Tesi sul tema "Ecology"

Ecology is the study of interaction of living organisms in the environment. However the modern meaning of the concept of ecology has a wider meaning than in the early decades of the development of this science. Currently, most often under the mistaken environmental issues are understood, above all, the protection of the environment. In many ways, this shift is due to sense more tangible consequences of human impact on the environment. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/31584

Phytoplankton embraces a large diversity of life forms, from pioneer oxygenic photosynthetic cyanobacteria to a broad spectrum of phylogenetically distant eukaryotic organisms. In many of the evolutionary branches, colonial organisms have appeared. The evolutionary reasons for the transition to larger sizes are not yet fully understood, but multicellularity is thought to be one of its consequences. Phytoplankton ecological success or failure, under certain conditions is the result of a balance between gains and losses. Unicellular and colonial organisms have to adapt their respective functional traits related to photosynthesis, resource acquisition, and predation, to changes in the environment. The advantages of a certain life-form (unicellular or colonial), could, hence, rely in the relevance of gain processes (light, nutrient related traits), or of losses as main drivers of phytoplankton evolution. Despite coloniality could suppose an opportunity in finding new paths to succeed, previous knowledge pointed to larger phytoplankton cells as worse competitors for nutrients than smaller cells and hence, as the size of the colonies may start to become a constraint for nutrient uptake and utilization. However, other issues changing with size can become advantageous for colonial phytoplankton. For example, large flagellate colonies can move and hence cover a greater space of resources likely to be exploited than small unicellulars, and also can have a larger storage capacity. Large cells (and colonies in particular) can take more advantage of the production of external enzymes since colonial forms, specially mucilaginous ones, could maintain exoenzymes close to the cells in this external matrix. In summary, any strategy by which there is not a proportional increase in the need for nutrients as body size enlarges can be regarded as a competitive advantage for colonial organisms. Besides, a possible advantage for large unicellulars and colonies could be related to the top-down control of the systems by grazers, as smaller unicellulars are subject of grazing by both, small and large filter feeders, whereas large colonies can override the edible size spectrum of some. Also the aggregation of cells to form large colonies harder to gulp or filter by zooplankton is considered a relative widespread defense strategy. The ubiquitousness of colonial forms of phytoplankton and its endurance until today is the basis for believing that there has been a significant selection for it in the ancient unicellular world. Yet it is difficult to guess what the main drivers for coloniality have been, Can we find out the selective forces favoring multicellular colonial forms in phytoplankton? Understanding the ecological advantage that colonial forms could hold in phytoplankton was the main objective of this thesis.
Los orígenes de los organismos que componen la comunidad fitoplanctónica se remontan a distintos eventos endosimbióticos; por ello, una de las principales características del fitoplancton es una enorme diversidad que atañe tanto en sus atributos morfológicos y fisiológicos como en sus formas de vida. A pesar de que la multicelularidad en algunas especies de fitoplancton podría suponer una estrategia para asegurar la conservación de la línea germinal, o para generar un medio interno estable que proteja a las células que forman la colonia del cambiante ambiente que la rodea, actualmente se desconoce el motivo que pudo haber favorecido la transición desde la unicelularidad a la colonialidad. Sin embargo, la existencia de organismos coloniales evolutivamente más avanzados en los que se observa una diferenciación celular y división de tareas, podrían empezar a definir una estrategia de vida compleja y jerarquizada más allá de la simple agregación celular. La gran variedad de formas, tamaños y configuraciones presentadas por las células y colonias, es una muestra de que no hay una estructura óptima, sino un gran abanico de posibilidades exitosas para afrontar los obstáculos a los que estos organismos se enfrentan durante su ciclo de vida. Por otro lado, el paso de una forma de vida unicelular a una colonial en los organismos fitoplanctónicos, implica un número de condicionantes ecológicos que determinan cuándo y cómo las formas coloniales pueden ser más viables. En cualquier caso, el hecho de que las formas unicelulares y coloniales sean ubicuas en el fitoplancton y hayan perdurado durante millones de años, nos da a entender que deben existir ciertas ventajas ecológicas conferidas por la colonialidad. Este trabajo se centra en investigar en qué modo los organismos coloniales han llegado a compensado las desventajas derivadas de la agregación para haberse convertido en una alternativa evolutivamente exitosa a la unicelularidad.

