Peatlands are important and common wetland ecosystems where the wet conditions result in formation and accumulation of peat, i.e., not fully decomposed organic matter. Many peatlands have been negatively affected by drainage (i.e., ditches) and restoration is conducted, although the effects on vegetation are not fully understood. This study aimed to investigate the differences in vegetation composition between natural and restored parts of peatlands and the effect of local conditions on vegetation composition. Data was collected on vegetation composition and local environmental conditions (pH, electrical conductivity and water table depth) of natural and restored parts of seven peatlands across Sweden. Statistically significant differences in the species composition between natural and restored parts were detected and natural parts were dominated by Sphagnum species while restored parts were characterised by shrubs and sedges. The environmental variables had a similar impact on the vegetation composition of both northern and southern sites and were in line with the microhabitat preferences of different species. Although restored parts still have a lower cover of Sphagnum, the vegetation community appears to develop towards compositions similar to those of natural peatlands as most plots are dominated by species found in both natural and restored parts. However, this study is based on vegetation data collected in one year and the results only show the current vegetation community composition and should be interpreted cautiously when evaluating the long-term development of vegetation composition after peatland restoration. As peatlands form during long periods of time, differences in vegetation composition after this relatively short time were expected and in line with previous research. Further studies and long-term follow-up surveys are needed to better understand the vegetation development after peatland restoration.

About 12% of earth’s peatlands have been drained for peat extraction or agriculture and turned peatlands into carbon sources with reduced biodiversity, water retention and downstream water quality. Rewetting is a strategy used to restore peatlands water table and peat forming vegetation, including Sphagnum spp. which are key species in facilitating water retention, peat- and carbon accumulation in bogs. Halmstad University and Sydvatten have been conducting a scientific study, including a one-year-baseline study on a drained bog in Halmstad, scheduled to be rewetted by ditch blocking. The collected data on bog vegetation in this thesis shall be used as baselines for the scientific study. The aim was to understand if rewetting increases the coverage of peat forming vegetation in drained bogs with the hypotheses that Sphagnum moss have higher degree of coverage in wet compared to drained bogs, and that the plant community in wet bogs are dominated by Sphagnum moss while the drained bog is dominated by brown moss. The estimated mean percent coverage of Sphagnum moss, brown moss (other Bryophytes), heather shrubs, sedges, and reeds was compared between the drained bog, scheduled to be rewetted to a wet bog where ditch clearing has not happened for the last 80 years. My result showed that brown mosses of woody species had a greater and dominant mean coverage at the drained bog, indicating a shift to forest vegetation following drainage. Reeds, sedges, and heathers showed no significant difference between sites. Sphagnum moss demonstrated a significantly higher mean coverage in the wet bog, dominating the vegetation. This reflects a typical bog succession, influenced by Sphagnum mosses capacity of outcompeting other plants. These findings support the hypothesis and indicate that within 80 years, there can be a shift to a peat forming-Sphagnum- dominated bog community in previously drained bogs, through ditch blocking.

