<p>Continuous measurements of carbon fluxes and meteorological variables were made at a newly initiated flux tower site at an oak-dominant temperate deciduous forest in Southern Ontario, Canada from January to December 2012. Results indicate this forest was a moderate carbon sink in 2012. Annual values of net ecosystem productivity (NEP), gross ecosystem productivity (GEP) and ecosystem respiration (R) were 263 ± 30, 1192 and 922 g C m^-2, respectively. An unusual warm period in March caused a strong increase in R. Erratic peaks of daily air temperature in April also increased R. A drought in July and early August reduced NEP rates when soil moisture values reached the lowest point of the year in late July and early August (minimum 0.023 m³ m^-3). This decrease in NEP was mostly caused by a decrease in GEP, rather than increased R. Water use efficiency at this deciduous forest was 2.86 g C kg^-1 H₂O, indicating conservative water use by the forest. Downwelling photosynthetic active radiation (PAR) was a dominant environmental control on photosynthesis, followed by air temperature and vapour pressure deficit, except in extreme dry periods when soil water stress affected carbon uptake. Extremely cloudy days in the growing season resulted in net carbon release due to low photosynthetic uptake values. Results indicate that large climatic fluctuations in this region may cause high instability in photosynthetic carbon uptake and release from soil carbon pools. This study helps to evaluate and quantify the responses of deciduous forests in the Great Lakes region to future climate change and extreme weather events.</p> / Master of Science (MSc)

Freshwater reservoirs store, process, and emit to the atmosphere large quantities of carbon (C). Despite the important role of reservoirs in the global carbon cycle, it remains unknown how human activities are altering their carbon cycling. Climate change and land use are resulting in lower dissolved oxygen (DO) concentrations in freshwater ecosystems, yet more frequent, powerful storms are occurring that temporarily increase DO availability. The net effect of these opposing forces results in anoxia (DO < 0.5 mg L-1) punctuated by short-term increases in DO. The availability of DO controls alternate redox reactions in freshwaters, thereby determining the rate and end products of organic C mineralization, which include two greenhouse gases, carbon dioxide (CO2) and methane (CH4). I performed ecosystem-level DO manipulations and evaluated how changing DO conditions affected redox reactions and the production and emission of CO2 and CH4. I also explored how the magnitude and drivers of CH4 emissions changed spatio-temporarily in a eutrophic reservoir using time series models. Finally, I used a coupled data-modeling approach to forecast future emissions of CH4 from the same reservoir. I found that the depletion of DO results in the rapid onset of alternate redox reactions in freshwater reservoirs for organic C mineralization and greater production of CH4. When the anoxia occurred in the water column (vs. at the sediments), diffusive CO2 and CH4 efflux phenology was affected, and resulted in degassing occurring during storms before fall turnover. I observed that the magnitude of CH4 emissions varied along a longitudinal gradient of a small reservoir and that the environmental drivers of ebullition and diffusion can change substantially both over space (within one hundred meters) and time (within a few weeks). Finally, I developed a forecasting workflow that successfully predicted future CH4 ebullition rates during one summer season. My research provides insight to how changing DO conditions will alter redox reactions in the water column and greenhouse gas emissions, as well as provides a new technique for improving future predictions of CH4 emissions from freshwater reservoirs. Althogether, this work improves our understanding of how freshwater lake and reservoir carbon cycling will change in the future. / Doctor of Philosophy / Freshwater reservoirs store a lot of carbon in their sediments and emit a lot of carbon as greenhouse gases (carbon dioxide and methane) to the atmosphere. However, climate change, land use, and water quality management can change the chemical reactions that are responsible for the production of carbon dioxide and methane, which could have substantial effects on the global carbon budget. Here, I manipulated the oxygen conditions of a freshwater reservoir and monitored the chemistry and greenhouse gas emissions in the experimental reservoir relative to an upstream reference reservoir. I then estimated the methane emissions from the reservoir to understand how the chemistry and greenhouse gas emissions in freshwater reservoirs may change in the future. I found that reservoir oxygen availability controls the magnitude and timing of the chemical reactions that produce carbon dioxide and methane, which in turn alters greenhouse gas emissions. Additionally, I developed models that showed how the magnitude and drivers of methane emissions changed within a small reservoir over time. Finally, I was able to predict the timing and magnitude of methane bubbling from the sediments. Altogether, this work provides evidence how climate change, land use change, and water quality management will affect future water chemistry and greenhouse gas emissions from reservoirs.

