Bangladesh is one of the most vulnerable countries to climate change, with coastal areas being especially vulnerable. Along the Bangladeshi coast lies mangrove forests that protect against storm surges, tropical cyclones, SLR, coastal erosion, and salt-water intrusion. On Char Kukri Mukri, a remote island in the Bay of Bengal, Keora-species (Sonneratia apetala) mangroves are planted. The forest is virtually a monoculture in degradation and thus needs restoration through enrichment. Therefore, this study aimed to explore the opportunities and limitations of mangrove enrichment as climate adaptation on Char Kukri Mukri. We conducted semi-structured interviews with local communities and other key stakeholders and analysed soil and water samples along the island's south coast to assess this. Our results indicate that the soil is highly saline, which, combined with projected climate impact, limits the abilities of more sensitive mangroves to survive there. Climate impacts severely affect the lives and livelihoods of the people living on Char Kukri Mukri. Successful adaptation requires further involvement of local communities, site-specific solutions, and a holistic approach to adaptation. However, a hindrance to adaptation measures is the lack of resources to fund large-scale projects, which leads to beneficiaries being required to provide money and land themselves to be considered for projects. This risks systematically excluding the landless poor, and there is therefore a need to reform adaptation financing systems so that measures benefit the most vulnerable. / Bangladesh är ett av de länder i världen som är mest sårbara för klimatförändringarna. Kustområdena är mest känsliga. Längs Bangladeshs kust finns mangroveskogar, som skyddar mot klimateffekter som stormar, cykloner, havsnivåhöjning, kusterosion, och saltvattenintrång. På Char Kukri Mukri, en avlägsen ö utanför Bangladeshs centralkust i Bengaliska viken, har mangrover av arten Keora (Sonneratia apetala) planterats. Skogen är praktiskt taget en monokultur som håller på att förstöras, och det finns därför ett behov av att restaurera skogen. Denna studie syftade till att undersöka möjligheterna och hindrena för restaurering av mangroveskogarna som klimatanpassning på Char Kukri Mukri. För att uppnå detta genomförde vi semistrukturerade intervjuer med lokalbefolkningen och andra nyckelintressenter, och analyserade jord- och vattenprover tagna vid öns sydkust. Våra resultat indikerar att jorden har hög salthalt, vilket i kombination med ökade klimateffekter minskar mer känsliga mangrovearters möjligheter att överleva i dessa områden. Klimateffekter påverkar människorna och deras försörjning på Char Kukri Mukri i hög grad. Lyckad klimatanpassning kräver mer inkludering av lokalbefolkningen i initativ, platsspecifika lösningar, samt ett holistiskt tillvägagångssätt. Resursbrist hindrar dock investeringar i storskaliga och långsiktiga projekt, vilket gör att förmånstagare behöver bidra med pengar och mark till projekten. Detta gör att fattiga människor som inte äger mark systematiskt exkluderas ur anpassningsprojekten. De nuvarande finansieringssystemen behöver därför reformeras för att projekten ska ge fördelar till de människor som är mest sårbara för klimatförändringarna.

The establishment of monoculture plantations of exotic tree species is common practice for supplementing native timber stocks. Such plantations typically provide inferior habitat for wildlife compared to native forest, which may result in a net reduction in biodiversity. However, some studies report that plantations may increase net biodiversity at the landscape scale by introducing novel habitats or supplementing existing natural forests. Using point count surveys, I examined six mature Norway spruce (Picea abies) plantations in western Massachusetts in 2016 and 2017 to evaluate bird use of these habitats relative to native forest stands. Count data were analyzed using N-mixture models to correct for imperfect detection, providing more accurate estimates of true abundance. Our findings showed that overall species richness for spruce plantations was not significantly lower than that of native forest habitats. Red-breasted nuthatch (Sitta canadensis) and golden-crowned kinglet (Regulus satrapa) were most abundant in spruce plantations. Conifer dependent species such as Blackburnian warbler (Setophaga fusca) and brown creeper (Certhia americana), were significantly more abundant in spruce plantations relative to native deciduous, hemlock, and mixed stands. Species that heavily associate with broadleaf habitat were rarely observed in spruce plantations. Species that associate with eastern hemlock habitat, such as Blue-headed vireo (Vireo solitarious) and black-throated green warbler (Setophaga virens) were observed using spruce plantations at similar levels as eastern hemlock stands. These results demonstrate that Norway spruce plantations can provide suitable habitat for native species associated with conifers, which is significant given projected continued decline of eastern hemlock in response to the hemlock wooly adelgid (Adelges tsugae). Although large-scale conversion of native forest to plantations would likely lead to a loss in biodiversity, land managers could be justified in allowing small-scale plantations to persist without suffering negative impacts to native biodiversity.

