Decreasing the nitrogen transport from land to surrounding seas is a major task throughout the world to limit eutrophication of the coastal areas. Several approaches are currently used, including the establishment of wetlands, to decrease the transport of nitrogen. Wetlands represent ecosystems where the nitrogen removal from water can be efficient given that they are appropriately designed. The aim of this thesis was to investigate and quantify the effect of critical factors that regulate the nitrogen removal in wetlands, and to develop better guidelines for wetland design. Studies were performed at different scales, from microcosms to full scale wetlands, and methods included modelling, mass balance calculations and process studies. A first order rate model was used to simulate the nitrogen transformations in two large wetlands treating wastewater containing both ammonium and nitrate nitrogen. It was found that the dynamics of the main itrogen transformation processes could not be satisfactorily described using this approach. Large wetlands containing vegetation are complex ecosystems, and the process rates vary in both time and space. The great diversity of microenvironments favours different nitrogen processes, and large differences in potential nitrification and denitrification rates were found between different surface structures within a wetland. The results from microcosms measurements showed that the highest potential for nitrification was on surfaces in the water column, while the denitrification capacity was highest in the sediment. For the sediment denitrification capacity, the plant community composition was shown to be of major importance primarily by supplying litter serving as a carbon and energy source, and/or attachment surfaces, for denitrifying bacteria. Denitrification rates may be affected more than three fold by different types of litter and detritus in the sediments. Intact sediment cores from stands of the emergent plants Glyceria maxima and Typha latifolia had higher denitrification potential than sediment cores from stands of the submersed plant Potamogeton pectinatus. However, the quality of the organic material for the denitrifying bacteria was highest in G. maxima and P. pectinatus stands. All sediment cores from the wetland were limited by carbon, and the lower denitrification capacity of the submersed plant, P. pectinatus, was likely due to lower amounts of organic matter. However, in another wetland, intact cores from stands of the submersed plant Elodea canadensis had a higher denitrification capacity than the cores from stands of T. latifolia and Phragmites australis. This was possibly due to a larger biomass, and better quality, of the organic matter from that submersed specie, or to epiphytic biofilms on the living plants. Those microcosms studies showed that both the quality of the organic matter as a substrate for the microbial communities, and the amount of organic material produced were important for the denitrification capacity. In pilot scale wetlands, the composition of the plant community was also a more important factor for high nitrate removal than the differences in hydraulic loads (equivalent of 1 or 3 d retention time), despite the cold climate. The greatest removal was found in wetlands with emergent vegetation dominated by P. australis and G. maxima, rather than in wetlands with submersed vegetation. In brief, the results presented in this thesis emphasize the importance of dense emergent vegetation for high annual nitrate removal in treatment wetlands.

I estimated patterns of shorebird abundance and species diversity in the Colorado River Delta and Upper Gulf of California wetlands in order to determine the relative contribution of intertidal wetlands and non-tidal anthropogenic wetlands to support shorebird habitat use. Species richness varied from 15 to 26 species among sites and 29 species were detected across sites. Density during the peak migration month was higher at the anthropogenic wetland Cienega de Santa Clara (mean = 168 ind/ha, 95% C.I. 29-367), and the intertidal Golfo de Santa Clara (mean = 153 ind/ha, 95% C.I. 17-323). Anthropogenic wetlands (playa and lagoons) supported high abundance of shorebirds along with intertidal wetlands in the Colorado River Delta (mudflats). In contrast, intertidal wetlands farther south on the Sonoran Coast presented lower abundance but higher diversity of shorebird, likely as a result of the higher diversity of habitats (rocky shore, sandy beach, estuary). I modeled water management scenarios for the Cienega in order to determine the response of the dominant vegetation (southern cattail, Typha domingensis Pers.) and the area of the outflow pool below the marsh to different scenarios of water management. The model indicates that if the inflow rate is reduced below the current 4-5 m³s⁻¹ the vegetated area of the Cienega that supports habitat for marsh birds would decrease in proportion, as would the area of the outflow pool in the Santa Clara Slough identified previously as shorebird habitat. Increases in salinity will also reduce the vegetated area due to the low salt tolerance of T. domingensis. In winter about 90% of inflow water exits the Cienega into the Santa Clara Slough due to low evapotranspiration contributing to inundate areas that are used by wintering and migrating shorebirds. Lastly, I explored the feasibility of using Vegetation Indices (NDVI and EVI) to model Yuma Clapper Rail detections in the Cienega de Santa Clara as well as the effects of adding other habitat variables and the presence of fire events in the performance of linear models based on NDVI. Both NDVI and EVI were positively related to the Yuma Clapper Rail detections. The relationship was weak to moderate, but significant (P<0.001), which suggests other factors besides the vegetation condition play an important role in the bird distribution pattern. A model including all the variability among years was a better predictor of the rails detected per transect, than models for fire and non-fire years. We did not find a significant effect from adding habitat features (water % or vegetation %), and we recommend to include variables at both microhabitat level and landscape level, relevant before and during the breeding season in order to increase the explanatory power of models.