Predictions of how forest productivity and carbon sequestration will respond to climate change are essential for making forest management decisions and adapting to future climate. However, current predictions can include considerable uncertainty that is not well quantified. To address the need for better quantification of uncertainty, we calculated and compared ecosystem model parameter, ecosystem model process, climate model, and climate scenario uncertainty for predictions of Southeastern U.S. pine forest productivity. We applied a data assimilation using Metropolis-Hastings Markov Chain Monte Carlo to fuse diverse datasets with the Physiological Principles Predicting Growth model. The spatially and temporally diverse data sets allowed for novel constraints on ecosystem model parameters and allowed for the quantification of uncertainty associated with parameterization and model structure (process). Overall, we found that the uncertainty is higher for parameter and process model uncertainty than the climate model uncertainty. We determined that climate change will result in a likely increase in terrestrial carbon storage and that higher emission scenarios increase the uncertainty in our predictions. In addition, we determined regional variations in biomass accumulation due to a response to the change in frost days, temperature, and vapor pressure deficit. Since the uncertainty associated with ecosystem model parameter and process uncertainty was larger than the uncertainty associated with climate predictions, our results indicate that better constraining parameters in ecosystem models and improving the mathematical structure of ecosystem models can improve future predictions of forest productivity and carbon sequestration. / Master of Science

This research investigated hydrologic connectivity, the intricate network of water pathways linking waterbodies, and its implications for biodiversity exchange in floodplains. Chapter 1 provides an exhaustive literature review encompassing factors influencing hydrologic connectivity, assessment approaches, scales, challenges, and management tools. Existing research often focuses on single scales and short-term periods, revealing a need for comprehensive multi-scale and extended temporal analyses. The absence of standardized definitions and methodologies in this field is also considered. Chapter 2 presents an innovative approach quantifying eight key connectivity metrics using remote sensing and GIS within the Lower Mississippi Alluvial Valley (LMAV). This adaptable method assesses connectivity between oxbow lakes and varying stream sizes, revealing spatial variability within the LMAV and enhancing scientific understanding of connectivity dynamics while ensuring portability. This research is crucial for effective ecosystem management and targeted conservation efforts, particularly regarding invasive species like the bigheaded carps (Hypophthalmichthys spp.).

Klimatförändringar, en ökande urbanisering samt en degraderad biologisk mångfald är utmaningar som gör att våra samhällen behöver anpassas och ställa om genom hållbara lösningar. Naturen kan hjälpa oss med flera av dessa utmaningar, tack vare det som kallas ekosystemtjänster (EST). EST är de nyttor, i form av tjänster och produkter, som naturen tillhandahåller människan vilka bidrar till vårt välmående och vår välfärd. Genom att lyfta fram ett EST-perspektiv i planering och beslutsfattande kan hållbara lösningar främjas för att möta framtidens behov, och för detta har miljöbedömningar identifierats som lämpliga verktyg. Syftet med denna studie är att undersöka hur väl ett EST-perspektiv i dagsläget integreras i miljöbedömningar, samt vilka utmaningar och förbättringsmöjligheter det finns för arbetet framgent. Detta har undersökts med konsultens roll i fokus. Metoden har involverat en litteraturstudie, en dokumentgranskning där miljöbedömningar för detaljplan har granskats, samt en mindre intervjustudie. Resultaten tyder på att konsulten har stor möjlighet att initiera ett EST-perspektiv i miljöbedömningar, och eventuellt även ett ansvar. Dock har ett antal utmaningar identifierats som gör att EST-perspektivet till stor del blir projekt- och kundberoende. En första utmaning är att termen ekosystemtjänster inte finns med