Chemical site preparation is used to enhance the productivity of loblolly pine plantations; however, it is most often combined with other methods and/or chemical release, and has been studied little on its own. Our study, conducted in the Virginia piedmont, compares the effects of various site preparation applications of imazapyr and their timings (July 23rd, September 3rd, and October 1st 2005) against a year-two chemical release (September 12th 2007), and an untreated check, all following a site preparation burn (June 15, 2005). Testing for additive effects, site preparation treatments were conducted with and without, sulfometuron methyl (SMAX) which targets herbaceous vegetation. Half of all treatments, including the check and release, received a year-one weed control treatment (H) of imazapyr and SMAX. Pines were measured every few years, including the latest measurement in year 14 (2019). Competing hardwood vegetation basal area was measured in year 14. All site preparation treatments reduced competition levels compared to the check, and an inverse relationship exists between competition level and pine volume. Adding SMAX resulted in less effective competition control, but had little effect on pine volumes. Adding H decreased average competition levels, and increased pine volumes. H treatments had the most effect at improving early season (July) applications. September and October treatments generally had more effect than July and the year-two release at controlling competing vegetation, and also showed higher individual pine tree volumes than all other treatments. Chemical site preparation treatments, even performed alone, appear to be valid means of improving pine stands. / Master of Science / Competing vegetation has a negative effect on planted pine production. Areas are often prepared with herbicides or mechanical removal of vegetation before crop-trees are planted (site preparation), or receive herbicide treatments after planting (release), to reduce levels of competition. Our study focuses on pre-planting herbicide (imazapyr with and without sulfometuron methyl) use at different timings (July 23rd, September 3rd, and October 1st). A chemical that targets herbaceous vegetation (sulfometuron methyl) was included in half of the pre-planting treatments, and half of all treatments, including the otherwise untreated check and year-two release, received an added weed control treatment in year-one. This was done to test for potential additive effects of chemical vegetation control options on pine productivity. September and October treatments have a greater effect at controlling competition 14 years since treatment and increasing pine volumes than the July, year-two release, and check. The added herbaceous control increased competition levels on average, without having an effect on the planted pine volumes. The year-one weed control decreased competition levels, and increased pine productivity, particularly within the July treatments. Overall, preparing sites with herbicide is beneficial to the pine stand, even when performed alone. Adding the herbaceous vegetation control is likely not necessary, and the extra year-one weed control may provide a boost to herbicide treatments applied earlier in the season.

The effect of the Civil War and Reconstruction on the southern planter elite remains a topic of interest to historians. Did the war ruin the planter class? Or, did they maintain economic, geographic, or social persistence? This study focuses on the persistence from 1850 to 1880 of five East Texas large planter families who owned one hundred or more slaves in 1860. An analysis of data primarily from county, state, and federal records formthe basis of this study. Four families persisted as wealthy influential members of their postbellum communities. One family remained geographically persistent but not wealthy. The experiences of these families suggest that large East Texas planter families found it possible to persist in spite of the Civil War and Reconstruction.

