A fragmentação do habitat causa a redução na diversidade de espécies, afetando as relações entre os hospedeiros vertebrados e os parasitos. Neste estudo se verificou se o tamanho do fragmento florestal influencia a diversidade das aves silvestres o que poderia afetar a prevalência dos carrapatos nas aves. As aves foram capturadas através de redes de neblina em 12 áreas florestais: quarto fragmentos pequenos (80-140 ha); quatro grandes (480-1850 ha) e quatro controles, no Parque Estadual Morro do Diabo (~36000 ha). Adicionalmente foram coletados também carrapatos de vida livre através de arrasto com a flanela branca ao longo de trilhas. A infecção de carrapatos por riquétsias foi avaliada atrvés de PCR. No total foram capturadas 1745 aves representando 80 espécies de 24 famílias. 223 (13%) das aves foram encontradas parasitadas por formas imaturas de carrapatos: 1800 larvas e 539 ninfas. A espécie mais comum parasitando aves foi Amblyomma nodosum. Outras espécies: Amblyomma coelebs, Amblyomma cajennense, Amblyomma ovale, Amblyomma longirostre, Amblyomma calcaratum, e Amblyomma naponense foram achados nas aves esporadicamente. Entre os carrapatos de vida livre, A. cajennense foi a espécie mais comum, seguindo A. coelebs, A. naponense, Amblyomma brasilense e Haemaphysalis juxtakochi. De dois carrapatos A. nodosum foram isoladas bactérias do gênero Rickettsia em células Vero. Os isolados foram caracterizados por PCR e os fragmentos dos genes gltA, htrA sequenciados, e quando possível ompA e ompB. Um isolado foi identificado como Rickettsia bellii e o segundo, como R. parkeri. Dos 174 A. nodosum testados para a presença de riquétsia, 41 (23.6%) foram infectados por R. parkeri e 10 (5.7%) por R. bellii. A diversidade de aves era maior em áreas do controle, mas varias espécies as aves e também dos carrapatos responderam ao fragmentaço em modo diferente. A. nodosum parasitando as aves era mais abundante em áreas pequenas, enquando A. cajennense encontrado nas aves e em vida livre, era mais abundante em áreas do controle e em áreas grandes. Essas differencias de occorencia dos carraptos podem ser relacionadas com a abundância dos hospedeiros principais e fatores ambientais como temperatura e humidade nas áreas amostradas. Isso é um resultado da fragmentação do habitat que ilustra a falta de equilíbrio entre relações de parasitos, hospedeiros e ambiente. / Habitat fragmentation causes reduction in species diversity, affecting the relationships between vertebrate hosts and parasites. We tested if patch size has influence on forest birds diversity, which could affect the prevalence of ticks on wild birds. During two years we conducted a bird survey, using mist net in 12 areas: four small patches (80-140 ha), four large ones (480-1850 ha) and four control areas within the Morro do Diabo State Park (~36000 ha). Free living ticks were also collected through dragging the vegetation. Identified ticks were tested in the laboratory for the presence of Rickettsia. A total of 1,745 birds were captured representing 80 species from 24 families. A total of 223 (13%) birds were found infested by immature forms of ticks: 1,800 larvae and 539 nymphs. The most common tick parazitizing birds was Amblyomma nodosum. Other species, Amblyomma coelebs, Amblyomma cajennense, Amblyomma ovale, Amblyomma longirostre, Amblyomma calcaratum, and Amblyomma naponense were found sporadically. Among free-living ticks collected in the environment, A. cajennense was the most common followed by A. coelebs, A. naponense, Amblyomma brasilense and Haemaphysalis juxtakochi. From two individuals of A. nodosum ticks, rickettsiae were isolated in Vero cell culture and the isolates were molecularly characterized using the rickettsial genes gltA, htrA, and when possible also ompA and ompB. The first isolate was identified as Rickettsia bellii and the second isolate, was identified as R. parkeri. Among 174 A. nodosum tested, 41 (23.6%) were found to be infected by R. parkeri and 10 (5.7%) were infected with R. bellii strain Pontal. Bird diversity was higher in control and large areas, but various species of birds and also ticks responded in different way for fragmentation. A. nodosum parasitizing birds was more abundant in small patches, while A. cajennense found on birds and in the environment was more abundant in control and large areas. These differences of the occurrence of ticks could be related with the abundance of main vertebrate hosts, or environmental conditions such as temperature and humidity in sampled areas. This is a result of fragmentation of habitat and shows the lack of balance between the environment-host-parasite relationships.

