Denna rapport utforskar effekterna av värmeböljor i urbana miljöer och utforskar användningen av olika stadsplaneringsverktyg för att mildra dessa effekter. Värmestress och värmerelaterade sjukdomar är betydande risker som orsakas av stigande temperaturer i städer, därmed analyseras gröna, blå och gråa lösningar i syfte att minska uppkomsten av värmeböljor i stadsmiljöer och därmed även minska dessa risker. Studien bygger på en omfattande litteraturstudie samt en fallstudie av Hornsbergskvarteren i Stockholm där en intervju även genomfördes med viktiga nyckelpersoner. Resultaten från studien pekar på att en kombination av gröna, blåa och gråa lösningar kan samverka för att minska temperaturen i stadsmiljöer. Gröna lösningar som parker, trädplanteringar, gröna tak och väggar kan bidra till att sänka temperaturen men också förbättra luftkvaliteten i städer, vilket skapar hälsosammare levnadsmiljöer. Blåa lösningar inkluderar olika vattenfunktioner i städer där denna studie främst fokuserat på effekterna av sjöar, dammar, kanaler och bäckar. Blåa lösningar har visat sig ha varierande effekter för temperaturregleringen i urbana miljöer, vilket indikerar att ytterligare undersökning är nödvändig för att förstå dess fulla effekt. Två aspekter som inte togs i beaktning under litteraturstudien men som uppkom som potentiella blåa lösningar under fallstudien var fontäner samt potentiella lösningar för fördröjning av regnvatten. Effekterna av dessa kan vidare utforskas i framtida studier för att ge en helhetsbild av blåa lösningars effekter i urbana miljöer. Gråa lösningar, såsom användningen av reflekterande material har visat sig bidra till att skapa svalare städer. Sammantaget pekar resultaten på att en tillämpning av gröna, blåa och gråa lösningar är viktiga för att hantera värmeböljor och mildra dess effekter, främst risken för hälsorelaterade problem. Dessa planeringsverktyg är viktiga för att främja hållbar utveckling och skapa resilienta städer. / This report explores the effects of heatwaves in urban environments and examines the use of various urban planning tools to mitigate these effects. Heat stress and heat-related diseases are significant risks caused by rising temperatures in cities, therefore, green, blue, and gray solutions are analyzed to reduce these risks in urban areas. The study is based on a literature review and a case study of the Hornsberg area in Stockholm, on which an interview was also conducted. The results from the study suggest that a combination of green, blue, and gray solutions can work together to reduce temperatures in urban environments. Green solutions such as parks, trees, green roofs and walls can help to lower temperatures but also improve air quality in cities, creating healthier living environments. Blue solutions include various water features in cities, where this study primarily focused on the effects of lakes, ponds, canals and streams. Blue solutions have shown varying effects on temperature regulation in urban environments, which means that further investigation is necessary to understand their full impact. Two aspects not considered during the literature review but which emerged as potential solutions during the case study, were fountains and rainwater retention basins. For these solutions, further studies need to be reviewed. Gray solutions, such as the use of reflective materials, have proven to contribute to cooler cities. Overall, the results indicate that the integration of green, blue, and gray solutions is important for managing heatwaves and mitigating their effects, primarily the risk of health-related issues. These planning tools are important for sustainable development and creating resilient cities.

