Phenol oxidases mediate the degradation of recalcitrant compounds, polyphenolics, in wetland soils and are considered to play a key role in the microbial carbon cycle of peatlands which predominate in boreal biomes. In order to validate a method for quantification of oxidative enzyme activity in acidic wetland environments, the relationship between pH and substrate oxidation was studied using the standard enzyme tyrosinase and in soils collected from six freshwater wetlands including three marshes in north Florida and peatlands of northern Minnesota. Phenol oxidase (PO) activity was quantified with two commonly used assay substrates, ABTS (2,2'-azino-bis(3-ethylobenzthiazoline-6-sulfonic acid) and L-DOPA (L-3,4-dihydroxyphenylalanine), across a pH range of 4 to 7 which matched the in situ pH range of the studied wetlands. The PO assay is sensitive and activity could be detected with either substrate across a pH range of 4 to 7. However, with the standard enzyme tyrosinase, it was shown that a large change or threshold in oxidation rates occurred at pH 5. At pH < 5, L-DOPA oxidation rates were greatly diminished and ABTS oxidation was at a maximum. Above pH 5, ABTS oxidation occurred at much slower rates and L-DOPA oxidation was at a maximum. The pH response of PO activity in wetland soils corroborated observations made with tyrosinase. Thus, ABTS is recommended to be an effective substrate for the quantification of PO activity at an in situ pH of < 5, while L-DOPA is recommended at an in situ pH of > 5. In soils collected from a northern Minnesota peatland, assays conducted at an in situ pH of 4 showed one to two orders of magnitude higher rates of PO activity in solid phase peat in comparison to porewater, indicating that the majority of PO activity is associated with the peat. At three Minnesota peatland sites, PO activity was shown to attenuate with depth in agreement with the activities of other enzymes and with rates of peat decomposition.

Bogs and fens, which comprise > 90% of the landscape near the De Beers Victor diamond mine, 90 km west of Attawapiskat, ON, provide different hydrological functions in connecting water flow pathways to the regional drainage network. It is essential to define their distribution, area and arrangement to understand the impact of mine dewatering, which is expected to increase groundwater recharge. Classification was achieved by developing a technique that uses IKONOS satellite imagery coupled with LiDAR-derived DEM derivatives to identify peatland classes. A supervised maximum likelihood classification was performed on the 1 m resolution IKONOS Red/Green/Blue without the infrared (RGB) and with the infrared (IR_RGB) band to determine the overall accuracy prior to inclusion of the DEM derivatives. Confusion matrices indicated 62.9% and 65.8% overall accuracy for the RGB and IR_RGB, respectively. Terrain derivatives were computed from the DEM including slope, vertical distance to channel network (VDCN), deviation from mean elevation (DME), percentile (PER) and difference from mean elevation (DiME). These derivatives were computed at a local (15-cell grid size) and meso (250-cell grid size) scale to capture terrain morphology. The mesoscale 250-cell grid analysis produced the most accurate classifications for all derivatives. However, spectral confusion still occurred (regardless of scale) most frequently in the Fen Dense Conifer vs. Bog Dense Conifer classes and also in the Bog Lichen vs. Bog Lichen Conifer. Despite this confusion, by combining the larger scale LiDAR DEM derivatives and the IKONOS imagery it was found that the overall classification accuracy could be improved by 13%. Specifically, the DiME derivative combined with the multispectral IKONOS (IR_RGB) produced an overall accuracy of 76.5%, and increased to 83.7% when Bog Lichen and Bog Lichen Conifer were combined during a post hoc analysis. This classification revealed the landscape composition of the North Granny Creek subwatershed, which is divided into north and south. The north portion comprises 67.4% bog, 13.6% fen and 18.9% water class, while the south is 63.7% bog, 15.2% fen and 21.1% water class. These proportions provide insight into the hydrology of the landscape and are indicative of the storage and conveyance properties of the subwatershed based on the percentage of bog, fen, or open water.

Thesis (M.S.)--Villanova University, 2008. / Biology Dept. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Stevens Point, 2008. / Includes bibliographical references.

No description available.

