The topic of my diploma thesis are Epidemiological and ecological impacts of floods in the Cesky Krumlov district. In the theoretical part I deal, from the perspective of epidemiology, with infectious diseases that may occur due to floods, I explain what information system was used by the regional hygiene stations in order to carry out the obligatory report, records, and analysis of occurrence of infectious diseases, and I would like to point out that from 1 January 2018 on, a new system started working for regional hygiene stations in the Czech Republic. Further, I deal with ecological impacts, and explain ecology in terms of Nature Conservation Act. Last but not least, I mention floods as such in the theoretical part, I define flood legislation, what administrative authorities work if such a crisis situation occurs, and what flood affected the region of Cesky Krumlov. The practical part analyses Epidat and the ISIN information system data using metaanalysis, searching for a link between them and infectious diseases during floods. I focused on infectious diseases that ma occur in connection to floods, such as Leptospirosis, Shigelosis, Cryptosporidiosis, Gastroenteritis caused by Campylobacteria and Norovirus, Virus Hepatitis type A, and Virus Hepatitis type E. The Discussion part evaluates the questionnaire aimed at the citizens of Cesky Krumlov region, also at the primary school pupils. What is their image of consequences of floods, and what may bet he cause. The results are then discussed in the conclusion of my diploma thesis. Creating an information leaflet meant for the lay public is another output of my diploma thesis.

Invasive insects are considered one of the most serious threats affecting forests today; however, surprisingly little research has addressed the impacts of invasive species establishment on native forest insect communities. Such information is lacking for even the most thoroughly studied invasive forest insect, the gypsy moth. Using gypsy moth as a case study, my thesis addresses the questions: What are the ecological impacts of an exotic forest insect upon its establishment in a new community of native species? Does the community shift after the invasive establishes, and if so, what are the drivers in this realignment? I used multivariate analysis to assess native caterpillar communities collected in forest stands with and without a history of gypsy moth outbreak. I found that gypsy moth outbreak history had no significant effects on native caterpillar communities; however, current gypsy moth abundance was related to shifts in the structure of late season caterpillar assemblages. These results suggest that gypsy moth may affect native caterpillar communities through short-term mechanisms but not through long-term ecological changes. I used quantitative food webs to investigate the effects of gypsy moth on native host-parasitoid webs from the same caterpillar communities, and found that food web structure was resilient to both gypsy moth outbreak history and current abundance. The gypsy moth shared few parasitoids with native species in my study sites, none of numerical significance, thus minimizing the opportunity for enemy-mediated indirect interactions. Finally, I conducted a greenhouse experiment and found that early spring feeding by forest tent caterpillar can indirectly influence gypsy moth susceptibility to its virus, demonstrating that the complex interactions that can occur between native and exotic species do not always benefit the invader. Overall, I argue that the establishment of the gypsy moth into North American forests will not cause major changes in native caterpillar communities.

Invasive insects are considered one of the most serious threats affecting forests today; however, surprisingly little research has addressed the impacts of invasive species establishment on native forest insect communities. Such information is lacking for even the most thoroughly studied invasive forest insect, the gypsy moth. Using gypsy moth as a case study, my thesis addresses the questions: What are the ecological impacts of an exotic forest insect upon its establishment in a new community of native species? Does the community shift after the invasive establishes, and if so, what are the drivers in this realignment? I used multivariate analysis to assess native caterpillar communities collected in forest stands with and without a history of gypsy moth outbreak. I found that gypsy moth outbreak history had no significant effects on native caterpillar communities; however, current gypsy moth abundance was related to shifts in the structure of late season caterpillar assemblages. These results suggest that gypsy moth may affect native caterpillar communities through short-term mechanisms but not through long-term ecological changes. I used quantitative food webs to investigate the effects of gypsy moth on native host-parasitoid webs from the same caterpillar communities, and found that food web structure was resilient to both gypsy moth outbreak history and current abundance. The gypsy moth shared few parasitoids with native species in my study sites, none of numerical significance, thus minimizing the opportunity for enemy-mediated indirect interactions. Finally, I conducted a greenhouse experiment and found that early spring feeding by forest tent caterpillar can indirectly influence gypsy moth susceptibility to its virus, demonstrating that the complex interactions that can occur between native and exotic species do not always benefit the invader. Overall, I argue that the establishment of the gypsy moth into North American forests will not cause major changes in native caterpillar communities.

