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1
Campos, Bruna Helena de. "Atributos de proteção às gemas laterais em espécies lenhosas distribuídas no gradiente latitudinal do Cerrado." Botucatu, 2018. http://hdl.handle.net/11449/153795.
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Orientador: Elza GuimarãesResumo: A variação em atributos de proteção, principalmente os foliares, pode ter importante papel no desempenho das espécies ao longo de um gradiente de condições ambientais ou em hábitats heterogêneos. O domínio Cerrado está inserido em um gradiente climático e suas formações savânicas estão submetidas a queimadas recorrentes. Neste trabalho nós caracterizamos atributos de proteção às gemas em três espécies lenhosas, coocorrentes em fitofisionomias savânicas ao longo do gradiente latitudinal N-S do Cerrado e investigamos a ocorrência de fogo em uma escala espácio-temporal. Caracterizamos a posição das gemas nas plantas, morfologia e anatomia e indicadores de flamabilidade das mesmas. De modo geral, as plantas de diferentes localidades apresentaram diferenças quanto a altura das gemas na planta em relação ao nível do solo, sendo que plantas mais altas foram observadas nas latitudes menores e as mais baixas nas latitudes maiores, provavelmente devido a maior produtividade associada à proximidade da linha do Equador. Primórdios com maior área ocupada por idioblastos fenólicos foram observados nas duas localidades mais próximas à linha do Equador, possivelmente devido a alta intensidade de radiação. Além disso, registramos distintos regimes de queimada nas cinco localidades nos últimos 15 anos. Considerando a ampla distribuição geográfica das três espécies deste estudo, podemos concluir que suas gemas axilares toleram certa variação nos fatores climáticos como a amplitude de temperatur... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The variation in protection traits, especially the foliar ones, can play an important role in species performance along a gradient of environmental conditions or in heterogeneous habitats. The Cerrado domain is inserted in a climatic gradient and its savannah formations are under recurrent burning. In this study, we characterized bud protection traits of three woody species that co-ocurr in savannah phytophysiognomys along the Cerrado latitudinal gradient and we investigated fire occurrence in a spatio-temporal scale. We characterized bud position in each plant species, its morphology, anatomy and flammability indicators. In general, plants of different locations showed differences in bud height in relation to soil level. Taller plants were observed at lower latitudes and the smallest ones at higher latitudes, probably due to the higher productivity associated to the proximity to Equator line. Primordia with a larger area occupied by phenolic idioblasts were observed in the two locations nearest to the Equator line, possibly due to high radiation intensity. Besides that, we registered different fire regimes at the five locations in the last 15 years. Considering the wide distribution of the three species of this study, we can conclude that their axillary buds tolerate some variation in climatic factors like temperature, solar radiation and pluviosity amplitude. Besides that, this species are capable of persisting in environments under different fire frequency. Additionally, b... (Complete abstract click electronic access below)
Mestre
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Nilsson-Örtman, Viktor. "Thermal adaptation along a latitudinal gradient in damselflies." Doctoral thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-62276.
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Understanding how temperature affects biological systems is a central question in ecology and evolutionary biology. Anthropogenic climate change adds urgency to this topic, as the demise or success of species under climate change is expected to depend on how temperature affects important aspects of organismal performance, such as growth, development, survival and reproduction. Rates of biological processes generally increase with increasing temperature up to some maximal temperature. Variation in the slope of the initial, rising phase has attracted considerable interest and forms the focus of this thesis. I explore variation in growth rate-temperature relationships over several levels of biological organization, both between and within species, over individuals’ lifetime, depending on the ecological context and in relation to important life history characteristics such as generation length and winter dormancy. Specifically, I examine how a clade of temperate damselflies have adapted to their thermal environment along a 3,600 km long latitudinal transect spanning from Southern Spain to Northern Sweden. For each of six species, I sampled populations from close to the northern and southern range margin, as well from the center of the latitudinal range. I reared larvae in the laboratory at several temperatures in order to measure indiviudal growth rates. Very few studies of thermal adaptation have employed such an extensive sampling approach, and my finding reveal variation in temperature responses at several levels of organization. My main finding was that temperature responses became steeper with increasing latitude, both between species but also between latitudinal populations of the same species. Additional genetic studies revealed that this trend was maintained despite strong gene flow. I highlight the need to use more refined characterizations of latitudinal temperature clines in order to explain these findings. I also show that species differ in their ability to acclimate to novel conditions during ontogeny, and propose that this may reflect a cost-benefit trade-off driven by whether seasonal transitions occur rapidly or gradually during ontogeny. I also carried out a microcosm experiment, where two of the six species were reared either separately or together, to determine the interacting effects of temperature and competition on larval growth rates and population size structure. The results revealed that the effects of competition can be strong enough to completely overcome the rate-depressing effects of low temperatures. I also found that competition had stronger effects on the amount of variation in growth rates than on the average value. In summary, my thesis offers several novel insights into how temperature affects biological systems, from individuals to populations and across species’ ranges. I also show how it is possible to refine our hypotheses about thermal adaptation by considering the interacting effects of ecology, life history and environmental variation.
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Heilmayer, Olaf. "Environment, adaptation and evolution: scallop ecology across the latitudinal gradient = Umwelt, Anpassung und Evolution: Ökologie der Jakobsmuscheln im latitudinalen Gradienten /." Bremerhaven : Alfred-Wegener-Inst. für Polar- und Meeresforschung, 2004. http://www.gbv.de/dms/bs/toc/385417098.pdf.
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Olsson, Katarina. "Population differentiation in Lythrum salicaria along a latitudinal gradient." Doctoral thesis, Umeå : Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-364.
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Cardillo, Marcel. "The evolution of the latitudinal gradient in species richness /." St. Lucia, Qld, 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16383.pdf.
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Acharya, Kamal Prasad. "Invasive Species: Genetics, Characteristics and Trait Variation Along a Latitudinal Gradient." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-27068.
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Globalization during the second half of the 20th century has accelerated the introduction and the spread of non-native species. Introduced species is considered the second largest threat to biodiversity after habitat destruction. It is therefore necessary to understand what makes introduced species successful in novel environments. Furthermore, introduced species provide unique opportunities to study the evolutionary processes that are involved in invasion success. We studied genetics, and evolution of higher phenotypic plasticity and local adaptation after introduction of one of the highly invasive species in Europe, Impatiens glandulifera, and compared trait variation in native and invasive Impatiens species along a latitudinal gradient in Europe. We found evidence of multiple introductions of the invasive I. glandulifera in Europe. Despite multiple introductions, there was a strong loss of genetic diversity in the invasive populations compared to native populations from Kashmir, India. Furthermore, loss of genetic diversity in the invasive populations does not constrain evolution of adaptive genetic differentiation. In another study, we did not find evidence that the species developed increased plasticity after introduction. A comparative study between a native, Impatiens noli-tangere, and an invasive species, Impatiens parviflora, showed that latitude has stronger effect on the performance of the invasive species in terms of plant height than on the native species. Surprisingly, the invasive species performed better under low nitrogen compared to high nitrogen conditions along the latitudinal gradient indicating that the invasive species is not constrained by low nitrogen conditions. All together these findings suggest that invasive species loose genetic variation, and do not adapt into more aggressive invasives, but they do evolve rapid adaptations to broad-scale environmental conditions in their introduced range
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Quadros, Alex Leite. "Diversidade dos Belytinae (Hymenoptera: Diaprioidea: Diapriidae) ao longo de um gradiente latitudinal de Mata Atlântica Ombrófila Densa." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/38/38131/tde-06102015-140638/.
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Os principais objetivos deste trabalho foram conhecer a distribuição da riqueza dos Hymenoptera parasitoides Diapriidae Belytinae ao longo de um gradiente latitudinal da Mata Atlântica e explicar as causas do padrão de riqueza encontrado por comparação com os padrões descritos para outros grupos. Os Belytinae exercem papel chave na regulação natural de populações de muitas espécies de Mycetophilidae e Sciaridae (Diptera) e o conhecimento sobre a diversidade desta subfamília no bioma Mata Atlântica é relativamente pequeno. O material utilizado neste estudo provém de coletas realizadas em 18 localidades regularmente espaçadas, da Paraíba à Santa Catarina, entre os anos de 2000 e 2002, no âmbito do projeto Riqueza e diversidade de Hymenoptera e Isoptera ao longo de um gradiente latitudinal na Mata Atlântica - a floresta pluvial do leste do Brasil (Biota/SP Fapesp). Através de um número padronizado de armadilhas Malaise e de Moericke, e varredura da vegetação foram obtidos 1241 exemplares separados em 115 morfoespécies e oito gêneros. Destes, Scorpioteleia é registrado pela primeira vez na região neotropical e sete (Aclista, Belyta, Cinetus, Odontopsilus, Scorpioteleia, Lyteba e Camptopsilus) são registrados pela primeira vez no Brasil. Foram feitos mapeamentos e diagnoses para todas as morfoespécies e gêneros; as morfoespécies foram todas ilustradas com pelo menos duas fotos. A maior parte das morfoespécies (86) está presente em apenas uma ou duas localidades. Nota-se uma tendência das localidades nas maiores latitudes de apresentarem riquezas de morfoespécies e gêneros significativamente maiores que as das localidades em latitudes menores, mesmo que estas apresentem quantidades de indivíduos significativamente maiores que as daquelas. Os resultados da análise da distribuição dos Belytinae indicam uma quantidade de morfoespécies exclusivas do sul do bioma (6 ou 8) ligeiramente maior que as exclusivas do norte (2), apesar das diferenças serem pouco significativas. A análise de similaridade indicou que a proximidade geográfica parece ser importante condicionante para o padrão de distribuição da fauna na maioria das localidades; os três agrupamentos principais formados nos dendogramas de índices de Sørensen e Jaccard sugerem a presença de dois sub-biomas (Sul + Sudeste e Nordeste). Indícios obtidos a partir das análises e dos dados do presente estudo combinados com informações da literatura ou de pesquisadores sobre a biologia, ecologia e distribuição da riqueza dos Belytinae, seus hospedeiros e fungos do solo, tornam plausível a ideia de que os Belytinae tenham a riqueza de espécies aumentada com o aumento da latitude, contrariamente ao padrão mais comum para a maioria dos grupos animais.The main objectives of this work were to describe the distribution of Hymenoptera parasitoids Diapriidae Belytinae richness along a latitudinal gradient of Atlantic Forest and to explain the reasons for the pattern of richness found, by comparison with patterns described for other groups. The Belytinae play a key role in the natural regulation of populations of many species of Mycetophilidae and Sciaridae (Diptera) and the knowledge about the diversity of this subfamily in the Atlantic Forest biome is relatively poor. The material used in this study comes from collections in 18 regularly spaced locations, from Paraiba to Santa Catarina, between the years of 2000 and 2002, under the project \"Richness and Diversity of Hymenoptera and Isoptera along a latitudinal gradient in the Atlantic forest - the Eastern Brazilian Rain Forest\" (Biota/SP - FAPESP). Using a standardized number of Malaise and Moericke traps, and sweeping the vegetation a total of 1241 specimens separated in 115 morphospecies and eight genera were obtained. Of these, Scorpioteleia is recorded for the first time in the neotropical region and seven genera (Aclista, Belyta, Cinetus, Odontopsilus, Scorpioteleia, Lyteba and Camptopsilus) are recorded for the first time in Brazil. Mappings and diagnoses were made for all morphospecies and genera; all morphospecies were illustrated with at least two pictures. There is a tendency of localities in the highest latitudes to present similar or significantly greater richness of morphospecies and genera than those of localities in lowest latitudes, even if these present quantities of individuals significantly higher than the latter. The results of the analysis of the distribution of Belytinae indicate a quantity of exclusive morphospecies of the southern biome (6 or 8) slightly higher than the exclusive northern (2), although these differences are not highly significant. Most morphospecies (86) are present in only one or two locations. The similarity analysis indicated that the geographical proximity appears to be important to define the pattern of distribution of fauna in most localities; the three main groups formed in dendograms with indices of Sorensen and Jaccard suggest the presence of two sub-biomes (South + East and Northeast). Evidences obtained with the data and analyzes of the present study combined with information deducted from or obtained through literature or researchers about the biology, ecology and distribution of the richness of Belytinae, their hosts and soil fungi, make plausible the idea that the Belytinae have the species richness increased with the increase of latitude, unlike the most common pattern displayed by most animal groups.
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Weber, Marcelo de Moraes. "BIOGEOGRAFIA DE MORCEGOS (CHIROPTERA) EM ÁREA DE TRANSIÇÃO FLORESTA-CAMPO NO SUDESTE DA AMÉRICA DO SUL." Universidade Federal de Santa Maria, 2009. http://repositorio.ufsm.br/handle/1/5287.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe variation on the richness species in regional scales has been debated a lot. Three of the hypotheses mot frequently discussed as determinants of regional variability in richness species are energy, contemporary climatic conditions and habitat heterogeneity. Studies at mesoscale are very important to discover different patterns that underlying the variability in richness species. As the bats are so common in whole world and ecologically diverse, these organisms are excellent environmental characterized. On this basis, the goals of this study were to link the bat species composition with the vegetation in forest-grassland transition area in the Southeastern of South America and to assess the space influence on the bat species richness by environmental variables. The study area includes the southeastern of South America. Species distribution data were obtained by museums, review and database on line .The distribution s estimate for each species was done on a map with 139 cells 1º latitude by 1º longitude. It was collected distribution data to 79 bat species. Rain Forest and Seasonal Forest had the largest species richness. The cluster analysis based on the cells revealed three major clusters: the Forest cluster (at north), the Araucaria cluster (at middle), and the Grassland cluster (at south). The Araucaria cluster was associated to the Grassland cluster. The cluster analysis based in the phytogeographic zones revealed four clusters, where the Araucaria Forest was associated with the forested regions. The contemporary climatic conditions hypothesis was the best explained the variability on the richness data, where the mean annual temperature the main predictor variable, followed by extent of relief and AET, respectively. With the whole variables, the OLS regression also indicated the mean annual temperature as the main predictor variable, followed by AET. These same variables also explained the variability in the species richness in Phyllostomidae, Molossidae and Vespertilionidae. The Araucaria Forest is a filter area to the dispersal of tropical species into subtropical and temperate areas of South America, because the hard winters in that area, what may be explained likely for the intolerance of some species in colder climates.