A cosmodern reading of David Mitchell’s Cloud Atlas creates a positive vision of the future for readers through various techniques of fragmentation including fragmentation of voice, language, and time. By fragmentation, I have in mind the consistent interruption of the novel’s voice, language, and time that requires an active and aware readership. The reader’s interaction with the text makes the novel re-constructive. In fact, the global nature of Mitchell’s novel, its hopeful ending, and its exploration of the effects of globalization can be considered as a means of exploring the dynamic relationships between the characters, the reader, and Mitchell’s authorial voice. Rather than falling back on familiar postmodernist truisms such as the hopelessness of genuine communication or the impossibility of truth, Mitchell creates a hopeful vision of the future of the world, one that champions the life, agency, and personal narrative of the individual.

No description available.

Globally, habitat fragmentation has had a major impact on the conservation and management of many species and is one of the primary causes of species extinction. Habitat fragmentation is loosely defined as a process in which a continuous habitat is reduced to smaller, disconnected patches as the result of habitat loss, restriction of migration or the construction of barriers to movement. Aquatic systems are particularly vulnerable to habitat fragmentation, and today an estimated 48% of rivers are fragmented worldwide. My dissertation evaluates how habitat fragmentation has influenced the populations of four different species of fish in the Lake Champlain basin. In chapter 1 I summarize the current state of habitat fragmentation research, I broadly describe habitat fragmentation, review how habitat fragmentation pertains to population genetics, and describe the legacy of habitat fragmentation in the Lake Champlain basin. In chapters 2, 3 and 4 I evaluate and discuss the impact of nine lake causeways on the population structure of slimy sculpin (Cottus cognatus), rainbow smelt (Osmerus mordax), and lake whitefish (Coregonus clupeaformis). The genetic effects of causeways are limited. However, causeways appear to have had a significant influence on rainbow smelt demographics, and the genetic structure observed in lake whitefish may be a product of reduced effective population size resulted from commercial harvest in the late 1800s. In chapter 5 I evaluate how the basin-wide population of tessellated darters (Etheostoma olmstedi) is naturally structured throughout Lake Champlain and three different major tributaries and evaluates the effect that different types of habitat fragmentation (dams, causeways, and natural fall lines) have on tessellated darter populations. Tessellated darters appear to be highly structured by river drainage but not by dams, causeways or fall lines. My dissertation highlights how comparative population genetic studies can be used to identify patterns of isolation within large populations. My results stress the value of reporting both the presence and absence of barrier induced population sub-structuring.

The understory insectivore guild is disproportionately affected by deforestation, and knowing the underlying mechanisms is critical to effective conservation. I investigated demographic, ecological, and behavioral responses of Chestnut-backed Antbird (Myrmeciza exsul) populations (a persistent understory insectivore) to a fragmented Costa Rican rainforest landscape where many ecologically similar species have declined. I estimated demographic rates to parameterize population models in three habitats differentially affected by forest fragmentation: contiguous, peninsular, and fragment. Models indicated that M. exsul are declining in the peninsula (λ=0.83), but increasing in fragments (λ=1.41). Sensitivity analyses suggested that population growth was most sensitive to adult survival and nesting success, suggesting these two variables as potentially important explanatory demographic parameters in this landscape. I studied nest predation using digital video and quantified breeding success and population density in each site. Nest predation rate was so high in the peninsula that few nests fledged any young, much lower in the fragments, and intermediate in the contiguous forest, inversely tracking M. exsul population density and corroborating population growth rate findings. Using 22,000 hours of active nest video recordings, one primary predator emerged, the bird-eating snake (Pseustes poecilonotus), responsible for 80% of nest attacks. Pseustes’ prevalence in the peninsula where predation rates were highest implies possible predation-limitation. Populations both declining and growing locally provided unique insights into the mechanisms of change in a deforestation-impacted landscape, but represent only some fragmentation consequences. Therefore, I reviewed regional studies to assess other potential contributions to understory insectivorous bird decline in the Sarapiquí. Empirical studies supported effects of habitat area loss, dispersal limitation, reduced microhabitat availability, and low physiological tolerances to changing climates. / acase@tulane.edu