La gestion par éclusées des aménagements hydroélectriques (plus de 150 en France) pour la production d'énergie de pointe engendre de brusques variations de débit sur les cours d'eau et est susceptible d’altérer la composition, l’abondance et la structure des populations de poissons et d’invertébrés, sur de longues distances. Les objectifs de cette thèse ont été (1) de développer une méthode de caractérisation des éclusées au sein des hydrogrammes, ainsi qu'un indicateur synthétique du niveau de perturbation hydrologique, et (2) de progresser dans la définition des mesures de mitigation des impacts des éclusées sur les poissons. A partir de l'analyse de 97 stations et 1575 années de données de débit, les gradients des variations naturelles de débit ont tout d’abord été caractérisés sur 8 gammes entre 5% et 4 fois le débit moyen interannuel (module). Des formules représentant les variations de débit « les plus rapides possibles naturellement » ont été construites en tenant compte du type de variation (hausse ou baisse), de la taille du cours d'eau (via le module) et de la gamme de débit sur laquelle se déroule la variation, pour ensuite discriminer les éclusées des événements naturels. A partir de l'analyse de 80 stations et 491 années de données de débit influencées par les éclusées, une méthode a été mise au point pour repérer au sein des hydrogrammes les éclusées dont les caractéristiques sont au-delà de ce qui peut se rencontrer en hydrologie naturelle, à partir de 3 critères : une amplitude minimale (≥ à 10% du module et ≥ à 20% du débit de base de l’éclusées), un gradient minimal (> au gradient naturel maximal) et une limite haute sur le débit maximum (pour éliminer les événements de crues). Une grande variabilité des régimes d'éclusées du fait de la diversité des aménagements hydroélectriques et des fluctuations des apports hydrologiques et de la demande énergétique, a été constatée et illustrée […]. / Hydropeaking management of hydroelectric facilities (more than 150 in France) generates sudden changes in flow on the river and can affect the composition, the abundance and the structure of fish and invertebrates populations over long distances. The objectives of this thesis were (1) to develop a method for characterizing hydropeaks within hydrograph and a synthetic indicator of hydrological disturbance, and (2) to progress in defining mitigation measures of hydropeaking impacts on fish. From the analysis of 97 stations and 1575 years of flow data, rate of change of natural flow variations have been characterized within 8 ranges between 5% and 4 times the mean inter-annual discharge. Formulas representing the "fastest variations possible naturally" and taking into account the type of change (increase or decrease), the size of the stream (via the mean inter-annual discharge) and the flow range over which the variation takes place have been constructed and then used to discriminate hydropeaks and natural events. From the analysis of 80 stations and 491 years of flow data affected by hydropeaks, a method was developed to identify, within the hydrograph, hydropeaks whose characteristics are beyond what can occur in natural hydrology, using 3 criteria: a minimum range (≥ 10% of the mean inter-annual discharge and ≥ 20% of the hydropeak base flow), a minimal rate of change (> to the maximum natural rate of change) and an upper limit on the maximum flow rate (to remove flood events). A large variation in hydropeaking regimes, due to the diversity of hydroelectric schemes and fluctuations in incoming flow and energy demand, was observed and illustrated […]

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Over the last 150 years the natural nighttime environment has been drastically altered by the proliferation of artificial light. The amount of artificial light at night is on the increase, and there is a current trend to replace older lighting with more energy efficient types such as light emitting diodes (LEDs) or ceramic metal halide; in Cornwall, UK, there has been a relatively recent replacement of the street lighting, from low pressure sodium to ceramic metal halide. Alongside the increasing amount of artificial nighttime light, recent research has highlighted declines in macro moth numbers. Given the well-known ‘flight-to-light’ behaviour of moths, and the negative effects this behaviour can have, alongside other known and potential ways in which nighttime light can affect moths, the increasing amount of artificial light in the environment is a suspected