A variação da riqueza de espécies em escala regional tem sido intensivamente discutida. Três das principais hipóteses que buscam explicar esse padrão de variação são as hipóteses energética, climática e de heterogeneidade do habitat. Estudos em meso-escala são importantes para descobrir padrões diferentes que influenciam a variação na riqueza de espécies. Como os morcegos são muito abundantes globalmente e bem diversificados ecologicamente, esses organismos são ótimos caracterizadores ambientais. Com base nisso, os objetivos deste estudo foram relacionar a composição das espécies de morcegos com a vegetação em área de transição floresta-campo no sudeste da América do Sul e avaliar a influência do espaço sobre a riqueza de morcegos através de variáveis ambientais. A área de estudo compreende a porção sudeste da América do Sul. Os dados de distribuição das espécies foram coletados através de visita a museus, revisão bibliográfica e consulta a bancos de dados on line. Foi feita a estimativa de distribuição para cada espécie sobre um mapa contendo 139 quadrículas de 1º de latitude por 1º de longitude. Foram obtidos dados de distribuição para 79 espécies de morcegos. Áreas de Floresta Ombrófila Densa e de Floresta Estacional possuíram a maior riqueza de espécies. A análise de agrupamento com base nas quadrículas formou três grupos nítidos: grupo Florestal (ao norte), Araucária (intermediário) e Campestre (ao sul). O grupo Araucária ficou associado ao grupo Campestre. A análise de agrupamento com base nas regiões fitogeográficas formou quatro grupos nítidos, sendo que a Floresta de Araucária ficou associada às formações florestais. A hipótese climática foi a que melhor explicou a variação dos dados de riqueza, sendo a temperatura média anual a principal variável preditora, seguida pela amplitude da altitude e pela AET, respectivamente. Considerando todas as variáveis, a regressão OLS também apontou a temperatura média anual como a principal variável preditora, seguida pela AET. Essas variáveis também explicaram a variação na riqueza de espécies das famílias Phyllostomidae, Molossidae e Vespertilionidae. A Floresta de Araucária é uma área filtro para a dispersão de espécies tropicais para as regiões subtropicais e temperadas da América do Sul, devido aos invernos rigorosos presentes nessa área, o que pode ser explicado principalmente pela intolerância de algumas espécies a climas mais frios.
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Pittera, Justine. "Adaptation des cyanobactéries marines du genre Synechococcus au gradient latitudinal de température." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066505/document.
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Les picocyanobactéries marines sont les organismes photosynthétiques les plus abondants de la planète. Parmi celles-ci, les Synechococcus marins sont détectés de l’équateur aux cercles polaires, suggérant qu’ils ont évolué des stratégies adaptatives très efficaces à la température. La première partie de ce travail de thèse a visé à étudier la thermophysiologie de différentes lignées de la radiation des Synechococcus marins. Les résultats d’expériences de variations thermiques à court et long terme associées à une étude de phyloécologie ont démontré l’existence de clades physiologiquement spécialisées dans des niches thermiques distinctes, i.e des thermotypes. Ces travaux ont de plus mis en évidence l’importance de l’optimisation de l’efficacité de l’appareil photosynthétique dans l’acclimatation à la température. Ainsi, la thermostabilité du photosystème II, complexe clé de la régulation de l’énergie, a été comparée chez différentes souches de Synechococcus marins. Ces travaux ont révélé de grandes différences de thermostabilité de l’antenne photosynthétique et de ses constituants, qui sont corrélées à la latitude d’isolement des souches. L’étude de modèles d’homologie de structure de phycobiliprotéines a permis de révéler certaines des adaptations moléculaires de ce complexe à la température. La fonctionnalité des complexes photosynthétiques est directement dépendante de la fluidité des membranes au sein desquelles ils sont insérés, un facteur physique très influencé par la température. Le troisième volet de cette thèse a permis de mieux comprendre les mécanismes de régulation des lipides membranaires chez les Synechococcus marins. Les résultats montrent que la composition en acides gras joue un rôle important durant l’acclimatation à différentes températures. De plus, par une approche de génomique comparative, ce travail de thèse montre que les Synechococcus marins présentent des équipements différents en enzymes désaturases, qui ont très probablement joué un rôle dans la colonisation de différentes niches thermiques. Les résultats de ce travail de thèse, discutés dans un contexte d’évolution de l’adaptation au gradient latitudinal de température chez les picocyanobactéries marines, soulèvent de nouvelles hypothèses exaltantes pour les travaux futursMarine picocyanobacteria are the most abundant photosynthetic organisms on Earth. Among them, Synechococcus displays a wide latitudinal distribution, ranging from the equator to polar circles, suggesting that they have evolved efficient adaptive strategies to cope with the latitudinal temperature gradient. The first part of this PhD work aimed at studying the thermophysiology of different lineages of the marine Synechococcus radiation. The combination of thermal acclimation and stress experiments with a phyloecology study allowed unveiling the existence of lineages physiologically specialized in distinct thermal niches, i.e. thermotypes. This work furthermore pointed out the importance of the capacities to optimize the photosynthetic apparatus efficiency for successful temperature acclimation. The thermostability of photosystem II, a key complex to the regulation of light energy utilisation, was compared within several marine Synechococcus strains. The results revealed that the photosynthetic antenna and its components have distinct thermostabilities, which are related to the strain isolation latitude. Structural homology models of phycobiliproteins thus revealed sites of molecular adaptation of the antenna to temperature. The function of the photosynthetic complexes is dependent on the fluidity of the membranes in which they are embedded, a physical factor regulated by temperature. The results a first lipidomic study suggested that the regulation of the composition in acyl chains plays an important role in temperature acclimation in marine Synechococcus. Furthermore, genomic comparative analyses revealed notably that marine Synechococcus have distinct sets of desaturase enzymes which have likely played a role in the colonization of different thermal niches. The results of this PhD thesis, which are discussed in the context of the Synechococcus adaptive evolution to the latitudinal gradient of temperature, raise new hypotheses for some future exciting work
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Pittera, Justine. "Adaptation des cyanobactéries marines du genre Synechococcus au gradient latitudinal de température." Electronic Thesis or Diss., Paris 6, 2015. http://www.theses.fr/2015PA066505.
Full textAbstract:
Les picocyanobactéries marines sont les organismes photosynthétiques les plus abondants de la planète. Parmi celles-ci, les Synechococcus marins sont détectés de l’équateur aux cercles polaires, suggérant qu’ils ont évolué des stratégies adaptatives très efficaces à la température. La première partie de ce travail de thèse a visé à étudier la thermophysiologie de différentes lignées de la radiation des Synechococcus marins. Les résultats d’expériences de variations thermiques à court et long terme associées à une étude de phyloécologie ont démontré l’existence de clades physiologiquement spécialisées dans des niches thermiques distinctes, i.e des thermotypes. Ces travaux ont de plus mis en évidence l’importance de l’optimisation de l’efficacité de l’appareil photosynthétique dans l’acclimatation à la température. Ainsi, la thermostabilité du photosystème II, complexe clé de la régulation de l’énergie, a été comparée chez différentes souches de Synechococcus marins. Ces travaux ont révélé de grandes différences de thermostabilité de l’antenne photosynthétique et de ses constituants, qui sont corrélées à la latitude d’isolement des souches. L’étude de modèles d’homologie de structure de phycobiliprotéines a permis de révéler certaines des adaptations moléculaires de ce complexe à la température. La fonctionnalité des complexes photosynthétiques est directement dépendante de la fluidité des membranes au sein desquelles ils sont insérés, un facteur physique très influencé par la température. Le troisième volet de cette thèse a permis de mieux comprendre les mécanismes de régulation des lipides membranaires chez les Synechococcus marins. Les résultats montrent que la composition en acides gras joue un rôle important durant l’acclimatation à différentes températures. De plus, par une approche de génomique comparative, ce travail de thèse montre que les Synechococcus marins présentent des équipements différents en enzymes désaturases, qui ont très probablement joué un rôle dans la colonisation de différentes niches thermiques. Les résultats de ce travail de thèse, discutés dans un contexte d’évolution de l’adaptation au gradient latitudinal de température chez les picocyanobactéries marines, soulèvent de nouvelles hypothèses exaltantes pour les travaux futursMarine picocyanobacteria are the most abundant photosynthetic organisms on Earth. Among them, Synechococcus displays a wide latitudinal distribution, ranging from the equator to polar circles, suggesting that they have evolved efficient adaptive strategies to cope with the latitudinal temperature gradient. The first part of this PhD work aimed at studying the thermophysiology of different lineages of the marine Synechococcus radiation. The combination of thermal acclimation and stress experiments with a phyloecology study allowed unveiling the existence of lineages physiologically specialized in distinct thermal niches, i.e. thermotypes. This work furthermore pointed out the importance of the capacities to optimize the photosynthetic apparatus efficiency for successful temperature acclimation. The thermostability of photosystem II, a key complex to the regulation of light energy utilisation, was compared within several marine Synechococcus strains. The results revealed that the photosynthetic antenna and its components have distinct thermostabilities, which are related to the strain isolation latitude. Structural homology models of phycobiliproteins thus revealed sites of molecular adaptation of the antenna to temperature. The function of the photosynthetic complexes is dependent on the fluidity of the membranes in which they are embedded, a physical factor regulated by temperature. The results a first lipidomic study suggested that the regulation of the composition in acyl chains plays an important role in temperature acclimation in marine Synechococcus. Furthermore, genomic comparative analyses revealed notably that marine Synechococcus have distinct sets of desaturase enzymes which have likely played a role in the colonization of different thermal niches. The results of this PhD thesis, which are discussed in the context of the Synechococcus adaptive evolution to the latitudinal gradient of temperature, raise new hypotheses for some future exciting work
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Weir, Jason Tyler. "Evolution of the latitudinal species diversity gradient of New World birds and mammals." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31743.
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The latitudinal diversity gradient in which species diversity is highest near the equator and declines toward the poles is well characterized in most higher level taxonomic groups and is strongest in the New World. However, the underlying causes of this gradient are poorly understood. By sampling New World birds and mammals, we found that the distribution of the evolutionary ages of sister species adheres to a latitudinal gradient. The time to divergence for sister species is shortest at high latitudes and longer in the tropics. Birth-death models fitting these data estimate that the highest recent speciation and extinction rates occur at high latitudes and decline toward the tropics suggesting that rates of species turnover are greatest where diversity is lowest. A pattern of endemism in boreal superspecies plausibly links the recent divergence of high latitude species to the fragmentation of the North American boreal forest by climatic oscillations during the Pleistocene ice ages. While all boreal superspecies tested date to the Pleistocene, only 56% of sub-boreal superspecies members date to this period. Similarly, montane tropical faunas, which were also directly impacted by buildup of glaciers during ice age cycles, were composed of younger species than low elevation faunas. Together these results suggest that faunas directly fragmented by expanding and retracting ice sheets experienced rapid rates of species turnover contributing to the lower species diversity of these regions. In contrast, the older ages of faunas at lower latitudes and altitudes suggest that long-term climatic stability promoted the gradual accumulation of high species diversity in these regions. Faunal interchange between continents may also have contributed to the exceptionally high species diversity of the New World tropics. Molecular dating suggests interchange rates between the distinctive avifaunas of North and South America were significantly faster after completion of the Central American landbridge three million years ago. Composition of tropical bird faunas were directly impacted by a relatively recent burst of faunal mixing which had the potential to elevate Neotropical species diversity over other tropical regions.Science, Faculty of
Zoology, Department of
Graduate
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Nakagawa, Yasunori. "Studies on Forest Drainage Water Chemistry along a Latitudinal Gradient in East Asia." Kyoto University, 1999. http://hdl.handle.net/2433/181384.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第8008号
農博第1077号
新制||農||788(附属図書館)
学位論文||H11||N3312(農学部図書室)
UT51-99-S298
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 武田 博清, 教授 谷 誠, 教授 三野 徹
学位規則第4条第1項該当
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Nardy, Olavo [UNESP]. "Gradiente latitudinal de riqueza de espécies e regra de Rapoport: uma meta análise." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/106554.
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Foram realizadas meta análises com o Gradiente Latitudinal de Riqueza de espécies, a Regra de Rapoport e sua interação para vertebrados ao longo de todo o Globo. Com os resultados é possível concluir que ambos os padrões são generalizáveis e consistentes para todos os grupos de vertebrados, no entanto nenhuma variável moderadora associada à característica ecológicas, biológicas ou biogeográficas pode ser confirmada como principal condicionante destes padrões, não apresentando padrões constantes entre hemisférios, continentes, classes, número de províncias biogeográficas, tamanho corpóreo ou outra variável analisada. Foram utilizados como effect sizes a inclinação da reta de regressão ou o coeficiente angular da regressão linear (b) e o Coeficiente de Correlação de Spearman corrigido por Z-Fisher (r), entre estes dois, o segundo apresentou melhores resultados referentes as suas adequações e restrições associadas a meta análise, tais como normalidade dos dados e pressupostos de viés de publicações. As variáveis moderadoras associadas a características metodológicas como poder do teste, significância e tamanho amostral apresentaram maior poder explicativo do padrão do que as demais variáveis, sugerindo uma necessidade de se adotar um padrão mais rigoroso no delineamento de estudos que abordem este tema. Para a Regra de Rapoport o método utilizado na confecção do teste foi a variável moderadora mais evidente para a detecção de uma estrutura nos dados.
In the present work where made meta analysis with Latitudinal Gradient of Species richness, Rapoport Rule and their interaction for vertebrates along a global scale. With the results is possible to conclude that both patterns are general for vertebrates, nevertheless none of the ecological, biological or biogeographical moderators variables could be confirmed as the primary cause of the patterns, don’t showing any constant pattern between hemispheres, continents, classes, number of biogeographical provinces or other analyzed variable. It will be used as effect size the angular coefficient or the linear regression (b) and the Spearman Correlation Coefficient transformed by Z-Fisher (r), among these two effect size, the second presents best results associated with restrictions and fits inherent to meta analysis, such as normality and publication bias. The moderator’s variables associates with methodological issues, like statistical power, significance and sample size show higher explanation strength than the others variables, suggesting a necessity of more strength methods in the studies that claim these global patterns. For Rapoport Rule the method used to do the test was the moderator variable more evident to detect some data structure.
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Costa, Yanna Dias. "Estudo da biologia reprodutiva de Nycticorax nycticorax no Parque Estadual Fontes do Ipiranga, São Paulo." Universidade Federal de São Carlos, 2015. https://repositorio.ufscar.br/handle/ufscar/7135.
