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1. Organisms of all species must balance their allocation to growth, survival and recruitment. Among tree species, evolution has resulted in different life-history strategies for partitioning resources to these key demographic processes.Life-history strategies in tropical forests have often been shown to align along a trade-off between fast growth and high survival, that is, the well-known fast–slow continuum. In addition, an orthogonal trade-off has been proposed between tall stature—resulting from fast growth and high survival— and recruit- ment success, that is, a stature−recruitment trade-off. However, it is not clear whether these two independent dimensions of life-history variation structure tropical forests worldwide. 2. We used data from 13 large-scale and long-term tropical forest monitoring plots in three continents to explore the principal trade-offs in annual growth, sur- vival and recruitment as well as tree stature. These forests included relatively undisturbed forests as well as typhoon-disturbed forests. Life-history variation in 12 forests was structured by two orthogonal trade-offs, the growth−survival trade-off and the stature−recruitment trade- off. Pairwise Procrustes analysis revealed a high similarity of demographic relationships among forests. The small deviations were related to differences between African and Asian plots. 3. Synthesis. The fast–slow continuum and tree stature are two independent di- mensions structuring many, but not all tropical tree communities. Our discovery of the consistency of demographic trade-offs and life-history strategies across different forest types from three continents substantially improves our ability to predict tropical forest dynamics worldwide.

Les macroinvertébrés benthiques entretiennent un ensemble complexe d’interactions. Les échelles spatiales et temporelles des processus formant la base de ces interactions ont traditionnellement limité leur étude empirique. Le premier chapitre du manuscrit tente une revue des outils de modélisation utilisés dans l’étude du benthos marin.Même si l’implémentation d’un modèle mécaniste semble s’ajuster aux communautés benthiques, son utilisation nécessite la création d’un nombre limité d’entités avec un rôle fonctionnel clair. Le second chapitre du manuscrit utilise l’hypothèse des groupes émergents, afin de faire cela via une procédure objective et testable. Le groupement est testé face aux postulats théoriques et les résultats supportent sa capacité à reproduire la diversité fonctionnelle dans l’estuaire de la Rance.Le manque de connaissances dans l’attribution des relations entre les composantes fonctionnelles reste important. Le troisième chapitre du manuscrit s’inscrit dans ce besoin, basé sur des théories écologiques qui prévoient l’existence de trade-offs fonctionnels opérant à grande et petite échelle. Dans un premier temps, ces éléments sont incorporés dans des modèles qualitatifs des groupes fonctionnels.Malgré l’intérêt du développement et de l’analyse de modèles qualitatifs, le but d’étudier la dynamique et le comportement spatialement explicite de la biodiversité ne peut être atteint que par un modèle avec ces mêmes caractéristiques. Le quatrième chapitre du manuscrit présente l’architecture d’un modèle individu-centré, en mettant l’accent sur le transfert des règles d’interactions des modèles qualitatifs vers un cadre dynamique et spatialement explicite. / Benthic macroinvertebrates are part of a complex network of interactions. The spatial and temporal scales of the processes that form the basis for these interactions have traditionally restricted their empirical investigation. The first chapter of the manuscript attempts a review of the modelling tools that have been employed for the study of the marine benthos.The implementation of a mechanistic modelling framework seems fitting, but it requires the derivation of a few model entities with a clear functional role. The second chapter of the manuscript employs the emergent group hypothesis to do that in a way that is objective and testable. The resulting grouping is tested against theoretical expectations and the results support its ability to represent functional diversity in the Rance estuary.The lack of knowledge for the attribution of relationships among functional components is still important. The third chapter of the manuscript addresses this issue based on ecological theories that predict the existence of functional trade-offs operating at both large and small spatial scales. In a first inception of the system, these elements are incorporated in the form of general rules of interaction into qualitative models of the functional groups.In spite of the interest in developing and analysing qualitative models, the goal of studying the dynamic and spatially explicit behaviour of benthic biodiversity can only be reached by a model with the same characteristics. The fourth chapter of the manuscript presents the architecture of an individual-based model, primarily transferring the rules of interaction from the qualitative models to a dynamic and spatially explicit framework.