i lagtext, vilket gör att den generella uppfattningen är att det inte finns tydligt ställda krav på att inkludera EST i miljöbedömningar. Detta gör i sin tur att ett EST-perspektivet sällan efterfrågas, varken av beställare eller Länsstyrelsen. På grund av detta läggs inte tillräckliga resurser på detta arbete. En andra utmaning är att det i dagsläget inte finns något standardiserat arbetssätt för att systematiskt arbeta med EST i miljöbedömningar. Arbetet framgent behöver därför fokusera på att ta fram ett sådant arbetssätt, så att EST kan integreras i miljöbedömningar på ett effektivt och träffsäkert sätt, och därigenom bidra till mervärden för miljöbedömningen genom ett holistiskt perspektiv. Denna studie har tagit fram ett antal rekommendationer för hur detta arbetssätt skulle kunna utformas. / Climate change, an increasing urbanization and a degraded biodiversity are challenges that force our cities to adapt to new conditions, by implementing sustainable solutions. Nature can help us handle these challenges by something called ecosystem services (ES). ES are benefits provided by the ecosystems - through services and products - which contribute to human well-being. By adopting an ES perspective in planning and decision-making we can promote sustainable solutions to meet the future needs. Environmental Impact Assessment (EIA) and Strategic Environmental Assessment (SEA) have been identified as suitable tools for this. The aim of this study is to examine how well an ES perspective is integrated in environmental assessments today, and to identify challenges and improvements for this work. This has been examined with the role of the consultant in focus. The methods of the study include a literature review, a document analysis where SEAs for detailed development plans are reviewed, and an interview study. The results indicate that the consultant has a large possibility to initiate an ES perspective into the EIA and SEA processes, and possibly also a responsibility of doing so. Furthermore, it has been shown that ES can contribute to added value to the environmental assessments through a holistic perspective. However, several challenges have been identified which makes the ES perspective dependent on the conditions of the project as well as the client’s ambitions. A first challenge is that the term ‘ecosystem service’ is not included in legislation. Because of this ES are seldomly asked for, neither from the clients nor the county administrative board, which are two important actors for setting the scope of the assessment. Consequently, not enough resources are allocated to the work of integrating an ES perspective. Another challenge is that there is no standardized method of systematically implementing an ES perspective into the assessments. Thus, future work needs to focus on developing this methodology, in order to integrate ES into the assessments in an effective and accurate way. The study presents a set of recommendations on how to develop the future work.

I den urbaniseringstrend som pågår och ansträngda situation som den moderna   människan orsakat, behöver naturen skapa sig ny motståndskraft i tidsepoken          antropocen. Om ekonomi och människor ska kunna fortsätta utvecklas behöver hela samhället bli bättre på att förhålla sig inom jordens planetära gränser. I takt med att förtätningar i städer sker riskerar grönområden försvinna eller transformeras till hårdgjorda ytor. Samhället måste ta ett större krafttag eftersom grönstrukturer och ekosystemtjänster bidrar med flera viktiga uppgifter. Förutom att grönområden har betydelse i uppfyllandet av olika klimat- och miljömål inom Agenda 2030, behöver beslutsfattare också utbildas från ett bredare biosfäriskt perspektiv. Om miljöarbetet bromsas upp av en bristfällig stadsplanering på lokal nivå, kan en lösning vara att ta fram olika förbättringsförslag för en grönare stadsplanering. Studiens syfte är att undersöka hur gröna skolgårdar kan bidra till social-ekolgisk resiliens i urbana miljöer, skapa välbefinnande och pedagogiska förtjänster för barn, samt belysa viktiga faktorer som myndigheter, kommuner och stadsplanerare bör beakta vid transformering av en befintlig svensk urban skolgård. Målet med studien har varit att presentera ett gestaltningsförslag, med