Wetlands are among the most species-rich environments and important for biodiversity. The area of Swedish wetlands has decreased significantly over the past century, primarily due to drainage for forestry and agriculture. The volume of standing trees on peatlands increased by 75% between 1980 and 2000. Large conservation efforts aim to protect and restore wetlands, necessitating informed and effective actions. This study investigates whether populations of wetland birds in Dalarna County, Sweden, have been affected by increased tree growthbetween the 1970s and the 2010s. Using data from bird inventories conducted by Dalarnas Ornitologiska Förening and Länsstyrelsen Dalarna on 110 wetlands, a linear regression model examined the relationship between changes in the number of selected wetland birds and vegetation changes per wetland area. Vegetation changes, derived from Naturvårdsverkets satellite-based monitoring program, showed that the proportion of areas with increased biomass varied from none to 11.5%. The study found no significant relationship between vegetation changes and changes in the total number of waders or in the number of individual wetland bird species. Key ecological requirements for wetland bird species, such as low tree height and wetness, may have remained sufficiently intact to avoid affecting bird numbers, given the relatively small vegetation changes detected. Identifying areas with high conservation values and understanding how the threat of increased biomass affects these values is important to achieve the environmental goal of "Thriving Wetlands", necessitating continued monitoring to detect possible future changes and address issues promptly.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-08-22T19:26:53Z No. of bitstreams: 1 2016 - Sidinei Julio Beutler.pdf: 3474278 bytes, checksum: 1adaf2ecd1077cf6ca3fa70c64954a43 (MD5) / Made available in DSpace on 2017-08-22T19:26:53Z (GMT). No. of bitstreams: 1 2016 - Sidinei Julio Beutler.pdf: 3474278 bytes, checksum: 1adaf2ecd1077cf6ca3fa70c64954a43 (MD5) Previous issue date: 2016-02-25 / CAPES / The Histosols are a major source of carbon storage in terrestrial environments and have high susceptibility to carbon losses when disturbed. The objective of this study was to generate pedotransfer functions (FPT) to assess the accuracy of previously published equations, applying them to predict soil bulk density (Bd) in organic soils from Brazil; to evaluate subsidence rate, and the variation of Bd and carbon of humic substances in Histosols over a period of one year; and to estimate stock and potential loss of carbon in Histosols from Rio de Janeiro State. For the first part of the study, there were used organic horizons, i.e., soil materials with total organic carbon (TOC) equal to or greater than 80 g kg-1 soil, totaling 280 horizons from different regions of Brazil. It was used the multiple linear regression technique and the equations were validated on independent data. There were tested 9 equations already published in the literature. The equations with better performance were the Hollis and FPT2, with R2 validation parameters of 0.48 and 0.49. When the clay fraction data is availlable, it is recommended to use the FPT1 equation; if there is no data on clay it is recommended the FPT2 and Hollis equations, which have only the TOC as a predictor variable. For the second part, a greenhouse experiment was carried out. For that, undisturbed samples were collected using PVC pipes, of two profiles of Organossolos Tiom?rficos, one in the neighborhood of Santa Cruz (SC Profile), city of Rio de Janeiro, and one in Mag? (Profile MG) municipality. There were evaluated 3 drainage levels, at 30, 60, and 100 cm deep, with 5 measuremts over time, being 0, 90, 180, 270, and 360 days (4 replicates). The MG profile presented the highest rates of subsidence, reaching 1.30 cm year-1 for the 100 cm drainage. Bd increased over time for both profiles, and the deeper drainage increased values in the SC profile. The deeper drainage favored the reduction of pH for both profiles. The TOC showed a decreasing trend over time. The values of carbon in the fulvic acid fraction (FAF), humic acid fraction (HAF), and humin fraction (HUM) showed no differences according to drainage levels. However, over time they showed high sensitivity to temperature changes, showing high levels of FAF and HAF at the end period and a consequent reduction in humin fraction. For the third and final section, there were used 43 soil profiles, where 18 of them did not have bulk density data, which were estimated by the FPTs. Comparisons between measured and estimated data groups was performed using the Wilcoxon test. The spatial distribution of the variables was performed using the IDW interpolation method. The average values of TOC was 228.0 g kg-1, Bd was 0.48 Mg m-3, the thickness of the profiles was 86 cm, the depth was 90 cm and the average stock TOC was 73.51 kg m-2. The spatialization showed qualitative differences for the variables in the different profile locations. The estimated TOC stock for the profiles form RJ State was 27,178,631.8 Mg. The estimated rates of loss were 10.87 kg m-2 for Histosols more recently drained and high TOC; of 7.16 kg m-2 for intermediate drained Histosols; and 1.46 kg m-2 for Histosols with longer time after drainage and low TOC. Soils with high TOC levels are more likely to have high losses TOC when disturbed. / Os Organossolos s?o uma importante fonte de estoque de carbono nos ambientes terrestres e possuem alta suscetibilidade ?s perdas de carbono quando perturbados. O objetivo do presente trabalho foi gerar equa??es, avaliar a acur?cia de equa??es j? publicadas, aplicando-as para a predi??o da densidade do solo (Ds) em solos org?nicos do Brasil; avaliar a taxa de subsid?ncia, a varia??o da Ds, e o carbono das subst?ncias h?micas em Organossolos ao longo do per?odo de um ano; e estimar o estoque e as potenciais perdas de carbono nos Organossolos do Estado do Rio de Janeiro. Para a primeira parte, trabalhou-se com horizontes org?nicos, i.e., materais de solo com teores de carbono org?nico total (COT) iguais ou maiores que 80 g kg-1 de solo, totalizando 280 horizontes em diferentes regi?es do Brasil. Foi empregada a t?cnica de regress?o linear m?ltipla e as equa??es foram validadas sobre dados independentes. Foram testadas 9 equa??es j? publicadas na literatura. As equa??es com melhor desempenho foram FPT2 e Hollis, com par?metros de valida??o R2 de 0,48 e 0,49. Em casos onde os teores de argila estejam quantificados, recomenda-se a equa??o FPT1, e na sua aus?ncia recomenda-se as equa??es FPT2 e Hollis, que possuem somente o COT como vari?vel preditora. Para a segunda parte, realizou-se um experimento em casa de vegeta??o. Foram coletadas amostras indeformadas em tubos de PVC, de dois perfis de Organossolo Tiom?rfico, sendo um no bairro Santa Cruz (Perfil SC), munic?pio de Rio de Janeiro, e outro no munic?pio de Mag? (Perfil MG). Foram avaliados 3 n?veis de drenagem, sendo de 30, 60, e 100 cm de profundidade, 5 avalia??es ao longo do tempo, sendo de 0, 90, 180, 270, e 360 dias (com 4 repeti??es). O perfil MG apresentou as maiores taxas de subsid?ncia, chegando a 1,30 cm ano-1 para a drenagem de 100 cm. A Ds aumentou ao longo do tempo para os dois perfis, e a drenagem mais profunda aumentou os valores no perfil SC. A drenagem mais profunda favoreceu a redu??o do pH para os dois perfis. Os teores de COT apresentaram tend?ncia de redu??o ao longo do tempo. Os valores de carbono da fra??o ?cido f?lvico (FAF), fra??o ?cido h?mico (FAH), e fra??o humina (HUM), n?o mostraram diferen?as de acordo com os n?veis de drenagem. No entanto, ao longo do tempo, apresentaram alta sensibilidade ?s varia??es de temperatura, mostrando elevados teores de FAF e FAH no per?odo final, e a consequente redu??o dos teores de HUM. Para a terceira e ?ltima parte do estudo, foram usados 43 perfis de Organossolos, sendo que 18 deles n?o apresentavam os dados de densidade do solo (Ds), os quais foram estimados por meio de FPTs. As compara??es entre os grupos de dados medidos e estimados foi feita pelo teste de Wilcoxon. A espacializa??o das vari?veis foi realizado atrav?s do m?todo de interpola??o IDW. Os valores m?dios de COT foi de 228,0 g kg-1, a Ds foi de 0,48 Mg m-3, a espessura dos perfis foi de 86 cm, a profundidade foi de 90 cm, e o estoque m?dio de COT foi de 73,51 kg m-2. A espacializa??o mostrou diferen?as qualitativas para as vari?veis nos diferentes locais. Foi estimado um estoque de COT de 27.178.631,8 Mg para os Organossolos do Estado do RJ. As taxas estimadas de perdas foram de 10,87 kg m-2 para Organossolos com drenagem mais recente e altos teores de COT; de 7,16 kg m-2 para Organossolos intermedi?rios; e 1,46 kg m-2 para Organossolos com menores teores de COT e longo tempo de drenagem. Solos com altos teores de COT est?o mais propensos a terem altas perdas de COT quando perturbados.