Peatlands cover 3% of the earth's surface, with approximately 110 to 130 million hectares in Canada and are important in terms of the long-term sequestration of atmospheric carbon. In contrast to their removal of CO2 from the atmosphere, peatlands represent 15 to 30% of the total methane emissions to the atmosphere with Canadian wetlands emitting approximately 0.1 to 1 x 1010 g yr^-1. Drainage and harvesting of peatlands generally reduces CH4 emissions to the atmosphere and increases CO2 emissions by up to 400%. However, recent studies have suggested that drained peatlands may represent a larger source of atmospheric CH4 than undisturbed peatlands. In the first part of this study, potential CH4 production and oxidation was determined from natural, harvested and recently restored peat. Total depth integrated CH4 production decreased with time post harvest where CH4 production at 2-yr > 7-yr > 20-yr cutover peat. This decrease in CH4 production was a result of a decreased source of labile carbon, a decrease in the methanogenic population, and an increase in the concentration of alternative electron acceptors. Restoration has altered CH4 production processes so that total depth integrated CH4 production was 2-yr > 7-yr >RESTORED> 20-yr cutover peat. Depth dependent trends in potential CH4 oxidation and production from each peat were dependent on the water table position while substrate quality was the main difference production values between the Lac St. Jean and Bois-des-Bel peat. Comparison of CH4 fluxes over the four field seasons showed restored site bare peat and mosses did not play a significant role in CH4 emissions from the peatland. However, the overall CH4 function of the peatland was directly related to the increase in CH4 emissions from vascular vegetation, remnant ditches and newly constructed ponds which were directly attributed to an increase in labile carbon for methanogenesis provided by vegetation. CH4 fluxes from ditches and ponds suggest that these features are the largest sources of CH4 from the peatland. However, when weighting the fluxes to the areal extent of each feature, ditches become secondary to vascular vegetation in total CH4 emissions while the ponds had a minimal impact on the amount of CH4 emitted from the peatland. Furthermore, ebullition from ditches and ponds was insignificant in comparison to the diffusive fluxes. When comparing CH4 emissions from this site to natural peatland systems (~10 g CH4 m^-2 a^-1), it is evident that the site is still a much smaller source of CH4 and that the carbon and CH4 process are still changing as the pool of labile carbon increases (develops). Vegetation succession is still occurring and more time and monitoring is needed in order to determine if this site will return to similar CH4 functions as natural peatlands. / Thesis / Master of Science (MSc)

Peatlands are unique and important landscape systems, providing valuable ecosystem services such as water and carbon storage, water supply and flood attenuation. They are known to account for more than 10% of the world’s terrestrial carbon store and represent 50 – 70% of the global wetland resource. The UK government’s decision to support the IUCN, UK Peatland Program Commission of Inquiry on Peatlands, recognises the importance and urgency with which action is needed to understand and restore damaged peatland landscapes, and their associated ecosystem services. To meet this need, it is recognised that peatlands in the South West of the UK are important as bio-climatically and functionally marginal peatlands that are undergoing extensive restoration to reinstate key ecological and hydrological function. This thesis aims to improve understanding of the temporal and spatial variability of the ecohydrological structure and function of peatland ecosystems in the South West UK, and will provide the first baseline for the spatially distributed extrapolation of change across larger landscape extents. The research seeks to characterise the structure and function of peatland ecohydrology across multiple spatial and temporal scales. This is accomplished by bringing together remote sensing analyses of ecohydrological structure and function coupled with an integrated and high resolution hydrological monitoring system to characterise the spatial and temporal variability of runoff production and water storage across two headwater catchments. Key outcomes of this research are: 1. The development of novel methods to assess the spatial distribution of near surface hydrology in upland ecosystems using airborne thermal imaging data, 2. Improved understanding of how laser altimetry data can be used to measure the ecohydrology of landscapes more appropriately. 3. An empirical understanding of both the spatial and temporal variability of hydrology across representative sites within the moorlands of the South West UK. The high-resolution monitoring data are the first to describe the hydrological processes operating in these peatlands systems effectively, and provide an insight into how these processes are controlled by the anthropogenic drainage networks that are present throughout this shallow marginal peatland system.

