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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Landscape Transformation of Cyprus from 1970 through 2070

January 2013 (has links)
abstract: This dissertation investigates spatial and temporal changes in land cover and plant species distributions on Cyprus in the past, present and future (1973-2070). Landsat image analysis supports inference of land cover changes following the political division of the island of Cyprus in 1974. Urban growth in Nicosia, Larnaka and Limasol, as well as increased development along the southern coastline, is clearly evident between 1973 and 2011. Forests of the Troodos and Kyrenia Ranges remain relatively stable, with transitions occurring most frequently between agricultural land covers and shrub/herbaceous land covers. Vegetation models were constructed for twenty-two plant species of Cyprus using Maxent to predict potentially suitable areas of occurrence. Modern vegetation models were constructed from presence-only data collected by field surveys conducted between 2008 and 2011. These models provide a baseline for the assessment of potential species distributions under two climate change scenarios (A1b and A2) for the years 2030, 2050, and 2070. Climate change in Cyprus is likely to influence habitat availability, particularly for high elevation species as the relatively low elevation mountain ranges and small latitudinal range prevent species from shifting to areas of suitable environmental conditions. The loss of suitable habitat for some species may allow the introduction of non-native plant species or the expansion of generalists currently excluded from these areas. Results from future projections indicate the loss of suitable areas for most species by the year 2030 under both climate regimes and all four endemic species (Cedrus brevifolia, Helianthemum obtusifolium, Pterocephalus multiflorus, and Quercus alnifolia) are predicted to lose all suitable environments as soon as 2030. As striking exceptions Prunus dulcis (almond), Ficus carica (fig), Punica granatum (pomegranate) and Olea europaea (olive), which occur as both wild varieties and orchard cultigens, will expand under both scenarios. Land cover and species distribution maps are evaluated in concert to create a more detailed interpretation of the Cypriot landscape and to discuss the potential implications of climate change for land cover and plant species distributions. / Dissertation/Thesis / Ph.D. Geography 2013
62

Diversidade e distribuição de Solanaceae em formações vegetais altomontanas no sul do Brasil

Vendruscolo, Giovana Secretti January 2009 (has links)
A família Solanaceae possui ampla distribuição geográfica e ocorre em diversos ambientes, sendo a maioria das espécies colonizadoras de ambientes abertos. A família possui representantes herbáceos, arbustivos, arbóreos, escandentes e epifíticos. O objetivo deste estudo foi analisar a diversidade e a distribuição de espécies de Solanaceae em formações vegetais altomontanas nos Aparados da Serra Geral, que ocorrem acima de 900 m, localizados no extremo sudeste de Santa Catarina e no extremo nordeste do Rio Grande do Sul (27°48' - 29°21'S e 49°15' - 50°10'W). Foram realizadas 12 saídas a campo, sendo percorridas todas as formações vegetais e consultadas exsicatas de 23 herbários, referentes aos municípios da região de estudo. Primeiramente, foi feita uma chave para identificação dos gêneros e espécies. Foram consideradas para a região de estudo cinco formações vegetais, oito estações de coleta e 10 faixas altitudinais que foram submetidas a técnicas multivariadas de ordenação e classificação para detectar padrões de distribuição geográfica. Análises de modelos de distribuição de espécies foram utilizadas para estabelecer a área potencial para as 17 espécies com maior ocorrência e avaliar quais as variáveis ambientais que influenciam esta distribuição. No levantamento foram encontrados 12 gêneros e 72 espécies de Solanaceae. A maior riqueza de espécies foi encontrada na Floresta Ombrófila Mista. A forma de vida predominante foi arbustiva e melitofilia e quiropterocoria foram as síndromes de polinização e dispersão mais comuns, respectivamente. O principal fator relacionado com a distribuição das espécies nas formações vegetais foi a luminosidade. A distribuição das espécies em faixas altitudinais evidenciou um decréscimo de espécies com o aumento da altitude e revelou um gradiente altitudinal de riqueza, também apresentado na distribuição das espécies em estações. Três grupos florísticos foram encontrados conforme a altitude, um formado entre 900 e 1.190 m, um segundo grupo entre 1.200 e 1.490 m e o terceiro grupo entre 1.500 e 1.822 m. A maioria das 17 espécies possui uma distribuição potencial ampla. As variáveis relacionadas com temperatura e precipitação atmosférica de estações mais quentes e úmidas foram as que mais influenciaram os modelos de distribuição gerados. / The family Solanaceae has wide geographical distribution and occurs in different environments. The majority of species colonizes open areas. The family present herbaceous, shrubs, trees, lianas and epiphytic representatives. The proposal of this study was to examine the diversity and distribution of Solanaceae species in "Aparados the Serra Geral" which are upper montane plant formations above 900 m in Santa Catarina and Rio Grande do Sul states, Brazil (27°48 '- 29°21' S and 49°15' - 50°10' W). We performed all plant formations in 12 travels to the field and analysed exsiccate of 23 herbaria referring to the study region. First, we made an identification key to the genera and species. We considered five vegetation types, eigth montane stations and 10 altitudinal belts that were submitted to ordination and classification techniques to detect patterns of geographical distribution. Analysis of models of species distribution were used to establish the potential area for 17 species with higher occurrence and to assess the role of environmental variables on their distribution. A total of 12 genera and 72 species of Solanaceae were found. The greatest richness of species was found in the Araucaria angustifolia forest. The predomintant life-form were shrubby and melittophily and quiropterocory were the most common pollination and dispersal syndromes, respectively. The main factor related to the species distribution was luminosity. The species distribution in altitudinal belts showed a decreasing number of species according to higher altitudes. We also verified a gradient based on species distributions and the formation of three species-groups, one related from 900 to 1.190 m, a second group from 1.200 to 1.490 m and a third group from 1.500 to 1.822 m. Most of the 17 species has a wide distribution potential. The variables related to temperature and precipitation of hot and wet seasons were the most influencing factors for the generated models.
63