Sexually selected ornaments are among the most spectacular traits in nature. Indeed, the extreme costs associated with producing sexual traits seem to play a crucial role in their evolution by enforcing honest levels of advertisement: only males with high levels of acquired resources (or high ‘condition’, as it is known in the literature) can afford to produce extravagant signals, a phenomenon which maintains signal reliability in a constant environment. In my thesis I examine many implications of this condition-dependent model of ornament and preference evolution for variation in age-dependent allocation to sexual signals and other life history traits. In Chapter 1, I review theoretical implications of condition-dependent signalling for life history and sexual selection theory. I note that a universal cost of expenditure in sexual advertisement is metabolic in nature: metabolites used to fund ornament expression are by definition unavailable to other life history traits that compete for a limited resource pool. This universal constraint on expenditure does more than maintain honesty (as noted above), however: the reliance of sexual displays on high levels of nutrient acquisition may help maintain genetic variation in sexual signals that would otherwise be eroded by strong mate choice, and without which the selective basis for good-genes choice would disappear. Three mechanisms in particular probably help to maintain genetic variation in acquisition. 1) Because acquiring resources and converting them efficiently to useful forms depends on the high function of many biochemical pathways, condition is undoubtedly highly polygenic, which slows the erosion of genetic variation under strong directional selection by females (especially in the presence of epistatic interactions). 2) The highly polygenic nature of condition also presents a large target for mutation, which continually restores variation at the loci under selection. 3) The many loci underlying condition may also be particularly sensitive to environmental heterogeneity in time or space. By favouring the most ornate males, females acquire high performing genes for their offspring, regardless of the precise allele combinations that have conferred the ability to acquire resources. Selection on specific alleles is liable to fluctuate over time or space whenever allelic performance is strongly context-specific. I close by noting the considerable challenges in advancing research on sexual selection and life history allocation, including the fact that two key processes central to life history (acquisition and allocation) are latent variables that interact in complexways and are intrinsically difficult to measure empirically. In the remainder of my thesis I conduct a series of experiments involving decorated crickets, Gryllodes sigillatus, which are useful models for studying life history because they enable precise measurement of male reproductive effort. Male G. sigillatus face important allocation decisions owing to the highly polyandrous nature of females, and the substantial costs involved in signalling and mating. Chapter 2 examines sex differences in age-dependent reproductive effort as a function of diet and development stage. I reared outbred crickets using four combinations of diet nutritional quality, and studied the effects of these combinations on male and female reproductive effort (calling effort in males and fecundity in females) and longevity. While I expected males to be more sensitive than females to variation in diet and developmental changes in its quality, I actually observed the opposite: males in all treatments increased calling effort over time, exhibiting consistently positive covariance between calling effort and longevity across treatments. By contrast, the relationships between female reproductive effort and longevity changed dramatically across treatments, and females who lived to intermediate ages had the highest fecundity. Although my results support sex-specific selection on life history allocation over time, a compelling additional explanation for my findings relates to the strategic role of calling for achieving male fitness. In the absence of positive feedback from potential mates, perhaps male allocation to sexual advertisement is careful and only increases gradually as a function of accumulating metabolic resources and increasing risk of intrinsic mortality. Alleles underlying condition are expected to be particularly sensitive to environmental heterogeneity. While this sensitivity may help maintain additive variation in male quality (which is essential for the sustenance of adaptive good-genes mate choice, as noted in Chapter 1), too much environmental sensitivity could also underiii mine the signal value of the male trait. For example, if there are strong genotypeby- environment interactions (GEIs) for sexual advertisement, in a rapidly changing environment females risk favouring a male whose alleles are no longer best suited to current conditions. This problem is particularly pressing for animals like crickets where males exhibit a behaviourally plastic sexual display (such as calling), and so may dynamically adjust signalling effort over time. In Chapter 3, I used inbred lines of decorated crickets to quantify age and diet dependent genetic variation in male signalling. I