Heteropteran bugs make an important contribution to the hyperdiversity of insects. As with other insect taxa, the proper species identification of heteropteran bugs requires diagnostic dichotomous keys. Faunistic studies can considerably benefit from the use of in-situ photographic records and biodiversity web resources, these two new taxonomical tools have the potential to expedite conservation-oriented research and engage the general public in the conservation of nature. Faunistic syntheses such as catalogs and datasets are essential for documenting where species occur and how they are distributed, and may effectively contribute to overcome the ‘Wallace shortfall’ associated with large scale distributional data. The establishment of a research-oriented ‘Heteropteran Bug Monitoring Scheme’ may prove to be an effective faunistic tool that guarantees the constant flow of fine-grain, high-value species data. The gap between taxonomy and conservation may be bridged by explicitly coupling faunistic survey efforts to the monitoring of state variables relevant to ecological research. The hierarchical view is an approach to quantitative ecology with the potential to simultaneously account for the stochasticity associated with the ecological and observation processes. Multi-species site occupancy models are effective quantitative tools that estimate species-specific probabilities of detection and occurrence, from which the size of the community (ie, species richness) may also be estimated. One important advantage of multi-species site occupancy models is the ease by which covariates are specified into the linear predictors of both the ecological and observation process levels. Bayesian methods are powerful inferential tools for the conduction of quantitative research. Estimation of a given parameter under a Bayesian approach results in a posterior probability distribution that provides not only the mean but most importantly its associated uncertainty. The Bayesian mode of inference allows researchers to focus on effect sizes rather than statistical significance. Results from Bayesian analyzes can be communicated clearly and effectively to conservation policy-makers. Species are imperfectly detected. The methods we use to survey insects are important sources of uncertainty that must be taken into account when studying their patterns of occupancy and species richness. Survey protocols should be specifically designed to include spatial and/or temporal replicates from which detection data can be estimated. Heteropteran bugs, as a group, are relatively common across spatial extents, and their communities, as observed at fine grains of resolution, include many rare species that are difficult to detect. The assumption that this pattern holds at bioregional or even larger spatial extents requires more empirical investigation. A properly replicated study, resolved at the municipality or shire level, could contribute to address this gap in knowledge. Novel grassland ecosystems supporting ruderal or spontaneous vegetation are rich depositories of heteropteran bug biodiversity. In urban landscapes, oldroughs and unmanaged urban herbaceous margins may play an important role in the conservation of heteropteran bug species and other insect taxa. Within urban green areas such as golf courses, the complexity of the vegetation structure has a positive effect on heteropteran bug species richness and the species-specific occurrence probabilities of most species. Heteropteran bug species respond to the surrounding landscape. In viticulture landscapes, the proportion of natural habitat surrounding vineyards has a positive effect on mean herbivorous guild-level probability of occurrence. This positive effect is more uncertain for the predatory-guild. In the urban landscapes, species richness of both herbivores and predators decreased along a gradient of increasing urbanization. Almost all species were ‘urban avoiders’, experiencing on average very large decreases in their probabilities of occurrence along the urbanization gradient. Heteropteran bugs in the Iberian Peninsula have a low probability of being detected. This probability varies markedly from family to family and from species to species. Macroecological variables have positive (area, altitudinal range, mean annual temperature and population density) or negative (mean annual precipitation) effects on the mean heteropterofauna detection probability. Methodologies that explicitly account for the observation process may prove fundamental for disentangling which components of species distributions at large bioregional scales are a consequence of imperfect detection as opposed to true patterns of occupancy.
Los heterópteros contribuyen de forma importante a la hiperdiversidad de los insectos. La elaboración de claves dicotómicas actualizadas, ajustadas a la región de estudio y basadas en caracteres de fácil observación, facilita la correcta identificación de los ejemplares. Los estudios faunísticos pueden beneficiarse considerablemente de la existencia de registros fotográficos in-situ y recursos electrónicos de registro de la biodiversidad, ya que ambas herramientas taxonómicas tienen el potencial de favorecer la investigación dirigida a la conservación, así como de implicar al público general en dicho proceso. Las síntesis, los catálogos y las bases de datos faunísticas son esenciales para registrar la ocurrencia y distribución de las especies. La utilización conjunta de estos recursos junto con variables ambientales relevantes para la ecología es clave para acortar la distancia que existe entre ciencias como la taxonomía y la conservación. La visión jerárquica supone una aproximación a la ecología cuantitativa, que tiene el potencial de incluir la estocasticidad asociada a los procesos ecológicos y de observación humana de la naturaleza. Los “modelos de ocupancia de lugar multiespecíficos (msSOM)“ suponen herramientas quantitativas efectivas para estimar la probabilidades de detección y ocurrencia específicas de especies y lugares, así como el tamaño de la comunidad. Los métodos bayesianos de inferencia estadística son herramientas poderosas para realizar análisis cuantitativos. La estimación de los parámetros viene asociada a su incertidumbre y al cálculo del “tamaño del efecto”. Y los resultados pueden comunicarse de forma clara y efectiva a los responsables de desarrollar políticas de conservación. Los heterópteros son detectados de forma imperfecta. Una buena fuente de incertidumbre depende de los métodos que utilicemos para muestrearlos, por lo que debe tenerse en cuenta el proceso de observación a la hora de analizar patrones de ocupancia y riqueza específica. Los protocolos de muestreo deberían estar diseñados de forma que incluyan réplicas espaciales y/o temporales que permitan calcular la detectabilidad. Los insectos heterópteros son relativamente comunes a lo largo de grandes áreas, y sus comunidades incluyen especies raras sólo detectables a pequeña escala. La asumpción de este patrón para la escala bioregional y superiores requiere mayor investigación. Los sistemas herbáceos noveles con vegetación ruderal o espontánea contienen una gran diversidad de insectos heterópteros. Como parte del paisaje urbano, los márgenes herbáceos y otras formaciones poco o nada gestionadas representan zonas importantes para conservar la diversidad de heterópteros y otros insectos. En cuanto a zonas verdes urbanas, como los campos de golf, la complejidad en la estructura de la vegetación tiene un efecto positivo en la biodiversidad de insectos. Los heterópteros se ven influenciados por el paisaje. En paisajes vitivinícolas, la ocurrencia de insectos herbívoros está favorecida por la proporción de hábitat natural favorable. En paisajes urbanos, la urbanizacion tiene un efecto negativo en la presencia de herbívoros y predadores. Ambos estudios, a partir de análisis distintos, convergen hacia una única conclusión.