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Data on the reproductive biology of birds are essential to test hypotheses regarding the evolution of different aspects of the life history of these animals. However, basic information on the reproductive behavior of most South American bird species are poorly known. Moreover, particularly for birds with wide geographic distribution, life history may vary according to the different environmental conditions. Thus, the study of reproductive behavior in different populations of the same species, allow the identification of patterns of variation to make inferences about the ecological and evolutionary mechanisms responsible for the diversification and facilitates the development of conservation strategies. The Black Crowned Night Heron, Nycticorax nycticorax (Ardeidae) is a cosmopolitan species very common in Brazil, which breeds in large colonies. Although data on the reproductive biology of this species are available for Europe and North America, is little studied in Brazil. Thus, the objective of this proposal is to describe the reproductive cycle of N. nycticorax in two colonies in the Parque Estadual Fontes do Ipiranga, São Paulo, southeastern Brazil. The breeding season extended from July of 2013 to January 2014, however the field work was performed from September to January, with peak activity in September. The nests were built average 3,55 ± 2,58 m high and 2,36 ± 1,62 m alway from the main trunk. A total of 38 nests were found, but just 29 were monitored. The clutch size was 2.41 ± 0.68 (1 - 3) n = 29, and the incubation period was 23,26±1,26. The nestlings began to leave the nest with an average of 17.4 ± 3.6 days of life, what we call the stay 1, and left the nest definitely with 25,71 ± 7,16 days, which we call the residence 2. From 70 eggs, 57.14 % hatched and 25 chicks survived and left the nest. The survival rate was 31% from laying to the left of the nest, Mayfield. We compared with other tropical populations and the Northern Hemisphere, we recorded a strong tendency in latitudinal gradients of larger clutch size at high latitudes, but reproductive success does not seem to be associated with it, should be more associated with habitat conditions and availability of resources than with the latitudes. Incubation seem to support the premise to be higher in tropical regions, but few incubation data and nestling data are available for comparison.
Dados sobre a biologia reprodutiva das aves são essenciais para se testar hipóteses referentes à evolução de diferentes aspectos da história de vida destes animais. No entanto, informações básicas sobre o comportamento reprodutivo da maioria das espécies de aves Sul Americanas são inexistentes. Além disso, principalmente para as aves com ampla distribuição geográfica, a história de vida pode variar de acordo com as diferentes condições ambientais. Desta maneira, o estudo do comportamento reprodutivo em diferentes populações de uma mesma espécie, além de permitir a identificação dos padrões de variação, possibilita inferir sobre os mecanismos ecológicos e evolutivos responsáveis pela diversificação e facilita o desenvolvimento de estratégias de conservação. O socó-dorminhoco, Nycticorax nycticorax (Ardeidae) é uma espécie cosmopolita muito comum no Brasil, que se reproduz em grandes colônias. Embora dados sobre a biologia reprodutiva desta espécie sejam disponíveis para a Europa e América do Norte, no Brasil é pouco estudada. Diante disso, o objetivo desta presente proposta, foi descrever o ciclo reprodutivo de N. nycticorax em dois ninhais no Parque Estadual Fontes do Ipiranga, São Paulo, sudeste do Brasil. O período reprodutivo se estendeu de Julho de 2013 a Janeiro de 2014, sendo que a coleta de dado foi de Setembro a Janeiro, com pico de ninhos ativos em Setembro. Os ninhos foram construídos numa média de 3,55 ± 2,58 metros de altura (0,44 – 7 m, n = 16 ninhos) e 2,36 ± 1,62 metros de distância do tronco principal (0,0 – 4,48 m, n = 20 ninhos). Um total de 38 ninhos foram encontrados, mas apenas 29 foram monitorados. O tamanho de ninhada foi de 2,41 ± 0,68 (1 – 3) n = 29 e o período de incubação foi de 23, 26 ± 1,26 dias. Os filhotes começaram a sair do ninho com uma média de 17.4 ± 3.6 dias de vida, o que chamamos de permanência 1, e deixaram o ninho definitivamente com 25.71 ± 7.16 dias, o que chamamos de permanência 2. De 70 ovos, 57,14% eclodiram e 25 filhotes sobreviveram e saíram do ninho. A taxa de sobrevivência de ninho foi de 31%, pelo método de Mayfield. Esses dados foram comparados com outras populações Tropicais e do hemisfério norte, notamos uma forte tendência em gradientes latitudinais, de maiores ninhadas em altas latitudes, porém o sucesso reprodutivo não parece estar associado a latitude, pode estar mais associado com as condições de habitat e de disponibilidade de recursos. Período de incubação parece corroborar com a premissa de ser maior nas regiões tropicais, porém poucos dados de incubação e permanência estão disponíveis para comparações.
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Parsons, Sheena Marie Aiko. "A generalist grasshopper species (Melanoplus femurrubrum) is adapted to variable environments along a latitudinal gradient." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/13093.
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Master of ScienceDepartment of Biology
Anthony Joern
Temperature and food quality vary across broad latitudinal gradients, greatly affecting performance by insect herbivores. The contribution of each varies latitudinally so that geographically distinct populations are challenged by differences in nutritional needs and energetic demands. While there has been extensive work studying diet selectivity and nutritional ecology of insect herbivores, few studies have focused on how insect herbivores adapt across such vast environmental gradients. The generalist-feeding grasshopper, Melanoplus femurrubrum (DeGreer), has a broad geographic range that extends across much of North America, making this species ideal for comparative investigations of intrinsic performance responses to extensive but predictable patterns of environmental variation. I compared responses by six populations collected from populations located from Texas to North Dakota (USA) using a common garden experimental design to investigate clinal responses in grasshopper performance. I examined responses in: (1) body size, (2) thermoregulation and adaptive coloration, (3) developmental and growth rates, (4) metabolic rates, (5) total consumption and rates, (6) diet ratio selection, and (7) digestive processing efficiencies across the latitudinal gradient. Grasshopper body size followed the Converse Bergmann’s Rule with decreasing body size as latitude increased. Temperature influenced all other responses, but responses to diet were not always significant or directional. Latitudinal trends for development and growth rates were observed but mass-specific metabolic rates were similar for all populations. Total consumption was body size dependent but independent of diet type. Mass-specific consumption varied but no single directional trend was detected. There was a shift in carbohydrate-biased diet preference at low latitude toward protein-biased diet ratios at higher latitudes, suggesting adaptations to different energetic demands by these populations. However, post-ingestive (digestive) efficiencies demonstrated variable responses with northern populations observing highest efficiencies for some indices but not all. Overall, this research documents phenotypic plasticity to environmental variability to some degree for digestive efficiencies, but ecotypic responses in body size and diet preference among M. femurrubrum populations were observed.
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Brambilla, Viviana. "Inferred calcification rate of a temperate non-zooxanthellate caryophylliid coral along a wide latitudinal gradient." Master's thesis, ISA/UL, 2014. http://hdl.handle.net/10400.5/8208.
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Mestrado em Gestão e Conservação de Recursos Naturais - Instituto Superior de Agronomia / Universidade de ÉvoraCorrelations between environmental parameters (sea surface temperature and solar radiation) and growth parameters (bulk skeletal density, linear extension rate and net calcification rate) of the solitary non-zooxanthellate Caryophyllia inornata, were investigated along an 8° latitudinal gradient on the western Italian coasts. Net calcification rate correlated positively both with bulk skeletal density and linear extension rate, showing that C. inornata allocates calcification resources evenly in thickening the skeleton and increasing linear growth. None of the three growth parameters correlated with any of the two environmental parameters, showing a different trend compared to most studies on zooxanthellate corals. However, the results are in agreement with the only previous analysis of an asymbiotic coral, Leptopsammia pruvoti studied along the same latitudinal gradient. These results support the idea that non-zooxanthellate corals could be more tolerant to temperature increases than symbiotic corals, at least for the few species whose all three growth components have been investigated so far, which are both from the Mediterranean Sea
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St-Germain, Jean-Luc. "Anatomie du bois de l'épinette noire le long d'un gradient latitudinal en forêt boréale continue /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2007. http://theses.uqac.ca.
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Thèse (M.Ress.Renouv.) -- Université du Québec à Chicoutimi, 2007.La p. de t. porte en outre: Mémoire présenté à l'Université du Québec à Chicoutimi comme exigence partielle de la maîtrise en ressources renouvelables. CaQQUQ Bibliogr.: [75]-82 f. Document électronique également accessible en format PDF. CaQQUQ
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Yeates-Burghart, Quick Sarah Loraine 1979. "A Survey of Photoperiodic Response and Morphological Variation Across a Latitudinal Gradient in Threespine Stickleback." Thesis, University of Oregon, 2009. http://hdl.handle.net/1794/9884.
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x, 36 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.Natural biological variation exists at different geographic scales. We compared phenotype distribution across latitude, region and habitat type in threespine stickleback (Gasterosteus aculeatus) to determine local adaptation. To quantify variation in photoperiodic response, the day length cue was used to time sexual maturation and morphological characters across these various scales. Using lab-reared lines, we developed an index of sexual maturation and experimentally determined critical photoperiod for Alaskan and Oregon populations. Results showed that photoperiodic response existed in Alaskan but not Oregon populations. We also collected morphological data and made comparisons between wild Alaskan and Oregon populations and found similarities within habitat type across latitude but differences across region and habitat type. These data support the hypothesis that local adaptation results in variation across geography and habitat and, in stickleback, parallel evolution of morphological phenotypes within similar but geographically distant habitats.
Committee in Charge: William E. Bradshaw, Chair; William A. Cresko; Christina M. Holzapfel
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Nardy, Olavo. "Gradiente latitudinal de riqueza de espécies e regra de Rapoport : uma meta análise /." Rio Claro : [s.n.], 2008. http://hdl.handle.net/11449/106554.
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Orientador: Harold Gordon FowlerBanca: Adler Guilherme Viadana
Banca: Wesley Augusto Conde Godoy
Banca: Marcelo Nogueira Rossi
Banca: Sofia Campiolo
Apresenta anexos em CD-ROM
Resumo: Foram realizadas meta análises com o Gradiente Latitudinal de Riqueza de espécies, a Regra de Rapoport e sua interação para vertebrados ao longo de todo o Globo. Com os resultados é possível concluir que ambos os padrões são generalizáveis e consistentes para todos os grupos de vertebrados, no entanto nenhuma variável moderadora associada à característica ecológicas, biológicas ou biogeográficas pode ser confirmada como principal condicionante destes padrões, não apresentando padrões constantes entre hemisférios, continentes, classes, número de províncias biogeográficas, tamanho corpóreo ou outra variável analisada. Foram utilizados como effect sizes a inclinação da reta de regressão ou o coeficiente angular da regressão linear (b) e o Coeficiente de Correlação de Spearman corrigido por Z-Fisher (r), entre estes dois, o segundo apresentou melhores resultados referentes as suas adequações e restrições associadas a meta análise, tais como normalidade dos dados e pressupostos de viés de publicações. As variáveis moderadoras associadas a características metodológicas como poder do teste, significância e tamanho amostral apresentaram maior poder explicativo do padrão do que as demais variáveis, sugerindo uma necessidade de se adotar um padrão mais rigoroso no delineamento de estudos que abordem este tema. Para a Regra de Rapoport o método utilizado na confecção do teste foi a variável moderadora mais evidente para a detecção de uma estrutura nos dados.
Abstract: In the present work where made meta analysis with Latitudinal Gradient of Species richness, Rapoport Rule and their interaction for vertebrates along a global scale. With the results is possible to conclude that both patterns are general for vertebrates, nevertheless none of the ecological, biological or biogeographical moderators variables could be confirmed as the primary cause of the patterns, don't showing any constant pattern between hemispheres, continents, classes, number of biogeographical provinces or other analyzed variable. It will be used as effect size the angular coefficient or the linear regression (b) and the Spearman Correlation Coefficient transformed by Z-Fisher (r), among these two effect size, the second presents best results associated with restrictions and fits inherent to meta analysis, such as normality and publication bias. The moderator's variables associates with methodological issues, like statistical power, significance and sample size show higher explanation strength than the others variables, suggesting a necessity of more strength methods in the studies that claim these global patterns. For Rapoport Rule the method used to do the test was the moderator variable more evident to detect some data structure.
Doutor
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Prata, Eduardo Magalhães Borges [UNESP]. "Estrutura e composição de espécies arbóreas em um trecho de floresta ombrófila densa atlântica no litoral norte do estado de São Paulo e padrões de similaridade florística em escala regional." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/87894.
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prata_emb_me_rcla.pdf: 2137879 bytes, checksum: f0087a39dbca5bca9a452e4b2037187e (MD5)Este trabalho foi desenvolvido em um trecho de Floresta Ombrófila Densa Atlântica no Núcleo Picinguaba do Parque Estadual da Serra do Mar, litoral norte do Estado de São Paulo, município de Ubatuba-SP. A área de estudo corresponde a uma das parcelas amostrais (Parcela D) do Projeto Temático “Composição florística, estrutura e funcionamento da Floresta Ombrófila Densa dos Núcleos Picinguaba e Santa Virgínia do Parque Estadual da Serra do Mar” do Programa BIOTA-FAPESP. Nosso estudo foi estruturado em três capítulos. No Capítulo 1, objetivamos descrever a composição florística e a estrutura da comunidade arbórea em uma parcela de 1 ha; avaliar o padrão de distribuição espacial das espécies e; investigar a ocorrência de correlações entre a distribuição das espécies e as variáveis ‘altitude média’, ‘desnível topográfico’, ‘cobertura rochosa’, ‘presença de água na superfície do solo’, ‘distância do rio’ e ‘luz no interior da parcela’, através de uma CCA. No Capítulo 2, investigamos a distribuição da riqueza e da diversidade de espécies ao longo do perfil vertical, considerando os estratos adultos e regenerantes da comunidade, buscando responder em quais níveis de altura está presente o maior número de espécies arbóreas. No Capítulo 3, avaliamos a distribuição das espécies e os padrões de similaridade florística entre áreas de Floresta Ombrófila Densa das Terras Baixas e Submontana situadas ao longo de um gradiente latitudinal entre os Estados do Rio de Janeiro e Santa Catarina. Nossos resultados revelaram valores elevados de riqueza (161 spp) e diversidade (H' = 4,0) no hectare analisado. Observamos padrões de distribuição espacial aleatórios para a maioria das espécies na comunidade, onde apenas Euterpe edulis, Alsophila sternbergii e Coussarea meridionalis var. porophylla apresentaram padrão agregado...