Biosolids, materials resulting from domestic sewage treatment, are surface applied to forest soils to increase nutrient availability. Retaining streamside management zones (SMZs) can limit nutrient pollution of streams. We delineated 15 m SMZs along three intermittent streams in an 18-year-old Pinus taeda L. plantation. We applied biosolids outside the SMZ on one side of each of the streams maintaining the other side of the stream as control. We collected water samples from the three treated and six reference streams as well as from the perennial stream both upstream and downstream from the intermittent streams for 12 months following treatment. Along transects perpendicular to the treated streams, we collected overland flow samples, soil solution samples at 60 cm and extracts from ion exchange membranes (IEMs) placed in the surface soil. We found elevated nitrate concentrations outside the SMZ in the treated side soil solution samples, in which concentrations remained below 1.5 mg L-1. Nutrient concentrations outside the SMZ in treated side IEM extracts increased following biosolids application, returning to near control levels after one year. Nutrient concentrations in IEM extracts were not elevated adjacent to the streams. We observed elevated phosphorus concentrations adjacent to the stream in overland flow during one period on the treated side of the stream. Stream nutrient concentrations showed few differences downstream from the treatment with concentrations below 1.5 mg L-1. Our results indicate that a 15 m SMZ protected streams from nutrient pollution for the first year following biosolids application to adjacent forestlands. / Master of Science

La plantation d'arbres est un outil d'aménagement permettant de restaurer les écosystèmes forestiers dont la résilience est compromise par l'intensité et la répétition d'une perturbation, mais peut être insuffisante si le régime de perturbation est maintenu. Les plantations de sapins baumiers sont utilisées sur l'île d'Anticosti pour restaurer l'habitat du cerf de Virginie. Pour favoriser la régénération naturelle ainsi que la croissance des sapins plantés, des enclos ont été érigés et les densités de cerf y ont été réduites afin de diminuer la pression de broutement. Notre objectif était d'identifier les facteurs qui influencent l'herbivorie à l'échelle du paysage et à l'échelle locale et d'identifier les facteurs influençant la croissance du sapin, notamment l'herbivorie, les caractéristiques du sol et la végétation avoisinante. Nous avons mesuré la croissance de 114 sapins baumiers situés dans deux enclos de gestion après 8 ans. Après le démantèlement des enclos, nous avons évalué l'intensité du broutement et l'occurrence d'écorçage des sapins. À l'échelle du paysage, l'intensité du broutement augmente en se rapprochant des peuplements de conifères matures, mais pas l'écorçage. L'intensité du broutement sur le sapin augmente également avec la densité d'épinettes blanches environnantes. L'abondance en sapin baumier et bouleau blanc augmente le risque des sapins d'être écorcés. Enfin, l'addition des effets négatifs du broutement et de la densité de végétation sur la croissance des sapins ont permis de mieux prédire la croissance des sapins une meilleure prédiction que les effets individuels de ces deux facteurs. En revanche nous n'avons pas observé d'effet de la composition chimique du sol sur la croissance. Nos résultats montrent que le succès de la restauration des écosystèmes forestiers par la plantation dépend de la végétation avoisinante qui influence indirectement la croissance via le broutement ainsi que directement par la compétition pour les ressources. / Tree planting is a management tool to restore forest ecosystems whose resilience is compromised by the intensity and repetition of a disturbance, but may be insufficient if the disturbance regime is maintained. Balsam fir plantations are used on Anticosti Island to restore white-tailed deer habitat. To promote natural regeneration and growth of planted fir trees, enclosures were erected and deer densities were reduced to decrease browsing pressure. Our objective was to identify factors influencing herbivory at the landscape and local scales and to identify factors influencing fir growth, such as herbivory, soil characteristics, and surrounding vegetation. We measured growth of 114 balsam fir trees located in two management enclosures after 8 years. After dismantling the enclosures, we assessed browsing intensity and the occurrence of fir bark. At the landscape scale, browsing intensity increased as we approached mature conifer stands, but bark stripping did not. Browsing intensity on fir increases with surrounding white spruce density. Abundance of balsam fir and white birch increases the risk of fir being bark stripped. Finally, the addition of the negative effects of browsing and vegetation density on fir growth resulted in a better prediction of fir growth than the individual effects of these two factors. In contrast we did not observe an effect of soil chemistry on growth. Our results show that the success of forest ecosystem restoration through planting depends on the surrounding vegetation, which influences growth indirectly via browsing as well as directly by the competition for resources.

