As wildfires increase in frequency, severity, and areal extent in western Canada’s boreal region, wildfire managers are challenged with maintaining current levels of effectiveness. Review of recent wildfire events have identified a need for an improved understanding of vegetation management as a means to mitigate risk of future fires in the wildland-urban and wildland- industry interfaces. Peatlands cover 21% of the land area in continental western Canada; however, there is a lack of peatland-specific fuel modification strategies. The unique ecohydrological feedbacks that operate in these ecosystems provide an opportunity to implement novel peatland-specific treatments in these areas. This thesis examines the effectiveness of novel peatland-specific fuel modification treatments derived from seismic line analogs in reducing the smouldering potential of near-surface moss and peat. An ecohydrological assessment of seismic lines bisecting bogs revealed that alterations to canopy structure and physical peat properties at the time of seismic line establishment leads to persistent changes to the ecohydrological structure and functioning of these systems, marked by limited regeneration of vegetation, dominance of Sphagnum groundcover, and greater near-surface volumetric water contents. Such traits are desirable in fuel modification strategies and therefore, we incorporated the seismic line framework into conventional fuel reduction approaches to create novel peatland-specific fuel modification treatments, involving alterations to canopy structure (thinning and clearing) and physical peat properties (compression). The short-term effects are compression-induced changes to hydrophysical properties including elevated mean near-surface volumetric water contents. Ecological and hydrological indicators of moss moisture stress suggest long-term effects likely include an expansion of Sphagnum moss ground cover within thinned and cleared areas. Ultimately, both short- and long-term effects contribute to the reduction of smouldering potential in near-surface moss and peat. We propose that these peatland-specific fuel modification treatments be incorporated into current FireSmart fuel strategies to reduce wildfire smouldering risk at the wildland-urban and wildland-industry interfaces. / Thesis / Master of Science (MSc)

The eastern massasauga rattlesnake, or massasauga, is threatened in Ontario. Massasaugas overwinter in habitat that is sufficiently moist, above the water table, and below the zero-degree isotherm in a physical space conceptualized as a resilience zone. A development project in the Eastern Georgian Bay subpopulation of massasaugas overwintering habitat necessitated restoration. The Toronto Zoo hibernacula design was deemed inappropriate for use in this bedrock dominated landscape, as the limited deep groundwater percolation would result in flooding of the habitat from the fall to spring. Massasaugas in EGB, overwinter above the water table in Sphagnum peat hummocks. The ecohydrological factors of these hummocks in confirmed massasauga habitat were evaluated in a mixed effect linear model. It was found that taller hummocks, taller shrubs, and less WT variability were the best predictor of suitable conditions. This information was combined into a restoration method that moves surficial peat material from a soon to be impacted wetlands to an adjacent depression with mean depths of 40-80 cm, with mean bottom substrates 15-30 cm, and varying proportions of open water and floating peat with different vegetation communities. This design limits water table variability and allows for the growth of tall shrubs. Unforeseen circumstances meant that peat to be used in the project had to be stockpiled, which increased peat bulk density and limited photosynthesis. Despite this, restored habitat had similar mean lengths of unsuitable conditions compared to confirmed massasauga wetland habitat. The physical size of available overwintering habitat, as well as the total duration of unsuitable conditions, was not significantly different between restored wetlands, unconfirmed wetlands, and confirmed wetlands. Amendments to increase the cover of live Sphagnum moss will likely increase the duration and size of suitable conditions in the restored wetlands. Based on this success with degraded materials this new method of restoration design shows great promise in this region. / Thesis / Master of Science (MSc)