In a time characterized by climate change, we globally face significant challenges that require new approaches in urban planning. Increased temperatures and more frequent heatwaves will negatively impact our cities, people, and the climate, which increases complexity for professionals while residents suffer. Huddinge Municipality is located in the southern part of the Stockholm region in Sweden and faces future challenges with climate adaptation to increased temperatures and heatwaves. To identify existing obstacles and goal conflicts, focus group interviews and document studies have been conducted in Huddinge Municipality. This work aims to contribute to the broader understanding of climate adaptation to heat issues in a Swedish context. Through interviews with municipal officials and document studies, ongoing strategies and approaches have been identified in four Swedish municipalities. Three planning tools have been utilized: the Public Health Agency of Sweden’s four measures to reduce heat stress in the existing environment, the green space factor, and the 3-30-300 rule. The results show that the case studies have clear strategic guidelines on how to work with climate adaptation to increased temperatures but see difficulties in implementing these strategic guidelines in urban planning. Challenges and improvement suggestions identified by the case studies include a need for clearer guidelines from the national level in terms of changed policies and legislation, as well as suggestions for nature-based solutions that are adapted to a Swedish climate. The study concluded that Huddinge Municipality should implement the green space factor in block areas where heat-regulating ecosystem services are included for multifunctional spaces, guidelines for canopy coverage need to be developed and evaluated, and the perspective of vulnerable groups needs to be more clearly integrated into the planning process. The conclusion shows a need for organizational changes and clearer responsibilities in Huddinge Municipality, which means collaboration both internally and externally between administrations, developers, organizations, universities, and research institutes. / I en tid som präglas av klimatförändringar står vi globalt inför stora utmaningar som kräver nya tillvägagångssätt inom samhällsplaneringen. Ökade temperaturer och fler värmeböljor kommer att påverka våra städer, människor och klimatet negativt, detta ökar komplexiteten för yrkesverksamma samtidigt som invånare far illa. Huddinge kommun är beläget i södra delen av Stockholmsregionen i Sverige och står inför framtida utmaningar med klimatanpassning till ökade temperaturer och värmeböljor. För att identifiera rådande hinder och målkonflikter har fokusgruppsintervjuer och dokumentstudier genomförts i Huddinge kommun. Detta arbete syftar till att bidra till den stora bilden av klimatanpassning till värmeproblematik i en svensk kontext. Genom intervjuer med tjänstepersoner och dokumentstudier har pågående strategier och tillvägagångssätt identifierats i fyra svenska kommuner. Som utgångspunkt har tre planeringsverktyg tillämpats: Folkhälsomyndighetens fyra åtgärder för att minska värmestress i den befintliga miljön, grönytefaktorn samt 3-30-300. Resultatet visar att fallstudierna har tydliga strategiska riktlinjer kring hur de ska arbeta med klimatanpassning till ökade temperaturer, men ser svårigheter i att implementera dessa strategiska riktlinjer i samhällsplaneringen. Några av de utmaningar och förbättringsförslag som fallstudierna identifierade var behovet av tydligare riktlinjer från nationell nivå genom förändrad politik och lagstiftning samt effektiva naturbaserade lösningar anpassade till ett svenskt klimat. Studien har kommit fram till att Huddinge kommun bör implementera grönytefaktorn på kvartersmark där värmereglerande ekosystemtjänster inkluderas för multifunktionella ytor, riktlinjer för krontäckningsgrad behöver tas fram och utvärderas samt perspektivet kring sårbara grupper behöver tydligare integreras i planeringsprocessen. Slutsatsen visar ett behov av organisatoriska förändringar och tydligare ansvarsfördelning i Huddinge kommun, vilket innebär samverkan internt och externt, mellan förvaltningar, byggaktörer, organisationer, universitet och forskningsinstitut.

Background: Numerous epidemiological studies have demonstrated a possible correlation between high temperature and mortality in different settings. Most of these studies have focused on urban settings in industrialized countries, concluding that urban populations are more vulnerable to heat effects than rural populations. This has mainly been attributed to the urban heat island (UHI) effect, a phenomenon which explains the elevated temperatures in urban areas. Others have contradicted this finding and concluded that rural residents are more vulnerable. For this study, we test the hypothesis that rural populations and sub-populations are also vulnerable to heat mortality. Method: A comprehensive literature search was conducted using PubMed, Web of Science and Google Scholar to identify peer-reviewed studies investigating heat mortality in rural settings. Using keywords and a set of rigorous inclusion and exclusion criteria, ten studies were selected. Meta-analysis was then performed using the Comprehensive MetaAnalysis V3.exe software. Results and discussion: The pooled relative risk (RR) was 1.191 (95% confidence interval: 1.130-1.251). Although rural populations may not be exposed to as high temperatures as urban populations, they remain vulnerable to heat effects. Conclusion: There is evidence of heat vulnerability in rural populations and subpopulations. Heat vulnerability is not only determined by heat exposure, but also by sensitivity and adaptive capacity. Rural populations and sub-populations may be vulnerable to heat mortality due to low adaptive capacity. Further studies are needed to assess risk factors that predispose rural populations and sub-populations to heat mortality in order to develop effective public health interventions.