Suite à l’abandon agricole, le nouveau milieu forestier en développement est souvent peu diversifié en espèces d’arbres de grande valeur économique. La solution qu’est la plantation d’enrichissement sous couvert doit intégrer l’effet d’interception lumineuse des manchons protecteurs contre le broutage. À cette fin, des ouvertures du couvert par bandes larges de 3, 6 et 9 mètres, combinées à deux manchons protecteurs à petites et grandes mailles et à un témoin, sont comparés. L’expérience analyse l’effet niveaux de lumière sur la croissance de plants de bouleaux jaunes et de chênes à gros fruits allant de 8 à 46 %. L’ouverture de 9 mètres a été la plus avantageuse pour la croissance en hauteur et en diamètre du bouleau jaune, et ce pour les deux types de protections. Le protecteur à petites mailles a limité la croissance de l’espèce dans les trois largeurs d’ouvertures. Le diamètre du chêne à gros fruits a été le plus faible dans cette même protection. Avec une lumière accrue, le diamètre du chêne à gros fruits a augmenté ainsi que la longueur moyenne des branches et la surface foliaire du bouleau jaune. La bonne croissance juvénile ou initiale du bouleau jaune en fait une espèce d’intérêt pour l’enrichissement en forêts. Une ouverture intermédiaire d’une largeur de six mètres est envisageable pour réduire les perturbations et les coûts. La protection de type grandes mailles améliore davantage la croissance que l’autre, sous toutes les tailles d’ouvertures. / Following abandonment of agricultural land, regrowth forests typically show a low diversity of tree species. One possible solution, enrichment underplanting, must consider protection against browsing, which hinders sunlight from reaching the seedlings. We examined the effects on growth of three different widths of strip opening (3, 6 or 9 meters) mixed with two protective sleeves (a small mesh and a large one). In the experiment, light levels reaching seedlings of yellow birch and burr oak range from 8 to 46 %PAR. The nine meters strip was the best to promote diameter and height growth of yellow birch, regardless of the protective sleeves used. The small mesh sleeve produced a smaller growth in all the openings, for both species in diameter and only for yellow birch in height. Burr oak diameter was also reduced by the small mesh protection. With increased light, mean length of branches and leaf area for yellow birch increased, as well as diameter for burr oak. Good growth of yellow birch makes it a species of interest for enrichment planting. A strip opening of 6 meters width could be enough to ensure artificial regeneration of yellow birch, while limiting disturbances and reducing costs. Large mesh sleeve would be best to maximize growth.