Darbo tikslas - įvertinti teršalų poveikį sėjamajai pipirnei (Lepidium sativum L.), augintai ant magelaninio kimino (Sphagnum magellanicum), pasyviai kaupusio gamyklų oro teršalus, terpės. Darbo metodika. Kiminų maišeliai buvo eksponuojami 5 savaites prie Lietuvos svarbiausių ir daugiausiai teršalų į aplinką išmetančių gamyklų – AB “Achema”, AB „Akmenės cementas“ ir AB „Mažeikių nafta“. Po ekspozicijos kiminai laboratorijoje buvo išdžiovinti +20º C ir sumalti. Iš sumaltų kiminų Petri lėkštelėse, įpylus po vienodą kiekį kiminų ir distiliuoto vandens buvo paruoštas biotestinio augalo – sėjamosios pipirnės - auginimui substratas. Į kiekvieną lėkštėlę buvo pasėta po 25 sėjamosios pipirnės sėklas. Lėkštelės antrą augimo parą buvo atidengtos, pipirnė buvo auginama 4 paras, 5 parą buvo atlikti sėjamosios pipirnės daigų morfometriniai matavimai. Tyrimo rezultatai. Lyginti atskirų transektų skirtingos vietos, mažiausi sėjamosios pipirnės daigeliai užaugo prie AB „Achema“ eksponuotuose kiminuose: viso augalo aukštis – 27,9 mm, stiebo aukštis – 20,0 mm, šaknies ilgis – 7,9 mm. Prie AB „Mažeikių nafta“ eksponuotų kiminų substrate išaugo šiek tiek aukštesni daigeliai, kurių atitinkami ilgiai (33,3 mm, 24,2 mm ir 8,1mm). Aukščiausi augalai (visas augalas – 39,9 mm, stiebas – 29,8 mm, šaknis – 10,1mm) išaugo prie AB „Akmenės cementas“ eksponuotuose kiminų substratuose. / Goal of the research: evaluate the influence of air pollution on cress (Lepidium sativum L.), that grows on sphagnum (Sphagnum magellanicum). Sphagnum (Sphagnum magellanicum) passively store pollutants extracted from factories. Methodology of the research: The bags of sphagnum were displayed near the most important and biggest Lithuanian factories (JS ‘Achema’, JS ‘Akmenes cementas’ and JS ‘Mazeikiu nafta’) for five weeks. Sphagnum were collected, dried at 20 º C temperature, and grinded in the laboratory. Grinded sphagnum were placed in the Petri dishes in equal parts with distil water and was prepared substratum for biological test. In each dish there were planted 25 seeds of cress. After two days the dishes were opened. The morthometric tests were made on five day after planting. Results. During the test different parts of cress were measured. The smallest sprouts of cress were measured in the area of JS ‘Achema’. The height of plants were – 27,9 mm, length of stems – 20,0 mm, length of roots – 7.9 mm. In the area of JS ‘Mazeikiu nafta’ area displayed sphagnum substratum cress plants were a little bit higher, appropriate the height of plants were - 33.3 mm, length of stems – 24,2 mm and length of roots – 8,1 mm. The highest cress plants were measured in the sphagnum substratum exposed in the areas of JS ‘Akmenes cementas’. The heights of plants were – 39,9 mm, length of stems – 29.8 mm, length of roots – 10,1 mm.

Human alteration of the global nitrogen (N) cycle has had major impacts on naturally N-limited ecosystems worldwide. Peatlands, dominated by peat mosses, Sphagnum species, represent one such sensitive ecosystem. I have studied how this ecosystem is affected by increased N availability, using a small-scale N fertilization experiment in combination with a gradient study of three peatlands with varying N deposition. I found both in the experiment and in the gradient a similar pattern of Sphagnum decline accompanied by an increase of vascular plants associated with enhanced N supply. For one common Sphagnum species - both in the experiment and in the gradient study - I also found an identical, linear increase in soluble amino acid N (NAA) accumulation. As soluble amino acids function as N storage compounds among Sphagna, NAA is a suitable measure for Sphagnum N status, and indicates accumulation of excess N not used for growth. My results show that NAA can be used as a sensitive indicator to signal N pollution before the slow, and gradual, regime shift from Sphagnum to vascular plant dominance is visible. In an N-uptake experiment using Sphagnum specimens from the three peatlands varying in N deposition, I found a reduced N-uptake by both investigated Sphagnum species from a high N deposition site, in south-western Sweden. This potential of Sphagna to adjust to high N loads through N uptake regulation will, however, not prevent tissue N accumulation, and as a result a shift from Sphagnum to vascular plant dominance. In general I found similar patterns of N induced changes both in Sphagnum tissue chemistry and vegetation structure in the experiment and along the gradient study. Thus, I conclude that long-term, small-scale field experiments seem to offer reliable estimates of both the direction and strength of key vegetation responses in Sphagnum dominated peatlands. This is likely related to the key role of Sphagna as ecosystem engineers. In the experiment I found a marked time lag in vegetation response to N application treatments. The closed Sphagnum carpet did not collapse until after eight years of continuous treatments. Another result was that dwarf shrubs, e.g. cranberry Vaccinium oxycoccos, first increased, but later declined due to severe attacks by fungal diseases. One important conclusion is that long-term, manipulative field experiments are necessary for our ability to understand how ecosystems will respond to environmental change.