demonstrate that while genetic correlations across diets were quite strong for morphological traits, correlations between measures of the male sexual trait rapidly approached zero as I increased the distance in time (i.e., across widely spaced ages) or diet (i.e., comparing more dissimilar dietary histories) between samples. While extrapolating from my laboratory experiments to nature is difficult, my findings nevertheless cast doubt on the value of behaviourally dynamic signals (such as cricket calls) for reliably indicating genetic quality in realistically complex environments. In Chapter 4 I used physiological assays to evaluate factors affecting metabolite storage and use over time in decorated crickets. I manipulated the acquisition ability of all males using artificial diets that varied linearly in nutrient quality, and manipulated access to female mates over the course of the second week of adult life. By sacrificing crickets at key stages before and after manipulating the diet and social environment, I was able to estimate changes in stored metabolites, and relate these changes to calling effort and longevity. During the first week of adulthood (in the absence of females), higher diet quality significantly increased calling effort and storage of lipid, glycogen, and carbohydrate (but not protein). The presence of females increased both the probability of calling and the amount of calling during the second week, whereas diet quality only improved calling effort. By the end of the second week, calling effort had decreased, even by high quality males in the presence of females, suggesting a depletion of resources. Furthermore, the loss of condition during week 2 covaried with calling effort during the previous week irrespective of diet. Males who started the second week in high condition lost more glycogen and carbohydrate than rivals; meanwhile, lipid accumulation covaried positively with calling effort during week 2. The contrasting patterns of storage and use for lipids compared to the ‘quick-release’ metabolites (glycogen and carbohydrates) affirms starkly distinct functions for the different storage components, and underlines the importance of specific physiological measures in life history research. Finally, in the general discussion, I attempt to synthesise my thesis’s contributions to the study of life history trade-offs involving behavioural sexual displays.

Introduction: En réponse aux exigences du gouvernement fédéral en ce qui concerne les temps d'attente pour les chirurgies électives d’hanche et du genou, les Organismes Canadiens de santé ont adopté des stratégies de gestion pour les listes d'attente. Cependant, il n'existe pas actuellement aucune information disponible concernant les effets imprévus, positive ou négative, de ces stratégies. Méthodologie: Un modèle qui a été construit est tombé en panne la gestion de la chirurgie d’hanche et du genou en différentes étapes, afin d'identifier les effets imprévus possibles pour chaque étape; le modèle a été validé auprès d'un panel d'experts. Cette étude a choisi quatre études de cas en fonction de leur durabilité: un cas qui a été durable, un cas qui a été modérément durable, et deux cas peu probable d'être durable. Dans cette étude qualitative, nous avons mené 31 entretiens semi-structurés entre Novembre 2010 et Juin 2011 avec les gestionnaires, les infirmières, les thérapeutes et les chirurgiens impliqués dans la gestion des stratégies du temps d’attente pour les chirurgies électives d’hanche et du genou. Les quatre cas ont été sélectionnés à partir de trois provinces / régions. Nous avons analysé les conséquences non intentionnelles aux niveaux systémique et organisationnelle en utilisant les stratégies dans chaque contexte. Enregistrements des entrevues ont été transcrits mot à mot et soumis à l'analyse du cadre. Résultats: Les effets négatifs sont la précarité des stratégies en raison du non-récurrente financement, l'anxiété chez les patients qui ne sont pas prêts pour la chirurgie, une redistribution du temps de chirurgie vers l’orthopédie au détriment des autres interventions chirurgicales, tensions entre les chirurgiens et entre les orthopédistes et anesthésistes, et la pression sur le personnel dans le bloc opératoire et postopératoire. Conclusion: La stratégie d’implémentation aux niveaux national et local devrait prendre en compte les conséquences potentielles, positives et négatives. Il y a des conséquences inattendues à chaque niveau de l'organisation des soins de santé. Individuellement et collectivement, ces conséquences peuvent positivement et négativement affecter les résultats. Par conséquent, la planification de la santé doit analyser et prendre en compte les conséquences inattendues en termes de bonnes résultats inattendues, compromis et les conséquences négatives afin d'améliorer les résultats. / Introduction: In response to federal government requirements regarding wait times for elective hip and knee surgeries, Canadian healthcare organizations have adopted wait list management strategies. However, there is currently no information available regarding the unanticipated effects, positive or negative, of these strategies. Methodology: A model was constructed that broke down the management of elective hip and knee surgery into different steps, in order to identify the