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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

The Non-Random Selection of Medicinal Plants Theory: a Case Study of a Kichwa Community in the Ecuadorian Amazon

Unknown Date (has links)
The non-random selection of medicinal plants theory, which states that phylogeny affects the selection of medicinal plants, was proposed by Daniel Moerman to indirectly prove that traditional medicinal systems are rational and based in part by the therapeutic efficacy of plants. The logic of this theory is that because members of a taxonomical group share similar characteristics, some groups will be more medicinal and will be over-used in pharmacopoeias, while other groups bereft of secondary metabolites and therapeutic potential will be under-used medicinally. To test this theory, Moerman linearly regressed the total number of medicinal plants per family against the total number of plants per family present in an area and examined residual values to find over-used and under-used medicinal plant families. The method has been praised for its simplicity. Nonetheless, shortcomings have been noted and criticized, inspiring researchers to propose new procedures to test for phylogenetic biases in pharmacopoeias. Negative Binomial regression and examination of studentized residuals, the method used in this investigation, ameliorates the original one with a few corrections, conserving the simplicity and solving for all the criticized flaws. Also, this study incorporated different sociodemographic factors to determine if the intracultural homogeneity of traditional knowledge affects the results of the non-random selection of medicinal plants theory analysis. By testing Moerman’s theory, which is one of Ethnobotany’s major theories, this investigation is in agreement with the call to have more hypothesis-driven research within a theoretical framework to continue to advance the Ethnobotany field. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection
42

Mobilização de reservas durante a germinação e estabelecimento plântulas de Macrolobium acaciifolium Benth. (Leguminosae) e seu papel na adaptação aos pulsos de alagamento na Amazônia / Storage mobilization during germination and seedling establishment of Macrolobium acaciifolium Benth. (Leguminosae) and its role on the adaptation to the inundation pulses in the Amazon

Ribeiro, Rayane de Tasso Moreira 08 April 2014 (has links)
Planícies amazônicas alagáveis apresentam espécies arbóreas que estão sujeitas a um pulso de inundação proveniente das chuvas anuais. Muitas destas espécies apresentam estratégias de adaptação ao alagamento, germinando suas sementes e estabelecendo as plântulas antes do próximo período de cheia. Este é o caso de Macrolobium acaciifolium (Benth) Leguminosae (Caesalpinoideae), que ocorre nas cotas altitudinais mais altas das várzeas e igapós amazônicos. Neste trabalho, pela primeira vez foi caracterizado o sistema de mobilização de reservas ao longo do período de germinação e estabelecimento das plântulas de M. acaciifolium, com o objetivo de compreender os mecanismos fisiológicos e bioquímicos relacionados à sua estratégia em face à inundação. O experimento teve duração de 56 dias, nos quais foram realizadas coletas destrutivas e análises não-destrutivas de sementes e de diferentes partes das plântulas para análises de crescimento, fotossíntese, carboidratos não estruturais (frutose, glucose, sacarose e amido), xiloglucano de reserva e análises citoquímicas correspondentes à detecção de proteínas, amido e xiloglucano de reserva. Após análises citoquímicas e de açúcares, é reportado pela primeira vez na literatura científica, a existência de uma semente que acumula simultaneamente amido e xiloglucano de reserva na parede celular. Não foi observada a presença de corpos protéicos, que é uma característica comum de armazenamento de nitrogênio em sementes de Leguminosae, o que indica que a plântula provavelmente estabelece a assimilação de nitrogênio pelas raízes ao invés de armazenar e mobilizar reservas para isto. Nas sementes de M.acaciifolium xiloglucano e amido juntos perfazem 21,6% da massa da semente quiescente. No início da germinação, parte do amido é degradado e há um aumento concomitante de xiloglucano que leva a um equilíbrio entre as duas reservas. Dos 10 aos 14 dias após a embebição (DAE), o amido dos cotilédones é exaurido com concomitante desenvolvimento das raízes e do caule das plântulas. A partir de 20 DAE, o xiloglucano passa a ser degradado e a mobilização ocorre sem alterações na estrutura do polissacarídeo na parede celular e simultâneo acúmulo transitório de galactose, glucose, xilose e amido. Os produtos de degradação do xiloglucano levam à produção de folhas e ao estabelecimento da fotossíntese. As observações feitas neste trabalho sugerem que M. acaciifolium apresenta mecanismos de adaptação aos pulsos de inundação da Amazônia durante o processo de germinação e estabelecimento das plântulas / The Amazonian floodplains display tree species that are subjected to yearly inundation pulses. Several of these species colonize these regions are well adapted to the flood pulses, germinating their seeds and establishing seedlings before the next pulse comes. This is the case of Macrolobium acaciifolium (Benth) Leguminosae (Caesalpinoideae) that occur in the upper part of the riverbanks of the amazonian várzeas and igapós. In the present work, we characterized for the first time the system of storage mobilization along the period of seed germination and seedling establishment with the objective of understanding the physiological and biochemical mechanisms related to the strategy of M. Acaciifolim to face the next flooding season. The experiment was performed for 56 days in which destructive and non-destructive analyses of the seed and different parts of seedlings were performed for analyses of growth, photosynthesis, non-structural carbohydrates (fructose, glucose, sucrose, raffinose and starch), storage xyloglucan and corresponding cytochemical analyses to detect proteins, starch and storage xyloglucan in cotyledon tissues. After cytochemical and sugar analyses, it is reported for the first time in scientific literature the existence of a seed that accumulates starch and storage xyloglucan on the cell wall simultaneously. The presence of protein bodies, a common feature of seeds of the Leguminosae, was not observed, indicating that seedlings probably establish nitrogen assimilation very quickly through the newly formed roots instead of using a storage mobilization system for this reserve type. In seeds of M. Acaciifolium starch and xyloglucan correspond to 21,6% of the quiescent seed mass. At the beginning of germination, some starch is degraded with a concomitant increase in storage xyloglucan so that the yields of the two polymers become equal. From 10 to 14 days after imbibition (DAI), all starch is mobilized to support root and stem growth. From 20 DAI, xyloglucan is completely degraded without changes in its structure and with transient accumulation of galactose, glucose, xylose and starch. The products of degradation of storage xyloglucan lead to the production of leaves and photosynthesis establishment. The observations made in this work suggest that M. Acaciifolium show unique mechanisms of adaptation to the inundation pulses in the Amazon during the germination and seedlings establishment
43