Réponses de plantes aquatiques invasives au réchauffement climatique / Response of aquatic invasive plants to climate warming

Gillard, Morgane 01 December 2016 (has links)
Les modèles climatiques prédisent une augmentation globale de la température de 1 à 4°C d’ici 2100. Les modifications de climat engendrées par ce réchauffement devraient favoriser les invasions biologiques. L’objectif général de cette thèse est d’explorer l’impact du réchauffement et du changement climatique sur quatre espèces de macrophytes invasifs en Europe. Le travail réalisé a porté sur la germination, la croissance, la physiologie et la distribution des ces espèces à travers des expérimentations en conditions contrôlées, en jardin expérimental, et via des modèles de distribution d’espèces. Nous avons montré que i) des températures plus élevées améliorent modérément les capacités de germination de Ludwigia hexapetala et Ludwigia peploides subsp. montevidensis, diminuent la survie des plantules mais augmentent leur production de biomasse, ii) l’effet d’une augmentation de température sur les macrophytes dépend de la saison à laquelle elle a lieu, iii) une augmentation de 3°C peut avoir des conséquences sur le métabolisme sans pour autant affecter la croissance, iv) la Jussie L. hexapetala est la seule espèce qui a de meilleures capacités de croissance à la fois apicale et latérale face à un réchauffement, v) les modèles prédisent une augmentation de l’aire de distribution de Ludwigia spp., Myriophyllum aquaticum et E. densa dans leurs aires d’invasion, et une diminution de leur distribution sur les autres continents, y compris dans leur aire d’indigénat. Ce travail permet de mieux comprendre les conséquences possibles des modifications climatiques sur les macrophytes invasifs, afin d’appréhender et d’anticiper leur potentiel de colonisation futur. / Climatic models predict a rise of globale surface temperature about 1 to 4°C by 2100. Climate modifications generated by this warming might favor biological invasions. The general objectif of this thesis was to explore the impacts of climate warming and climate change on four macrophytes invasive in Europe. This work focused on germination, growth, physiology and distribution of these species, through experiments in controlled conditions, in experimental garden and by using species distribution models. We showed that i) higher temperatures favor moderately the germination capacity of Ludwigia hexapetala and Ludwigia peploides subsp. montevidensis, decrease the seedlings survivorship but improve their biomass production, ii) the effect of increased temperature on macrophytes depends on the season, iii) a 3°C warming can modify metabolism without generating changes on the growth, iv) the water primroses L. hexapetala is the only species that showed both better apical and lateral growth when facing a warming, v) models predict an increase of the distribution surface of Ludwigia spp., Myriophyllum aquaticum and E. densa in their invasive ranges, and a decrease of their distribution area in the other continents, including their native range. This thesis offer a better understanding of climate changes consequences on invasive macrophytes in order to anticipate their futur colonisation potential.
64

Interpreting Paleoclimate and Species Distributions of Red Spruce and Fraser Firs in the Southern Appalachians to Predict Impacts of Climate Change on Forest Habitats