unanticipated potential effects for each step; the model was validated with a panel of experts. This study chose four case studies based on their sustainability: one case that was sustainable, one case that was moderately sustainable, and two cases considered unlikely to be sustainable. In this qualitative study, we conducted 31 semi-structured interviews between November 2010 and June 2011 with managers, nurses, therapists and surgeons involved in wait time management strategies for hip and knee surgeries. The four cases were selected from three provinces/areas. We analyzed potential unintended consequences at the systemic and organizational levels of using these strategies in each setting. Interview recordings were transcribed verbatim and subjected to framework analysis. Results: Negative effects were the strategies’ precariousness due to non-recurrent funding, anxiety in patients not ready for surgery, a redistribution of surgical time toward orthopaedics at the expense of other surgeries, tensions between surgeons and between orthopaedic surgeons and anaesthesiologists, and significant pressure on personnel in the operating suite and in post-operative care. Conclusions: Strategy implementation at the national and local levels should take into consideration any potential consequences, positive and negative. There are unintended consequences at each level of healthcare organization. Individually and jointly, these consequences can positively and negatively affect outcomes. Therefore, health planning should analyze and take into account unintended consequences in terms of serendipities, trade-offs and negative consequences in order to improve results.

This study investigates the Louisiana 2012 Coastal Master Plan’s ability to reconcile conflicting economic and ecological demands on coastal resources. The Louisiana Coastal Master Plan was unique in combining flood control and coastal restoration under one authority. However, the objectives of flood control and coastal restoration can be in conflict. The plan was also unique in its approach of restoration from a working coast perspective. However, the objectives of ecological restoration and economic productivity do not always agree. By conducting semi-structured interviews with major coastal stakeholders, this research will explore how the planning process has accommodated the views and values of key stakeholder parties. This research aims to make more transparent the inherent environmental tradeoffs of restoration from a working coast perspective. A working coast is a compromise between economic and environmental stakeholder needs. The approach requires a balance of power to ensure that the projects selected best serve the needs of all parties. The study found that while there is industry buy in, mechanisms for mitigating economic externalities is lacking in the plan, corporate infrastructure benefits while wildlife resources are in decline.

De nos jours plus que jamais, il est nécessaire d’anticiper et de comprendre les réponses évolutives des organismes vivants, face à des habitats instables et hétérogènes. Mais à quel point cela est-il possible ? Reproduire l’ensemble du déroulé d’une trajectoire évolutive nécessite de pouvoir décrire, d’une part, le « matériel » disponible pour s’adapter (c’est-à-dire les effets phénotypiques associés à la variabilité génétique produite), d’autre part, comment agissent les forces évolutives, associées à un contexte écologique, pour aboutir à un certain « assemblage » de ce matériel. Dans sa version la plus simple, ce processus évolutif peut-être décrit par plusieurs cycles d’évènements de mutations-sélection conduisant à l’adaptation d’une population à son environnement. Cette dynamique correspond assez bien à celle qui est décrite par les populations bactériennes dans les expériences d’évolution contrôlées en laboratoire. Parallèlement, les modèles de paysages adaptatifs (phénotypiques), et en particulier le modèle géométrique de Fisher, sont des outils très puissants pour formuler des prédictions générales et quantitativement testables sur ces trajectoires évolutives. Cependant, ils restent très théoriques et ont été largement pensés dans un contexte écologique simplifié. Au cours de cette thèse, nous avons identifié les déterminants (mutationnels et sélectifs) des trajectoires évolutives à long terme de populations bactériennes s’adaptant dans différents contextes environnementaux. Une première partie des résultats est mise en lumière par la validation expérimentale et la reconstruction de la topographie du paysage adaptatif généré par différentes doses d’un antibiotique, le long d’un gradient. Une deuxième partie expérimentale vise à intégrer une composante biotique (une autre bactérie) à ce même contexte environnemental. Les processus évolutifs intervenant au cours d’une coévolution à long terme maintenue par sélection fréquence-dépendante, y sont étudiés. / Today more than ever, it is crucial to anticipate and understand the evolutionary responses of living organisms faced with heterogeneous and unstable habitats. But to what extent is this possible? To reproduce an entire evolutionary trajectory, we must first describe the “material” available for adaptation (e.g. the phenotypic effects associated with the existing and novel genetic variability), and second describe