Zahlreiche Studien den Stand der Forschung in Bezug auf die Ökosystemdienstleistungen untersucht. Dennoch wurde die Dimension „Volumen und Höhe“, d.h. die dritte Dimension städtischer Systeme, in den Studien zu Ökosystemdienstleistungen in städtischen Gebieten ignoriert. Die Forschungsziele und Fragestellungen dieser Dissertation lauten: i) Stand der aktuellen Forschung zur dritten Dimension von Ökosystemdienstleistungen im städtischen Raum, ii) Beurteilung des Zusammenhangs von urbanen mehrdimensionalen Indikatoren (zwei- und dreidimensionalen Indikatoren) für die Oberflächentemperatur in der Stadt und iii) Unterschiede zwischen Innen- und Außentemperaturen in urbanen Räumen. Diese Dissertation ist in vier Kapitel gegliedert. Im ersten und zweiten Kapitel werden die Forschungslücken und das Ziel der vorliegenden Untersuchung erläutert. Kapitel 3 enthält die veröffentlichten Artikel. Das letzte Kapitel behandelt die Ergebnisse der veröffentlichten Artikel. Diese Dissertation betont die Bedeutung von dreidimensionalen Studien in urbanen Ökosystemen, um das Konzept der Nachhaltigkeit in Städten voranzutreiben. Deshalb werden kontinentübergreifende Forschungen für weitere Studien empfohlen, die die dreidimensionale Struktur aller städtischen Komponenten und ihre Auswirkungen auf die Außen- und Innentemperatur berücksichtigen. / Among the studies on ecosystem services undertaken in urban areas, a ‎dimension ‘volume and height’, i.e., the third-dimension of urban environment is largely ignored. More specific, three-dimensional spatial models will increase the knowledge of how complex environment ‎shape the micro-climate in urban ‎environment. The research objectives and questions of this dissertation is: i) the status of the current research addressing the third-dimension of ‎ecosystem services in urban area, ii) assessing the association of urban multi-dimensional (two- and three- ‎dimensional) indicators on urban surface temperature and iii) variation of indoor and outdoor urban temperature pattern. This dissertation is organized into four chapters. The ‎first and second chapter explain the gaps in literature and the aim of this research. Chapter 3 holds the published articles. The last chapter discusses the results of the published articles. This dissertation emphasizes the importance of three-dimensional studies in urban ecosystems to advance the concept of sustainability in cities. Therefore, cross-continental studies that consider the three-dimensional structure of all the urban components and its impact on outdoor and indoor temperature is recommended for future research. / به جرات می توان گفت که در مطالعات خدمات اکوسیستم، بخصوص خدمات اکوسیستم شهری ، بعد سوم که شامل "ارتفاع و حجم" می باشد اصلا مورد توجه قرار نگرفته است. هدف از این پایان نامه، تلفیق مفهوم بعد سوم در خدمات اکوسیستم شهری و استفاده از فواید آن می باشد. مطالعه بعد سوم دانش ما را در نحوه شکل گیری اقلیم خُرد شهری افزایش می دهد. هدف این پروژه دکتری پاسخ به سوالات ذیل می باشد: 1) سطح آگاهی تحقیقات از بعد سوم خدمات اکوسیستم شهری، 2) ارزیابی ارتباط شاخص های چندبعدی (دو و سه بعدی) با دمای سطح و 3) ارزیابی الگوی دمای درونی و بیرونی در شهر. جهت پاسخ دادن به سوال های مطرح شده، این پژوهش به چهار فصل تقسیم شده است. فصل اول و دوم، که جایگاه خدمات اکوسیستم را در مطالعات شهری بررسی و جای خالی مفهوم بعد سوم در مطالعات خدمات اکوسیستم شهری را جستجو می کند. فصل سوم، شامل سه مقاله چاپ شده در راستای این پروژه دکتری می باشد. فصل چهارم، که نتایج بدست آمده را تجزیه و تحلیل می کند. نتایج بدست آمده نشان می دهد که مطالعات خدمات اکوسیستم شهری از معنی کلی و بنیادی به سمت سازش پذیری شهرها با پدیده تغییر اقلیم در حال تغییر است. همچنین نتایج نشان می دهد که ساختار متفاوت شهری بر شکل گیری الگوی دمای بیرون و داخل ساختمان ها موثر می باشد. استنتاج نتایج بدست آمده از این پایان نامه دو مورد را پیشنهاد می کند. اول، بررسی نقش ساختار های دو بعدی و سه بعدی بر روی دیگر شهر ها و تاثیر آن بر شکل گیری دمای بیرون و درونی ساختمان ها.