contributor to the declines. It is particularly important to understand how modern lighting technologies will impact upon moths, as different spectra of light are known to vary in terms of how attractive they are. As a means to determine the potential impact of different street lighting types on moths, particularly the ceramic metal halide lighting rolled out in Cornwall, UK, we compared the attractiveness to macro moths, of a number of increasingly used, energy efficient, street lighting types. We found that shorter wavelength metal halide lighting attracted significantly more individuals and species of moth than longer wavelength high pressure sodium lighting. In a second experiment, we also found ceramic metal halide lighting to be more attractive to macro moths than LED lighting. Reduced emissions of short wavelength UV light was deemed the likely reason behind the fewer macro moths attracted to the high pressure sodium and LED lighting. Interestingly, we also found striking differences in the relative attractiveness of the different lighting types to different moth groups. The metal halide lighting attracted significantly more Noctuidae than high pressure sodium lighting, whereas both high pressure sodium and metal halide lighting were equally attractive to Geometridae. Understanding accurately the extent to which different groups of moth are attracted to different wavelengths of light could be useful in determining the impact of artificial light on moth populations. In addition to impacting moths through attraction, artificial light has the potential to alter the day length as perceived by organisms, which at mid- to high latitudes is utilised by certain species as an abiotic cue to ensure the coincidence of development with favourable environmental conditions. Due to a paucity of knowledge on how raised ambient nighttime light levels affect moths and the trophic levels with which they interact, we carried out analyses into the impact of nighttime light on the winter moth and its host plant oak; a well-studied model system, where synchrony between moth egg hatch and oak budburst is important for the moth’s survival. Firstly we carried out an analysis looking at the relationship between the amount of nighttime light and the date of oak budburst. Spatially referenced budburst dates were matched with satellite imagery of nighttime lighting and average spring temperature data, and the relationship between the variables was analysed. Model predictions suggested that oak budburst occurs earlier in brighter areas. In addition, the predicted advance of budburst in brighter areas was still apparent when analysing only the data points that fell outside of large urban areas, where the urban heat island effect is likely reduced. The findings suggested that artificial nighttime light may be causing an advance in oak budburst. To follow up the spatial analysis we carried out a field experiment. We used light cages that simulated various nighttime lighting scenarios to test whether oak budburst and winter moth egg hatch were affected by low intensity light at night. In contrast to the spatial analysis, there was no significant relationship found between light treatment and the phenology of either oak budburst or winter moth egg hatch. However, there was a suggestion in the data that the higher buds of the oak saplings emerged earlier in the yellow light treatment, highlighting the need for further research into the potential impact of artificial nighttime light on phenology and species interactions. In conclusion, the findings of this research project provide information useful to those seeking ecologically sensitive lighting solutions, and also highlight a potential tool to assist in determining whether light at night is a causative factor behind apparent moth declines. In addition, they suggest that artificial light at night may be affecting the phenology of an ecological system at a national scale. Finally, this research project has highlighted the complexity of the ecological impacts of artificial light at night, and also a need for further research.

In diploma work was created analysis and synthesis of ecological and social impacts of brownfields in South Bohemia. The theoretical part was specialized in the main definitions of environmental and social impacts of brownfields. In the practical part was created a case study of brownfields regeneration. Diploma thesis is part of being solved grant GAČR-Economic Aspects of regeneration of brownfield sites in South Bohemian region.