The restoration of drained afforested blanket bogs is a cost-effective management approach in peatland conservation that aims to restore key ecosystem functions such as biodiversity and carbon storage and sequestration. Although arthropods are one of the most abundant and widespread animal groups in peatlands, little research has been carried out to assess their response to the variety of restoration management techniques that have been applied in afforested blanket bogs. We assessed the effectiveness of restoration by investigating the restoration trajectory of arthropod assemblages in formerly afforested blanket bog. We first looked at the long-term trajectory of arthropod assemblages, as well as carabid and moth taxa, in a chronosequence of tree-felled/drain-blocked treatments. Then, we looked at the short-term response of arthropod and carabid assemblages in treatments under varying regimes of brash management. General arthropod assemblages, and the functional traits of carabids and moths, were used to further investigate what type of biotic and abiotic parameters might be of importance during restoration. Lastly, we looked at potential biondicators of restoration progress to be used in restoration monitoring. The long-term restoration trajectory showed that typical bog assemblages are yet to be achieved due to persistence of generalists, as well as absence of bog specialists. Divergence in assembly trajectory was found at 18 years since onset of restoration, suggesting the emergence of an alternative state. Short-term restoration shows that brash might act as temporary habitat at early stages, where carabids favour lower structurally complex habitats than arthropods. Broad patterns of moth distribution revealed trait syndromes associated with blanket bog, whilst abiotic components such as vegetation structure, temperature, plot perimeter and blanket bog connectivity were found to be key for arthropod assemblages. The latter suggests potential legacy and edge effects associated with the restoration process. Arthropods and carabids showed high habitat specificity and fidelity, providing high bioindicator potential for restoration progress. This thesis shows that typical bog arthropod assemblages largely rely on habitat microstructure, particularly Sphagnum mosses, and associated microclimates for survival. Management can provide temporary refuge for arthropods, but the re-establishment of peat-forming vegetation and water table depth is essential for the return of typical bog assemblages. Though trade-offs might be encountered in the long-term restoration of peatland functions, a restoration framework is provided for the monitoring of arthropod assemblages.

Vacuum harvested peatlands typically do not spontaneously regenerate peatland species and more importantly the peat-forming Sphagnum mosses. Thus harvested and abandoned peatlands require restoration to return the peat-forming Sphagnum moss to the ecosystem. Restoration can create a hydrological environment that is suitable for peatland species’ regeneration and results in substantial Sphagnum moss growth. Bois-des-Bel was restored in the winter of 1999 and studied in the following three years (2000-2002), then again after 10 years (this study). Immediately following restoration the conditions were deemed favourable for Sphagnum regeneration (i.e. soil water pressures and water tables, > -100 cm and -40 cm respectively) (~ 15-20 cm in 10 years), while evaporation from the surface was reduced due to the straw mulch that was applied as part of the restoration measures. Although the hydrological conditions were suitable for peat revegetation, Bois-des-Bel was still a net exporter of carbon during first three years. The purpose of this thesis is to understand the hydrological evolution of Bois-des-Bel since the initial assessments and document the hydrophysical properties that could limit net carbon sequestration. This is done with a combination of field and laboratory (monolith) experiments through comparison of its hydrology and hydraulic parameters to that of a natural reference site. Since the initial assessment a water table rise of ~ 5-10 cm has occurred at the Restored site with an average water table of -27.3 (± 14.9) with respect to the cutover peat (pre-restoration surface) and ~ -42.3 (± 20.9) cm with respect to the regenerated Sphagnum surface. This water table is still much further from the capitula and more variable than at the Natural site (33.2 ± 9.0 cm). Both evapotranspiration (242 mm) and runoff (7 mm) from the Restored site maintained the same relationships in 2010 as during the initial assessments, compared to the Unrestored site (290mm and 37 mm, respectively). Although lower evapotranspiration equated to less water lost from the system, evapotranspiration at the Restored site was not indicative of the Natural site (329 mm), chiefly due to limited surface Sphagnum moisture at the Restored site. After ten years following restoration, the large scale hydrological processes are still controlled by the cutover peat and not the regenerated Sphagnum moss; thus the Restored site is still divergent from the Natural site. Wells paired with the soil moisture measurements resulted in average water tables of -53.7 ± 17.8 cm at the Restored site and -31.9 ± 8.3 cm at the Natural site. In addition to much lower water tables, the upper layers of regenerated Sphagnum (θ2.5 cm – 0.12 and θ7.5 cm – 0.11) on average were far drier than the same species at the Natural site (θ2.5 cm – 0.23 and θ7.5 cm – 0.32) under only Sphagnum. Furthermore the Restored site was very dry just above the cutover peat (θ17.5 cm – 0.19), compared to the same probe depth at the Natural site (0.57). At the Natural site under ericaceous and Sphagnum the soil moisture contents were generally double that of the Sphagnum-only site. In addition to poor soil water retention at the Restored site, high specific yield was observed in the Restored site (0.44) monoliths while the water table fluctuated within the Sphagnum compared to both the Natural (0.10) and Unrestored (0.05) monoliths. These retention characteristics at the Restored site are due to far lower fraction of water filled pores for a given pore diameter than the same species (S. rubellum) at the Natural site. The high abundance of large pores do not generate the necessary capillary force to draw water from the relatively wet cutover peat into the Sphagnum moss, resulting in a capillary barrier. Although after ten years the Restored section of Bois-des-Bel had somewhat representative bog peatland ecology, the hydrological conditions needed for net carbon sequestration were not present. The lack of water transmission from the cutover peat to the regenerated Sphagnum moss due to large pores and the inability of the Sphagnum moss to retain water are both retarding the restoration. For Bois-des-Bel to become a net carbon sequestering further lateral infilling of the Sphagnum leaves and branches along with decomposition of the basal layer will be need. In addition to these two processes, planting of ericaceous shrubs could lower the water loss through evaporation, thus increasing the capitula moisture content and creating healthier mosses. If Bois-des-Bel continues on its current ecohydrological trajectory it is likely that it will self-regulate and make the necessary structural changes to become a net carbon sequestering system.