Orientadores: João Vasconcellos Neto, Gustavo Quevedo Romero
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: A estrutura do hábitat tem sido um tema recorrente na literatura, havendo diversos estudos que correlacionaram uma maior complexidade estrutural do hábitat à riqueza e abundância dos mais variados taxa. Contudo, este é um tema de difícil generalização e as abordagens experimentais ainda são raras. A vegetação é um elemento que proporciona complexidade estrutural ao hábitat devido às diversas organizações arquiteturais de seus módulos. Diversos estudos demonstraram que os artrópodes associados às plantas são um dos grupos mais afetados pela arquitetura da vegetação, particularmente as aranhas. Logo, o objetivo deste estudo foi avaliar os possíveis efeitos da arquitetura da vegetação sobre a abundância e riqueza de guildas de artrópodes, com ênfase na comunidade de aranhas. O estudo foi dividido em duas partes: (1) uma pesquisa exploratória, cujo objetivo foi correlacionar diferentes elementos arquiteturais das plantas com a comunidade de artrópodes, de forma a avaliar se determinados grupos de artrópodes são mais ou menos abundantes em determinadas configurações arquiteturais da vegetação; (2) uma pesquisa experimental, cujo objetivo foi manipular a arquitetura vegetal agrupando e espaçando os ramos vegetativos, de forma a avaliar os efeitos da densidade vegetal sobre a comunidade de artrópodes. Um total de 17 espécies de plantas e oito características arquiteturais foi utilizado na pesquisa exploratória. Já o experimento foi feito para três espécies de plantas e repetido em duas estações climáticas diferentes (seca e chuvosa) para avaliação dos efeitos sazonais sobre a resposta da comunidade de artrópodes à manipulação arquitetural da vegetação. Todos os dados de abundância e riqueza de artrópodes foram expressos por unidade de biomassa de planta e a disponibilidade de presas para os predadores (i.e., o total de artrópodes exceto o grupo de predadores sendo estudado) foi colocada como co-variável. Os padrões de abundância da comunidade de aranhas foram fortemente correlacionados à arquitetura da vegetação, tanto na pesquisa experimental quanto na exploratória. Já as guildas de outros artrópodes, com algumas exceções, foram pouco afetadas pela arquitetura da vegetação. Algumas guildas de fitófagos tiveram padrões consistentes de distribuição em plantas com diferentes arquiteturas. Estes padrões, por sua vez, ocorreram tanto na pesquisa exploratória quanto na experimental. A abundância de parasitóides e predadores (exceto aranhas) foi mais explicada pela disponibilidade de presas do que pela arquitetura per se. O padrão de distribuição das aranhas sobre as plantas pode ser explicado, em grande medida, pelo favorecimento que determinadas arquiteturas proporcionam aos hábitos de forrageio de cada guilda. Já o padrão de abundância das guildas de fitófagos em plantas com diferentes arquiteturas provavelmente decorre de uma modulação da taxa de predação, uma vez que a arquitetura da planta está vinculada à disponibilidade de refúgios
Abstract: Habitat structure has been a recurrent subject in literature and there have been several researches that correlated a greater structural complexity of habitat to the richness and abundance of diverse taxa. However, this represents a subject of hard generalization and experimental approaches are still rare. Vegetation is an element that provides structural complexity to habitat due to diverse architectural organization of their modules. Many researches demonstrated that arthropods associated to plants are one of the most affected groups by the vegetation architecture, especially the spiders. Thus, the objective of present research was to evaluate possible effects of vegetation architecture on the richness and abundance of arthropod guilds, with special emphasis on spider community. The research was divided in two parts: (1) a survey research, whose objective was to correlate diverse architectural traits of plants with the arthropod community, this in order to assess whether certain groups of the arthropod community are more or less abundant in certain plant architectural configurations; (2) an experimental research, whose objective was to manipulate plant architecture by grouping and spacing the vegetative branches in order to evaluate the effects of plant density on the arthropod community. A total of 17 plant species and eight architectural traits was used in survey research, whereas the experiment was performed in three plant species and repeated in two seasons (dry and wet) for evaluation of seasonal effects on the arthropod community response to manipulation of the plant architecture. All data referring to arthropod abundance and richness were given per unit of plant biomass and the prey availability for predators (i.e., all arthropods except the group of predators being studied) was set as a covariate. The abundance patterns of spider community were strongly correlated to the plant architecture, both in experimental and in survey research. Nevertheless, the other arthropod guilds, with some exceptions, were weakly affected by vegetation architecture. Some phytophagous guilds had consistent patterns of distribution on plant with different architectural traits. These patterns, by the way, occurred as in survey as in experimental research. The abundance of parasitoids and predators (except spiders) was more explained by the prey availability than by the plant architecture per se. Patterns of spider distribution on plants can be quite explained by the advantages that some plant architectures provide to the foraging habits of each guild. Abundance patterns of phytophagous guilds on plants with different architectural traits, nevertheless, were probably due to modulation of predation rates, since the plant architecture could determine refuge availability
Mestrado
Mestre em Ecologia