L'anthropisation croissante des territoires a conduit à la transformation profonde des écosystèmes et à une perte massive, rapide et irréversible de la biodiversité. La réglementation nationale française impose aujourd'hui aux aménageurs du territoire d'évaluer, a priori et a posteriori, les impacts environnementaux de leurs projets de construction (ex : infrastructures routières) et notamment les impacts sur la biodiversité. Cette réglementation impose également de proposer des mesures d'évitement, de réduction, et de compensation, lorsqu'il existe des impacts résiduels, par la création ou la restauration de la biodiversité dégradée. En l'absence d'outils performants à disposition des gestionnaires, les échecs de la prédiction des impacts et de l'évaluation de l'efficacité des mesures conservatoires sont nombreux. L'objectif général de cette thèse est de proposer une nouvelle approche méthodologique pour (i) caractériser les processus et les paramètres abiotiques impactant la diversité végétale des communautés, (ii) analyser l'efficacité d'un projet de création et (iii) proposer, à la lecture de ces résultats, des nouvelles mesures de valorisation de la biodiversité végétale du site d'étude. Le site étudié est un aménagement paysager autoroutier, au sein duquel des semis et des plantations ont été réalisées par le constructeur, deux ans avant le début de notre étude. Nous avons restreint l'étude mécaniste du compartiment abiotique à celle du fonctionnement hydrologique (modélisé à l'aide d'HYDRUS-1D). [...] Suite et fin du résumé dans la thèse. / Human activities are responsible for high modifications in ecosystems functioning. It is recognized that these impacts cause definitive and high losses rate of biodiversity in every components of wildlife. Due to regulation, construction companies are bound to evaluate environmental impacts of the infrastructure construction projects (eg: roads), and more particularly, impacts on biodiversity. Companies are also bound to propose measures to avoid, reduce or mitigate residuals impacts by the creation or restoration planning of biodiversity. Unfortunately, there are not existing tools and methods clearly defined by regulation for such plans. Most of the time, predictions and environmental evaluations fail in measuring the impacts on biodiversity and efficiency of conservation planning. The research program that we conducted aimed at (i) proposing a new methodological approach in order to characterise processes and abiotic parameters which impact biodiversity of plant communities, (ii) analysing conservatory plans efficiency and (iii) proposing measures for biodiversity valuation in our study case. Our study was realised in a landscaping project zone along the A19 highway, Loiret, France. Seedling and planting were done two years before our study began. Only hydrological processes were studied based on mechanistic modelling using Hydrus-1D software. Last and final summary in the thesis.

In agriculture-dominated areas, water pollution resulting from nutrients migrating from farms to water bodies is a major concern. The migration is further exacerbated by traditional tile drain known as Uncontrolled Tile Drainage (UCTD), which removes excess water from areas to keep the water table low enough for crops to grow. UCTD, commonly used in Ontario, Canada, is believed to contribute to water quality issues, whereas Controlled Tile Drainage (CTD) is an alternative technique in which a structure controls the outlets of the drains so that water only leaves a field when the water table level exceeds a desired threshold. Considered as a Best Management Practice (BMP), CTD has been documented as an efficient practice preventing nutrients from migrating out of agricultural fields. This thesis aims to improve our understanding of the environmental benefits of replacing UCTD with CTD. Three significant contributions were achieved. The first contribution of the thesis is the improvements of the algorithm for calculating nitrates in tile flows in the Soil and Water Assessment Tool (SWAT) model. Researchers have simulated CTD by dynamically changing tile depth to mimic the operation of outlet structure gates, but it has been demonstrated that doing so results in inaccuracies, and so the algorithm in the model has been improved subsequently. The current author proposed and tested a new algorithm for calculating nitrates in tile flows that better represents the dynamics of water and nutrients in soil layers for the SWAT model. A model for the South Nation watershed, located in Ontario, Canada, was then developed and successfully calibrated using the improved SWAT model. The second contribution was the extension of the SWAT model to simulate riverine hydraulic and water quality processes by coupling it with the QUAL2Kw model. In this thesis, a procedure