Studies of predator-prey and predator-predator interactions are needed to provide information for decision-making processes in land management agencies. Mountain lions (Puma concolor) are opportunistic carnivores that prey on a wide variety of species. In the Sierra National Forest, CA, they have not been studied since 1987 and their current interactions with their prey and other predators are unknown. Forest managers in this region are concerned with declines of fishers (Pekania pennanti) and studies have shown intraguild predation to be a leading cause of fisher mortality in this area. Managers are interested in learning more about mountain lion predation patterns with regard to prey preference, but also how lions traverse and use the landscape and how anthropogenic activities may be increasing lion predation risk on fishers. Using GPS radio-collar technology, we examined mountain lion kill rates and prey composition at 250 kill sites. We found mule deer (Odocoileus hemionus) to be their main source of prey (81%) with gray foxes (Urocyon cinereoargenteus) comprising 13.2% of prey composition. We did not detect any fisher predation during our 2-year study; however, during our study, the Kings River Fisher Project experienced extremely low juvenile fisher survival. To gain a better understanding of seasonal resource selection by mountain lions, we developed resource selection functions (RSF) while they were moving through the landscape and when killing prey. We developed RSF models for all data across the study area, as well as, for a subset of data encompassing an area where LiDAR (Light Detection and Ranging) data had been collected. Within the LiDAR study area, we digitized unmapped roads and skid trails using a Bare Earth data set. We found mountain lion ‘moving’ locations showed selection for close proximity to streams during summer months and selection for ruggedness and steeper slopes during both summer and winter. With 3 of the 4 RSF models at kill sites showing high risk of predation within close proximity to either digitized roads/skid trails or mapped roads, we recommend managers map all anthropogenically created linear landscape features and consider restoring these linear features to pre-treatment landscape conditions following timber harvest.

A pergunta que move este trabalho é se existem indícios, na atual construção argumentativa sobre a regulação internacional da internet, da conformação de um regime internacional da internet. Para respondê-la, o primeiro passo é explorar os significados do fenômeno da fragmentação do direito internacional. A partir da identificação de algumas linhas de pensamento, este trabalho adota o diagnóstico de que a fragmentação do direito internacional se liga a uma transposição da diferenciação funcional social para o campo do direito. Dessa forma, trabalhar com o direito internacional fragmentado exige levar em conta a presença de regimes diversos, constituídos por construções argumentativas movidas por um ethos próprio. Esses regimes produzem linguagem técnica que leva a um gerencialismo e que se volta contra outras linguagens, gerando disputas hegemônicas. Para o jurista, é essencial assumir seu papel dentro das construções argumentativas, tomando consciência da política dos regimes e utilizando instrumentos interdisciplinares que atinjam também o que é rotulado como não-direito. Uma vez definida, esta abordagem é aplicada para o estudo da regulação internacional da internet, como um segundo passo deste trabalho. A análise começa pelas batalhas que foram travadas pela alma da internet desde sua criação e os atores envolvidos nessas batalhas. Depois, aborda as representações sobre a regulação da internet durante os períodos de desenvolvimento dessa tecnologia. Diante de uma previsão sobre o último período, começa a olhar para as construções sobre a internet desde 2011. Na literatura analisada, a internet é definida de acordo com o que compõe sua regulação, sua extensão e seus limites. A literatura aponta vários atores e instituições que participam dessa regulação e o Estado aparece com papéis variados, mas a governança multissetorial tem destaque. Os autores divergem ao falarem sobre a aplicação do direito internacional às questões que consideram mais importantes na internet. Eles discordam sobre os problemas da regulação, sobre se e quais direitos deveriam ser aplicados e como os atores devem agir para essa regulação. Contudo, todos têm o movimento de suas argumentações em comum. Todos constroem exceções quanto ao direito em geral quando pensam na melhor regulação para a internet. O terceiro passo da pesquisa é então analisar o que isso significa, tendo em mente o quadro teórico de que partiu. Ela conclui que há indícios da conformação de um regime internacional da internet, tendo em vista que a defesa da especialização do direito para a internet se move com um propósito comum de diferenciar o mundo online do mundo off-line. Finalmente, ela indica algumas agendas de pesquisa que podem ser adotadas a partir desses resultados / The question that drives this work is whether there is evidence, within the current argumentative construction on international Internet regulation, of an international internet regime. To answer that, the first step is to explore the meanings of the phenomenon of fragmentation in international law. After the identification of some schools of thought on the subject, this paper adopts the diagnosis that the fragmentation of international law is due to a transposition of social functional differentiation to the legal field. Given that, dealing with a fragmented international law requires taking into account the presence of various schemes, consisting of argumentative constructions driven by their own ethos. These schemes produce a technical language that leads to managerialism and that pits itself against other languages, generating hegemonic disputes. Lawyers should assume their role within these argumentative constructions, becoming aware of regimes politics and using interdisciplinary tools to reach also what is labeled as non-legal. This theoretical approach is applied to the international internet regulation, as the second step of this research. The analysis begins with the battles that were fought for the soul of the Internet since its inception and the actors involved in these battles. The paper then addresses the representations on the regulation of the Internet during periods of development of this technology. Faced with a prediction about the last period, it looks at the constructions on Internet since 2011. In the examined literature, the Internet is defined according to what constitutes its regulation, its extent and its limits. The literature points to several actors and institutions that participate in this regulation and the State appears with varying roles, but multi-sectorial governance has central emphasis. The authors diverge when discussing the application of international law to issues that they consider most important on the Internet. They disagree on the issues of regulation, on whether and which duties should be imposed and how actors should act towards this regulation. However, all of them have the movement of their arguments in common. All develop exceptions to international law when they elaborate about a better regulation for the Internet. The third step of the research is then to analyze what this means, bearing in mind the theoretical framework adopted. It concludes that there is evidence of the construction of an international regime of the internet, as long as the defense of internets specialty moves along with a common purpose to differentiate the online world from the offline world. Finally, the paper points to some research agendas that can be derived from its results.