en typisk svensk urban skolgård som utgångspunkt, utformat mer som ett sammanflätat social-ekologiskt system. Som verktyg för detta ändamål användes ett interaktivt metodupplägg, där kunskap mellan miljövetare och arkitekt integrerades. Genom en fallstudie utförd på Adolf Fredriks musikklassers skolgård i centrala Stockholm visar studien på möjligheten till att skapa nya planeringsstrategier för att barn ska få ett mer kvalitativt utrymme i den urbana miljön. Genom ett litteraturunderlag från tidigare forskning pekar resultat på att ett ökat fokus på ekosystembaserad förvaltning av skolgårdar och ett pedagogiskt lärande utomhus har god potential för att öka välbefinnande hos barn i urbana miljöer. Studiens resultat belyser hur bevarande av arter, ekosystem och dess ekosystemtjänster kan få förbättrat utrymme till att på skolgårdar frodas mer i samklang med barnen. Studien visar även att interaktiv forskning, mellan arkitekt och miljövetare, har möjlighet att konkretisera resultat som kan fungera vägledande med en metodik som även kan appliceras för att göra våra universitetsområden miljövänligare och mer resilienta. Om studiens resultat får tillräckliga spridningseffekter med att gå från ritbord till verklig handling, lämnas öppet för framtida studier att utforska. Om barn ska inspireras till ett större miljöengagemang i samhället, är en bra start att börja transformera Sveriges urbana skolgårdsytor mer som urbana grönområden. / In the ongoing urbanization trend and the strained situation caused by modern man, nature needs to create new resilience in the Anthropocene era. If economy and   people are to be able to continue to develop, the earths planetary boundaries need to be taken in consideration by its inhabitants. As urban densification occurs, green areas risk disappearing or being transformed into hard surfaces. Society must therefore take a greater step because green structures and ecosystem services contribute to several important tasks. In addition to the fact that green areas are important in the fulfillment of various climate and environmental goals within Agenda 2030, decisionmakers also need to be educated from the biospheric perspective. If environmental work is slowed down by inadequate urban planning at the local level, a solution may be to develop improvement proposals for a greener urban planning. The purpose of the report is to investigate how green schoolyards can contribute to social-ecological resilience in urban environments, create well-being and educational benefits for children, and highlight factors that authorities, municipalities and urban planners should consider when transforming an existing Swedish urban schoolyard. The goal of the study has been to present a design proposal, with a typical Swedish urban school yard as a starting point, designed more like an intertwined social-ecological system. As a tool for this purpose, an interactive methodology was used, where knowledge between an environmental scientist and architect was integrated. Through a case study carried out at Adolf Fredrik's music class schoolyard in central Stockholm, the study shows the possibility of creating new planning strategies for children to have a more qualitative space in the urban environment. Through a literature from previous research, results indicate that an increased focus on ecosystem-based management of schoolyards and pedagogical learning outdoors has good potential for increasing the well-being of children in urban environments. The study's results highlight how the conservation of species, ecosystems and their ecosystem services can be improved in order to thrive in schoolyards more in harmony with the children. The study also shows that interactive research, between architect and environmental scientist, can concretize results that can serve as guidelines a methodology that can also be applied to make our university campuses more environmentally friendly and more resilient. Whether the study's findings have sufficient spillover effects to move from the drawing board to real action is left open for future studies to explore. If children are to be inspired to a greater environmental commitment in society, a good start is to transform Sweden's urban schoolyard areas more like urban green areas.