is developed to couple the SWAT model and the QUAL2Kw model to enable continuous simulations of 13 water quality parameters in the South Nation River system. The coupled model was calibrated and verified at various observed locations along the river during the five seasons of growth from 2006 to 2010. The simulation results suggested that CTD also improved the water quality of the river by lowering biologically available N levels of NO2--N, and NO3--N, thereby impeding phytoplankton growth in the river. The third contribution is the verification of the benefits of replacing UCTD with CTD in the future climates. The confirmation was done using the SWAT model alone, and then the coupled SWAT/QUAL2K models, using a matrix of climate change experiments performed with several Global Climate Models and Regional Climate Models. The results suggest that nutrient loading from the watershed will increase in the 2021–2050 period compared to the 1985–2006 period. Thus, pollution from agricultural fields will worsen with the current UCTD approach, while the results also show that CTD would perform effectively and stably in future climate scenarios and could counterbalance the effects of climate change on water quality. To the author’s knowledge, this study is the first attempt to date to assess the environmental effects of CTD on a watershed and river by coupling the SWAT and QUAL2Kw models. The findings expand the current scope of knowledge on the environmental effects of CTD on watersheds and rivers under current and future climate change regimes. Long periods of continuous simulation and a matrix of climate change scenarios also make this study stand out from other studies. It laid a foundation for future investigations.

<p dir="ltr">Coastal ecosystems are critically important habitats for the services they provide on a global and local scale. Maritime forests are found within the southern Atlantic coast, and they serve as a boundary between the ocean and land. These forests stabilize coastlines, recharge groundwater, and provide a protective buffer against storm damage. Southern live oak (<i>Quercus virginiana</i>) was historically the dominant canopy species in maritime forests; however, previous land conversions to loblolly pine (<i>Pinus taeda</i>) plantations have shifted the abundance of loblolly pine to become the dominant canopy tree in maritime forests. Loblolly pines are fast growing, and they regenerate vigorously but they are not well adapted to coastal stressor. In recent decades, outbreaks of southern pine beetle (<i>Dendroctonus frontalis</i>) have provided restoration practitioners an opportunity to clear tracts of pine dominated maritime forest to restore live oak to the canopy. This research project is comprised of two experiments studying the performance of planted <i>Q. virginiana</i> seedlings on maritime forest restoration sites in coastal Georgia. The first experiment evaluated planting density (1-meter, 2-meters, 3-meters), mulch (with or without), and fertilizer (with or without). Overall seedling survival was 99% after four years. The application of fertilizer had an initial positive effect on seedling diameter after the first growing season. The application of mulch increased seedling height in the second to fourth growing seasons, diameter in third and fourth, and crown width in the fourth growing season. Planting density had no consistent effect over the first four years, and no biological significance was observed for foliar nutrient content. The second experiment examined eight different groupings of intra- and interspecific competition between <i>Q. virginiana</i> and <i>P. taeda</i> including: oak or pine alone; oak surrounded by oak, pine, or oak/pine; pine surrounded by pine, oak, or pine/oak at 0.5-m spacing between all seedlings. Two years after outplanting, survival did not vary by treatment. Oak centered competition plots were positively impacted by border tree height and diameter in year one and border height positively affected the center tree height in year two. Pine centered competition plots were positively impacted by border tree height in year one and year two. Oak centered competition plots with a mix of oak and pine on the border had significantly lower osmotic potential than other pine centric treatments after two years. Overall, oak centered treatments had lower osmotic potential than pine centered treatments. Ectomycorrhizal (EMF) species composition changed, and relative abundance increased from the initial planting to two years later but there was no variation between treatments and most EMF species were generalists. These results highlight the importance of mulch and fertilizer to reduce transplant shock and how competing seedlings can train seedlings to allocate photosynthate to shoot growth to help promote aboveground growth.</p>