This practicum is a reference for vertical gardeners in cold climates. Winnipeg, Manitoba is explored, however findings may be applied to other cities in similar climates. First, the history of vertical gardening is discussed, then the types of vertical gardens currently on the market are described. These can be classified into two categories: soil bearing or non-soil bearing. Most designs are modular pre-planted systems that can be attached to any wall, as long as it satisfies the structural requirements recommended by the manufacturer. The benefits of vertical gardening have been shown to be rather extensive, covering a wide range of areas. Aesthetic improvement, reduction of the Urban Heat Island (UHI) effect, improvement of air quality, stormwater absorption, noise reduction, native habitat integration, reduction of heating and cooling costs for buildings, food production, marketing, and biophilia are all benefits explored in detail. Difficulties associated with vertical gardening are discussed, specifically the lack of knowledge and awareness of vertical gardens, lack of empirical evidence (or missing details in existing research), overall cost and lack of financial incentives, lack of industry codes, and various associated risks. Design framework exists within microclimate conditions unique to vertical gardens, as well as neighbourhood and regional (micro)climates. Theories relating to the study of green walls covered include the human ecosystem model, urban reconciliation ecology, habitat templating, the urban cliff hypothesis, and wall ecology. Suitable habitat templates identified for vertical gardens in Winnipeg are cliffs, sand dunes, alvars, mixed grass prairie and prairie potholes. Design parameters to be followed for vertical garden design in Winnipeg are to ensure that lightweight materials are used, to provide insulation to protect plants from sudden temperature changes, to choose plants that grow in the region and are adapted to grow in areas with limited soil, increased wind, varying degrees of sunlight (depending on orientation), and increased pollution and salt spray depending on location. / October 2015

Understanding climate change and variability at urban scale is essential for water resource management, land use planning, and development of adaption plans. However, there are serious challenges to meet these goals due to unavailability of observed and / or simulated high resolution spatial and temporal climate data. Recent efforts made possible the availability of high resolution climate data from non-hydrostatic regional climate model (RCM) and statistically downscaled General Circulation Models (GCMs). This study investigates trends in climate and urbanization and their impact on surface water supply for the city of Addis Ababa, Ethiopia. The methodology presented in this study focused on the observed and projected NIMRHadGEM2- AO model and Special Report on Emissions Scenarios (SRES) of B2 and A2 of HadCM3 model are also employed for rainfall, maximum temperature and minimum temperature data using for climate analysis. Water Evaluation and Planning (WEAP) modeling system was used for determination of climate and urbanization impacts on water. Land-Sat images were analyzed using Normalized Differencing Vegetation Index (NDVI). Statistical downscaling model (SDSM) was employed to investigate the major changes and intensity of the urban heat island (UHI). The result indicates monthly rainfall anomalies with respect to the baseline mean showing wet anomaly in summer (kiremt) during 2030s and 2050s, and a dry anomaly in the 2080s under A2 and B2 scenarios with exception of a wet anomaly in September over the city. The maximum temperature anomalies under Representative Concentration Pathways (RCPs) also show warming during near, mid and end terms. The mean monthly minimum temperature anomalies under A2 and B2 scenarios are warm but the anomalies are much lower than RCPs. The climate under the RCP 8.5 and high population growth (3.3 %) scenario will lead to the unmet demand of 462.77 million m3 by 2039. Future projection of urban heat island under emission pathway of A2 and B2 scenario shows that, the nocturnal UHI will be intense in winter or dry season episodes in the city. Under A2 scenario the highest urban warming will occur during October to December (2.5 ºC to 3.2 ºC). Under RCP 8.5 scenario the highest urban warming will occur during October to December (0.5 ºC to 1.0 °C) in the 2050s and 2080s. Future management and adaptation strategies are to expand water supply to meet future demand and to implement demand side water management systems of the city and UHI / College of Agriculture and Environmental Sciences / Ph. D. (Environmental Management)