In introduction I want mention a briefly about ecology, then I will mention some problems and solution. Ecology is the study of the ways in which organisms (plants and animals) depend upon each other and upon their surroundings. Each organism requires conditions in order to be able to live and breed. These conditions are its environment by changing the ecological conditions. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/31578

What can I say, about ecology. Word of “Ecology” become to wide. Nowadays human brought many benefits. Related to a huge developed science-technological progress but in that time put life on earth is on the brink of ecological disaster, Population growth, intensification of production and emission of polluting the Earth, led to dramatic changes in the nature and affect the very existence of man. Some of these changes is extremely strong and is so widespread that there are global environmental problems. There are serious problems of pollution (air, water, soil), acid rain, radiation damage to the area and the loss of individual species of plants and living organisms, the impoverishment of biological resources, deforestation and desertification of areas. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/31706

This thesis reports the effect of the non-toxic cyanobacterium Oscillatoria agardhii CYA29 and its spent medium on the cell-bound toxin levels in Microcystis aeruginosa PCC7820 and Nodularia sp. PCC7804. Microcystin levels were elevated when O. agardhii or its spent medium were added to cultures of M. aeruginosa PCC7820. This effect was also observed for two nodularin variants in Nodularia PCC7804. However, growth of M. aeruginosa in its own spent medium did not lead to elevated microcystin levels. Some Gram-negative bacteria use quorum sensing, the determination of population density by pheromones, to regulate the expression of traits in a density dependent manner. The presence of the bacterial pheromones, acyl-homoserine lactones (AHLs), was investigated in cyanobacteria and a simple and fast synthesis for AHLs employed. No AHLs have been found in the cyanobacterial species tested, neither by Chromobacterium violaceum CV026 nor by Escherichia coli HB101 pUCD607 bioassay. No changes in dry weight or microcystin concentration were observed in M. aeruginosa PCC7820 grown in the presence of the AHL N-hexanoyl-DL-homoserine lactone. The activity of the spent medium of O. agardhii CYA29 was retained when it was heated up to 100°C for 20 min, frozen or freeze-dried. Molecular weight cut-off filtration showed the active compound to be less than 1 kD in size. The active component could not be extracted by dichloromethane or methanol, and activity was lost upon acidification. A small peptide of five amino acid moieties was isolated from an active fraction of the spent medium, four of which have been identified by 1H NMR to be serine, glycine, alanine, and the modified serine(thiazole). To my knowledge this is the first report of serine(thiazole) in natural products and the first thiazole containing peptide from O. agardhii.

My project is an Ecological center with three programs: an educational part, primary for children, a veterinary station and a NGO Centre. During the study trip to Ahmedabad I couldn’t help to notice the bad condition of the stray dogs. There’s problems with rabies and lack of animal birth control of the dogs. I also saw cases when children were hurting dogs and doves, throwing rocks at them, and I also read that Collage students hit stray dogs with sticks in the University havens because they got scared when the animals starts to flock there. I was confused how India, where all living being is considered having a "God value" and should be treated in that way, and also with an outspread vegetarianism would have this condition. For me it seemed like people didn't care or hadn't found a solution for this problem. Then the second reason for creating this project was that I was missing green areas in Ahmedabad, which also is one of the most polluted cities in India. With providing a "chawk" with green parts and bring knowledge of the importance of having a sustainable environment, the kids will learn how to treat nature and animals so they can bring this knowledge further in their surroundings and future city-scaping.