No / Presents comprehensive descriptions of the most significant membrane computing tools developed for various models Describes the most relevant applications, facilitating a better understanding of how the tools are used in building, experimenting with and analysing membrane computing models of complex problems arising in robotics, automatic design of P systems, image processing, ecosystem modelling, systems and synthetic biology, and bioinformatics Discusses efficient software and hardware solutions, together with the algorithms and platforms used

Le concept d’écosystème joue un rôle fondamental dans la réflexion environnementale actuelle. En effet, la façon dont nous le comprenons influence directement les pratiques de conservation et de restauration utilisées en écologie. Les importantes perturbations que subissent les écosystèmes dans le contexte de la crise climatique actuelle amènent les écologues à s’interroger sur les composantes nécessaires d’un écosystème stable (Pesson 1978, 4; Larrère 1994, 33), la conception écosystémique de la nature étant souvent liée à l’idée que cette dernière doit être équilibrée (Blandin 2009, 38). Or, l’aspect polysémique du concept d’équilibre rend son utilisation un peu ambiguë et demande de plus amples précisions (Lepart 1994, 139). Cette idéologie semble être de plus en plus débattue dans le contexte de la conservation, puisqu’un état d’équilibre n’empêche pas la fragilité d’un écosystème (Pesson 1978, 5) et que la présence d’équilibre naturel a également été remise en question (Lepart 1994, 132). En ce qui concerne le concept d’écosystème, le fait que chacun d’entre eux soit unique rend la tâche de définition complexe, car il existe autant de types d’écosystèmes qu’il y a d’écosystèmes (Maris 2010, 63). Cette grande diversité rend également difficile la tentative de définir un critère universel d’équilibre écosystémique, si un tel critère est réellement possible. Ce projet de recherche vise d’abord à mettre de l’avant les différentes façons dont les concepts d’équilibre et d’écosystème ont été mobilisés en épistémologie contemporaine de l’écologie. Il sera ensuite possible d’esquisser une réponse à la question de l’applicabilité du concept d’équilibre à la réalité des écosystèmes. / The concept of ecosystem plays a fundamental role in current environmental thinking. Indeed, the way we understand it directly influences the conservation and restoration practices used in ecology. The significant disturbances that ecosystems are undergoing in the context of the current climate crisis lead ecologists to question the necessary components of a stable ecosystem (Pesson 1978, 4; Larrère 1994, 33), the ecosystemic conception of nature often being linked to the idea that the latter must be balanced (Blandin 2009, 38). However, the polysemous aspect of the concept of balance make its use a little ambiguous and requires further clarification (Lepart 1994, 139). This ideology seems to be increasingly debated in the context of conservation, since a state of equilibrium does not prevent the fragility of an ecosystem (Pesson 1978, 5) and the presence of natural balance has also been questioned (Lepart 1994, 132). Regarding the concept of ecosystem, the fact that each of them is unique makes the task of defining them complex, because there are as many types of ecosystems as there are ecosystems (Maris 2010, 63). This great diversity also makes it difficult in the attempt to define a universal criterion of a balanced ecosystem, if such a criterion is really possible. This research project aims first to highlight the different ways in which the concepts of balance and ecosystem have been used in the contemporary epistemology of ecology. It will then be possible to outline an answer to the question of the applicability of the concept of balance to the reality of ecosystems.

Overfishing in the Benguela Current Large Marine Ecosystem (BCLME) resulted in degradation of the ecosystem. This study used the Driver-Pressure-State-Impact-Response (DPSIR) indicator framework to determine whether the ecosystem is now recovering. Indicator trends were analysed using various data sources that included government institutions and intergovernmental institutions. The results showed that the overall effect of Driver indicators was negative. This was mainly because of socio-economic pressure such as the need to create more jobs in light of rising national unemployment and the declining contribution of the fisheries sector to Gross Domestic Product (GDP). In addition to scientific advice, socio-economic factors also influenced the determination of Total Allowable Catches (TACs). The overall trend of Pressure indicators was positively influenced by the effect of TACs. The TACs reduced the quotas allocated for commercial fishing. Environmental factors did not seem to play a significant role in this study. State indicators had mixed results with the indicators assessed almost split in the middle between those showing a positive trend and those showing a negative trend. On the other hand, Impact and Response indicators showed overall positive results. Therefore, the conclusion of the study was that the degradation of the BCLME has slowed down and there are some signs of recovery. / Environmental Sciences / M.Sc. (Environmental Science)