This study was conducted in a stretch of Atlantic Rain Forest at Núcleo Picinguaba do Parque Estadual da Serra do Mar, northern coast of São Paulo State, municipality of Ubatuba-SP. The study area represents one of the sample plots (Plot D) of the Project Composição florística, estrutura e funcionamento da Floresta Ombrófila Densa dos Núcleos Picinguaba e Santa Virginia do Parque Estadual da Serra do Mar Programa BIOTA-FAPESP. Our study was structured in three chapters. In Chapter 1, we aimed to describe the floristic composition and tree structure in a plot of 1 ha; assess the pattern of spatial distribution of species and, to investigate the occurrence of correlations between species distribution and the variables 'average height', 'topographic gap', 'cover rock ', 'presence of water on soil surface', 'distance from the river' and 'light in the interior of the plot', through a CCA. In Chapter 2, we investigated species richness and diversity distribution along the vertical profile, involving both regenerating and adult strata, in order to answer which height levels show the greatest number of tree species. In Chapter 3, we assessed species distribution and the occurrence of patterns on floristic similarities between areas of Lowlands and Submontanes Atlantic Rain Forests areas along a latitudinal gradient between Rio de Janeiro and Santa Catarina states. Our results revealed high richness (161 spp) and diversity (H' = 4.0) values in the area examined. We observed random patterns on spatial distribution for most species in the community, where only Euterpe edulis, Alsophila sternbergii and Coussarea meridionalis var. porophylla showed clumped patterns. Significant correlations between species and environmental variables matrices were detected for axis 1 of CCA (p = 0.001). The regenerating stratum showed greater floristic richness than adult stratum and higher values... (Complete abstract click electronic access below)
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Rose, Alexandra P. "A classic life history pattern revisited : day length and the latitudinal gradient in avian clutch size /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2009. http://uclibs.org/PID/11984.
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Tunon, Meagan. "Time Constraint and Genetic (Phenotypic) Variation in Wing Shape in a Damselfly Along a Latitudinal Gradient." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-410764.
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This degree project examined the effect of time constraint on wing shape and phenotypic variation in wing shape along a latitudinal gradient in the damselfly species Lestes sponsa. Fore and hind wings from individuals originating from three different latitudes: North (66°N), Central (59°N) and South (54°N) Europe were treated with their native temperature and photoperiod. In addition, the north and south populations were treated with south and north conditions respectively, resulting in five groups in total. Morphometric analyses of the wings revealed a positive correlation between body mass and wing centroid size, along with a difference in wing shape between the groups. Forewings and hindwings from the northern group were broader and rounder than wings from the central and southern groups. Additionally, the wings from the transplant groups resembled those of the native group of their treatment, indicating a phenotypic plasticity in wing shape. Lastly, statistical tests of phenotypic variation revealed that variation was highest in relative warp 2 in the forewings and hindwings, and this warp represents the curvature of the wing both upwards/downwards or towards the inside/outside of the wing. These results on phenotypic variation indicate that even in a new or changing environment, L. sponsa could be capable of adapting to varying temperatures and environmental conditions. This study builds our understanding of how this damselfly species, and potentially insects, will be affected by current and future potential climate change.
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Bengston, Sarah Elizabeth. "A Colony-Level Behavioral Syndrome In Temnothorax Ants: Explaining Risk-Taking Variation Across A Latitudinal Gradient." Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/556615.
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Between individual behavioral variation has been described in nearly every animal taxa where it has been measured. Often, these behavioral variations correlate across contexts, forming a behavioral syndrome. Despite a recent push to better understand the origins and consequences of behavioral syndromes, there still is no cohesive framework that describes this phenomenon. Here, I develop a social insect species into a model for measuring and testing behavioral syndromes at a new level of biological organization; the colony. This builds upon the rich literature describing between-colony variation in behavior and provides novel insights into the evolution of behavioral syndromes. In my first chapter I show that colonies do not vary from one another in foraging distance, nor is foraging distance directly associated with colony size. This was my first step in demonstrating that colony behavioral variation is not simply a byproduct of colony size. In chapter two, I expanded upon this finding by testing colonies both in the lab and in the field for a variety of ecologically relevant behaviors. Here, I found that there was a behavioral syndrome that reflected foraging distance, foraging effort to novel and familiar resources, response to threat and aggression. While there is a gradient of phenotypes, some colonies either travel farther to forage for food and respond more aggressively when confronted with a conspecific invader, but appear to invest less in each given incident or food source. I consider this to be more risk-tolerant; they increase their risk of external mortality for potentially larger pay-offs. On the other hand, risk-averse colonies deploy more foragers to exploit closer resources, increase their overall activity in the response to threat, but avoid travelling farther distances or aggressively engaging invaders. Additionally, there is between population variations in risk-taking phenotype. Across the western United States, colonies at more northern latitudes are more risk-tolerant than colonies at more southern latitudes. In chapter 3, I expand upon this latitudinal gradient in behavioral phenotype by investigating what ecological factors predict a colonies level of risk-tolerance. Specifically, I focused on ecological traits that reflected predation, competition, food resource availability and abiotic stress. I found that competition for nest sites and spatial clustering predicted behavioral type; colonies at high levels of nest site competition or spatial clustering were more risk-tolerant than colonies at lower levels of competition or were more spatially dispersed. In chapter 4, I used a common garden and brood transfer experiment to investigate if the relationship between the ecological environment and behavior was the result of phenotypic plasticity or local adaptation. I show that local adaptation is the most likely explanation, as colonies with more workers from the donor colony are more, behaviorally, like the donor colony than colonies with fewer donor workers. In chapter 5 I test if the risk-taking behavioral syndrome is the result of life history strategy variation. I test the growth rate and energy allocation towards either somatic effort or reproductive effort. I found that colonies which are risk-tolerant also grow faster and dedicate more energy towards reproductive effort, which is consistent with predictions built from life history theory. This body of work shows that behavioral syndromes can exist at a new level of organization, the colony, and that variation in behavioral type is the result of differential selection pressure between populations. This directly connects behavioral syndrome research to life history strategy research. As life history strategy theory is a well-understood field, this represents a true advancement in the field of behavioral syndromes.
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BULINSKI, KATHERINE VICTORIA. "Relationship of sample-level properties to biodiversity at multiple scales: analyses of Upper Ordovician and Cenozoic ecological and latitudinal gradients." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1212001254.
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Dahlø, Eva Sofie. "Variation in chemical composition and genetic differentiation among bilberry (Vaccinium myrtillus L.) populations on a latitudinal gradient." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12795.
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Bilberry (Vaccinium myrtillus) is native to Europe and North America and constitutes an important nutritional resource for both humans and animals. Over the years, a series of chemical analyses have revealed several health-beneficial compounds in bilberry, and with the current demand of the berries mainly covered by Sweden and Eastern Europe, there has become an increasing desire to cultivate bilberry in Norway. In order for such cultivation to be successful an increased knowledge about bilberry is seen as essential and thus several studies have investigated the chemical composition of the berry. However, the underlying genetic diversity and the variation between populations in biochemical compounds remain to be thoroughly investigated. Therefore, the aim of present study was to investigate the differences in biochemical composition between populations of bilberry distributed on a latitudinal gradient, and estimate the level of genetic variation within and among the populations. This in order to examine whether biochemical composition was reflected by observed levels of genetic variation.Bilberries from four Norwegian populations at three regions differing in latitude were analysed for content of total phenolics (TPH), total anthocyanins (ACY) and antioxidant activity (FRAP). Furthermore, metabolic profiling was performed by gas chromatography-mass spectrometry (GC-MS) to reveal biochemical differences between the populations in content of sugars, acids and some simple phenolics. Multivariate statistics were performed and revealed a clustering of samples from the two locations in Mid-Norway, and a clustering of the northern with the southern population. In addition, there were found significant differences in some of the compounds between the populations.Genetic analyses using four microsatellites were carried out to examine whether metabolic differences between populations were reflected by genetic differentiation. Despite the significant differences between populations in the concentrations of some metabolites no significant genetic differentiation was found. Thus, it seems that the variation in biochemical compounds discovered among populations could be environmentally induced differences on a similar genetic background. However, due to the limited number of working microsatellites and the fact that these molecular markers are neutral, there is still a possibility that the genetic differences causing compound concentrations to differ could be so minor as to remain undetected. Hence, further studies utilizing more microsatellite markers or new state-of-the-art molecular techniques are needed to determine whether this result holds and is valid also for genetic variation in coding parts of the genome.
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Bublys, Kasparas. "Diet variability in Eurasian perch (Perca fluviatilis) as a response to environmental variables along a latitudinal gradient." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-365794.
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Climate change is expected to have a profound impact on freshwater fish communities, especially at higher latitudes. In this study I investigated potential effects of climate change on the niche structure of Eurasian perch (Perca fluviatilis) by looking at their diet across a latitudinal gradient and at varying light climate. Dietary niche width of Eurasian perch did not differ significantly between boreal and temperate latitudes. Additionally, no significant difference in the prevalence of specialist individuals was found along the latitudinal gradient and water transparency levels. Habitat was the main factor that significantly affected niche width and level of specialization with both being significantly higher in the littoral habitat. Taken together my results suggest that climate change might indirectly affect niche patterns by altering fish densities through changes in productivity resulting in niche and specialization variation among habitats.
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CARDELLI, VALERIA. "Changes occurring in the topsoil and in rhizosphere under fagus sylvatica along a small latitudinal-altitudinal gradient." Doctoral thesis, Università Politecnica delle Marche, 2017. http://hdl.handle.net/11566/245508.
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Durante il triennio di dottorato è stato studiato l'effetto del cambio di temperatura sulle proprietà chimiche e biochimiche di due componenti di suoli sotto faggio (Fagus sylvatica) dell'Appennino centrale (Italia): la rizosfera e il topsoil (orizzonti organici e il primo orizzonte minerale). Il disegno sperimentale ha considerato un transetto altitudinale (800 e 1000 m), con una differenza di temperatura media annua dell'aria di 1°C, e un transetto latitudinale, dove non si hanno differenze di temperatura media annua, ma ve ne sono in termini di escursione termica estate-inverno. La ricerca è stata preceduta dalla messa a punto di un metodo strumentale per ottenere più rapidamente dati di carbonio e azoto totali (TN) che siano affidabili e non distruttivi (Paper I). Risultati significativi sono stati ottenuti analizzando la rizosfera che, soprattutto a 1000 m, ha mostrato maggiori contenuti di carbonio organico totale (TOC), di sostanza organica estraibile in acqua (WEOM) e P disponibile del suolo bulk. Con l'aumento di 1°C si potrebbe così verificare un'accelerazione del ciclo dei nutrienti negli ambienti forestali a 1000 m (Paper II). Questo risultato è stato confermato da un maggior contenuto di zuccheri, fenoli solubili e tannini nella WEOM degli stessi suoli (Paper III). Comparando i risultati lungo la latitudine, gli orizzonti minerali sottosuperficiali sono risultati molto simili. Al contrario, il topsoil ha mostrato differenze chimiche e biochimiche attribuibili all’escursione di temperatura estate-inverno, con differenti andamenti delle attività enzimatiche secondo il ruolo degli enzimi nella degradazione della lettiera. In ogni caso, nel topsoil e negli orizzonti sottosuperficiali, l'altitudine è responsabile dell’incremento del TOC, del TN e dello spessore degli orizzonti organici, confermando che l'aumento di temperatura a queste quote potrebbe accelerare la velocità di mineralizzazione della sostanza organica (Paper IV).The research conducted during the three years doctoral activity was focused on the effect of temperature change on chemical and biochemical properties of two different soil components of beech (Fagus sylvatica) forest soils from central Apennines (Italy): i) rhizosphere, which was contrasted with the bulk soil, and ii) organic horizons (OLn, OLv, OH) and the first mineral horizon (A). In the experimental design a small altitudinal transect (800 and 1000 m) with a different mean annual air temperature of 1°C was considered, together with a latitudinal transect with no difference in the mean annual air temperature but different for the summer-winter thermal excursion. The research was preceded by the development of a method to obtain data of total carbon and nitrogen with non-destructive and less time-consuming instruments in order to develop rapid and reliable field analyses (Paper I). Significant results were obtained with the rhizosphere, which showed marked differences with respect to the bulk at 1000 m, particularly for the greater content of total organic carbon (TOC), water extractable organic matter (WEOM), and available P concentration due to rhizodeposition processes. The enriched micro-environment of the rhizosphere also fosters a rapid nutrients' cycle (Paper II). This was confirmed by the higher content of sugars, soluble phenols and tannins in the rhizosphere WEOM at 1000 m (Paper III). Comparing results along the latitudinal transect, in the subsoil only small differences were recorded. Conversely, the topsoil (O+A horizons) showed chemical and biochemical differences ascribable to the summer-winter thermal excursion trend, with different behaviors of the enzymatic activities depending on their role in litter decomposition. However, in both topsoil and subsoil, horizons thickness and the TOC and total nitrogen contents were higher at 1000 than at 800 m, so confirming that an increase of temperature at these altitudes will increase the mineralization rate (Paper IV).
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Mancuso, Arianna <1987>. "Growth and shell properties variations in the clam Chamelea gallina along a latitudinal gradient of environmental parameters." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amsdottorato.unibo.it/9061/1/TESI%20the%20End.pdf.
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Important ecological interactions between the organisms and their environment can be prompted by the studies along the latitudinal gradients, where it is possible to explore the varying environmental pressures on both biological and evolutionary processes. Thermal conditions vary with latitude and the ability to understand the relationship between growth and temperature is important because global climate change will be a thermal challenge to most ectotherms. Molluscs are particularly sensitive to different environmental parameters, showing macroscale shell morphology variations in response to environmental parameters. The aim of this thesis is to investigate variations in shell skeletal properties, mineral composition and growth along a latitudinal gradient (~400 km) in the Adriatic Sea (Italian cost) in relation to different environmental parameters. Shell morphology of the most irradiated and warmest populations was characterized by lighter, thinner, more porous and fragile shells, likely affecting the economic aspects of fisheries and the survival of the species. No variation was observed in shell CaCO3 polymorphism (100% aragonite), indicating no effect of the environmental parameters on the basic biomineralization processes. Moreover, C. gallina showed an increase in shell linear extension and net calcification rates towards South where warmer seawater, low fluctuations in salinity and high diversity of phytoplankton seem to be the most favourable environmental conditions for its growth. Because of the importance of C. gallina as commercial resource in the Adriatic Sea, variations in shell properties and in growth rates along the latitudinal gradient may have economic implications for fisheries and the observations from this research could help to guarantee the biological and economic sustainability of this resource.