the way evolutionary forces, shaped by the ecological context, result in specific “assemblies” of this material. At its simplest, this evolutionary process can be described by several cycles of mutation-selection events, leading to the adaptation of a population to an environment. This process is reflected in the evolutionary trajectories of bacterial lineages undergoing controlled experimental evolution in the lab. Concurrently, adaptive (phenotypic) landscape models, and especially Fisher’s geometrical model of adaptation, are powerful tools to formulate general predictions, which can then be tested on such evolutionary trajectories. However, they remain highly theoretical, and are widely conceived in a simple ecological context. In this thesis, we identified the (mutational and selective) determinants of the evolutionary trajectories of bacterial lines adapting to various environmental contexts. A first set of results regards evolution along a gradient of antibiotic doses, and their relevance is highlighted by experimental validation and by the reconstruction of the underlying adaptive landscape. A second experimental part integrates a biotic component (another bacteria) to the same environmental context. The evolutionary processes acting throughout the resulting long-term coevolution – maintained by frequency-dependent selection – are studied.

La crise financière de 2008-2009 a conduit à reconsidérer la relation entre politique monétaire et stabilité financière, soulignant la nécessité pour les banques centrales d’être plus attentives aux risques financiers. Cette crise a également mis en évidence les limites du cadre de régulation (micro)prudentielle existant, renforçant ainsi l’importance d’une approche macroprudentielle visant à contenir le risque systémique. La présente thèse s’articule autour de ces questions. L’objectif est d’analyser dans quelle mesure un cadre de politique monétaire avec pour objectif principal la stabilité des prix (tel le ciblage d’inflation), pourrait accentuer le risque d’instabilité financière. Il s’agit en outre de souligner et discuter le rôle que peuvent jouer les politiques monétaire et macroprudentielle pour assurer et renforcer la stabilité du secteur financier (Chapitre I). Les résultats de l’analyse suggèrent que les banques centrales cibleuses d’inflation ont été mieux à même de contenir les conséquences de la récente crise financière (Chapitre II). Cependant, il semble que le risque d’instabilité financière soit plus fort au sein des pays émergents cibleurs d’inflation (comparé aux non-cibleurs), malgré les réponses des banques centrales aux déséquilibres financiers (Chapitre III). Ceci remet en cause l’efficacité de la stratégie du leaning against the wind. Nos conclusions montrent que cette stratégie génère un conflit d’objectif entre stabilité macroéconomique et stabilité financière. La mise en place d’un cadre macroprudentiel efficace, associé à une politique monétaire plus sensible aux risques financiers, permettrait de garantir un environnement économique globalement plus stable (Chapitre IV). Par ailleurs, il apparait que les pays émergents cibleurs d’inflation s’appuient sur le contrôle du taux de change pour faire face à la forte vulnérabilité de leur système financier aux chocs externes; ceci en dépit de l’exigence de flexibilité du change que requiert cette stratégie de politique monétaire (Chapitre V). / The 2008/2009 global financial crisis has revived the debate on the concern for financial stability in themonetary policy-making, stressing the need to reconsider the role of central banks in ensuring financialstability. The crisis has also pointed some flaws in the existing (micro) prudential regulation and therelevance to move toward a broader regulatory framework aiming to prevent systemic risk. This thesis isbuilt upon these issues. It investigates the extent to which financial stability may be of particular concernin a context where the main monetary policy objective is inflation stabilization (typically, in an inflationtargeting regime –IT–). It further assesses how the macroprudential framework and monetary policy canbe articulated to ensure the best outcome in terms of macroeconomic and financial stability (Chapter I).The conclusions derived from this work suggest that, faced with the recent global financial turmoil,inflation targeting central banks have been more able to mitigate the shock, certainly thanks to higherpolicy credibility (Chapter II). However, we evidence that IT countries (especially in EMEs) are morefinancially vulnerable than their non-IT counterparts, despite central banks’ response to financial risks(Chapter III). Following the latter conclusion, we investigate more closely the effectiveness of the leaningagainst the wind strategy. We show that such a policy response generates trade-offs between thefinancial and macroeconomic stability objectives of the monetary authorities. The best stabilizationoutcome is achieved when an effective macroprudential framework is implemented, combined withhigher central bank’s concern with financial risks (Chapter IV). Furthermore, we show that in EMEsITers, foreign exchange interventions are used to mitigate their financial vulnerability to external shocks,although the IT regime requires a fully floating exchange rate regime (Chapter V).