Ghana has experienced a remarkable degradation and depletion of its forest resources over the last 100 years. This process has undermined the socio-economic and socio-cultural importance of the forests for millions of rural people who depend on the resource to support their livelihood. Many rural households have over the past three decades developed strategies to minimize the effects of forest depletion on their livelihood. The establishment of smallholder forest plantation on agricultural land has emerged as an important form of land-use for households to diversify their sources of income and also improve their socio-economic well-being. The main objective of the study was to identify and analyze the endogenous and exogenous factors inducing farm household’s decision to establish farm forest plantation and to analyze its financial contribution to household’s income and livelihood strategies. The study involved a survey of 280 randomly selected farm households from five communities in the Offinso district in Ghana. The multi-stage stratified random sampling technique was used to select as many as 165 households with farm forest plantation as well as 115 without farm forest plantation. A mixture of tools including semi-structured questionnaire, focus group discussions, wealth ranking, forest inventory and market surveys were used to collect the required data. Results from logistic regression analysis revealed that the age of the household head, the number of years of education of the household head, the amount of household labor, the size of household landholding, the ownership of permanent land, the availability of non-agricultural land and household’s participation in past forest plantation development projects are the most important endogenous factors influencing the farm household’s decision to establish farm forest plantation. On the other hand, exogenous factors such as the availability of market and buyers for farm forest products and farm household’s satisfaction with market prices for farm forest products positively influenced the household’s decision to establish farm forest plantation. Prohibitive rules and regulations relating to the harvesting of trees and transportation of timber from private lands and uncertainty in tree tenure as a result of ambiguous policy framework, however, negatively influenced the decision to establish smallholder forest plantation on their agricultural land. The results from household income portfolio analysis show that cash income from selling farm forest products contributed an average of $273.6 to total household’s income in one agricultural season. This amount accounted for 17.6% of total household’s income and represented the second most important source of income after agriculture. The profitability of different land-uses practiced by the households was analyzed using a conventional economic method (Net Present Value). The results from a comparative financial analysis show that the establishment of teak plantation on agricultural land inter-cropped with food crops is the most profitable form of land use for the households compared to pure teak plantation and maize-plantain cultivation. The results of the study underscore the potential contribution of smallholder farm forest plantation to increase the overall household’s income and thereby improve household’s well-being. / Ghana hat während der letzten 100 Jahre eine bemerkenswerte Degradation und Verminderung seines Waldvorkommens erlebt. Dieser Prozess hat die sozio-ökonomische und sozial-kulturelle Bedeutung des Waldes als Einkommensquelle zur Unterstützung des Lebensunterhalts für Millionen ländlicher Einwohner geschwächt. Während der letzen 30 Jahre haben viele Kleinbauern Haushalte Strategien entwickelt um den Effekt, den die Verminderung des Waldvorkommens auf ihren Lebensunterhalt hat, zu minimieren. Die Anlage kleinflächiger Forstplantagen auf Ackerland hat sich dabei als wichtige Form der Landnutzung erwiesen, da sie eine Einkommensquelle zusätzlich zu den vorhandenen bedeuten. Sie haben das Potential, die sozio-ökonomiche Situation der Bevölkerung zu verbessern. Ziel der Studie war die Identifizierung von internen und externen Faktoren, die bedeutend zur Entscheidung von Haushalten über die Errichtung kleinflächiger Forstplantagen beitragen. Desweiteren sollten der finanzielle Beitrag der Forstplantagen zum Einkommen und zu Strategien der Kleinbauern analysiert werden. Für die Sudie werden Datensätze von 280 zufällig ausgewählten landwirtschaftlichen Haushalten aus fünf Gemeinden im Offinso Distrikt in Ghana erfasst. Die mehrstufig aufgebaute zufällige Auswahltechnik wurde benutzt, um die 165 Haushalte mit Forstplantagen und 115 Haushalten ohne Forstplantagen für die Studie auszuwählen. Mehrere Instrumente, wurden genutzt um die benötigten Daten zu sammeln darunter vor allem semi-strukturierte Befragungen, fokusierte Gruppendiskussionen, Wohlstandsranking der Haushalte und eine Forstinventur. Ergebnisse einer logistischen Regressionsanalyse ergaben, dass das Alter des Haushaltsvorstands, die Anzahl der Ausbildungsjahre des Haushaltsvorstands, die Anzahl der im Haushalt vorhandenen Arbeitskräfte, die Größe des dem Haushalt zur Verfügung stehenden Ackerlandes, das Eigentum an Ackerland, verfügbare nicht-landwirtschaftlich nutzbare Flächen und die Teilnahme der Haushalte an Projekten zur Forstplantagenentwicklung die