Therwere large changes in species composition on Åkhultmyren. For instance <i>Scheuchzeria palustris</i> had disappeared from the investigated area. Further, the cover of Scots pine (<i>Pinusylvestris</i>) had increased, which can be explained by a changed ground-water table regime. Monitoring of pines growing on a bog over a ten-year period showed that pines growing higher above the ground-war table had higher survival than lower-growing pines.</p><p>Experimental addition of nitrogen during 3-4 years reduced <i>Sphagnum </i>growth in bogs and poor fens repressenting a wide range of ambient nitrogen deposition. A changed interspecific competitive relation was found between <i>S. lindberg</i>and <i>S. balticum</i> when increasing nitrogen influx, but the competitive relations between two hummock-growing species pairs did not change in a three-year nitrogen fertilization study. Sulphur additiodid not affect the production or length increment in <i>S. balticum</i>. An increased temperature reduced <i>Sphagnum </i>growth, but there were no indications of altered competitive relationshipbetween hummock and hollow inhabiting <i>Sphagnum </i>species in a four-year experiment.</p>

This thesis investigates the reclamation of mires (fens and bogs) in Sweden with a focus on the early modern period. Today, the mires are valued natural habitats and their cultivation is controversial. International research describes wetland reclamation and the related knowledge transfer between European countries already from the 12th century. In Sweden, despite some early records of reclamation of mires in the 17th century, has earlier research focused on reclamation during the 19th and 20th centuries. The aim of the thesis is to study the landscape, actors and driving forces behind the early reclamation (before 1800). Understanding the early reclamation can provide a new perspective on current views on wetlands. It is also an interesting example of how the landscape is changed constantly by people with different goals through history. The subject is studied through a multimethod approach using sources such as historical maps, diaries, 17th- and 18th-century literature and place names. The main conclusions of the study are that reclamation of mires is seen already in 17th-century maps, with local wider distribution during the 18th century. The crown and scientists expressed a growing interest in reclamation of the mires from the early 18th century. Links to Europe, in particular Holland, can be seen within this discourse. In both literature and the experimentation that took place, the Swedish migrant group, the Dalecarlians, played a key role. They shared with the early Dutch groups the practical knowledge needed in major reclamation projects. Furthermore, this study shows that a number of actors assumed at various times the role of mobile innovation spreaders. Dutch farmers and experts, labour migrants, landlords and scientists all acted to spread knowledge of mire reclamation. Ample resources, networking and geographical mobility appear to have been prerequisites for all actors, from peasants to landlords, but they had different underlying motives for the practice.