The gliding petaurids are small sized arboreal and nocturnal marsupials restricted to Australia and the New Guinean region. They have suffered range contractions since European settlement, and most of the species are of conservation concern, either nationally or at a state level. This study applied molecular approaches to investigate several questions involving Petaurus species which may provide valuable insights for their conservation and management of species. The objectives of this study included an examination of phylogenetic and evolutionary relationships among Petaurus species, an assessment of phylogeographic structure within P. breviceps and an investigation of genetic diversity, social structure and mating system of P. breviceps in fragmented habitats. A broad molecular systematics study of the genus Petaurus was first undertaken. Two mitochondrial genes (ND2 and ND4) and a nuclear gene marker (ω-globin) were screened for sequence variation in samples obtained from across the distribution of petaurid species, including Australia, New Guinea and its surrounding islands. Phylogenetic analyses confirmed the monophyly of the genus Petaurus and revealed that, with the exception of P. gracilis, the currently recognised species were associated with divergent mtDNA clades. It also revealed considerable mtDNA diversity within the widely distributed species P. breviceps. The existence of at least seven distinct and divergent mtDNA lineages within P. breviceps was supported, with two lineages located in Australia and at least five lineages in New Guinea. However, the distribution of these evolutionary lineages did not correspond with current morphological subspecies boundaries. Analyses of ω-globin sequence provided support for a number of these distinct populations, suggesting the possible presence of cryptic species within P. breviceps. Molecular analyses also suggested that squirrel gliders, P. norfolcensis, may occur in both South Australia and the Northern Territory, extending the current known range of the species. The presence of P. norfolcensis in SA was further verified by examining museum skins. Population structure and current pattern of gene flow within P. breviceps in Australia was examined further to elucidate phylogeographic structure within the species, and explore potential causes of geographic variation. Evidence for significant phylogeographic structuring across the range of the species in Australia was provided from population genetic (AMOVA) and phylogenetic analyses of both mitochondrial DNA and the ω-globin gene. In particular, there was evidence for the existence of two divergent clades that were distributed over distinct geographical regions. Divergence dates calculated for the two major mtDNA clades suggested that environment and climate changes which occurred during the Pliocene may have facilitated this diversification. Habitat fragmentation is generally considered to be a major factor threatening the viability of forest dependent species such as gliders. Effects of habitat fragmentation were therefore investigated in P. breviceps in the highly disturbed landscape of southeastern South Australia. Genetic mating system and social structure of the species in these fragmented habitats was explored in 13 populations, using nine polymorphic microsatellite loci. Social groups consisted of two to seven gliders, and these were often close relatives, including parents with their offspring. Parentage analyses provided some evidence for a polygamous mating system, with a number of males found to have fathered offspring from multiple female partners. Some direct evidence of inbreeding was also found within a small isolated patch. Genetic diversity within P. breviceps populations was moderate compared to the range reported in other marsupial species. Population structure analyses indicated that gene flow between some patches was restricted. Small patches surrounded by a matrix of pine were more likely to show inbreeding and potentially suffer from inbreeding depression, although further data are required to verify this result. Overall, results suggest that, although the species is still present in these small and isolated patches, it may face threats from a lack of dispersal and inbreeding. Maintaining the size of patches and establishing corridors between isolated populations needs to be considered in conservation and management of species in these fragmented habitats. / http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1295224 / Thesis (Ph.D.) -- School of Earth and Enviromental Sciences, 2007