Tato práce se zaměřuje na představení městské zeleně jako důležitý prvek udržitelné výstavby, a především jako prvek, který zbavuje okolní vzduch znečištění a přispívá k lepšímu prostředí ve městech. Dále se tato diplomová práce zabývá vztahem mezi městskou zelení a znečištěním ovzduší oxidem uhličitým v Brně. Ve městě byla prováděná měření koncentrací oxidu uhličitého, kyslíku a sekundárních veličin po dobu půl roku od června do listopadu roku 2019. Měření byla prováděna na čtyřech místech v Brně a dále tato data byla mezi sebou porovnána. Dále byla navrhnuta zelená opatření. Ve dvou vybraných lokalitách v Brně byly vybrány střechy, na které byla navrhnuta extenzivní zelená střecha.

Introduction is focused on analyze green roof like a part of buiding construction, when thesis assembly principles of right proposal green roof layers. Main part describes characteristic properties green roofs at global impact. We get some added values after comparison with classic roof types. Master thesis consists of survey of added values of green roofs in these categories: life cycle assessment, microclima, outdoor climate, water retention. End of thesis devote to psychological effect of green roofs include questionnare about relationship between czech society and green roofs.

This thesis presents the implementation of data fusion techniques for sustainable urban development. Recently, increasingly more geospatial data have been made easily available for no cost. The immeasurable quantities of geospatial data are mainly from four kinds of sources: remote sensing satellites, geographic information systems (GIS) data, citizen science, and sensor web. Among them, satellite images have been mostly used, due to the frequent and repetitive coverage, as well as the data acquisition over a long time period. However, the rather coarse spatial resolution of e.g. 30 m for Landsat 8 multispectral images impairs the application of satellite images in urban areas. Even though image fusion techniques have been used to improve the spatial resolution, the existing image fusion methods are neither suitable for sharpening one band thermal images nor for hyperspectral images with hundreds of bands. Therefore, simplified Ehlers fusion was developed. It adds the spatial information of a high-resolution image into a low-resolution image in the frequency domain through fast Fourier transform (FFT) and filter techniques. The developed algorithm successfully improved the spatial resolution of both one band thermal images as well as hyperspectral images. It can enhance various images, regardless of the number of bands and the spectral coverage, providing more precise measurement and richer information. To investigate the performance of simplified Ehlers fusion in practical use, it was applied for urban heat island (UHI) analysis. This was done by sharpening daytime and nighttime thermal images from Landsat 8, Landsat 7, and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The developed algorithm effectively improved the spatial details of the original images so that the temperature differences between agricultural, forest, industrial, transportation, and residential areas could be distinguished from each other. Based on that, it was found that in the study city the causes of UHI are mainly anthropogenic heat from industrial areas as well as high temperatures from the road surface and dense urban fabric. Based on this analysis, corresponding mitigation strategies were tailored. Remote sensing images are useful yet not sufficient to retrieve land use related information, despite high spatial resolution. For sustainable urban development research, remote sensing images need to be incorporated with data from other sources. Accordingly, image fusion needs to be extended to broader data fusion. Extraction of urban vacant land was therefore taken as a second application case. Much effort was spent on the definition of vacant land as unclear definitions lead to ineffective data fusion and