wichtigsten internen Faktoren für die Entscheidung der Kleinbauern zur Errichtung von kleinflächiger Forstpantagen darstellen. Andererseits beeinflussten externe Faktoren wie das Vorhandensein von Markt und Käufern für Produkte der Forstplantagen und die Zufriedenheit der Haushalte mit den gebotenen Marktpreisen für diese Produkte die Entscheidung der Kleinbauern zur Errichtung von Forstplantagen positiv. Demgegenüber beeinflussten Verbote und einschränkende Regelungen zur Ernte und zum Transport von Bäumen auf Privatland und die Unsicherheit bezüglich des Eigentums an den Bäumen als Ergebniss unklarer politischer Vorgaben die Entscheidung zur Errichtung von kleinflächiger Forstplantagen auf Ackerland negativ. Das Ergebniss der Analyse verschiedene Haushaltseinkommensquellen zeigt, dass das Jahreseinkommen der Haushalte mit Forstplantagen höher ist als das der Haushalte ohne Forstplantagen. Der Beitrag zum Jahreseinkommen aus dem Verkauf von Produkten der kleinflächiger Forstplantagen betrug im Durchschnitt 273,6 USD in einer landwirtschaftlichen Saison. Dies entsprach 17,6 % des gesamten Haushaltseinkommens und stellte somit die zweitwichtigste Einkommensquelle nach der Landwirtschaft dar. Die Rentabilität der verschiedenen Landnutzungsarten wurde mit der Kapitalwertmethode (Net Present Value) ermittelt. Diese vergleichende Analyse zeigte, dass kleinflächiger Forstplantagen auf Agrarland bei gleichzeitigem Anbau von Nahrungsmittel die profitabelste Art der Landnutzung für die Haushalte im Vergeich zu ausschließlichem Teakanbau und zum Anbau von Mais mit Kochbanane ist. Die Ergebnisse der Studie unterstreichen das Potential kleinflächiger Forstplantagen, einen Beitrag zur Steigerung des gesamten Haushaltseinkommens und zur Verbesserung des Lebensstandards der Haushalte leisten zu können.

La ressource forestière en Guyane occupe une place maîtresse au sein de la région et est encore majoritairement préservée, mais la filière bois parvient difficilement à valoriser la biodiversité locale en raison de l’hétérogénéité de la ressource. Identifier les essences à planter demain représente aujourd’hui un enjeu à la fois environnemental, économique et social pour la Guyane. Bagassa guianensis Aubl. et Cordia alliodora (Ruiz & Pav.) Oken. vont à l’encontre des modèles usuels en associant vitesse de croissance et qualité du bois et sont identifiées comme prometteuses pour la plantation. Dans un premier temps, l’étude de la dynamique de croissance des deux espèces révèle un modèle écologique singulier, à la fois pionnières et longévives. La variabilité de l’infradensité dans l’arbre est l’élément clé qui permet un tel développement, favorisant une croissance rapide dans les premières années tout en assurant la longévité de l’individu. Dans une seconde partie, l’analyse d’un large panel de propriétés du bois (retrait, module, durabilité) en lien avec le développement de l’arbre confirme les qualités technologiques des deux espèces et permet l’émergence de résultats novateurs tels que le rôle des extractibles sur le retrait, le contrôle de la croissance grâce aux variations d’infradensité, l’évolution des traits foliaires au cours de l’ontogénie ou encore la mise en place de contrefil dans l’arbre pour assurer son maintien. La connaissance acquise vis-à-vis du mode de développement de ces deux espèces et des facteurs influençant la qualité de leur bois permet aujourd’hui de définir avec plus de précision le cadre d’un projet de plantation et les conditions de son succès. Les résultats de cette étude permettent finalement d’orienter la recherche de nouvelles espèces d’avenir pour la plantation en Guyane. / The forests of French Guiana occupy a central part of the region’s potential resource base, but as yet remain almost completely unexploited. This stems from the forestry industry struggling to valorize wood stocks of a high diversity with an extremely heterogeneous distribution. Indeed, identifying essences for future propagation is an issue of both environmental and socio-economic importance for the region. Bagassa guianensis Aubl. and Cordia alliodora (Ruiz & Pav.) Oken. go against conventional models, in that they display the life history characteristics of rapid growth and wood of high quality, and thus are species of high potential for future plantations. Firstly, our study of growth characteristics reveals a defined strategy half way between long-lived species and pioneer species. It is the variability of basic density of wood which is a key trait allowing for such a development, favoring rapid growth in initial years whilst allowing for tree longevity. Secondly, the analysis of a range of wood properties (shrinkage, modulus of elasticity, durability) in relation to tree growth confirms the technologic quality of the two species. It also enables the emergence of new results like the effect of extractives on wood stability, the control of growth as a result of basic density variation, the evolution of leaf traits throughout tree development or the improvement of trunk maintenance thanks to interlocked grain. The knowledge gained in relation to the developmental traits of these two species, and to the quality of their wood allows for the elaboration of plantation projects and what will be required for their success. The results of this study can orientate future studies on novel species for commercialization in French Guiana.