Cette thèse est consacré à l'analyse de modèles de croissance et de mouvement intervenant en biologie et en écologie. Nous regardons en particulier deux types de modèles: des équations de dynamique de populations structurées et des modèles de diffusion croisée. Dans une première partie consacrée au travail sur les populations structurées, nous étudions d'abord des modèles linéaires de croissance en environnement périodique en temps. Ces modèles sont caractérisés par l'existence d'un exposant de croissance, appelé valeur propre de Floquet, dont nous comparons les propriétés avec celui qui apparaît en environnement stationnaire. Nous mettons en évidence grâce à un contre exemple le fait qu'il n'y a pas de comparaison générale possible entre l'exposant de croissance en milieu périodique et celui associé à un milieu moyenné. Les résultats de convexité de Kingman sur le rayon spectral des matrices positives sont étendus à la valeur propre de Floquet. Nous étudions également le comportement de cette valeur propre dans des cas dégénérés, où certains paramètres peuvent s'annuler ou exploser. Dans cette partie est également exposé une justification de la dérivation d'un modèle d'équations aux dérivées partielles pour la réplication du prion. Ce modèle est vu comme approximation d'un système infini d'équation différentielles ordinaires. Ceci se fait grâce à des résultats de compacité faible et la preuve permet de proposer des pistes pour un modèle plus complet. La deuxième partie est consacrée à l'étude de modèles de diffusion croisée. Nous nous plaçons dans le cas d'un domaine bornée et en absence de termes de réactions. Le but est de questionner la stabilité de l'équilibre homogène. L'application de techniques de dualité utilisées pour les système de réaction-diffusion permettent d'obtenir des bornes qui servent elles-même ensuite, combinées à la régularité elliptique à obtenir l'existence globale pour une version régularisée du système. Ladite régularisation est dépendante d'un paramètre dont les valeurs déterminent la stabilité ou l'instabilité linéaire de l'équilibre homogène. La valeur critique du paramètre de régularisation est d'ailleurs une valeur de bifurcation pour les équilibres.

Se donnant un mécanisme de branchement critique ou sous-critique, on définit une procédure d'élagage de l'arbre aléatoire continu de Lévy associé. Cette procédure d'élagage est définie en plaçant des marques sur l'arbre grâce à des techniques de serpent de Lévy. On démontre alors que le sous-arbre obtenu après élagage est encore un arbre aléatoire continu de Lévy. Ce résultat est démontré en utilisant une propriété de Markov spéciale et un problème de martingale pour les processus d'exploration. On construit ensuite, par couplage, une autre procédure d'élagage qui définit un processus de fragmentation sur l'arbre. On calcule la famille de mesures de dislocation associée à cette fragmentation. Dans un deuxième travail, on considère une diffusion aléatoire dans un milieu Lévy stable. On montre que le processus des temps locaux renormalisé et recentré au minimum de la vallée standard de hauteur log t, converge en loi vers une fonctionnelle de deux processus de Lévy conditionnés à rester positifs indépendants. Pour démontrer ce résultat, on montre que la loi de la vallée standard est proche de celle de deux processus de Lévy conditionnés à rester positifs concaténés en 0. On obtient également la loi limite du supremum du temps local renormalisé.