Thesis (Ph.D.)--University of Waikato, 2006. / Includes bibliographical references (p. [75]-85) Also available via the World Wide Web.

The aim of this thesis was to determine limitation of methanogenesis in restored peatlands and effect of different substrates on potential methane production in restored bog and spruce swamp forest soil. Study sites were located in Šumava National Park in the Czech Republic.

The effect of drainage and restoration on the ecology of different types of peatlands in the Šumava Mountains was investigated. The study was focused primarily on peat properties, vegetation dynamics, carbon gas fluxes and their linkages under the affected hydrological regimes.

Holding approximately 89,000 Tg of organic carbon, tropical peatlands are one of the largest pedological sinks of carbon (Page et al., 2011). Waterlogged conditions in undisturbed peatlands reduce heterotrophic respiration and provide environments in which organic matter accumulates (Moore et al., 2013). However, from 1990 to 2010, the forest cover in the peatlands of South East Asia fell from 77% to 36%; at this rate of decline, all of the undisturbed peatlands are likely to have disappeared by 2030 (Li et al., 2007; Koh et al., 2011; Miettinen et al., 2011). Land-use changes in these ecosystems can have important consequences for carbon (C) budgets (Page et al., 2002; Hooijer et al., 2010). Recently a number of studies have been carried out on tropical peatlands (e.g. Couwenberg et al., 2010; Hergoualc'h and Verchot, 2011; Hirano et al., 2012; Jauhiainen et al., 2005, 2012; Li et al., 2007; Melling et al., 2005; Page et al., 2009), but some parts of the C budget are yet to be quantified. In order to fill these gaps in our knowledge, the goal of this work was to assess heterotrophic and total soil respiration, litterfall, litter decomposition and evaluate peat properties in an intact peat swamp forest, a transitional logged drained forest and an oil palm plantation located on the same alluvial peat plain. This in-situ research lasted two years, and heterotrophic and total soil respiration were separated using the trenching method. Our results from the carbon dioxide flux monitoring in the three land uses showed that the trenched plots provided a good proxy for heterotrophic respiration. The annual integrated total soil respiration was lower in the intact and drained forest than in the oil palm plantation, at 20.2 ±3.4, 18.7 ±1.1 and 26.4 ±1.7 Mg C ha-1 y-1, respectively. A similar pattern was seen in the heterotrophic respiration for the same land uses, 9.6 ±7.7, 15.7 ±1.0 and 22.9 ±2.0 Mg C ha-1 y-1, respectively. When extrapolated to the landscape, the percentage of heterotrophic 4 respiration appeared to have significantly increased following drainage, even before the conversion to oil palm, with percentages of 47.6 ±10.1, 83.9 ±7.3, 86.6 ±1.9 for intact forest, drained forest and oil palm plantation, respectively. The average litterfall in the three land uses was not significantly different, at 26.3 ±4.1, 23.2 ±4.2 and 18.6 ±3.5 kg dry litter ha-1 d-1 respectively. Overall, the C fluxes results produced in this thesis point towards a negative C balance (i.e. net ecosystem loss of C) for the drained forest, a pronounced negative C balance for the oil palm plantation and a near neutral balance for the intact forest. Other relevant findings in the study were: (1) the impacts of N fertilizer application in the oil palm plantation lasted only a few days and were unlikely to have significant consequences on the annual C budget; (2) concerns over the diurnal variability of carbon dioxide fluxes are not particularly pertinent in these tropical peatlands; and (3) the principal soil property affected by drainage and land-use change was the abundance of logs in the soil. In summary, the results produced in this thesis represent noteworthy data about the C budget and C dynamics in tropical peatlands and will help decision making by policy makers and land managers for sustainable use of these ecosystems.

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.

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This study examined the usefulness of remote sensing to monitor peatlands, and more specifically Sphagnum moss ‘health’. Results from this study show that thermal imaging can be used to monitor Sphagnum productivity, as when the surface temperature of Sphagnum exceeds a threshold value (30.8 °C in the field and 18.2 °C in the laboratory), Sphagnum quickly changes from being productive to being unproductive. The Enhanced Normalized Difference Vegetation Index (ENDVI) can also be used in a similar manner, where if the ENDVI value is high (above 0.11 in the field and -0.12 in the laboratory), Sphagnum will be productive, and otherwise, it will be stressed. A classification scheme was developed to monitor peatland recovery to fire disturbance. By utilizing the ENDVI, leaf area index and aboveground biomass within a recovering peatland can be mapped, as well as the recovery trajectory of the groundcover. The findings of this study highlight the potential use of remote sensing to assess the driving factors of Sphagnum moss stress, as well as quickly and expansively aid in peatland recovery trajectory. / Thesis / Master of Science (MSc)

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