Alors que la superficie des forêts de plantation continue d'augmenter dans le monde, leurcontribution à la conservation de la biodiversité reste controversée. L’objectif de cette thèse estd'identifier les facteurs clés, à la fois au niveau de l'habitat local et à celui du paysage, qui influent surla diversité des papillons de jour dans les paysages en mosaïque dominés par des plantations de pins.Les communautés de papillons ont été échantillonnées en lisière et à l’intérieur de plantations de pinmaritime, pare-feux, ripisylves et fragments de forêts de feuillus variant par la taille et le degréd’isolement spatial. Les traits biologiques et écologiques des papillons ont été liés auxcaractéristiques de l’habitat et aux variables paysagères.Les éléments les plus importants pour la conservation des papillons dans les paysages dominés parles plantations de pins sont les habitats semi-naturels: forêts de feuillus, pare-feux et lisières. Lesripisylves se révèlent être les plus riches en papillons forestiers, abritant des espèces spécialisées. Lespare-feux hébergent deux fois plus d'espèces que les autres types d'habitats et sont importants pourla conservation de plusieurs espèces menacées. Toutefois les plantations de pin ne sont pas vide depapillons. La qualité de l'habitat, notamment la présence de plantes hôtes, est le facteur le plusdéterminant de la composition des communautés de rhopalocères. La composition et laconfiguration du paysage ont également une influence importante sur la diversité des papillons. Denombreuses espèces de papillons ont été observées dans plusieurs types d'habitat suggérant que lacomplémentation et supplémentation des ressources soient des processus clés pour maintenir ladiversité des papillons dans les paysages forestiers hétérogènes. / While the area of plantation forests continues to increase worldwide, their contribution to theconservation of biodiversity is still controversial. The aim of this thesis is to identify key habitat andlandscape factors that drive butterfly diversity in mosaic landscapes dominated by pine plantations.Butterfly communities were sampled at edges and interiors of five successional stages of pine stands,in firebreaks, riparian forests and in deciduous woodlands varying in fragment size and isolation.Biological and ecological traits of butterflies were related to habitat patch attributes and tolandscape composition and configuration.The results highlighted the critical importance of semi-natural habitats for butterfly conservation inpine plantation mosaics, i.e. deciduous woodlands, firebreaks and edges. Riparian forests wereespecially rich in forest butterfly species, harboring specialized species with both narrow habitat andthermal ranges. Firebreaks had twice as many species as other habitat types and were ofconservation value for several threatened butterfly species. Our results also showed that pine standswere not ‘free of butterflies'. Habitat quality, particularly the presence of host plants, was the mostimportant driver of butterfly community composition. Landscape composition and configuration alsoinfluenced butterfly diversity. Many species used more than one distinct habitat type, suggestingthat resource complementation and supplementation are important mechanisms of butterflydiversity persistence in pine plantation mosaics.