Wetlands are recognized for the diverse range of ecosystem services they provide. However, most economic valuations focus on the biophysical ecosystem services and disregard the cultural ecosystem services. A better understanding of the cultural ecosystem services that suburban wetlands provide supplements wetland valuations and contributes to wetland preservation and sustainable suburban development. This study, which was conducted in Sherwood Park, Alberta, explores how suburban residents use, perceive, and value suburban wetlands and draws conclusions about the cultural ecosystem services provided by suburban wetlands. Suburban wetlands have implicit existence value; they are aesthetically pleasing; and they provide recreational, spiritual, and intellectual opportunities. Suburban wetlands are venues for relaxation, stress relief, and connecting with nature. Residents have strong positive feelings toward suburban wetlands, and a strong preference for incorporating natural wetland elements into suburban developments. Incorporating natural wetlands contributes to sustainable suburban development and produces economic, social, and ecological benefits.

The aim of this research was to investigate the possibility of using soil magnetic susceptibility to differentiate wetland soil from non0wetland soil, thereby enabling the identification of a wetland boundary. The initial methodology to test the viability of using magnetic susceptibility for wetland delineation was carried out at nine sites in three areas of Kwazulu-Natal, South Africa. Changes in vegetation were used to identify the permanently, seasonally and temporarily wet zones at each site to provide a quick indication of the various boundaries. At least one transect was studied at every site, extending from the outer edge of the temporary zone to the water's edge. Magnetic susceptibility readings, soil samples and/or elevations were taken in each zone. It was found that the magnetic susceptibility readings could be used to differentiate between the various wetland zones but boundaries were not identified due to the reconnaissance nature of the work, a specific protocol had yet to be discovered. This methodology was a reconnaissance phase to assess the potential of using soil magnetic susceptibility. A second methodology was designed specifically to identify a wetland boundary. The wetland zones were identified using vegetation indicators from the South African field procedure for delineating wetlands. Magnetic susceptibility readings were done on transects perpendicular to the suspected boundary and a critical value was identified. A magnetic susceptibility boundary was marked according to the critical value and verified by taking readings along transects parallel to it on both sides. The boundary was then identified using South African field procedure according to soil indicates. The soil data showed a similar boundary to the magnetic susceptibility boundary but indicated a 'boundary zone' of approximately l2m in width rather than a specific line. A final methodology was planned to improve the resolution of the magnetic susceptibility boundary. A grid was laid out over a strip through the wetland including the boundary area on both sides. This was to provide accurately spaced points at which to take magnetic susceptibility readings and elevations. The critical value, a value that separates wetland from non-wetland soil, was identified and verified using soil indicators. The field procedure was more difficult to carry out than using the magnetic susceptibility sensor, yet both methods identified the same boundary with a resolution of about 3m. This initial study demonstrates the potential for using magnetic susceptibility for wetland delineation. Although the results at the final site proved the method to be successful, it was not suitable for use at all sites and the results were often difficult to interpret. Limitations include factors such as plinthic horizons close to the soil surface and shallow, rocky soils. Thus further research is required before magnetic susceptibility can be used to delineate wetlands in KwaZulu-Natal, South Africa. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2002.