The doctoral research revolves around a comparative study of timber modern methods of construction for low-rise, residential buildings in Scotland. The building techniques studied involve both timber-frame panel construction (open-panel and closed-panel systems and structural insulated panels) and massive-timber construction (cross-laminated and nail-laminated timber panels). A non-timber technique is also included in the study: more traditional, load-bearing masonry (blockwork). These different building techniques have been analysed from two complementary aspects: environmental impacts and thermal performance. The environmental study is based on the life-cycle assessment methodology and embraces various aspects: environmental impacts (e.g., climate change, acidification, eutrophication, ozone depletion, etc.), consumption of energy (renewable and non-renewable resources) and production of waste (from non-hazardous to radioactive). The assessment takes a cradle-to-gate approach and, in its structure and method, is informed by the current recommendations of the international standards in the field (i.e., ISO 14040 series). Various environmental trade-offs between construction methods have been identified. In terms of global-warming potential (excluding biogenic carbon sequestration), results suggest that timber-frame buildings show a better performance than masonry buildings; this is particularly true for the open-panel system, which emits about 10% less carbon than the masonry counterpart. Massive-timber buildings tend to cause more carbon emissions than masonry ones. In terms of consumption of non-renewable primary energy, timber buildings do not generally show significant advantages with respect to blockwork-based masonry. In particular, structural-insulated panel systems tend to show very high energy requirements. Timber-based buildings show a tendency to cause increased acidification, eutrophication and creation of low ozone than their masonry counterpart. The level of offsite fabrication that is employed for the erection of the buildings plays an important role in the magnitude of most environmental impacts, which show an average decrease between 5% and 10% when some of the operations are shifted from the construction site to the factory. v The thermal study investigates the performance of the building envelope, and, in particular, of external walls, by means of tests whereby the thermal behaviour of a sample of walls (of full-size section) has been observed and measured over time. On the outside, the walls were exposed to real, natural weather variations throughout the summer. The study especially focuses on the time-dependent response of three different walling systems (which results from their individual cross-sectional arrangements of building components and the associated combination of heat-storage capacity and thermal resistance): a timber-framed wall, a cross-laminated-timber wall and a masonry wall. Thus, the main goal of the study was to characterise the thermal-inertia parameters of these walls. This type of thermal behaviour is related to the repercussions of global climate change at UK level, especially in terms of increase in solar irradiance and temperature, which requires an adaptation of the building-envelope such that it can perform well both during wintertime and summertime, by providing maximum indoor comfort with minimum economic and environmental costs from the construction and operation of buildings. The timber-framed wall possesses the greatest capacity to slow down the propagation of temperature waves from the outer surface to the inner surface (time lag), whereas the masonry wall performs best with respect to reducing the amplitude of temperature oscillation on the inner surface (decrement factor). The cross-laminated-timber wall exhibits intermediate values of both time lag and decrement factor, relative to the other two walls. Both the thermal and life-cycle assessment of the construction alternatives aim at assisting the design and decision-making process in the residential field and at suggesting areas that need to be addressed and improved, towards a coherent evolution of the building techniques included in this study and a step forward in the realisation of sustainable, low-rise dwellings.