Mosher, Danika L., Joyner, T. Andrew 12 April 2019 (has links)
Spruce-Fir forests are relicts from the Pleistocene and have migrated back north after the previous warming period as well as up in elevation in the southern Appalachian mountains. This in turn created sky islands of isolated, endemic, and disjunct species. These refugal forests require certain climatic parameters similar to Canada’s boreal mountains but also need additional cloud immersion and precipitation. These forests have experienced stressors in the past, but face continued threats such as air pollution and climate change. Due to limited immigration for the majority of the species on these mountains, a significant number of organisms are at risk of being endangered or extinct. Analyzing the relationships and patterns between species distribution and climatic parameters both in the past and present will help create future prediction maps. These will potentially anticipate where habitat reduction might occur and will benefit management and conservation purposes. The first study will analyze current distributions of Spruce-Fir forests to see which model and variable combination best approximates the unique mountain forests environments. Using the optimal model from the first study, the second study will examine which distributional changes may occur in the future and how these changes compare to paleo-environmental distributions. Anticipated results will show a reduction of habitat in lower peaks with minimal impact at higher peaks based on the known projected trends of cloud ceilings. This research will help with forest and conservation management and will impact a multitude of species that rely on this forest to survive.
65

NINE-BANDED ARMADILLOS IN SOUTHERN ILLINOIS: DISEASES, SPATIAL DISTRIBUTION, AND LIVE-CAPTURE TECHNIQUES

Haywood, Carly 01 December 2020 (has links)
Originally endemic to South America, the nine-banded armadillo (Dasypus novemcinctus) has recently expanded its range northward to Illinois. With this range expansion comes concern from both wildlife managers and the general public regarding potential incoming pathogens and unknown impacts on native wildlife. My research, conducted during 2018-2020 in southern Illinois, addressed the following 3 objectives intended to provide information regarding this novel species: (1) test for the presence of Trypanosoma cruzi and Mycobacterium leprae, (2) model the potential distribution of armadillos, and (3) attempt several different armadillo capture methods. For Objective 1, I tested roadkilled specimens for T. cruzi and M. leprae, 2 pathogens known to infect humans, using PCR and ELISA, respectively. All 81 samples tested for T. cruzi and all 25 samples tested for M. leprae were negative. The latter case is consistent with the enemy release hypothesis, suggesting armadillos have evaded parasites present in their native environment due to geographical distance. The absence of T. cruzi in the sampled individuals implies dispersing individuals are more robust than those at the center of their range. For Objective 2, I used MAXENT to model potential armadillo distribution in 51 counties in southern Illinois using 39 presence locations. Modeling identified low-intensity development to be the most important predictor of armadillo presence. For Objective 3, I attempted to capture armadillos using spotlighting on roads, staking out burrows, unbaited single-door cage traps, and unbaited double-door cage traps. Based on trap nights per capture, I found the use of double-door cage traps to be the most efficient method. My study will aid in managing colonizing armadillo populations by presenting information regarding dynamics of disease transmission, predicting areas of armadillo presence, and capture methods.
66

Modelling the response of Antarctic marine species to environmental changes. Methods, applications and limitations.

Guillaumot, Charlène 09 July 2021 (has links) (PDF)
Among tools that are used to fill knowledge gaps on natural systems, ecological modelling has been widely applied during the last two decades. Ecological models are simple representations of a complex reality. They allow to highlight environmental drivers of species ecological niche and better understand species responses to environmental changes. However, applying models to Southern Ocean benthic organisms raises several methodological challenges. Species presence datasets are often aggregated in time and space nearby research stations or along main sailing routes. Data are often limited in number to correctly describe species occupied space and physiology. Finally, environmental datasets are not precise enough to accurately represent the complexity of marine habitats. Can we thus generate performant and accurate models at the scale of the Southern Ocean ?What are the limits of such approaches ?How could we improve methods to build more relevant models ?In this PhD thesis, three different model categories have been studied and their performance evaluated. (1) Mechanistic physiological models (Dynamic Energy Budget models, DEB) simulate how the abiotic environment influences individual metabolism and represent the species fundamental niche. (2) Species distribution models (SDMs) predict species distribution probability by studying the relationship between species presences and the environment. They represent the species realised niche. (3) Dispersal lagrangian models predict the drift of propagules in water masses. Results show that physiological models can be developed for marine Southern Ocean species to simulate the metabolic variations in link with the environment and predict population dynamics. However, more data are necessary to highlight detailed physiological contrasts between populations and to accurately evaluate models. Results obtained for SDMs suggest that models generated at the scale of the Southern Ocean and future simulations are not relevant, given the lack of data available to characterise species occupied space, the lack of precision and accuracy of future climate scenarios and the impossibility to evaluate models. Moreover, model extrapolate on a large proportion of the projected area. Adding information on species physiological limits (observations, results from experiments, physiological model outputs) was shown to reduce extrapolation and to improve the capacity of models to estimate the species realised niche. Spatial aggregation of occurrence data, which influenced model predictions and evaluation was also succefully corrected. Finally, dispersal models showed an interesting potential to highlight the role of geographic barriers or conversely of spatial connectivity and also the link between species distribution, physiology and phylogeny history. This PhD thesis provides several methodological advice, annoted codes and tutorials to help implement future modelling works applied to Southern Ocean marine species. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
67