incorrect site extraction results. Through an intensive study of the current research and the available open data sources, a vacant land typology is proposed. It includes four categories: transportation-associated land, natural sites, unattended areas or remnant parcels, and brownfields. Based on this typology, a two-level data fusion framework was developed. On the feature level, sites are identified. For each type of vacant land, an individual site extraction rule and data fusion procedure is implemented. The overall data fusion involves satellite images, GIS data, citizen science, and social media data. In the end, four types of vacant land features were extracted from the study area. On the decision level, these extracted sites could be conserved or further developed to support sustainable urban development.

L’urbanisation transforme et fragmente le paysage en plus de changer son climat et d’induire une homogénéisation biotique mondiale, c’est-à-dire une perte de biodiversité inter-habitats. Qu’elles soient historiques ou contemporaines, naturelles ou humaines, les nombreuses perturbations au sein d’une ville compliquent l’étude des relations entre les plantes et leur environnement, mais l’originalité de cette thèse est de les décortiquer soigneusement à diverses échelles de temps et d’espace. Mes recherches visent à comprendre l’effet de l’urbanisation sur la diversité floristique et fonctionnelle des boisés. L’étude se déroule à Montréal et sur trois îles environnantes, au cœur de la région la plus peuplée du Québec. J’examine d’abord les changements temporels des communautés végétales d’un boisé, et identifie les processus en cause. La comparaison d’inventaires effectués au Bois-de-Saraguay (96 ha), avec ceux d’une étude similaire menée 30 ans plus tôt, a permis d’atteindre cet objectif. Je regarde ensuite s’il est possible de recourir aux ptéridophytes pour estimer l’intégrité forestière urbaine. À cette fin, la diversité ptéridologique a été répertoriée au sein de 82 boisés (paysage) et de 225 quadrats (microhabitats). Des variables révélatrices des perturbations ont servi à définir les niveaux d’intégrité. En troisième lieu, j’identifie les rôles des contraintes (filtres) associées à l’urbanisation et des processus sous-jacents dans l’assemblage des communautés de sous-bois. Pour ce faire, la diversité des plantes vasculaires de sous-bois a été recensée dans 50 boisés et 431 quadrats. Avec ces données, 18 aspects de la diversité taxinomique et fonctionnelle ont été examinés. Des filtres de grande (paysage) et fine (habitat) échelles ont été définis à partir de variables environnementales et spatiales. Mon dernier objectif consiste à dresser le portrait de la flore de l’aire d’étude. Mon analyse des communautés du Bois-de-Saraguay révèle qu’une homogénéisation fonctionnelle du sous-bois s’y est produite. Celle-ci résulte d’une réorganisation spatiale des populations dans laquelle des espèces similaires — comprenant les plantes ligneuses à fruits charnus et clonales — sont devenues dominantes. Selon mes résultats, ces changements ont commencé grâce à des événements de dissémination des espèces, puis en suivant les perturbations anthropiques en place. Mon analyse de la diversité ptéridologique montre qu’elle diminue dans les boisés perturbés par l’effet d’îlots de chaleur et par l’effet de lisières. Des niveaux d’intégrité du paysage forestier et des microhabitats peuvent donc être indiqués par les ptéridophytes. Mon analyse de la flore de sous-bois montre que les caractéristiques contemporaines des forêts, de la matrice urbaine et des habitats locaux représentent les trois catégories de filtres qui façonnent le plus d’aspects de la diversité végétale. L’histoire forestière influence peu d’aspects, hormis la présence de plantes exotiques par exemple. L’assemblage des communautés est principalement contrôlé par l’environnement et très secondairement par des processus spatiaux tels que la dissémination végétale. L’analyse des filtres révèle que les grands boisés sont riches en espèces, alors que les petits ou ceux de formes allongées favorisent les plantes clonales ou de grande taille. Les plantes se disséminant sans assistance se rencontrent davantage