Eva Novozámská Dynamics of moss overgrowth in ditches in restorated drained mires in area of Modrava bogs (Šumava NP) Abstract This thesis is devoted to a research of induced and natural Sphagnum overgrowth in dammed ditches in restorated drained mires of Šumava National Park within the "Programme of Peatland restoration". Induced overgrowth was studied on the peatlands Cikánská slať, Luzenská slať and Novohuťské močály and 36 permanent experimental sites were established for its study. In 2006 Sphagnum fallax or Sphagnum majus were placed in each site in dependence on the type of locality. For four years increase or decrease of Sphagnum were monitored. The study of natural overgrowth was investigated on the same localities as induced overgrowth. The Sphagnum cover was noted in the year 2009 at 65 sites. The depth of the ditch and the flow of water were the most important variables influencing natural overgrowth and the cover was almost the same on all localities. In the case of induced overgrowth the most important parameters were depth and width of the ditch, amount of the branch support and the interaction of depth and width. The depth of the ditch in the case of natural overgrowth was used to generate a model for prediction of Sphagnum cover. It was possible to compare the induced overgrowth with the...

<p>Mires surface energy and water budgets govern the conditions for climatic, hydrological, ecological and carbon balance processes. The components of the water and surface energy budgets were quantified over two growing seasons for an open boreal mire. The measurements of fluxes were complemented with data on the spatial variation of water content and temperature in different micro-relief elements (hummocks and hollows). Since measurements on mires are scarce, special investigations of aerodynamic properties were done as well as a calibration of TDR function for peat. The partitioning of available energy at the surface depended mainly on air temperature and relative humidity. There was a trend of falling Bowen ratio both during the day and during the season from May (monthly value 0.9) to September (0.6). The bulk surface resistance (<i>r</i>_s) to evapotranspiration was considerable and varied little (mean <i>r</i>_s = 160 s m^-1). The cause of its relatively large value could be found in a great aerodynamic resistance within the canopy layer, and the peat wetness variation influenced little. In the scale of the whole mire, the water storage were similar over the central, open areas. On a smaller scale, the presence of a pronounced micro-topography caused a variation of the surface wetness. This was also reflected in the spatial variation of soil temperatures. The heat storage in hummock was largely influenced by lateral heat fluxes. There were considerable effects of peat elasticity and approximately 40 % of the changes in water storage was caused by swelling/shrinking of the whole peat mound. This effect should be incorporated in future models of mire-water dynamics.</p>

Mires surface energy and water budgets govern the conditions for climatic, hydrological, ecological and carbon balance processes. The components of the water and surface energy budgets were quantified over two growing seasons for an open boreal mire. The measurements of fluxes were complemented with data on the spatial variation of water content and temperature in different micro-relief elements (hummocks and hollows). Since measurements on mires are scarce, special investigations of aerodynamic properties were done as well as a calibration of TDR function for peat. The partitioning of available energy at the surface depended mainly on air temperature and relative humidity. There was a trend of falling Bowen ratio both during the day and during the season from May (monthly value 0.9) to September (0.6). The bulk surface resistance (rs) to evapotranspiration was considerable and varied little (mean rs = 160 s m-1). The cause of its relatively large value could be found in a great aerodynamic resistance within the canopy layer, and the peat wetness variation influenced little. In the scale of the whole mire, the water storage were similar over the central, open areas. On a smaller scale, the presence of a pronounced micro-topography caused a variation of the surface wetness. This was also reflected in the spatial variation of soil temperatures. The heat storage in hummock was largely influenced by lateral heat fluxes. There were considerable effects of peat elasticity and approximately 40 % of the changes in water storage was caused by swelling/shrinking of the whole peat mound. This effect should be incorporated in future models of mire-water dynamics.