Malgré leur importance reconnue pour la santé publique et la conservation, les études sur l’écologie et l’évolution des maladies infectieuses dans les populations sauvages souffrent de contraintes sur la disponibilité de données permettant l’identification des processus impliqués dans les systèmes considérés. Les méthodes sérologiques (i.e., détection d’anticorps dans des échantillons biologiques) permettent de retracer l’exposition à des agents infectieux spécifiques mais leur interprétation est complexe. Par exemple, la prévalence d’individus séropositifs dans une population résulte d’une combinaison de dynamiques épidémiologiques (ex. : l’incidence de la maladie) et démographiques (ex. le taux de renouvellement de la population). Dans ce contexte, l’objectif de cette thèse est de montrer comment les processus sous-jacents à la circulation d’agents infectieux en populations sauvages peuvent être inférés à partir de données sérologiques. Tout d’abord, j’illustre comment les études transversales focalisée sur une espèce sentinelle à l’interface entre populations sauvages et humaines peuvent permettre d’efficacement décrire informer sur les patterns d’exposition à une hiérarchie d’échelles spatiales. Ensuite, je compare les avantages et inconvénients de ce type d’approches transversales à ceux d’approches longitudinales basées sur les suivis d’individus marqués et je propose une solution pour intégrer ensemble ces deux types de données pour quantifier les dynamiques éco-épidémiologiques. Finalement, en utilisant une population menacée d’oiseaux longévifs régulièrement touchée par des épizooties de choléra aviaire comme cas d’étude, j’illustre les bénéfices de combiner la sérologie avec d’autres approches. Ce travail souligne la valeur des études à long-terme de l’exposition d’hôtes à des agents infectieux en milieu naturel, où les processus écologiques et évolutifs sont clés pour comprendre les dynamiques éco-épidémiologiques et peuvent avoir d’importantes implications pour la conservation de la biodiversité
Despite their increasingly recognized interest for public health and biodiversity conservation, investigations on the ecology and evolution of infectious diseases in wildlife have been hampered by the difficulty of collecting data allowing efficient inference of underlying processes. Serology (i.e., detection of antibodies in biological samples) is a useful tool to detect past exposure to specific infectious agents. Still, interpreting serological data is not straightforward. For instance, the prevalence of seropositive individuals in a population is driven by a combination of epidemiological (e.g., disease incidence) and demographic (e.g., population turnover) dynamics. In this context, the objective of this thesis is to show how processes underlying infectious agent circulation in wild populations can be inferred from serological data. First, I illustrate how cross-sectional studies focusing on a sentinel species at the wildlife-human interface can efficiently inform on patterns at a hierarchy of scales. Then, I compare the pros and cons of such cross-sectional approaches to longitudinal sampling designs involving marked individuals when attempting to quantify the dynamics of infectious agents and I propose a way to integrate those two approaches in future studies. Finally, using avian cholera epizootics in a threatened long-lived seabird on an isolated island as a case study, I illustrate the benefits of combining serology with other approaches. This work notably highlights the value of detailed long-term studies of host exposure to infectious agents in the wild, where ecological and evolutionary processes are likely critical drivers of disease dynamics and can have important implications for biodiversity conservation

La ecología es una ciencia importante, tanto desde el punto de vista práctico como desde el teórico, que recientemente a comenzado a atraer la atención de los filósofos profesionales. Con todo, la investigación sobre los fundamentos filosóficos de la ecología, en particular sobre sus prácticas explicativas, está aún poco desarrollada; y ello pese a que los propios ecólogos perciben que el debate sobre la explicación ecológica es importante. En esta tesis doctoral comparo las principales tesis ontológicas y epistemológicas de tres proyectos filosóficos que ofrecen un análisis de la explicación científica en términos de mecanismos, con la descripción de dos casos de explicación en ecología basados en mecanismos, tal como los entienden los ecólogos, los mecanismos de facilitación y la competencia ecológicas. Los ejemplos que analizo aquí provienen del campo de la sucesión ecológica, aunque tanto la facilitación como la competencia son interacciones muy extendidas en todo el ámbito de la ecología. Sobre la base de mi análisis, sostengo que si bien las contribuciones epistemológicas que los proyectos filosóficos estudiados han realizado al debate de la explicación científica son importantes, pero que aún hay mucho espacio para mejorar la caracterización de la naturaleza de los mecanismos ecológicos y de la explicación mecanísmica en ecología. Basado en el trabajo previo del filósofo sistemista Mario Bunge, propongo que los mecanismos ecológicos son procesos específicos que ocurren en sistemas y que las explicaciones mecanísmicas en ecología pueden asumir diversas formas, pero que consisten en descripciones de esos procesos en el marco de la descripción más general del sistema de interés.
Ecology is a science of practical and theoretical importance that has recently begun to appeal to professional philosophers. Yet, work on the philosophical foundations of ecology, particularly on its explanatory practices, is still scarce, even though ecologists perceive the debate on ecological explanation as an important one. In this dissertation, I contrast the main theses of three different philosophical projects that attempt to account for scientific explanation in terms of mechanisms descriptions with two cases of ecological explanation based on mechanisms, as ecologists understand the term: the mechanisms of ecological facilitation and competition. The examples I study come from the subfield of ecological succession, though both facilitation and competition are widespread along the whole of ecology. Based on my analysis of those cases I argue that those projects have contributed important elements to the ontology and epistemology of scientific explanation, but that there is still room for improvement towards an adequate characterization of the precise nature of ecological mechanisms and mechanismic explanation in ecology. Following the lead of previous work by systemist philosopher Mario Bunge, I suggest that ecological mechanisms are specific processes in systems, and that, even though they may take different forms, mechanismic explanations consist in descriptions of those processes in the context of a description of the system of interest.