Vacuum harvested peatlands typically do not spontaneously regenerate peatland species and more importantly the peat-forming Sphagnum mosses. Thus harvested and abandoned peatlands require restoration to return the peat-forming Sphagnum moss to the ecosystem. Restoration can create a hydrological environment that is suitable for peatland species’ regeneration and results in substantial Sphagnum moss growth. Bois-des-Bel was restored in the winter of 1999 and studied in the following three years (2000-2002), then again after 10 years (this study). Immediately following restoration the conditions were deemed favourable for Sphagnum regeneration (i.e. soil water pressures and water tables, > -100 cm and -40 cm respectively) (~ 15-20 cm in 10 years), while evaporation from the surface was reduced due to the straw mulch that was applied as part of the restoration measures. Although the hydrological conditions were suitable for peat revegetation, Bois-des-Bel was still a net exporter of carbon during first three years. The purpose of this thesis is to understand the hydrological evolution of Bois-des-Bel since the initial assessments and document the hydrophysical properties that could limit net carbon sequestration. This is done with a combination of field and laboratory (monolith) experiments through comparison of its hydrology and hydraulic parameters to that of a natural reference site. Since the initial assessment a water table rise of ~ 5-10 cm has occurred at the Restored site with an average water table of -27.3 (± 14.9) with respect to the cutover peat (pre-restoration surface) and ~ -42.3 (± 20.9) cm with respect to the regenerated Sphagnum surface. This water table is still much further from the capitula and more variable than at the Natural site (33.2 ± 9.0 cm). Both evapotranspiration (242 mm) and runoff (7 mm) from the Restored site maintained the same relationships in 2010 as during the initial assessments, compared to the Unrestored site (290mm and 37 mm, respectively). Although lower evapotranspiration equated to less water lost from the system, evapotranspiration at the Restored site was not indicative of the Natural site (329 mm), chiefly due to limited surface Sphagnum moisture at the Restored site. After ten years following restoration, the large scale hydrological processes are still controlled by the cutover peat and not the regenerated Sphagnum moss; thus the Restored site is still divergent from the Natural site. Wells paired with the soil moisture measurements resulted in average water tables of -53.7 ± 17.8 cm at the Restored site and -31.9 ± 8.3 cm at the Natural site. In addition to much lower water tables, the upper layers of regenerated Sphagnum (θ2.5 cm – 0.12 and θ7.5 cm – 0.11) on average were far drier than the same species at the Natural site (θ2.5 cm – 0.23 and θ7.5 cm – 0.32) under only Sphagnum. Furthermore the Restored site was very dry just above the cutover peat (θ17.5 cm – 0.19), compared to the same probe depth at the Natural site (0.57). At the Natural site under ericaceous and Sphagnum the soil moisture contents were generally double that of the Sphagnum-only site. In addition to poor soil water retention at the Restored site, high specific yield was observed in the Restored site (0.44) monoliths while the water table fluctuated within the Sphagnum compared to both the Natural (0.10) and Unrestored (0.05) monoliths. These retention characteristics at the Restored site are due to far lower fraction of water filled pores for a given pore diameter than the same species (S. rubellum) at the Natural site. The high abundance of large pores do not generate the necessary capillary force to draw water from the relatively wet cutover peat into the Sphagnum moss, resulting in a capillary barrier. Although after ten years the Restored section of Bois-des-Bel had somewhat representative bog peatland ecology, the hydrological conditions needed for net carbon sequestration were not present. The lack of water transmission from the cutover peat to the regenerated Sphagnum moss due to large pores and the inability of the Sphagnum moss to retain water are both retarding the restoration. For Bois-des-Bel to become a net carbon sequestering further lateral infilling of the Sphagnum leaves and branches along with decomposition of the basal layer will be need. In addition to these two processes, planting of ericaceous shrubs could lower the water loss through evaporation, thus increasing the capitula moisture content and creating healthier mosses. If Bois-des-Bel continues on its current ecohydrological trajectory it is likely that it will self-regulate and make the necessary structural changes to become a net carbon sequestering system.