Peatlands are carbon sinks and occupy approximately 13% of Canada’s terrestrial surface of which 0.02% have been harvested for horticultural peat. The extraction of peat from natural peatlands alters the hydrology which affects the growth and survival of Sphagnum the primary peat forming vegetation. Ericaceous shrubs do not require specific water content and soil water pressure conditions for their existence and in cutover peatlands they occupy more than 70% of the surface. Rainfall interception, transpiration and root water uptake and redistribution are processes that alter water availability at the soil surface. The high abundance of shrubs at cutover peatlands will influence the surface water balance and more importantly soil water availability and, inevitably determine the success of Sphagnum reestablishment at the site. This study seeks to understand the role that ericaceous shrubs play in the surface hydrological balance at a cutover site and how these changes impact Sphagnum development. Rainfall interception, transpiration, litter layer evaporation and soil water flux was investigated in the field and lab. Approximately 334 mm of rainfall was measured over the season. The shrub canopy and litter had a maximum storage capacity of 4 and 1.2 mm respectively and intercepted ca. 36.7% (120 mm) of rainfall over the season. The effects of rainfall intensity and duration were more important than gross rainfall in determining the amount of water intercepted by the canopy, while the thickness and mass of the litter layer largely determined the storage capacity. Evapotranspiration from shrubs averaged 2.5 mm day-1 with a total of 211 mm over the season. Transpiration was 68% (142 mm) of total evapotranspiration losses, and represented the greatest water loss from the shrub canopy. From these analyses only 22% (72 mm) of rainfall is available for other soil processes and moss development. The evaporation under a litter cover is lower than bare peat and in the field represents water storage of 17 mm over the season. Reduced water input by litter interception is offset by the increased water storage under the litter. Laboratory analyses of soil water flux under ericaceous shrubs show that water loss under the shrubs was greater than bare peat. Water use under the shrubs was highest between -10 and -30 cm and was ca. 2 times greater than bare peat at the same levels. Volumetric water content (θ) decreased throughout the day and water use by shrubs during the day was twice that at night. The shrubs also maintained θ and soil water pressure (ψ) above the threshold values of 50% and -100 cm, respectively, needed for Sphagnum survival. Based on these analyses the shrubs will be beneficial to Sphagnum reestablishment and survival once the primary water losses have been compensated. I recommend raising the water table above -20 cm. In peatland restoration activities, at this level, water used between -10 and -30 cm can quickly be recharged and surface moisture maintained above threshold by capillary rise helping to offset water loss by interception and transpiration through capillary rise.

Peatlands are carbon sinks and occupy approximately 13% of Canada’s terrestrial surface of which 0.02% have been harvested for horticultural peat. The extraction of peat from natural peatlands alters the hydrology which affects the growth and survival of Sphagnum the primary peat forming vegetation. Ericaceous shrubs do not require specific water content and soil water pressure conditions for their existence and in cutover peatlands they occupy more than 70% of the surface. Rainfall interception, transpiration and root water uptake and redistribution are processes that alter water availability at the soil surface. The high abundance of shrubs at cutover peatlands will influence the surface water balance and more importantly soil water availability and, inevitably determine the success of Sphagnum reestablishment at the site. This study seeks to understand the role that ericaceous shrubs play in the surface hydrological balance at a cutover site and how these changes impact Sphagnum development. Rainfall interception, transpiration, litter layer evaporation and soil water flux was investigated in the field and lab. Approximately 334 mm of rainfall was measured over the season. The shrub canopy and litter had a maximum storage capacity of 4 and 1.2 mm respectively and intercepted ca. 36.7% (120 mm) of rainfall over the season. The effects of rainfall intensity and duration were more important than gross rainfall in determining the amount of water intercepted by the canopy, while the thickness and mass of the litter layer largely determined the storage capacity. Evapotranspiration from shrubs averaged 2.5 mm day-1 with a total of 211 mm over the season. Transpiration was 68% (142 mm) of total evapotranspiration losses, and represented the greatest water loss from the shrub canopy. From these analyses only 22% (72 mm) of rainfall is available for other soil processes and moss development. The evaporation under a litter cover is lower than bare peat and in the field represents water storage of 17 mm over the season. Reduced water input by litter interception is offset by the increased water storage under the litter. Laboratory analyses of soil water flux under ericaceous shrubs show that water loss under the shrubs was greater than bare peat. Water use under the shrubs was highest between -10 and -30 cm and was ca. 2 times greater than bare peat at the same levels. Volumetric water content (θ) decreased throughout the day and water use by shrubs during the day was twice that at night. The shrubs also maintained θ and soil water pressure (ψ) above the threshold values of 50% and -100 cm, respectively, needed for Sphagnum survival. Based on these analyses the shrubs will be beneficial to Sphagnum reestablishment and survival once the primary water losses have been compensated. I recommend raising the water table above -20 cm. In peatland restoration activities, at this level, water used between -10 and -30 cm can quickly be recharged and surface moisture maintained above threshold by capillary rise helping to offset water loss by interception and transpiration through capillary rise.

This thesis is an investigation of the effects of long-term drainage on plant community composition, biomass and productivity in boreal continental peatlands. Because bogs are ombrotrophic, I hypothesized that bog plant community composition, biomass and productivity would be affected by drainage less than fens. I identified six Alberta peatlands (2 bogs, 4 fens) that were affected by long-term drainage through road construction or drainage ditches. I found that understory species composition in fens changed more in response to drainage than in bogs, and was related to the degree of canopy closure. Woody biomass increased in all poor fens sites with drainage, while understory biomass was not affected. I investigated the influence of drainage on primary productivity in two sites, and found that tree and moss productivity responded differently. These results have implications for peatland carbon cycling, as an increase in woody biomass will affect litter quality and future fire risk.