A suitable methodology for mapping wetlands in South Africa has not been agreed upon. This investigation aimed at developing a methodology for the accurate and efficient delineation of wetland areas using satellite imagery and other relevant spatial datasets. Both summer and winter LANDSAT ETM+ satellite imagery covering the study area of the Midmar sub-catchment were processed using various image classification techniques. These included the supervised, unsupervised and level slicing classifications. The accuracy of each technique was tested against the only existing verified wetland dataset that covers the study area. A ground truthing exercise was also undertaken. The different classification techniques resulted in different classification accuracies when compared to the verified wetland dataset. Accuracies for the different classification techniques were as follows: unsupervised 20 class classification (summer) 55%, (winter) 39%, unsupervised 255 class classification (summer) 71%, (winter) 47%; supervised classification (summer) 65%, (winter) 41%; level slicing classification (summer) 65%, (winter) 45%. The inaccuracies could mostly be attributed to a change in land cover as there seems to be an overall loss of wetland areas. However, the ground truthing exercise resulted in higher classification accuracies especially with unsupervised 255 class classification. This study concluded that LANDSAT ETM+ satellite imagery was useful for detecting wetlands areas during summer by using a fine classification technique (255 class). A finer classification technique is also suited for the detection of both large and small wetland areas. Major recommendations include: the use of summer imagery in a high rainfall period; the unsuitability of using winter imagery due to the spectral confusions created; the use of high resolution satellite sensors (SPOT) for monitoring purposes while lower resolution sensors (LANDSAT) should be used for mapping; the increased use of topographical modelling for wetland detection; the use of an appropriate scaled land cover database and the use of field verification exercises for comparing classifications. / Thesis (M.Env.Dev)-University of Natal, Pietermaritzburg, 2001.

This study examined the responses of algae and invertebrates to a single application of nutrients in a series of experimental wetland enclosures in the Interlake Region of Manitoba during 1989 and 1990. Water, sediment and vegetation chemistry were also monitored. The 3 fertilization treatments were: dissolved inorganic high (6200 $ mu$g/l N, 420 $ mu$g/l P), dissolved inorganic low (3200 $ mu$g/l N, 210 $ mu$g/l P) and organic high (alfalfa: 6200 $ mu$g/l N, 420 $ mu$g/l P). / Dissolved nutrients in the high and low treatments were quickly depleted from the system but dissolved N increased in the alfalfa treatment as decomposition progressed. No changes in sediment or vegetation chemistry were detected. Phytoplankton biomass increased in all the fertilized enclosures while epiphytic periphyton exhibited only minor responses. Epipelon biomass increased in the alfalfa treatment and metaphyton standing crops were extensive in the high treatment enclosures. / In the alfalfa treatment, high microbial respiration rapidly decreased dissolved oxygen concentrations which negatively affected invertebrates. This trend reversed as oxygen levels increased. Dominant nektonic and benthic herbivores-detritivores increased in the high and alfalfa treatment enclosures. Orthocladiinae emergence increased in the high and alfalfa treatments while Chironominae and Tanypodinae increased in the alfalfa treatment. Responses by algae and invertebrate communities to the fertilization treatments were minimal during 1990. Annual single pulse fertilization has the potential to increase the productivity of Interlake wetlands.