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Mellberg, Jenny. "Descriptive Analysis of Ground Frost Patterns in Sweden (1991-2007)." Thesis, Uppsala University, Department of Social and Economic Geography, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-87223.
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McManis, Anne Elise. "Phenology of a Southern Population of Mountain Pine Beetle (Dendroctonus ponderosae)." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7006.
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Mountain pine beetle (Dendroctonus ponderosae, Hopkins) is a major disturbance agent in pine ecosystems of western North America. Adaptation to local climates has resulted in primarily univoltine (one generation per year) generation timing across a thermally diverse latitudinal gradient. We hypothesized that this pattern in total development time is shaped by selection for slower developmental rates, altered developmental thresholds, or oviposition rates in southern populations inhabiting warmer climates. To investigate traits responsible for latitudinal differences we measured lifestage-specific development of southern mountain pine beetle eggs, larvae and pupae across a range of temperatures. We also describe and model oviposition of southern US MPB. Using a novel technique that included frequent X-ray imaging, oviposition rate and fecundity were estimated separately and shown to both be significant and independent sources of variation. When compared with previously collected data for a northern MPB population, total oviposition time predicted for southern MPB at a constant 20°C was slightly longer than that of northern MPB, but the delay was too small to account for significant differences between the populations in total development time.
Developmental rate curves for eggs, larvae, and pupae were fit using maximum posterior likelihood estimation with a Bayesian prior to improve fit stability. When compared to previously published data for a northern population (Régnière et al. 2012), observed developmental rates of the southern and northern populations were similar across all studied lifestages at 20 and 25°C, although southern individuals were generally faster at temperature extremes (10 and 27°C). These findings were inconsistent with our hypothesis that southern individuals would have consistently slower rates. Optimal development of southern individuals occurred at higher temperatures, with higher development thresholds, as compared with northern individuals. Our results suggest that evolved traits in the remaining unstudied lifestage, teneral (i.e., pre-emergent) adult, likely influence latitudinal differences in mountain pine beetle generation time.
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Gillespie, Lauren. "Impact of tree diversity and climate change on soil microbial functioning in European forests along a latitudinal gradient." Thesis, Montpellier, 2020. http://www.theses.fr/2020MONTG004.
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Les microorganismes du sol sont des acteurs principaux des cycles biogéochimiques terrestres car ils sont impliqués dans la séquestration du C dans les sols, la fertilité des sols ou l’émission de gaz à effet serre dans l’atmosphère. L’activité de ces microorganismes est fortement influencée par les caractéristiques des communautés des plantes, notamment leur abondance, composition et diversité. Cette influence des plantes est susceptible d’être modifiée par des conséquences du changement climatique comme par exemple des périodes de sécheresse qui sont prédites d’augmenter en fréquence dans l’avenir proche. Lors de cette thèse, j’ai cherché à comprendre comment le mélange des espèces d’arbres en interaction avec la sécheresse influence le fonctionnement microbien. J’ai comparé des communautés d’arbres dominées par une seule espèce avec des communautés composées de trois espèces dominantes d’arbres dans quatre types de forêt le long d’un gradient latitudinal en Europe.Avec différentes mesures d’activités microbiennes telles que l’utilisation de plusieurs substrats carbonés ou l’activité de dénitrification dans des sols échantillonnés dans ces forêts européennes, j’ai évalué l’impact du mélange des espèces d’arbres à travers des traits de litière et de racines absorptives sur le fonctionnement microbien. Des modèles linéaires généraux et des modèles d'équations structurelles ont montré que le fonctionnement microbien n’était pas systématiquement affecté par le mélange des espèces d’arbres, mais qu’il existait potentiellement des effets de cascades via la qualité de la litière et la colonisation des racines par les ectomycorhizes.Avec une expérience en microcosme à l’Ecotron Européen de Montpellier, j’ai testé comment des cycles d’asséchement et réhumectation (DRW) répétés affectent la diversité taxonomique et catabolique microbienne ainsi que le fonctionnement microbien, et si ces effets étaient modifiés par le mélange des espèces d’arbres. Malgré une large gamme de types de sol et de forêts, j’ai trouvé une association robuste entre les forêts mélangées et i) une résistance plus élevée de la respiration et de l’activité de dénitrification microbiennes ainsi que ii) des niveaux de stress des microorganismes du sol plus bas en réponse aux cycles DRW répétés, un scénario amené à devenir plus commun avec le changement climatique actuel.Ces résultats nous renseignent sur les mécanismes de l’impact du mélange des espèces d’arbres et des cycles de sécheresse sur le fonctionnement des communautés microbiennes du sol forestier et suggèrent qu’un mélange de différentes espèces d’arbres pourrait rendre les communautés microbiennes du sol et leur fonctionnement plus résistant face au changement climatiqueForest soil microorganisms are important drivers of biogeochemical cycling, influencing thus soil C sequestration, soil fertility, and the emission of greenhouse gases into the atmosphere. Microbial activity is strongly affected by plant communities, their composition and diversity, and the abundance of particular species. Climate change factors such as the predicted increased droughts are susceptible to modify these plant effects. In this PhD thesis, I aimed to understand how tree species mixing and increased drought interactively influence the activity of soil microbial communities. I compared forest communities dominated by one single tree species with communities co-dominated by three different tree species in four different European forest types along a climatic gradient.By measuring different microbial processes, such as the respiration induced by different carbon substrates or denitrification activity, in soil samples collected in the different European forests, I tested the relative influence of tree species mixing through litter traits and absorptive root traits on microbial functioning. Generalized mixed-effects linear models and structural equation models showed that the soil microbial functioning was not consistently affected by tree species mixing, but it potentially had cascading effects via litter quality and the colonization rate of roots by ectomycorrhizal fungi.I then used a microcosm experiment set up in the European Ecotron in Montpellier to test how repeated drying-rewetting (DRW) cycles affect taxonomic and catabolic diversity of soil microbial communities and their functioning, and whether tree species mixing modifies these effects. I found that tree species mixing had no influence on the composition of soil microbial communities. However, despite a wide range of soil and forest types, our results showed a robust and consistent association between mixed tree species forests and higher resistance of soil microbial respiration and denitrification, as well as with lower soil microbial stress levels in response to repeated DRW cycles, a scenario expected to become more common with ongoing climate change.These results help to better understand the underlying mechanisms of how tree species mixing and DRW, predicted to become more frequent under future climatic change, affect soil microbial communities and their functioning. The data suggest that microbial communities from mono-specific forest stands resist less to increased drought than those from mixed tree species forests which may thus mitigate drought effects
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Bognounou, Fidele [Verfasser]. "Restauration écologique et gradient latitudinal : Utilisation, diversité et régénération de cinq espèces de combretaceae au Burkina Faso / Fidele Bognounou." München : GRIN Verlag, 2011. http://d-nb.info/1189915278/34.
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Hendy, Austin J. W. "Cenozoic Molluscan Biodiversity: An Examination of Patterns of Biodiversity Change at Global, Regional, and Local Spatial Scales." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1189714325.
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Bolosha, Uviwe. "Revising the distribution of mangrove forests in South Africa and changes in growth of mangrove species along a latitudinal gradient." Thesis, Rhodes University, 2017. http://hdl.handle.net/10962/7544.
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Mangrove forests are a diverse assemblage of trees and shrubs that are adapted to a saline and tidally inundated environment. The global spread of mangrove species is affected by climate, with most confined to areas that are warmer and moist. At a global scale, temperature limits the distribution of mangrove forests but on a regional scale and local scale, rainfall, river flow and tidal exchange have a strong effect on the distribution and biomass of mangrove forests. Other factors that play a role in limiting growth and distribution of mangroves include accessibility of suitable habitats for growth and also conditions that are suitable for propagule dispersal. The objectives of this study were to review the distribution of mangroves in South Africa and determine the number of extreme temperature events that may limit further distribution and secondly to measure growth rates of mangrove species at Mngazana and Nahoon Estuary and the nutrient pools in the sediment of these forests. In 1982, Ward and Steinke published a list of estuaries where mangroves were present. The current study sampled the population structure, microclimate and level of expansion in two estuaries within and outside of the published range. The minimum, maximum temperature and number of extreme temperature events were measured using iButtons. Mangrove expansion will be limited by minimum temperatures (1.1 ° C) and an increase in extreme temperature events (830) (<5 ° C and 5- 10 ° C) at the latitudinal limits. Expansion of A. marina at Kwelera and Tyolomnqa Estuary was evident but sapling survival was low. Mangroves have expanded within and outside the range proposed by Ward and Steinke (1982), but are limited by physical factors, restricted by the presence of saltmarsh and other estuarine macrophytes and natural disturbance regimes. An increase in population growth was recorded over the years at both Mngazana and Nahoon Estuary. Nutrients, (ammonium, nitrates + nitrites and soluble reactive phosphorus) varied amongst sites and were related to seasonality. Nitrogen in both estuaries was available in the form of ammonium (NH4) and its concentration was generally higher (1.3-76.2 pm) than other forms of nitrogen (0.07-6.3 µm). Soluble reactive phosphorus (SRP) was higher during the wet seasons in both estuaries. An increase in porewater salinity since 2007 (41.3 practical salinity unit (PSU)) was measured at Mngazana and this is a result of freshwater abstraction and low rainfall. A. marina saplings and adults grew significantly faster at Nahoon Estuary (the distributional limit) (11.1 ± 1.1 cm year-¹) compared to Mngazana Estuary (5.3 ± 1.8 cm year-¹). Different mangrove species and forests respond differently to environmental factors and changes in mangrove distribution is expected in South Africa but changes are expected to happen slowly and opportunistically.
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Avenant, Casper. "Diet of the Tropicalised Herbivore Siganus fuscescens Across a Broad Latitudinal Gradient and Comparisons With Temperate Seagrass-associated Omnivorous Fishes." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2018. https://ro.ecu.edu.au/theses/2139.
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Rising sea temperatures are facilitating range shifts of tropical biota towards higher latitudes. The rabbitfish Siganus fuscescens is a tropical herbivore whose distribution has extended into rocky reefs and seagrass meadows of temperate southwestern Australia. The aim of this study is to determine if the poleward range shift of S. fuscescens could result in competition for food sources with temperate seagrass-associated omnivorous fish and/or increase the grazing rates of seagrasses in temperate seagrass meadows that do not normally experience high levels of grazing. The diet of S. fuscescens was compared across a tropical to temperate gradient, comprising the Kimberley, Shark Bay and Perth. In all regions, red algae were the primary dietary component. Leathery macrophytes were also consumed in the temperate region, while filamentous Sphacelaria was grazed in subtropical Shark Bay and corticated foliose Dictyota in the tropical Kimberley. Seagrass was consumed in all regions, except in the tropics, where meadows are often sparse and ephemeral. The Kimberley was also the only region where fauna were consumed in significant proportions, in the form of epiphytic hydrozoans, most likely due to a lack of diversity of preferred food sources. While S. fuscescens would appear to be primarily algivorous, it will opportunistically consume seagrass and even invertebrates should algae not be available. Large volumes of seagrass consumed by this species in the temperate region indicate that its migration into temperate seagrass meadows will increase consumption rates of seagrass in the region as it establishes its population.
Posidonia-dominated habitat was trawled in two nearshore locations in Perth, WA, to determine whether the diet of S. fuscescens was similar to a range of temperate seagrass-associated omnivorous fish species through gut content and stable isotope analysis. Diets were significantly different between species and locations. While seagrass was consumed by S. fuscescens in large quantities at one location, red (Hypnea and Chondria) and brown (Ecklonia and Sargassum) algae were consumed in greater quantities at the other locations. In comparison, the temperate omnivores Haletta semifasciata, Heteroscarus acroptilus and Scobinichthys granulatus, which were shown to be the most abundant omnivorous fish species in the seagrass meadows, consumed seagrass in moderate quantities, but showed distinct interspecies differences in their diets. These differences were also characterised by different gut length ratios, with S. fuscescens possessing the elongated gastrointestinal tract typical of herbivores. Stable isotope analysis and mixing models showed that S. fuscescens assimilated carbon and nitrogen from red and brown algae, but almost negligibly so from seagrass. While H. acroptilus sourced significant proportions of assimilated nutrients from seagrass, all temperate omnivores primarily utilised animal sources. While there is some dietary overlap between all native species, niche partitioning is likely to reduce competition between the tropical and temperate species. The tropicalisation of S. fuscescens into temperate seagrass meadows is therefore unlikely to impact on native omnivorous species unless the densities of the species become large.
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Kavagutti, Vinicius Silva. "Biotic factors drive bacterioplankton community in a tropical coastal site of the equatorial atlantic ocean." Universidade Federal de São Carlos, 2016. https://repositorio.ufscar.br/handle/ufscar/8694.
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The relationship between latitude and microbial diversity in the ocean is controversial. Niche models predict higher richness at high latitudes in winter, while snapshot field-sampling point towards higher richness at intermediate latitudes, with lower values both towards equatorial and Polar Regions. However, given the dynamic nature of ocean’s ecosystem it is difficult to account for temporal variations in empirical assessments of microbial biodiversity. Here, we compared the components of diversity (richness and evenness) and microbial population stability (coefficient of variation) in two coastal ocean observatories with similar trophic state located in contrasting latitudes, one located in the Equatorial Atlantic Ocean, and one temperate located in the Northwestern Mediterranean Sea, to evaluate which factors drive the dynamics of microbial communities in each site. Our observations support the view that, as animals and plants, microbial communities exhibit higher (or at least similar) richness towards the equator, at least in the coastal ocean. We also found evidence of increasing stability with increasing evenness in tropical microbial communities when compared to the temperate ones. Temperature and silicates drove temperate free-living prokaryotic communities, while tropical ones were driven by stochastic factors such as biotic interactions with eukaryotes. We propose a conceptual framework where microbial community composition would be driven by deterministic factors in higher latitudes and once the factor temperature is removed moving towards the equator, more stochastic factors such as biotic interactions would emerge as the main factors shaping microbial communities. This study highlights the importance of comparative studies on Eulerian time-series distributed at different latitudes to fully understand the diversity patterns of microbial communities in the ocean.