dans les boisés des zones faiblement urbanisées, les arbustes exotiques dans les zones résidentielles et les espèces à fruits adhésifs dans les zones fortement bâties. Les îlots de chaleur font chuter la diversité de traits fonctionnels. À petite échelle, la couverture arborée et arbustive influence fortement le type de diversité des sous-bois. De plus, mes inventaires dévoilent que les boisés étudiés sont très riches en plantes indigènes, qu’ils recèlent encore de nouvelles espèces pour le Québec, et ne comptent pas moins de 20 % de la flore provinciale. En somme, ma thèse milite en faveur de la conservation de l’ensemble des boisés urbains, même ceux de petite taille. / Urbanization transforms and fragments the landscape. It also changes its climate and induces a global biotic homogenization, namely a loss of between-habitat biodiversity. Whether historical or contemporary, natural or human, the numerous disturbances within a city make it difficult to study the relationships between plants and their environment. The originality of this thesis is to dissect them at various scales of time and space carefully. In this context, my main aim is to understand the effect of urbanization on the floristic and functional diversity of woodlands. My study takes place in Montreal and on three surrounding islands of the most populated region of Quebec. I first examine the temporal changes of communities in a forest park and identify the processes involved. The comparison of inventories carried out in the Bois-de-Saraguay (96 ha), with similar surveys conducted 30 years ago, made it possible to achieve this objective. Second, I consider the possibility of using pteridophytes to estimate the urban forest integrity. To this end, I recorded pteridological diversity among 82 woodlands (landscape) and 225 quadrats (microhabitats). I used metrics of disturbances to define the integrity levels. Third, I identify the roles of constraints (filters) associated with urbanization and underlying processes in the assembly of understorey communities. To this aim, I identified the diversity of understorey vascular plants in 50 woodlands and 431 quadrats. From these data, I examined 18 taxonomic and functional diversity aspects. I defined large (landscape) and fine (habitat) scale filters based on environmental and spatial variables. My final objective is to describe the flora of the study area. My analyses reveal that a functional homogenization occurred in the understorey communities of the Bois-de-Saraguay. This homogenization results from a spatial reorganization of communities in which species with similar traits — including woody plants with fleshy fruits and clonality — became dominant. According to my results, these changes began through species dispersal events, then following anthropogenic disturbances in place. Pteridological diversity decreases in woodlands disturbed by the heat island effect and by the edge effect, suggesting that this group of species is a good surrogate for urban forest integrity. My analyses of the understorey flora show that the contemporary features of forests, urban matrix and local habitats represent the three categories of filters that shape the most aspects of plant diversity. Forest history influences few aspects, apart from the presence of exotic plants for example. The assembly of communities is mainly controlled by the environment and secondarily by spatial processes such as plant dispersal. Analysis of the filters reveals that large woodlands are species rich, while small or elongated ones favor tall or clonal plants. Plants with unassisted dispersal are more common in forests located in weakly urbanized areas, exotic shrubs in residential areas, and adhesive-fruit species in highly built-up areas. Urban heat islands significantly reduced the diversity of functional traits. At the fine scale, tree and shrub cover strongly influences the type of understorey diversity. Finally, my inventories reveal that the studied forests are very rich in native plants. They still harbor unrecorded species for Québec and account for no less than 20% of the provincial flora. Overall, my thesis argues for the preservation of all the urban forests, even small ones.