A grande quantidade de resíduos sólidos gerados nas cidades é um desafio para o saneamento ambiental no Brasil. A fim de se reduzir os impactos gerados ao meio ambiente e à saúde pública, é necessário que haja um gerenciamento adequado, desde a coleta até a disposição final, desses resíduos sólidos urbanos. Os aterros sanitários permitem um maior controle ambiental, desde que sejam bem projetados e operados. A decomposição da matéria orgânica presente nesses resíduos, somada às águas das chuvas gera o lixiviado, líquido com alto potencial poluidor. Várias formas de tratamento são propostas com a finalidade de tornar o lixiviado menos poluente ao meio ambiente. Wetlands construídos tem se mostrado uma alternativa eficiente para a remoção de poluentes em lixiviados, além dos baixos custos operacionais e de implantação. O presente estudo investigou o uso de wetlands subsuperficiais em escala-piloto para o tratamento de um lixiviado prétratado. Os wetlands foram monitorados com a finalidade de se obter remoções de matéria orgânica e nitrogênio amoniacal. As maiores reduções percentuais de concentração de nitrogênio amoniacal, DQO e COD foram, 91%, 42% e 35%, respectivamente. As maiores reduções percentuais em carga de nitrogênio amoniacal e DQO foram, 67% e 50%, respectivamente. Os resultados dos ensaios de toxicidade realizados com os organismos Vibrio fischeri e Danio rerio revelaram que, a toxicidade do lixiviado foi reduzida ao ser tratado pelo wetland. / Large amounts of solid wastes are generated in cities and this is a challenge for environmental sanitation in Brazil. In order to reduce impacts to the environment and to public health, it is necessary to manage these municipal solid wastes appropriately, from their collection to their final disposal. Landfills allow a greater environmental control, provided that they are well designed and operated. Landfill leachate generation results from the decomposition of the organic matter in the wastes, combined with the rainwater that percolates the waste. Landfill leachate has a high pollution potential. Various forms of treatment are proposed in order to attenuate the potential of the leachate to pollute the environment. Constructed wetlands seem to be efficient alternatives in removing leachate pollutants with low operational and implementation costs. The present study investigated the use of subsurface wetlands in pilot scale in a pretreated leachate treatment. The wetlands were monitored in order to obtain results in reducing the concentration and loads of pollutants. The best removal performance of the concentration of ammonia nitrogen, COD and DOC were 91%, 42% and 35%, respectively. The best removal performance of the load of ammonia nitrogen and DOC were 67% and 50%, respectively. The results of the toxicity tests conducted with Vibrio fischeri and Danio rerio revealed that wetlands were effective in reducing the toxicity of the leachate.

Spontaneous restoration of wetlands on arable field was observed in the part of South Bohemia. The main aim of the study was to describe colonization of the newly formed wetlands by plants in relation to character of the site and its surroundings (age and size of the wetland, distance to the field margin and to a nearest permanent wetland). Data were collected during six seasons (2011, 2012, 2013, 2014, 2015, 2016) and analyzed using regression analyses, scatterplots and ordination analyses (DCA, CCA). There were found no significant effects of the distance to the permanent wetland and the distance to the edge of the field on species composition of the newly created wetlands. The effect of successional age of wetlands on their species composition was significant. Species with a higher colonization ability were relatively more frequent in those wetlands located in a longer distance form the edge of the field. Participation anemochorious and hydrochorious species increased during a succesional time on studied wetlands, the proportion zoochorious and hemerochorious species decreased. These conclusions, however, be taken with caution, because it captured with a relatively small margin successional age. In general, it was shown that spontaneous restoration of wetlands on arable land is possible and runs to (semi)natural wetland vegetation.