A relação entre a latitude e diversidade microbiana no oceano é controversa. Modelos de nicho preveem maior riqueza em altas latitudes no inverno, enquanto amostragens pontuais indicam uma maior riqueza em latitudes intermediárias, com valores mais baixos para regiões equatoriais e polares. No entanto, dada a natureza dinâmica do ecossistema oceânico, é difícil explicar variações temporais da biodiversidade microbiana nas avaliações empíricas. Nesse trabalho comparamos os componentes da diversidade (riqueza e equitabilidade) e estabilidade das populações microbianas (coeficiente de variação) em dois observatórios oceânicos costeiros com estados tróficos semelhantes, localizados em latitudes contrastantes: um localizado no Oceano Atlântico Equatorial e um em clima temperado localizado no noroeste do Mar Mediterrâneo, a fim de avaliar quais fatores estruturam a dinâmica das comunidades microbianas em cada local. Observamos que tal como animais e plantas, as comunidades microbianas exibem maior (ou pelo menos similar) riqueza no equador pelo menos em águas costeiras. Também encontramos evidências de aumento da estabilidade com o aumento da uniformidade nas comunidades microbianas tropicais, quando comparadas com as de clima temperado. De modo geral, temperatura e silicatos foram as variáveis que condicionaram as comunidades procariotas de vida livre no observatório da região temperada, enquanto que no observatório tropical, fatores estocásticos tais como interações bióticas com eucariotos, foram os fatores que mais influenciaram as comunidades bacterianas. Assim, propomos um quadro conceitual onde a composição da comunidade microbiana seria impulsionada por fatores determinísticos em latitudes mais elevadas, enquanto que em latitudes menores, seriam determinados por fatores mais estocásticos, como interações bióticas. Nosso estudo destaca a importância de estudos comparativos utilizando series temporais Eulerianas em diferentes latitudes para entender os padrões de diversidade das comunidades microbianas no oceano.
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Akther, S. M. Lovely. "Effects of water stress on Alnus glutinosa populations across the species distribution range." Master's thesis, ISA, 2019. http://hdl.handle.net/10400.5/19572.
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Mestrado em Gestão da Floresta e dos Recursos Naturais no Mediterrâneo (MedFor) - Instituto Superior de AgronomiaAlnus glutinosa (Black alder) is paramount species in the riparian ecosystem for supporting ecosystem functioning and the services it provides. This species is declining in an alarming rate which is a prominent threat to devastate native priority forests across Europe, so understanding population responses to environmental change is key for its proper management. In this study, we characterized vegetative phenology and investigated morphological, structural and physiological responses to imposed drought across five populations from countries ranging the species distribution limits (Sweden, Italy, Spain, Portugal, and Morocco). First, we registered 5 stages of budburst of the 120 seedlings of alder (24 by population) in open space. Then, we established a greenhouse experiment where we imposed progressive (Field capacity-FC, 75%FC, 50%FC and 25%FC) water stress (17.06.2019 to 01.08.2019) on 40 seedlings (S), keeping 40 at field capacity, as control until the end of experiment (CE). During 45 days, we performed physiological and morphological measurement at different percentages of FC to compare treatments and populations. Destructive harvest was performed on 40 seedlings (from the total 120) at the onset of the experiment (CO), and then, at the end of the experiment control (CE) and stress (S) seedlings were also destroyed to analyze the structural and functional responses of alder among CE, S and CO and also to compare the variations among populations. We found significant differences among populations on the number of days to reach each phenological stage where northern populations displayed delayed budburst than the southern. As a result of imposed drought, growth and development of A. glutinosa was generally reduced under water restrictions compared to control plants, yet none of the parameters reflected severe plant stress. Conversely, we observed that several of the studied parameters were significantly different among the studied populations likely reflecting intraspecific diversity and environmental conditions
N/A
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Levasseur, Valérie. "Analyse dendroécologique de l'impact de la tordeuse des bourgeons de l'épinette (choristoneura fumiferana) suivant un gradient latitudinal en zone boréale au Québec :." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0020/MQ55561.pdf.
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Gagné, Caroline. "Le potentiel de compétition apparente entre l’orignal (Alces alces) et le caribou forestier (Rangifer tarandus caribou) varie le long d’un gradient latitudinal." Master's thesis, Université Laval, 2014. http://hdl.handle.net/20.500.11794/25498.
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À la suite d’une coupe forestière, les parterres en régénération peuvent subir un enfeuillement favorable à l’orignal. L’accroissement des populations de loups qui s’en suit affecte alors les populations du caribou forestier. Ce projet vise à évaluer si la contribution de la coupe forestière à cette compétition apparente varie selon un gradient latitudinal. Nous avons modélisé la sélection d’habitat d’orignaux, de loups et de caribous. Après la prise en compte de l’âge de la coupe, l’enfeuillement des parterres diminuait avec la latitude. La sélection des parterres de coupe par les orignaux et les loups augmentait en fonction de leur enfeuillement. Les caribous évitaient les coupes, particulièrement celles riches en feuillus. La cooccurrence de l’orignal et du loup dans les coupes augmente donc en fonction de l’enfeuillement. Ainsi, la contribution de la coupe forestière à la compétition apparente dans le système orignal-loup-caribou devrait diminuer vers le nord de la forêt boréale.Moose benefit from deciduous vegetation that becomes increasingly available during the regeneration of logged forests. This numerical response of moose populations can lead to an increase in gray wolf abundance, which impacts forest-dwelling caribou populations. This study evaluates if the contribution of logging to such apparent competition could vary along the latitudinal axis. We modelled habitat selection behaviour of moose, wolves and caribous monitored by telemetry. After controlling for time since harvest, deciduous vegetation availability decreased with increasing latitude. Moose and wolves avoided cutovers with low deciduous vegetation availability, while they selected harvested stands with high deciduous vegetation availability. Caribou avoided cutovers, and their avoidance increased with the level of deciduous regeneration. The co-occurrence between moose and wolves in cutovers increased with deciduous vegetation availability. Therefore, the contribution of logging to the apparent competition in the moose-wolf-caribou system should be stronger in southern than in northern boreal forest.
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Pédron, Nicolas. "Structure génétique, réponses bioénergétiques et traits de vie, de populations de flets (Platichthys flesus) soumises au réchauffement climatique, sur un gradient latitudinal." Thesis, Brest, 2016. http://www.theses.fr/2016BRES0058/document.
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Le flet européen (Platichthys flesus) est un poisson catadrome dont l’aire de répartition dans le Nord-Est Atlantique s’étend du cercle polaire Arctique jusqu’au Portugal. Depuis quelques décennies, la limite Sud de son aire de distribution remonte le long des côtes Portugaises. Une étude préliminaire sur la biologie des populations de flet a identifié un métabolisme énergétique spécifique pour une population périphérique Sud au Portugal vs des populations situées dans le Golfe de Gascogne et en Manche. Dans la présente étude, nous avons combiné une approche en génétique de populations avec des challenges expérimentaux menés en situation de common garden, pour approfondir nos connaissances sur la différentiation génétique entre les populations de flets sur la façade Atlantique et sur le possible différentiel phénotypique qui pourrait en résulter, particulièrement en terme de bioénergétique et de traits d’histoire de vie. L’approche génétique considérant le polymorphisme de marqueurs de type microsatellites et de différents gènes candidats met en évidence une différentiation génétique très significative entre les populations de la Péninsule Ibérique et celles situées plus au Nord. Une pression de sélection différentielle s’exerce probablement sur un gène impliqué dans le métabolisme énergétique (GAPDH) et confirme la particularité génétique des populations Ibériques. Un challenge thermique et hypoxique conduit sur des poissons juvéniles et mettant en oeuvre une combinaison d’approches ciblées (activités enzymatiques sur des proxies du métabolisme énergétique en aérobiose vs anaérobiose, et de l’anabolisme) et sans a priori (protéomique par électrophorèse 2D) suggère une meilleure aptitude des populations centrales (Canche et Vilaine, France) et de la population périphérique (Lima, Portugal) à se maintenir respectivement en conditions froide vs chaude et hypoxique. Enfin, l’analyse de normes de réaction des traits de vie pour des stades embryo-larvaires exposés à un gradient thermique met en évidence une probable adaptation locale des populations de flet à leur environnement thermiqueThe European flounder (Platichthys flesus) is a catadromous fish species distributed along the North-East Atlantic coasts, from the Arctic polar circle to the Iberian Peninsula. For several decades, the southern limit of its distribution area is shifting towards the North of the Portuguese coast. A preliminary study on the flounder population biology has detected a specific energetic metabolism for a southern peripheral population in Portugal compared to Northern populations located in the Bay of Biscay and in the Channel. In the present study, we have combined population genetics with experimental challenges in the laboratory to improve our knowledge on the genetic structure of flounder populations over Europe, and on the potentially resulting phenotypic differences among populations, mainly considering bioenergetics and life-history traits. The polymorphism of microsatellite markers and of several candidate genes highlighted a significant genetic differentiation between Iberian Peninsula populations and Northen populations. A thermal and hypoxia challenge has been conducted on flounder juveniles, considering (1) enzymatic activities linked to energetic metabolism (aerobiosis and anaerobiosis) and anabolism, and (2) a proteomic approach; this common garden experiment suggested a higher capacity of central populations (from Canche and Vilaine, France) and of one peripheral Southern population (from Lima, Portugal) to cope with respectively cold condition, warm and hypoxia condition. Finally, the analysis of thermal reaction norms in fish early life history traits, considering embryo-larval stages submitted to a thermal gradient, underlined a possible local adaptation of the flounder populations to their thermal environments
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Levasseur, Valérie. "Analyse dendroécologique de l'impact de la tordeuse des bourgeons de l'épinette (choristoneura fumiferana) suivant un gradient latitudinal en zone boréale au Québec : /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2000. http://theses.uqac.ca.
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Elliott, Christine Eleanor. "Physical Rock Weathering Along the Victoria Land Coast, Antarctica." Thesis, University of Canterbury. Geography, 2006. http://hdl.handle.net/10092/1305.
Full textAbstract:
The purpose of this research was to investigate the physical weathering of rock along the Victoria Land Coast, Antarctica. It was designed to contribute to the Latitudinal Gradient Project, a joint initiative between the New Zealand, Italian and United States Antarctic Programmes. The Latitudinal Gradient Project aims to improve our understanding of the ecosystems of the Dry Valleys and ice-free areas of the Ross Sea Region and, by using latitude as a proxy measure, identify how they might be affected by future climate change. The approach taken for this research was to use information on rock (from one rock group) temperature and moisture conditions gathered from three field locations to inform laboratory simulations. The laboratory simulations would then be used to investigate the weathering of small rock blocks and aggregates. Two temperature cycles approximating those experienced during summer and spring/autumn were identified and simulations undertaken in a specially adapted freezer. Three levels of moisture were applied: no moisture, half saturation and full saturation. Results of the laboratory simulations indicated that although rocks responded in different ways to different processes, granular disintegration took place even in the absence of additional moisture and did not require crossings of the 0 OC isotherm, nor were high levels of moisture required for across zero temperature cycling to produce weathering effects. A model that related weathering to latitude was developed and changes in climate explored. It was found that the weathering effect of summer and spring/autumn cycles was different and depended on rock characteristics rather than latitude. Increasing the ratio of summer to spring/autumn temperature cycles by 10% indicated that weathering could decrease or remain the same depending on the particular rock. Changes in temperature were found to be more important than changes in moisture. A weathering index that related local climate and rock properties to weathering was also developed and this highlighted the difficulties of using laboratory results to predict field rates of weathering. There were some surprising results from the field, including the presence of much more moisture on the surface of the rock, primarily from blowing snow, than had been predicted for this dry environment. This occurred even in the presence of negative rock surface temperatures. In addition, winter rock surface temperatures can fluctuate up to 25 OC, getting as warm as -10 OC. Macro-climate and changes in air temperature in response to foehn and katabatic winds were the drivers for these fluctuations.
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Zaffos, Andrew A. "Diagnosis and prediction of variations in the environmental distributions of marine fossil taxa across space and time." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1415625754.
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Chovanec, Kevin. "Non-anguimorph Lizards of the Late Oligocene and Early Miocene of Florida and Implications for the Reorganization of the North American Herpetofauna." Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/etd/2384.
Full textAbstract:
Paleokarst deposits from the Oligo-Miocene of northern Florida preserve undescribed herpetofaunal remains that fill important temporal and geographic gaps in our understanding of Cenozoic lizard evolution. Here I describe and discuss the non-anguimorph lizard diversity of the Brooksville 2 (Ar2) and Miller (He1) local faunas to test for patterns of regional and latitudinal provincialism in the contemporary North American record. Collectively, the sites are significant for documenting 1) extralimital occurrences of the tropical clades Anolis and Corytophaninae, 2) a substantial temporal range extension of the modern southeastern endemic Rhineuridae, 3) the earliest record of eublepharid gekkotans from North America, and 4) the early Miocene arrival of “cnemidophorine” teiids from South America. This work complements recent studies of older, Eocene lizards by others and lends paleontological support to aspects of the tropical conservatism hypothesis: lineages now confined to the tropics were present at higher latitudes when megathermal climates were more extensive.
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Tanniou, Anaëlle. "Etude de la production de biomolécules d'intérêt (phlorotannins, pigments, lipides) d' algues brunes modèles par des approches combinées de profilage métabolique et d'écophysiologie." Thesis, Brest, 2014. http://www.theses.fr/2014BRES0055/document.