The aim of the study was to verify the influence of the soluble phenolic compounds on the activity of extracellular enzymes. We tested the effect of aerobic and anaerobic conditions and addition of soluble phenolic compounds on potential activity of extracellular enzymes in two laboratory experiments. The results showed, that potential activities of oxidative extracellular enzymes such as phenol oxidase and peroxidase did not decline in anaerobic incubations, and have no oxygen requirement. Potential activities of hydrolytic enzymes was not inhibited by phenolic compounds and are oxygen related or have no oxygen relationship. No negative relationship between hydrolytic enzymes and phenolic compounds was observed. In summary, our results do not support the ''enzymatic latch'' hypothesis.

Net ecosystem carbon dioxide exchange (NEE) was measured using the eddy covariance (EC) technique at a wetland tundra-sedge fen near Churchill, Manitoba, Canada during two consecutive growing seasons (2007 and 2008). Mean daily NEE at the fen (DOY 157-254) was -3.5 (± 0.26 S.E.) g CO2 m-2 d-1 in 2007 and -4.6 (± 0.36) g CO2 m-2 d-1 in 2008. The fen was a net carbon dioxide (CO2) sink during both the 2007 and 2008 growing seasons of -343 (± 79) and -450 (± 87) g CO2 m-2, respectively. Mean air temperature during the summer (June 1-August 31) was about 1°C greater than the historical average (1971-2000) in 2007 and about 2°C greater in 2008. Growing season precipitation was 107.5 mm below normal in 2007 and 359.5 mm above normal in 2008. These data suggest that if future climate change brings warmer temperatures and near-to-above average precipitation maintaining the water table near the surface, similar subarctic ecosystems will experience increased gross ecosystem productivity enhancing CO2 sequestration during the growing season.