Les services écosystémiques (SE) réfèrent aux bénéfices que produisent et soutiennent la biodiversité et les écosystèmes et qui profitent à l’être humain. Dans beaucoup de cas, ils ne sont pas pris en compte dans le système économique. Cette externalisation des SE engendre des décisions sur l’utilisation du territoire et des ressources naturelles qui ignorent leur contribution à la qualité de vie des communautés. Afin notamment de sensibiliser l’opinion publique à l’importance des SE et de mieux les intégrer dans les processus décisionnels, ont été développées des démarches d’évaluation économique des SE. Dans cette thèse, nous avons cherché à comprendre à la fois comment l’utilisation passée et actuelle des sols dans la région de Montréal affecte la valeur des SE et comment ces aménités naturelles sont perçues et valorisées par la population, dans une perspective d’aménagement futur du territoire. Pour ce faire, nous avons utilisé deux approches : l’analyse spatiale recourant aux systèmes d’information géographique et l’analyse des préférences exprimées par des techniques d’enquête. Pour l’analyse spatiale, nous avons combiné des analyses cartographiques à des valeurs monétaires associées aux SE publiées dans la littérature. Nous avons alors estimé la valeur des écosystèmes d’un territoire par le transfert de bénéfices, de prix de marchés directs et de coûts évités. Cette démarche nous a permis de comprendre la relation entre l’utilisation actuelle du territoire du Grand Montréal écologique et la valeur des services fournis par les écosystèmes, que nous avons estimée à 2,2 milliards de dollars par année. Elle nous a permis aussi de mesurer les effets sur la valeur des SE du changement d’utilisation des sols entre les années 1960 et 2010. Nous avons montré que malgré différentes politiques de contrôle et d’encadrement de l’étalement urbain au cours de cette période, les pertes économiques non marchandes liées aux SE s’élèvent à 236 millions de dollars par année. Pour l’analyse des préférences exprimées, nous avons utlilisé deux méthodes, l’évaluation contingente et le choix multi-attributs, avec l’objectif de mesurer le consentement à payer de répondants pour des variations dans l’aménagement du territoire. Nous avons montré d’une part que les répondants valorisent significativement l’incidence des pratiques agro-environnementales sur la qualité de l’environnement et des paysages en consentant à payer entre 159 et 333 dollars par ménage par année pour une amélioration de la diversité du paysage agricole. D’autre part, leur volonté à payer pour l’amélioration de l’état des milieux humides du Québec est estimée entre 389 et 455 dollars par ménage par année. L’utilisation conjointe des deux méthodes nous a permis d’en comparer les résultats. Nous avons en outre démontré que le choix du format de question de valorisation de l’évaluation contingente affecte la convergence des résultats. Enfin, nous avons proposé des pistes de recherches futures portant sur l’intégration des démarches d’analyse biophysique, économique et politique dans des outils de prise de décision mieux adaptés à la dynamique des écosystèmes, de la biodiversité et des communautés humaines. / Ecosystem services (ES) refer to benefits produced and sustained by biodiversity and ecosystems that benefit humans. In many cases, they are not considered in the economic system. This externalization of SE generates decisions on land use and natural resources that ignore their contribution to the well-being of communities. In order to raise awareness of the importance of ES and better integrate them into decision-making processes, economic approaches to value ES have been developed. In this thesis, we sought to understand both how the past and current land use in the Montreal area affects the value of ES and how these natural amenities are perceived and valued by the population in a future planning and management perspective. To accomplish this, we used two approaches: spatial analysis using geographic information systems and analysis of stated preferences by survey techniques. In the spatial analysis approach, we combined cartographic analyzes to monetary values associated to ES published in the literature. We then estimated the value of ecosystems using benefit transfer, direct market prices and avoided costs methods. This approach has allowed us to understand the relationship between the current land use in the Greater Montreal and the economic value of the services provided by ecosystems, which we estimated at 2.2 billion dollars per year. It also allowed us to estimate the effects of land use changes between 1960 and 2010 on the value of ES. We showed that despite different land use planning policies implemented to manage urban sprawl during this period, non-market economic losses related to ES have reached 236 million dollars per year. In the stated preferences approach, we used two methods, contingent valuation and choice experiment, with the aim of measuring the willingness to pay of respondents for proposed changes in their environment. In a first study, we showed that respondents significantly value the impact of agri-environmental practices on the quality of the environment and landscapes and are willing to pay between 159 and 333 dollars per household per year on improving the diversity of agricultural landscape. In a second study, their willingness to pay on improving the status of wetlands in Quebec is estimated at between 389 and 455 dollars per household per year. The combined use of the two methods allowed us to compare the results. We also demonstrated that the choice of valuation question format in contingent valuation affects the convergence of the results. Finally, we propose directions for future research related to the integration of ecological, economic and political analyzes of ES that would lead to better assessments of the dynamics of ecosystems, biodiversity and human communities.