The Importance of Human Population Characteristics in Modeling Aedes aegypti Distributions and Assessing Risk of Mosquito-Borne Infectious Diseases

Obenauer, Julie F., Joyner, T. Andrew, Harris, Joseph B. 15 November 2017 (has links)
Background: The mosquito Aedes aegypti has long been a vector for human illness in the Southeastern United States. In the past, it has been responsible for outbreaks of dengue, chikungunya, and yellow fever and, very recently, the Zika virus that has been introduced to the region. Multiple studies have modeled the geographic distribution of Ae. aegypti as a function of climate factors; however, this ignores the importance of humans to the anthropophilic biter. Furthermore, Ae. aegypti thrives in areas where humans have created standing water sites, such as water storage containers and trash. As models are developed to examine the potential impact of climate change, it becomes increasingly important to include the most comprehensive set of predictors possible. Results: This study uses Maxent, a species distribution model, to evaluate the effects of adding poverty and population density to climate-only models. Performance was evaluated through model fit statistics, such as AUC, omission, and commission, as well as individual variable contributions and response curves. Models which included both population density and poverty exhibited better predictive power and produced more precise distribution maps. Furthermore, the two human population characteristics accounted for much of the model contribution-more so than climate variables. Conclusions: Modeling mosquito distributions without accounting for their dependence on local human populations may miss factors that are very important to niche realization and subsequent risk of infection for humans. Further research is needed to determine if additional human characteristics should be evaluated for model inclusion.
68

Contextualizing chimpanzee research within the socioecological landscape of the Forestière region of the Republic of Guinea, Africa / アフリカ・ギニア共和国の森林地帯における景観とチンパンジー調査

Maegan, Annette Fitzgerald 26 July 2021 (has links)
付記する学位プログラム名: 霊長類学・ワイルドライフサイエンス・リーディング大学院 / 京都大学 / 新制・課程博士 / 博士(理学) / 甲第23406号 / 理博第4741号 / 新制||理||1680(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 平田 聡, 教授 村山 美穂, 教授 伊谷 原一 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
69

The Zoogeography of Marine Tardigrada

Kaczmarek, Lukasz, Bartels, Paul J., Roszkowska, Milena, Nelson, Diane R. 01 January 2015 (has links)
This monograph describes the global records of marine water bears (Phylum Tardigrada). We provide a comprehensive list of marine tardigrades recorded from around the world, providing an up-to-date taxonomy and a complete bibliography accompanied by geographic co-ordinates, habitat, substrate and biogeographic comments. A link is provided to an on-line interactive map where all occurrences for each species are shown. In total we list 197 taxa and their 2240 records from 39 oceans and seas and 18 Major Fishing Areas (FAO). It is hoped this work will serve as a reference point and background for further zoogeographic and taxonomic studies on marine tardigrades.
70

Applications of Species Distribution Modeling for Palaeontological Fossil Detection: Late Pleistocene Models of Saiga (Artiodactyla: Bovidae, Saiga Tatarica)

Jurestovsky, Derek, Joyner, T. Andrew 01 June 2018 (has links)
Few studies utilise modern species distribution data and modeling to make predictions for examining potential fossil localities. Instead, species distribution modeling is often used for palaeoenvironmental interpretations. Using palaeoclimate data to model potential past distributions for a species provides a prediction showing areas where its fossil remains may be found. In this study, the current, Last Glacial Maximum, and Last Interglacial potential distributions of the arid steppe-obligate saiga antelope (Artiodactyla: Bovidae, Saiga tatarica) were modeled using the species distribution model Maxent. Few fossil records exist, but available fossil locality records were used to validate both palaeo models, resulting in speculative predictions about where the saiga may have lived. Known fossil localities of saiga from the Last Glacial Maximum time period were located within predicted moderately suitable environments, while four of seven Last Interglacial fossil localities were located within predicted moderately suitable environments, suggesting that models can accurately identify areas where fossils for the saiga can be found. Specifically, these models suggest saiga fossils may be located in northwestern and northeastern China, the western and central regions of the Middle East, and southern Alaska. The predicted areas in northeastern China are of particular interest because saiga fossils have not been identified in this region, but some palaeontologists theorize that northeast China may have been suitable for saiga in the past. The models lend credence to this argument.

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