A grande quantidade de resíduos sólidos gerados nas cidades é um desafio para o saneamento ambiental no Brasil. A fim de se reduzir os impactos gerados ao meio ambiente e à saúde pública, é necessário que haja um gerenciamento adequado, desde a coleta até a disposição final, desses resíduos sólidos urbanos. Os aterros sanitários permitem um maior controle ambiental, desde que sejam bem projetados e operados. A decomposição da matéria orgânica presente nesses resíduos, somada às águas das chuvas gera o lixiviado, líquido com alto potencial poluidor. Várias formas de tratamento são propostas com a finalidade de tornar o lixiviado menos poluente ao meio ambiente. Wetlands construídos tem se mostrado uma alternativa eficiente para a remoção de poluentes em lixiviados, além dos baixos custos operacionais e de implantação. O presente estudo investigou o uso de wetlands subsuperficiais em escala-piloto para o tratamento de um lixiviado prétratado. Os wetlands foram monitorados com a finalidade de se obter remoções de matéria orgânica e nitrogênio amoniacal. As maiores reduções percentuais de concentração de nitrogênio amoniacal, DQO e COD foram, 91%, 42% e 35%, respectivamente. As maiores reduções percentuais em carga de nitrogênio amoniacal e DQO foram, 67% e 50%, respectivamente. Os resultados dos ensaios de toxicidade realizados com os organismos Vibrio fischeri e Danio rerio revelaram que, a toxicidade do lixiviado foi reduzida ao ser tratado pelo wetland. / Large amounts of solid wastes are generated in cities and this is a challenge for environmental sanitation in Brazil. In order to reduce impacts to the environment and to public health, it is necessary to manage these municipal solid wastes appropriately, from their collection to their final disposal. Landfills allow a greater environmental control, provided that they are well designed and operated. Landfill leachate generation results from the decomposition of the organic matter in the wastes, combined with the rainwater that percolates the waste. Landfill leachate has a high pollution potential. Various forms of treatment are proposed in order to attenuate the potential of the leachate to pollute the environment. Constructed wetlands seem to be efficient alternatives in removing leachate pollutants with low operational and implementation costs. The present study investigated the use of subsurface wetlands in pilot scale in a pretreated leachate treatment. The wetlands were monitored in order to obtain results in reducing the concentration and loads of pollutants. The best removal performance of the concentration of ammonia nitrogen, COD and DOC were 91%, 42% and 35%, respectively. The best removal performance of the load of ammonia nitrogen and DOC were 67% and 50%, respectively. The results of the toxicity tests conducted with Vibrio fischeri and Danio rerio revealed that wetlands were effective in reducing the toxicity of the leachate.

O presente trabalho tem o objetivo de avaliar a metodologia de construção, de plantio, de manutenção, de operação e a eficiência de um sistema de tratamento por wetland construído como etapa de polimento da Estação de Tratamento de Lixiviado (ETC) de Aterro já encerrado de Resíduos Sólidos Urbanos na Região Metropolitana do Rio de Janeiro. Parte do efluente tratado por lodos ativados na ETC foi direcionado e tratado no wetland construído. Foi escolhido o projeto de Fluxo Horizontal Subsuperficial e a vegetação selecionada foi a taboa (Typha latifolia) que é nativa da área do aterro. Em média, foram feitas três amostragens mensais do afluente e do efluente do wetland, de maio a outubro de 2013. A eficiência do sistema foi avaliada por meio de parâmetros físico-químicos e de parâmetros coletivos específicos. A eficiência de remoção de Demanda Química de Oxigênio (DQO) foi de 60%, nitrogênio amoniacal de 67%, nitrito de 72% e nitrato de 57%. Outro parâmetro avaliado foi a toxicidade aguda, foram utilizados os organismos teste Danio rerio (peixe), a Daphnia similis (microcrustáceo) e a Aliivibrio fischeri (bactéria luminescente). Durante o período foram coletados diariamente as vazões de entrada e saída, a condutividade elétrica e o índice pluviométrico. Os resultados mostraram que o uso de wetland como etapa de polimento pode ser uma alternativa para o tratamento de lixiviado. / This paper aims to evaluate the methodology of construction, planting, maintenance and efficiency of a constructed wetland treatment system as a constructed wetland polishing step of the leachate treatment (ETC) of the closed Landfill station. One amount of the effluent from the activated sludge plant was directed and treated in a constructed wetland. We used an Horizontal Subsurface Flow plant and the selected vegetation was the Cattail (Typha latifolia) which is native to the disposal area. Three samples of influent and effluent of the constructed wetland were made on average per month in the period from May up to October 2013. The system efficiency was evaluated by physical-chemical parameters and parameters of specific groups. The COD (chemical oxygen demand) removal efficiency was 60%, ammonia nitrogen was 67%, nitrite and nitrate was 72% and 57%, respectively. It was also evaluated acute toxicity, the test organisms used were: Danio rerio, a Daphnia similis e a Aliivibrio fischeri. It was collected flow rates of input and output, eletric conductivity and rainfall daily. The results showed that the use of wetland, as a polishing step, may be an alternative for treatment of leachate.