A climate controlled, dynamic chamber was used to measure carbon dioxide (CO$ sb2$) and methane (CH$ sb4$) exchange on an ombrotrophic peatland. The study periods were July to early November 1995, and early May to July 1996. Five sample sites, showing ecological and hydrological contrast, were investigated. Measurements of Net Ecosystem Exchange showed peak photosynthetic capacity (GP$ sb{ max})$ ranging from 0.52 $ pm$ 0.04 mg C m$ sp{-2}$ s$ sp{-1}$ (June 1996) to 0.03 $ pm$ 0.02 mg C m$ sp{-2}$ s$ sp{-1}$ (early November 1995). Dark respiration measurements ranged from $-$0.21 $ pm$.02 mg C m$ sp{-2}$ s$ sp{-1}$ (June 1996) to $-$0.02 $ pm$.01 mg C m$ sp{-2}$ s$ sp{-1}$ (late May 1996), and showed significant relationships to soil temperature at all sites. Site average methane measurements ranged from 29-72 mg m$ sp{-2}$ d$ sp{-1}$, and showed a strong relationship to water table on a seasonal basis, but a poor correlation to simultaneous NEE. Modelled Net Ecosystem Productivity (NEP) among sites ranged from 17.1 to 115 gC over the entire study period. The CO$ sb2$ exchanges in late spring and early fall made a large contribution to the figure due to the imbalance in the photosynthetic and dark respiration components of the carbon budget. No discernible relationship was found between seasonal NEP and methane release. The results suggest a large importance of the extreme ends of the growing season in an analysis of the carbon budget of peatlands, periods hitherto little investigated. They also suggest that NEP/methane connections may be restricted in their significance to mainly flooded mires.

The relationship between fen vegetation and water and soil chemistry gradients in an alkaline slope fen was studied during the growing season of 2005. Owned by Irving Materials Inc. (IMI), the fen is a two hectare property in north-central Henry County, Indiana. The objectives of the study were (1) to conduct a floral inventory of the site and determine the floristic quality index for the site; (2) to visually characterize and stratify the site into areas of similar vegetation or community types; (3) to characterize relationships, if any, existing between vegetation and chemical and hydrological gradients; and (4) to quantify spatial and temporal patterns of ground water alkalinity throughout the fen. The floral inventory revealed 287 species, representing 180 genera in 79 families. Of the documented flora, 246 are native, 41 are adventives, and 20 represent Henry County records. The Floristic Quality Index and the mean Coefficient of Conservatism suggest that the site is of nature preserve quality and contains noteworthy remnants of the region’s natural heritage. They also suggest that the adventives are having a minimal negative impact on the native flora. For quantitative vegetation analysis, fixed transects were monitored three times during the growing season (spring, summer, fall). Basic subsurface water chemistry and levels were monitored bi-weekly and 30 soil and 30 surface water samples (10 each to coordinate with the vegetation survey) were analyzed for over 35 physical parameters. In all cases, the parameters fell within the ranges of typical Midwestern fens, but most noticeably for calcium carbonate. Applying the Floristic Quality Assessment to the vegetation occurring along fixed transects, 26 species were identified with an importance value greater than one. Nonmetric, multidimensional scaling analysis of fen species dominance delineate spatial and temporal patterns in vegetation. Joint plot vectors indicate the strength and direction of correlations between soil and water chemistry variables. Nine physical parameters were useful to separate vegetation into groups. The relationship between the plants and these nine parameters is described and discussed. / Department of Biology

Net ecosystem carbon dioxide exchange (NEE) was measured using the eddy covariance (EC) technique at a wetland tundra-sedge fen near Churchill, Manitoba, Canada during two consecutive growing seasons (2007 and 2008). Mean daily NEE at the fen (DOY 157-254) was -3.5 (± 0.26 S.E.) g CO2 m-2 d-1 in 2007 and -4.6 (± 0.36) g CO2 m-2 d-1 in 2008. The fen was a net carbon dioxide (CO2) sink during both the 2007 and 2008 growing seasons of -343 (± 79) and -450 (± 87) g CO2 m-2, respectively. Mean air temperature during the summer (June 1-August 31) was about 1°C greater than the historical average (1971-2000) in 2007 and about 2°C greater in 2008. Growing season precipitation was 107.5 mm below normal in 2007 and 359.5 mm above normal in 2008. These data suggest that if future climate change brings warmer temperatures and near-to-above average precipitation maintaining the water table near the surface, similar subarctic ecosystems will experience increased gross ecosystem productivity enhancing CO2 sequestration during the growing season.

The thesis is part of project "Bohemian Revitalization of wetlands and peatlands". The aim is to catch up the current state (before revitalization) of vegetation and flora with possibility of the existence of rare endagered species in Fir Stream plains in the Southern Bohemia, district Prachatice, cadastral area Volary. There was engaged generic list of plants in this interest locality. There was defined by the 6 permanent areas with dimensions 4x4 m. I made a complete inventory of all found species. Overall, it was found 38 plant species: 11 monocotyledonous plants, 25 dicotyledonous plants and 2 bryophytes.