My extensive studies throughout the maritime Antarctic allowed me to discover many new localities where the two Antarctic vascular plants (Colobanthus quitensis and Deschampsia antarctica) occur, including extending their known range to the farthest south site in the world for flowering plants. As a result of my interest in the cryptogamic flora of the maritime Antarctic, and because of my knowledge of the aquatic bryophytes of the Signy Island, I was invited to examine material of the farthest south collection of an aquatic moss by a team of American limnologists. This led to a brief review of Antarctic aquatic mosses [a related study of aquatic bryophytes from the highest Scottish lochs is referred to here, but is not included as part of the Doctorate submission]. An interesting situation has developed over the past 20 years at Signy Island. This concerns the interaction between a rapidly increasing population of fur seals (from a few dozen in 1965 to 13,350 in 1987) and the fragile and highly vulnerable plant communities. Much of the island's vegetation has been devastated or eradicated during the past five years and I have been able to quantitatively assess the changes induced by the seals by reanalysing several of precisely the same sites I studied 20 years earlier. During an ecological survey of part of Livingston Island, South Shetland Islands, and having an increasing interest in the spread of fur seals and their impact on terrestrial ecosystems, I undertood an investigation of the early history of the Antarctic fur seal industry in the 1800s and of the 'archaeological' sites (sealers' refuges) which abound on that island. My ecophysiological research included a study of the influence of growth-form on the water relations of mosses at Signy Island. Some comparable studies at a continental site are being prepared for an international symposium in Kiel, West Germany, September 1987. Several studies have been made of the chemistry of South Georgia and Signy Island plants, including one on the amount of DNA in the chromosomes of alien and native vascular species; low DNA levels in the former category of plants at South Georgia and in Europe have provided a possible explanation for the survival of certain plants under extreme climatic conditions. A review paper on plant nutrient cycling in the Antarctic and sub-Antarctic was an invited keynote presentation read at a major international symposium in South Africa. Ecological studies at both South Georgia and throughout the maritime Antarctic resulted in extensive collections of all plant groups being made. Many accounts by specialists in bryophyte and lichen taxonomy have been published based on these collections, but I have published several largely ecological papers on fungi and introduced vascular plants, including stranded trees. The combined studies of tussock grass, plant communities, the ecology and chemistry of individual native and introduced phanerogams (especially Poa annua) on South Georgia, in conjunction with a major study of the introduced reindeer on that island by another biologist, has led to a series of papers on the impact of reindeer on the vegetation. The wide spectrum of my research has allowed me to build up a high degree of first-hand knowledge and expertise in Antarctic and sub-Antarctic plant ecology, and of biological and environmental features generally. Consequently, I have written several general or popular accounts, as well as major review works. More recently I have also become involved in matters concerning conservation areas (Sites of Special Scientific Interest and Specially Protected Areas), environmental impact and conservation policy as it relates to national activities throughout the Antarctic and sub-Antarctic biomes. I co-edited a book on conservation areas in the Antarctic, writing eleven of the SPA/SSSI accounts from first-hand experience of each.

Though the pervasive rumor that the “traditional” dissertation persists because of the “I suffered, so they too should suffer” mentality — the professor revenge theory — students are often the ones eager to pin down writing genres so that they can master them. However, hopes to stabilize and thus capture the secret or equation of the dissertation genre are futile, since genres, like language, are alive: rhetorical, evolving, and flexible. Thus, to demonstrate the contemporary context of the dissertation genre, the conflicting perspectives of university stakeholders, the forces working on the genre to enact change, and the process by which genre knowledge develops and transfers in the highest levels of university writing, Mapping Dissertation Genre Ecology explores the discourse, both written and spoken, which constitutes the dissertation as a discursive construct — what I call the dissertation genre ecology. To better understand how dissertations are shaped institutionally, I ask the following questions: How is the dissertation as a genre constituted by various stakeholder groups at the university? How do these myriad accounts contribute to a larger system, a dissertation genre ecology at the university? And, ultimately, how does the dissertation genre ecology affect genre change? Through the use of rhetorical genre theory, my study develops a broad, interdisciplinary conception of genre, one that is not mired in formalistic worries about fixing genre in place. I use the voices of students and faculty from the humanities and social sciences as well as interdisciplinary documents as data for this project. By examining these discursive artifacts and making institutional tensions explicit, my project has broad implications for WAC/WID literature in transfer and genre studies.