Full textAbstract:
Notre étude s’inscrit dans un processus de recherche de nouveaux composés d’origine naturelle à activités biologiques avérées à partir de macroalgues brunes, avec d’éventuelles perspectives d’exploitation industrielle. Ainsi, dans un premier volet nous avons testé des méthodologies innovantes en matière d‘extraction en utilisant trois espèces d’algues brunes comme modèles. Nous avons optimisé le protocole d’extraction solide/liquide en estimant divers paramètres cruciaux qui influent sur le rendement d’extraction et sur les activités antiradicalaires des composés extraits. Soucieux de trouver une méthodologie innovante d’extraction plus « verte » répondant aux normes européennes, nous avons donc testé des méthodes d’extraction utilisant des solvants dans leur état supercritique ou sous forme pressurisés. La comparaison avec le procédé d’extraction solide/liquide nous a permis de sélectionner l’extraction par fluides pressurisés (PLE) employée avec un mélange Ethanol-Eau pour l’extraction de composés antiradicalaires avec une haute efficacité. Dans une deuxième partie nous nous sommes intéressés aux variations quantitatives et qualitatives des principales macromolécules présentes chez l’espèce invasive Sargassum muticum en Europe. L’emploi de deux techniques analytiques, RMN HR-MAS et spectroscopie IR, nous a permis d’avoir une vue d’ensemble des compartiments susceptibles de subir des variations selon la position géographique d’une même espèce à large répartition. Cette étude nous a montré comment une espèce est capable de changer sa composition biochimique en fonction de son environnement et ainsi s’acclimater à des milieux assez différents. Ce travail a mis en évidence les effets de différents paramètres environnementaux sur les compartiments lipidique (analysés en GC), protéique ainsi que sur les quantités de carbohydrates et de pigments (analysés en HPLC). L’influence de ces paramètres sur la taille des individus de Sargassum muticum a également été discutée. La dernière partie de cette étude nous a permis de décrire les variations quantitatives et qualitatives des phlorotannins chez l’espèce invasive Sargassum muticum sur une grande échelle spatiale, le long d’un gradient latitudinal (Norvège-Portugal). Dans un premier temps cette variabilité a été appréhendée grâce à un suivi temporel et spatial des teneurs en phlorotannins. L’étude des variabilités intra-spécifiques et intra-individuelles nous a permis de mettre en évidence un effet du stade de développement et de la partie de l’algue considérée : les teneurs et activités des phlorotannins sont plus importantes dans les crampons et chez les individus matures. Après la recherche d’un protocole simple pour la semi-purification des composés phénoliques présent chez Sargassum muticum, nous avons pu mettre en évidence la présence de composés de type phlorethol au moyen de techniques de RMN à deux dimensions (2D). Ces fractions semi-purifiées possèdent des activités antiradicalaire et antibactérienne notoires. Enfin, l’utilisation de plusieurs techniques de séparation membranaires nous a permis d’estimer le poids moléculaire des différents composés présents dans le pool de composés phénoliques extrait. Enfin, suite aux constats effectués sur les populations, l’effet de l’intensité lumineuse et de la température de l’eau a pu être apprécié isolément : les radiations UVA et UVB boostent la production de CP alors qu’une augmentation de la température fait chuter la production de CP chez S. muticumOur study is part of the research process for new compounds of natural origin with biological activities and possible industrial perspectives. In a first part, we tested innovative extraction methodologies using three brown algae species as model. We optimized the solid/liquid extraction protocol by estimating diverse crucial parameters which influence the extraction yield and radical scavenging activities of extracts. In order to find an innovative and more "green" extraction methodology answering the European standards, we thus tested more recent extraction methods using solvents in their supercritical state or under pressure. The comparison with the solid/liquid process allowed us to select pressurized liquid extraction (PLE) using an ethanol-water mixture for the extraction of active compounds with a high efficiency, but also to select Sargassum muticum as an interesting model for further investigations. In a second part, we were interested in the quantitative and qualitative variations of the main macromolecules present in the invasive species S. muticum in Europe. The employment of two analytical techniques (NMR HR-MAS and IR spectroscopy), allowed us to have an overview of biochemical parts of the algae, which vary according to the geographical position of this wide spread species. This study showed how a species is able to modify its biochemical composition, and then to acclimate, according to the environment. We then focused on molecules, which showed important variations along the latitudinal range of S. muticum. This work highlighted the effects of environmental parameters on lipid (GC analysis) and protein compartments as well as on carbohydrates and pigments quantities (HPLC analysis). The influence of these parameters on the size of individuals was also discussed. The last part of this study allowed us to describe the quantitative and qualitative variations of phlorotannins in S. muticum on a large spatial scale, along a latitudinal gradient (Norway-Portugal). At first this variability was measured thanks to temporal and spatial follow-up of the phlorotannins contents. The study of intra-specific and intra-individual variabilities allowed us to highlight an effect of the development stage and of the seaweed part: phlorotannins contents and activities are more important in holdfast and in mature individuals. After the research of a simple protocol for the phenolic compounds semi-purification present in Sargassum muticum, we were able to highlight the presence of compounds of only phlorethol type in this species by means of 2D RMN techniques. These semi-purified fractions possess notorious radical scavenging and antibacterial activities. Finally, the use of several membrane separation techniques allowed us to consider the molecular weight of the various compounds present in the extracted pool of phenolic compounds. Finally, under controlled conditions, the effects of the light quality and the seawater temperature were tested: UV-A and UV-B radiations boost the production of CP while an increase of the temperature makes the phlorotannins production decreasing in S. muticum
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Perrigo, Allison L. "Diversity Underfoot : Systematics and Biogeography of the Dictyostelid Social Amoebae." Doctoral thesis, Uppsala universitet, Systematisk biologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-210074.
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Dictyostelids (Amoebozoa) are a group of social amoebae consisting of approximately 150 species, which are found in terrestrial habitats worldwide. They are divided into eight major clades based on molecular phylogeny, and within these clades are many species complexes. Some species are seemingly cosmopolitan in distribution, while others are geographically restricted. In this thesis dictyostelids were recovered from high latitude habitats (soils in Sweden and Iceland) as well as from the soles of shoes. Morphological characters and DNA sequence analyses were used to identify isolates that were recovered and delimit new species, as well as to investigate the monophyly of Dictyostelium aureostipes. Nine species were reported from Northern Sweden and four from Iceland. Among the isolates recorded in Sweden were two new species, described as D. barbibulus and Polysphondylium fuscans. P. fuscans was among the four species recovered from footwear, contributing evidence for anthropogenic transport of dictyostelids. Ecological patterns were assessed using linear regression and generalized linear models. The ecological analyses of dictyostelids recovered from Iceland indicate that these organisms are most frequently found in soils of near-neutral pH, but also exhibit a species richness peak in moderately acidic soils. These analyses indicate that in Iceland dictyostelid species richness decreases with altitude, and in the northern hemisphere the species richness increases with decreasing latitude. A three-region analysis of the D. aureostipes species complex indicated that this species is in fact made up of at least five phylogenetically distinct clades, and in light of this the group is in need of taxonomic revision. These results indicate that the dictyostelid species richness is higher than previously known, especially in high-latitude regions, and that even seemingly well-defined species may harbour cryptic diversity. Presently, species ranges may be expanding via anthropogenic dispersal but despite this, the dictyostelids are found to exhibit biogeographic trends well known from macroorganisms, such as a latitudinal gradient of species richness.
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Manincor, Natasha de. "Ecologie des plantes et des pollinisateurs dans les prairies calcaires le long d'un gradient latitudinal en France : diversité des espèces et structure des réseaux d'interaction plantes-pollinisateurs." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1R024/document.
Full textAbstract:
Dans le contexte actuel de crise de la biodiversité et des risques associés de dégradation des services écosystémiques, les réseaux plantes-pollinisateurs sont parmi les réseaux mutualistes les plus étudiés. Sans pollinisateurs, de nombreuses plantes sauvages et cultivées ne pourraient pas se reproduire. Il est important de comprendre les réseaux plantes-pollinisateurs si nous souhaitons empêcher la destruction des interactions de pollinisation et des services écosystémiques connexes. Dans ces réseaux, les espèces doivent être présentes au même endroit et au même moment pour interagir. En France, l'abondance, la richesse des plantes et des pollinisateurs diffèrent le long du gradient latitudinal, qui correspond aux variations naturelles de la biodiversité. Ces variations pourraient potentiellement affecter la structure du réseau. En outre, les réseaux d'interactions sont souvent décrits sur la base de données agrégées dans le temps, mais en réalité les interactions varient dans le temps. Les grands ensembles de données sur les interactions plantes-pollinisateurs, couvrant toute la saison de floraison ou plusieurs années et permettant des comparaisons pertinentes entre les réseaux le long du gradient environnemental, sont rares. En raison de leur complexité et de leur variation interannuelle, la plupart des études sur les réseaux mutualistes se sont concentrées sur la comparaison des mesures classiques des réseaux qui sont toutes influencées par la taille des réseaux (le nombre d'espèces). De plus, la plupart de ces réseaux sont fondés sur des interactions observées sur le terrain, ce qui fait que certains liens ne sont pas observés. Ainsi, ces réseaux représentent un sous-échantillon d'interactions possibles, ce qui nécessite l'élaboration de nouvelles approches méthodologiques pour mieux explorer les processus écologiques qui déterminent les interactions entre les espèces. L'objectif général de cette étude est de comprendre et d'aider à prédire les effets des changements environnementaux sur les communautés de plantes et de pollinisateurs en étudiant les associations plantes-pollinisateurs selon un gradient environnemental. Je fournis et analyse ici une nouvelle base de données constituée de données géolocalisées caractérisant les associations plantes-pollinisateurs au niveau de l'espèce, la variation spatiale de la structure des communautés et l'assemblage des traits, en me concentrant sur six prairies calcaires le long d'un gradient latitudinal en France. J'ai d'abord comparé la variation de la diversité taxonomique dans l'espace (inter et intra-région) et dans le temps (tout au long de la saison). Ensuite, j'ai utilisé une nouvelle approche méthodologique pour comparer des réseaux de tailles différentes et pour étudier les conséquences des gradients environnementaux sur la probabilité d'interaction plante-pollinisateur. Pour comprendre à quel point notre vision des réseaux échantillonnés selon des méthodes classiques est déformée, j'ai construit des réseaux d'interaction plus complets en utilisant le pollen trouvé sur les insectes. Enfin, j'ai étudié le mécanisme de variation géographique des odeurs florales et les différences entre les populations liées à la variation de la communauté des pollinisateurs. En raison de la complexité et variabilité des interactions plantes-pollinisateurs, notre étude a souligné l'importance de tenir compte de toute la saison de floraison et de la période de vol des insectes, en utilisant des identifications au niveau de l'espèce, afin de démêler le rôle écologique des espèces et les variations du réseau. L'utilisation d'une nouvelle approche méthodologique nous a permis de faire des comparaisons de réseaux le long du gradient environnemental et de diversité en évitant des problèmes de circularité. La grande quantité de données fournies dans cette thèse a permis d'effectuer des comparaisons à différents niveaux, du réseau dans son ensemble aux variations entre populations d’une même espèceIn the current context of biodiversity crisis and the associated risks of ecosystem service failure, plant-pollinator networks are among the most studied mutualistic networks. Without pollinators, many plants could not reproduce and set seed, and 70% of agricultural production directly depends on them. However, pollinating insects constitute some of the terrestrial taxa most affected by global changes. As such, understanding plant-pollinator networks is of particular relevance if we are to prevent catastrophic disruption of pollination interactions and associated ecosystem services. In plant-pollinator networks, species need to be present in the same site and at the same moment for interactions to occur. In France, plant and pollinator abundance, richness and presence differ along the latitudinal gradient, which correspond to natural variations in biodiversity, and these variations could potentially affect network structure. Moreover, interaction networks are often reported based on temporally aggregated data, but in truth pollination interactions are not static and vary in time, since different plant and pollinator species display different phenologies. Large datasets on plant-pollinator interactions which comprise the entire flowering season or multiple years and allow relevant comparisons among networks along environmental gradient are rare. Due to their complexity and variation among years, most studies of mutualistic networks have focused on predicting and comparing classic network metrics which are all influenced by network size, i.e. the number of plant and insect species. Furthermore, most of these networks are based on interactions observed in the field, and thus some existing links between species remain unobserved. As such, visit-based networks represent a subsample of possible interactions, which call for the development of new methodological approaches to better explore the ecological processes determining species interactions. The general aim of this study is to understand and help predict the effects of environmental changes on plant and pollinator communities by studying plant-pollinator associations along an environmental gradient. Here, I provide and analyse a new database made of geo-localized data characterizing plant-pollinator associations at the species level, spatial variation in community structure and trait assemblage, focusing on six different calcareous grasslands along a latitudinal gradient in France. I first compared the taxonomical diversity variation in space (between and within region) and time (along the season). Then, I used a new methodological approach to compare networks of different size and to study the consequences of environmental gradients on plant-pollinator interaction probability. To understand how much distorted is our vision of plant-pollinator networks sampled following classic methods, I built more complete interaction networks using the pollen found on insects. Finally, I studied the mechanism behind geographical variation of floral scents and among-populations differences linked to the variation in the pollinator community. Because of the complexity and variation of plant-pollinator interactions, our study highlighted the importance to consider the entire flowering season and insects flying period, using species-level identifications, to disentangle the ecological species' role and the network variations. The use of new methodological approach allowed us to make networks comparison along the environmental and diversity gradient avoiding data circularity. The high amount of data provided in this thesis permitted to make comparisons at different level, from the entire network to species-specific variation among-populations
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Manincor, Natasha de. "Ecologie des plantes et des pollinisateurs dans les prairies calcaires le long d'un gradient latitudinal en France : diversité des espèces et structure des réseaux d'interaction plantes-pollinisateurs." Electronic Thesis or Diss., Université de Lille (2018-2021), 2019. http://www.theses.fr/2019LILUR024.