This project predominantly investigated the implications of spatial heterogeneity in the ecological processes of competition and infection. Empirical analysis of spatial heterogeneity was carried out using the lepidopteran species Plodia interpunctella. Using differently viscous food media, it was possible to alter the movement rate of larvae. Soft Foods allow the movement rate of larvae to be high, so that individuals can disperse through the environment and avoid physical encounters with conspecifics. Harder foods lower the movement rate of larvae, restricting the ability of individuals to disperse away from birth sites and avoid conspecifics encounters. Increasing food viscosity and lowering movement rate therefore has the effect of making uniform distributed larval populations more aggregated and patchy. Different spatial structures changed the nature of intraspecific competition, with patchy populations characterised by individuals experiencing lower growth rates and greater mortality because of the reduced food and space available within densely packed aggregations. At the population scale, the increased competition for food individuals experience in aggregations emerges as longer generational cycles and reduced population densities. Aggregating individuals also altered the outcome of interspecific competition between Plodia and Ephestia cautella. In food media that allowed high movement rates, Plodia had a greater survival rate than Ephestia because the larger movement rate of Plodia allowed it to more effectively avoid intraspecific competition. Also the faster growth rate, and so larger size, of Plodia allowed it to dominate interspecific encounters by either predating or interfering with the feeding of Ephestia. In food that restricts movement, the resulting aggregations cause Plodia to experience more intraspecific encounters relative to interspecific, reducing its competitive advantage and levelling the survival of the two species. Spatial structure also affected the dynamics of a Plodia-granulosis virus interaction and the evolution of virus infectivity. Larval aggregation forced transmission to become limited to within host patches, making the overall prevalence of the virus low. However potentially high rates of cannibalism and multiple infections within overcrowded host aggregations caused virus-induced mortality to be high, as indicated by the low host population density when virus is presented. Also aggregated host populations cause the evolution of lower virus infectivity, where less infective virus strains maintain more susceptible hosts within the aggregation and so possess a greater transmission rate. The pattern of variation in resistance of Plodia interpunctella towards its granulosis virus was found using two forms of graphical analysis. There was a bimodal pattern of variation, with most individuals exhibiting either low or high levels of resistance. This pattern was related to a resistance mechanism that is decreasingly costly to host fitness.

Thesis: M. Arch., Massachusetts Institute of Technology, Department of Architecture, 2018.
Cataloged from PDF version of thesis. Page 82 blank.
Includes bibliographical references (pages 80-81).
The spaces we inhabit influence the way we experience our surroundings, but this causal relationship is much weaker than designers and architects like to imagine. The Ecology of Truth investigates these weak effects as a mesoscope; a device designed to interrogate the spaces and relationships between the microscopic-the lab, and the macroscopic-the Institute. The work draws on the aesthetic of the laboratory at MIT-both transparent and reflective-visible, yet inaccessible. In addition to its aforementioned aesthetic influences, The Ecology of Truth derives its esthetic influence from the solipsistic world of architectural language, blending it with scopic histories that run throughout the development of modern science. If the project has a single inspiration it is the Wunderkammer-also known as cabinet of curiosities-the idea that a unified curation of its contained objects re-assembles their spatial lives, turning 'real' objects into a mythic, often singular narratives of the world-a miniature ecological prism, with various competing truths. The life of the work is dynamic-moving around the institute, it captures scientific curios bound for the trash, repurposing them as a narrative gallery of failed objets-types-modern tools transformed into contingent objects of contemporary space. While on the move, the cabinet turns eyes, and hopefully some of the minds behind those puzzled and curious glances. If not, the artist hopes the viewers enjoyed seeing a reflective box, punctuated by apertures, filled with shiny things! Who doesn't like shiny things?
by Samuel Schneider.
M. Arch.

Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 86-90).
In this thesis, I explore relationships between form generation, material properties, and design constraints in search of a new framework for designing with unpredictable or unstable material systems using glass 3D printing as a case study. Molten glass forming has always been difficult to accurately predict or model, but also offers a high degree of geometric complexity or hierarchy through organic formations. Top-down design approaches to material tunability and control are enabled by new digital fabrication tools and technologies that offer some of most successful attempts to design at scales approaching that of nature [38] [20]. Bottom-up, material-driven systems design functionality, itself, around organically formed structures to challenge our perspective of designing for utility, and how to define that utility [18]. The glass 3D printer, developed by The Mediated Matter Group in collaboration with the MIT Glass Lab, has been an important case study long in the making. A novel type of glass forming quickly gave way to a dialogue with highly unstable material behaviors, structures too complex to model in real time and visually compelling, frozen in time with cooling temperatures. The process generates new types of glass structures and visual output, enabling new design typologies for the product and architectural scale. Here I present an array of over a hundred unique design experiments that offer insight into this brand new design space created by complex glass behavior under control of a digital machine and harnessing structural instability. Close study not only of the objects generated but also their behavior during fabrication is key to understanding how the glass responds to the motion of the machine. Analysis of the project workflow itself provides the foundation for a framework capable of handling an active and complex material system, identifying how and when machine control can be used directly, how and when organic material formation can take place, and how the two interface from design tool to fabrication tool to design product. Finally, I look ahead to the potential for new product and architectural functionalities enabled by this platform, and I establish concepts for using the highly complex forms with the mapped "design space" as a guide for what we understand to be possible. The goal is to form new knowledge about material-informed digital fabrication through the generation of new glass forms and designs.
by Daniel Lizardo.
S.M.

The fungus Hypocreopsis rhododendri forms orange-brown, distinctively lobed stromata on the stems of trees and shrubs. It is found both in Corylus avellana (hazel) scrub on the western fringe of Europe, and on understory shrubs in the Appalachian woodlands of eastern North America. On the basis of its narrow distribution and perceived threats to its Atlantic hazel habitat, H. rhododendri has been prioritised for conservation action in Scotland. A lack of knowledge regarding the species' ecology, however, presents a significant obstacle to effective conservation action. This thesis reports on investigations into the ecology of H. rhododendri, with the aim of providing a scientific basis upon which decisions regarding the species' conservation may be taken. The research yielded the following key findings:  Investigations into the population genetics of the fungus provided evidence of a genetic bottleneck in H. rhododendri's European population, and hinted at fairly recent gene flow between the species' European and North American populations. On this basis it is hypothesised that H. rhododendri established in Europe recently, following dispersal from North America.  Research into the genetic constitution of H. rhododendri's stromata, the distribution of its mycelia in stems and its ability to degrade wood in vitro provided strong support for the hypothesis that H. rhododendri is a superficial parasite of the wood decay fungus Pseudochaete corrugata.  Field surveying revealed that H. rhododendri has a fairly high rate of population turnover, with stromata typically surviving for less than two years. It also revealed that the species' distribution is not strongly influenced by the structure and exposure of its scrub habitat. In view of the above findings and the fact that conservation action is already being undertaken to conserve the species' Atlantic hazel habitat, it is not recommended that conservation action specifically targeted at H. rhododendri is carried out in Scotland.

Until recently the planet was a large world in which human activities and the nature were in balance. Acid rain, global warming, ozone reduction, widespread desertification and species loss: we have to face them now. Ecology and economy are very closely connected.

Ecology implies the relationship of organisms, communities among themselves and with the environment. Russia has enough difficult situation with ecology, because Russia is one of the most polluted countries in the world. Economic situation exacerbates ecological one, and the severity of the prevailing negative trends is growing every day. Major rivers shallows, large amount of small rivers vanish; superficial water pollution, depletion and pollution of the groundwater, drinking water quality degradation, seas pollution, deforestation are big problems in the Russian Federation. Plowing up of turf-covered slopes, low quality agricultural methods cause accelerated soil erosion. Also there was a large degradation of the land resources in the recent years. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/36069

Mesembryanthemaceae is one of the main plant families in the Succulent Karoo biome of South Africa. While its pollination ecology still remains largely unstudied, the system is thought to be overall generalised. This study sought to verify whether Mesemb species flowering during September and October in Vrolijkheit Nature Reserve have generalised or specialised pollination interactions. The determinants of insect choice to a particular plant species were investigated and possible mechanisms adopted by different plant species to prevent interspecific pollen transfer were explored. The system was found to have a generalisation level of 24.7%, indicating that one of four possible interactions actually took place. A relatively high degree of overlap in insect visitors was found between the three white-flowered species (Mesemhryanthemum longistylum, Phylloholus grossus and P. splendens). Colour was one of the main determinants of insect choice, whereby Drosanthemurn speciosum, the only red-flowered species in the study showed the highest degree of specialisation. Both scent and nectar production were relatively important in attracting flower visitors. Seasonality in flowering appeared to be a very important mechanism used to reduce overlap in insect visitors, especially among intrageneric species and those that had flowers of the same colour. Daily patterns in scent and nectar production also appeared to play a role in lowering pollinator-sharing. Given the general floral structure of most Mesemb flowers, these mechanisms are likely to be very important in contributing to species reproductive isolation and the low occurrence of hybrids recorded in natural conditions.