Full textAbstract:
Dans le contexte actuel de crise de la biodiversité et des risques associés de dégradation des services écosystémiques, les réseaux plantes-pollinisateurs sont parmi les réseaux mutualistes les plus étudiés. Sans pollinisateurs, de nombreuses plantes sauvages et cultivées ne pourraient pas se reproduire. Il est important de comprendre les réseaux plantes-pollinisateurs si nous souhaitons empêcher la destruction des interactions de pollinisation et des services écosystémiques connexes. Dans ces réseaux, les espèces doivent être présentes au même endroit et au même moment pour interagir. En France, l'abondance, la richesse des plantes et des pollinisateurs diffèrent le long du gradient latitudinal, qui correspond aux variations naturelles de la biodiversité. Ces variations pourraient potentiellement affecter la structure du réseau. En outre, les réseaux d'interactions sont souvent décrits sur la base de données agrégées dans le temps, mais en réalité les interactions varient dans le temps. Les grands ensembles de données sur les interactions plantes-pollinisateurs, couvrant toute la saison de floraison ou plusieurs années et permettant des comparaisons pertinentes entre les réseaux le long du gradient environnemental, sont rares. En raison de leur complexité et de leur variation interannuelle, la plupart des études sur les réseaux mutualistes se sont concentrées sur la comparaison des mesures classiques des réseaux qui sont toutes influencées par la taille des réseaux (le nombre d'espèces). De plus, la plupart de ces réseaux sont fondés sur des interactions observées sur le terrain, ce qui fait que certains liens ne sont pas observés. Ainsi, ces réseaux représentent un sous-échantillon d'interactions possibles, ce qui nécessite l'élaboration de nouvelles approches méthodologiques pour mieux explorer les processus écologiques qui déterminent les interactions entre les espèces. L'objectif général de cette étude est de comprendre et d'aider à prédire les effets des changements environnementaux sur les communautés de plantes et de pollinisateurs en étudiant les associations plantes-pollinisateurs selon un gradient environnemental. Je fournis et analyse ici une nouvelle base de données constituée de données géolocalisées caractérisant les associations plantes-pollinisateurs au niveau de l'espèce, la variation spatiale de la structure des communautés et l'assemblage des traits, en me concentrant sur six prairies calcaires le long d'un gradient latitudinal en France. J'ai d'abord comparé la variation de la diversité taxonomique dans l'espace (inter et intra-région) et dans le temps (tout au long de la saison). Ensuite, j'ai utilisé une nouvelle approche méthodologique pour comparer des réseaux de tailles différentes et pour étudier les conséquences des gradients environnementaux sur la probabilité d'interaction plante-pollinisateur. Pour comprendre à quel point notre vision des réseaux échantillonnés selon des méthodes classiques est déformée, j'ai construit des réseaux d'interaction plus complets en utilisant le pollen trouvé sur les insectes. Enfin, j'ai étudié le mécanisme de variation géographique des odeurs florales et les différences entre les populations liées à la variation de la communauté des pollinisateurs. En raison de la complexité et variabilité des interactions plantes-pollinisateurs, notre étude a souligné l'importance de tenir compte de toute la saison de floraison et de la période de vol des insectes, en utilisant des identifications au niveau de l'espèce, afin de démêler le rôle écologique des espèces et les variations du réseau. L'utilisation d'une nouvelle approche méthodologique nous a permis de faire des comparaisons de réseaux le long du gradient environnemental et de diversité en évitant des problèmes de circularité. La grande quantité de données fournies dans cette thèse a permis d'effectuer des comparaisons à différents niveaux, du réseau dans son ensemble aux variations entre populations d’une même espèceIn the current context of biodiversity crisis and the associated risks of ecosystem service failure, plant-pollinator networks are among the most studied mutualistic networks. Without pollinators, many plants could not reproduce and set seed, and 70% of agricultural production directly depends on them. However, pollinating insects constitute some of the terrestrial taxa most affected by global changes. As such, understanding plant-pollinator networks is of particular relevance if we are to prevent catastrophic disruption of pollination interactions and associated ecosystem services. In plant-pollinator networks, species need to be present in the same site and at the same moment for interactions to occur. In France, plant and pollinator abundance, richness and presence differ along the latitudinal gradient, which correspond to natural variations in biodiversity, and these variations could potentially affect network structure. Moreover, interaction networks are often reported based on temporally aggregated data, but in truth pollination interactions are not static and vary in time, since different plant and pollinator species display different phenologies. Large datasets on plant-pollinator interactions which comprise the entire flowering season or multiple years and allow relevant comparisons among networks along environmental gradient are rare. Due to their complexity and variation among years, most studies of mutualistic networks have focused on predicting and comparing classic network metrics which are all influenced by network size, i.e. the number of plant and insect species. Furthermore, most of these networks are based on interactions observed in the field, and thus some existing links between species remain unobserved. As such, visit-based networks represent a subsample of possible interactions, which call for the development of new methodological approaches to better explore the ecological processes determining species interactions. The general aim of this study is to understand and help predict the effects of environmental changes on plant and pollinator communities by studying plant-pollinator associations along an environmental gradient. Here, I provide and analyse a new database made of geo-localized data characterizing plant-pollinator associations at the species level, spatial variation in community structure and trait assemblage, focusing on six different calcareous grasslands along a latitudinal gradient in France. I first compared the taxonomical diversity variation in space (between and within region) and time (along the season). Then, I used a new methodological approach to compare networks of different size and to study the consequences of environmental gradients on plant-pollinator interaction probability. To understand how much distorted is our vision of plant-pollinator networks sampled following classic methods, I built more complete interaction networks using the pollen found on insects. Finally, I studied the mechanism behind geographical variation of floral scents and among-populations differences linked to the variation in the pollinator community. Because of the complexity and variation of plant-pollinator interactions, our study highlighted the importance to consider the entire flowering season and insects flying period, using species-level identifications, to disentangle the ecological species' role and the network variations. The use of new methodological approach allowed us to make networks comparison along the environmental and diversity gradient avoiding data circularity. The high amount of data provided in this thesis permitted to make comparisons at different level, from the entire network to species-specific variation among-populations
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Surget, Gwladys. "Processus adaptatifs des végétaux marins face au changement climatique à différentes échelles de temps et d'espace : dynamique de populations, métabolomique, écophysiologie et potentiels de valorisation." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0056/document.
Full textAbstract:
Trois modèles invasifs à large répartition en Europe, le long d'un gradient latitudinal Norvège-Portugal, ont été choisis : Sargassum muticum, Codium fragile et Gracilaria vermiculophylla. Cette thèse a pour objectif l'étude de la phénologie, de l'écophysiologie et du métabolome de ces macrophytes invasifs face à une variation de facteurs environnementaux 1) à une échelle locale, 2) à l'échelle du gradient latitudinal (en lien avec le changement climatique global) ainsi que l'étude 3) des voies de valorisation possibles des métabolites de stress par bio-inspiration. Le gradient latitudinal, se traduisant par un gradient thermique, permet de mimer le réchauffement climatique car les conséquences de ce changement climatique sur les espèces en milieu naturel ne sont généralement appréciables qu'à l'échelle de dizaines d'années. Les suivis de l'écologie, dumétabolome ainsi que des impacts potentiels de ces espèces à une échelle locale en France, a permis d'étudier le développement et le cycle de vie des espèces. En particulier, G. vermiculophylla se caractérise par une phénologie spécifique (avec la prépondérance de petits fragments végétatifs, <3cm) en Rade de Brest et par une tolérance accrue à l'envasement jusqu'à 12 cm de profondeur en acclimatant son métabolome tout en maintenant une physiologie dormante. Cette espèce ingénieur impacte en profondeur l'écosystème vaseux de la Rade. Le suivi le long du gradient latitudinal a permis d'illustrer la plasticité phénologique des espèces et notamment un potentiel invasif contrasté de C. fragile entre les différentes latitudes. Lors de marée basse de vives eaux, les espèces présentent une acclimatation de leur photo-physiologie en fonction de la latitude avec la mise en évidence d'une photoinhibition du PSll, lié au stress engendré par les conditions environnementales.Enfin, ce travail a illustré les propriétés multifonctionnelles d'extraits enrichis en composés phénoliques, présentant des activités antioxydantes mais également photoprotectrices ou ostéogéniques, soulignant l'émergence de voies de valorisation originales par bio-inspiration pour divers secteurs tels que la cosmétologie et les biomatériaux en santé humaineThree model species with a large distribution along European coasts, along a latitudinal gradient from Norway to Portugal was chosen: Sargassum muticum, Codium fragile and Gracilaria vermiculophylla. The aims of this PhD thesis were to study the phenology, ecophysiology and the metabolom of these non-native marine macrophytes and their ability to cope with a variation of environmental factors 1) at a population scale, 2) along the latitudinal gradient (in relation with the global climatic change) and to propose 3) bio-inspired molecules for industrial purposes. The latitudinal gradient corresponding to a thermic gradient, allows to imitate the global warming as climatic change ¡mpacts are most of the time only visible at decennial scale.Monitorings of ecology, metabolome and potential impacts of these macroalgae, at a population scale, allowed to study the development and life cycle of these models. In particular, G. vermiculophylla exhibited a specific phenology (with a majority of small vegetative fragments, <3cm) in the Bay of Brest and a highly tolerance to burial until 12 cm depth in the sediment by acclimatizing its metabolome together with the ability to maintain a dormancy physiology. This engineer species modifies deeply muddy shores of this Bay. Latitunal gradients's monitoring highlighted the phenological plasticity and a contrasted invasive potential of C.fragile between latitudes. During low spring tides, species exhibited an acclimation of their photophysiology between latitudes with photoinhibition process related to induce environmental stress. Furthermore, this work showed the multifunctional properties of polyphenols enriched extracts with antioxidant, photoprotective or osteogenic activities, highlighting the emergence of original bio-inspired pathways for cosmetic or biomaterial applications
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Scherer, Adriano. "Estrutura e aspectos fitogeográficos de remanescentes florestais na Restinga Sulbrasileira." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/17479.
Full textAbstract:
As restingas constituem um mosaico de ambientes presentes nas planícies costeiras brasileiras. Sua vegetação se desenvolve em areias quartzosas e engloba variadas formações, de comunidades herbáceas de dunas até florestas. A restinga sulbrasileira se estende entre as latitudes 28°30'S, no estado de Santa Catarina, e 33°45'S, no extremo sul do Rio Grande do Sul. Esta tese visou compreender, em escala geográfica mais ampla, a influência de variáveis ambientais sobre a estrutura e composição dos componentes arbóreo e herbáceo-subarbustivo nas florestas da restinga sulbrasileira. Em 15 remanescentes florestais distribuídos nessa região, realizou-se a caracterização florística e fitossociológica do componente arbóreo e verificou-se a relação entre diversidade, latitude e variáveis climáticas. O levantamento do componente arbóreo foi feito em áreas de 0,1 ha em cada remanescente, subdivididas em 10 parcelas de 10 x 10 m. Todas as árvores com DAP>= 3,0 cm foram registradas. Com os parâmetros estruturais usuais em fitossociologia foi feita uma análise da variância, comparando-se os remanescentes. Também foi avaliada a composição do solo superficial (20 cm de profundidade) dos remanescentes. Os dados de riqueza e informações sobre temperatura atmosférica e precipitação foram empregados em análises de regressão para verificar sua relação com a latitude. Realizou-se ainda uma Análise de Agrupamento para avaliar a similaridade florística entre as áreas. A composição e estrutura do componente herbáceo-subarbustivo sob diferentes níveis de uso por gado bovino nos remanescentes também foi estudada. A fitossociologia da sinúsia herbácea-subarbustiva foi feita em 10 parcelas de 1,0 m² e a florística, nas 10 parcelas de 10 x 10 m. Registrou-se a intensidade de uso por gado através de visualização direta ou vestígios dos animais. Foram feitas análise da variância e Análise de Coordenadas Principais com índices estruturais da sinúsia herbácea-subarbustiva nos remanescentes, comparando-os quanto à intensidade de uso por gado bovino. Registraram-se 116 espécies arbóreas no total, porém a riqueza variou de 11 a 43 espécies por remanescente. Espécies provenientes por mais de uma rota de imigração e pelo corredor atlântico contribuíram com 43% e 39% dessa flora, respectivamente. A diversidade arbórea variou de 1,372 a 3,175 nats/ind. O componente arbóreo apresentou densidade entre 1.520 e 3.830 ind./ha, porte baixo e predomínio de diâmetros pequenos. Constataram-se diferenças significativas na estrutura do componente arbóreo entre alguns remanescentes. Essas diferenças podem estar relacionadas a variações nas condições de fertilidade, acidez e teores de alumínio no solo. Houve uma distinção florística no componente arbóreo entre o norte e o centro-sul da restinga sulbrasileira, além de gradientes de riqueza e diversidade no sentido norte-sul relacionados às condições de temperatura e precipitação. Para a sinúsia herbácea-subarbustiva, constataram-se diferenças significativas no conjunto de variáveis estruturais (cobertura, altura e medidas de diversidade) entre remanescentes sob níveis médio e alto de uso por gado bovino. Sob alta intensidade de uso por gado bovino, a sinúsia herbácea-subarbustiva apresenta menores valores de altura, riqueza, diversidade e equabilidade e alta dominância de poucas espécies. O estudo destes componentes permitiu verificar que variáveis edáficas, climáticas e antrópicas condicionam a estrutura florestal em diferentes intensidades e/ou escalas espaciais.(Structure and phytogeographic features of forest remnants in south Brazilian restinga). Restingas comprise a mosaic of environments present in Brazilian coastal plains. Its vegetation grows in quartzarenic sands and includes several formations, from dune herb communities to forests. South Brazilian restinga extents between latitudes 28°30'S, in Santa Catarina state, and 33°45'S, in the extreme southern of Rio Grande do Sul. This thesis aimed to investigate, in broader geographical scale, the influence of environmental variables on structure and composition of tree and herb-subshrubby components in south Brazilian restinga forests. We analysed the floristic and phytosociological patterns of tree component and the relation among diversity, latitude and climatic variables into 15 forest remnants distributed in this region. Tree component survey was carried out in 0.1 ha areas, subdivided in 10 x 10 m plots. All trees with DBH >= 3.0 cm were sampled. With structural parameters usually estimated in phytosociology an ANOVA was performed to seek for relations among the remnants. The composition of superficial soil (20 cm deep) was also assessed in the remants. Richness, atmospheric temperature and rainfall data were employed in regression analyses to verify its relation to latitude. A Cluster Analysis was also performed to evaluate floristic similarity among areas. Composition and structure of herb-subshrubby component under different levels of cattle usage in remnants was studied as well. Phytosociology of herb-subshrubby synusiae was carried out in 10 plots of 1.0 m² and the floristics was accomplished in those 10 x 10 m plots. The intensity of cattle usage was registered by direct observation or animal traces. We performed an ANOVA and Principal Coordinates Analysis with herb-subshrubby structural data among remnants to compare them in relation to cattle usage levels. We sampled 116 tree species, but remnant richness varied from 11 to 43 species. Species from more than one immigration route and from the Atlantic route contributed with 43% and 39% of this flora, respectively. Diversity of trees varied from 1.372 to 3.175 nats/ind. Tree synusiae had density between 1,520 and 3,830 ind./ha, low height and predominance of small diameters. Significant differences in tree component structure were observed among some remnants. These differences may be related to variations in conditions of soil fertility, acidity and aluminium content. A floristic distinction between the northern and the central-southern portion of south Brazilian restinga was verified, besides richness and diversity gradients towards north-south associated to temperature and rainfall conditions. For herb-subshrubby synusiae, significant differences were observed in the set of structural variables (coverage, height and diversity measures) among remnants under moderate and high cattle-using levels. Under high cattle-using levels, herb-subshrubby synusiae shows lower values of height, richness, diversity and eveness, and higher dominance of few species. The study of these components permited to verify that soil, climatic and anthropic variables determined forest structure in different intensities and/or spatial scales.