Moléculas, morfologia e geologia: uma abordagem multidisciplinar para entender a história evolutiva de lagartos do gênero Loxopholis (Squamata: Gymnophthalmidae) no norte da América do Sul / Molecules, morphology and geology: a multidisciplinar approach to understand the evolutionary history of Loxopholis (Squamata: Gymnophthalmidae) lizards in the north of South America

Sergio Marques de Souza 16 January 2017 (has links)
A Amazônia abriga uma grande parcela da biodiversidade mundial, no entanto, existem grandes incertezas sobre os processos de geração e manutenção dessa enorme diversidade, com várias hipóteses propostas até o momento. Diversas características como tamanho pequeno, baixa capacidade de dispersão e fidelidade ao ambiente estritamente florestal fazem de lagartos do gênero Loxopholis (Squamata: Gymnophthalmidae) candidatos ideais para rastrear a história de modificações da paisagem no norte da América do Sul durante o Neogeno. Nesta tese, revisamos a variação morfológica, taxonomia e a distribuição geográfica das espécies do gênero Loxopholis, assim como estimamos as relações filogenéticas e o tempo de divergência entre as espécies com base em sequências de DNA provenientes do genoma mitocondrial e nuclear. Com essa base de dados, construímos um modelo de como ocorreu a história evolutiva de Loxopholis, discutindo os resultados a partir de reconstruções geológicas provenientes da literatura, e fornecendo uma datação independente para eventos geológicos que potencialmente influenciaram a história evolutiva do gênero. Neste estudo, também revelamos que a atual diversidade descrita para Loxopholis está severamente subestimada. Encontramos que a espécie L. osvaldoi representa um complexo de espécies crípticas, contendo de 8 a 14 potenciais espécies novas, com profundas divergências genéticas tanto nos genomas mitocondrial e nuclear, praticamente dobrando a diversidade conhecida no gênero. No entanto, a morfologia em Loxopholis é extremamente conservada, dificultando a diagnose das espécies novas. Finalmente, descrevemos a primeira população bissexual da espécie partenogenética L. percarinatum, discutindo as implicações deste achado para o entendimento relativo a aparição da partenogênese em Loxopholis / The Amazon rainforest houses a significant portion of the world biodiversity, however, there is still a lot of uncertainty about the processes involved in its generation and maintenance, with several hypotheses proposed so far. Loxopholis lizards (Squamata: Gymnophthalmidae) are small-sized; show low vagility, and high fidelity to the humid forest environment, making them ideal to test hypotheses on the history of landscape modifications in Northern South America, during the Neogene. In this thesis, we revise the morphological variation, the taxonomy, and the geographic distribution of Loxopholis species, as well as estimated a phylogenetic hypothesis and divergence times for these species based on sequences from mitochondrial and nuclear DNA. With this dataset, we build a model for the evolutionary history of Loxopholis and compared the results with geologic reconstructions of the Amazon available in the literature, which provided independent time estimates for geological events that potentially affected the evolutionary history of genus. In this study, we also showed that the actual diversity described for Loxopholis was severely underestimated. We found that L. osvaldoi represents a complex of cryptic species with 8-14 potential new species, and strong divergences in both the mitochondrial and the nuclear genomes, virtually doubling the actual diversity in the genus. Finally, we describe the first bisexual population for the parthenogenetic species L. percarinatum, discussing its implications to the origin of parthenogenesis in the genus
44

Agricultural rents, ecosystem services, and land-use incentives in the Brazilian Amazon

Mann, Michael January 2012 (has links)
Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / I explore the ecological, economic, and policy determinants of agricultural land conversion in the Brazilian Amazon. Economic drivers of land-use change are quantified by rent, which is calculated using ecological and physiological models of biological productivity and spatial economic models for the costs of moving agricultural products to market. The validity of this approach is tested empirically by estimating spatially efficient logit models that simulate land-use change in the Mato Grosso region between 2001 and 2004. My empirical measures for agricultural rent are used to quantify the desirability of a particular plot of land, which previous research represents with simple proxies, such as distance to roads or urban areas, climate, and soil type. Statistical results indicate that my measure of economic rent subsumes the explanatory power of previous proxies. This result is consistent with economic theory, which posits that it is not simply access or variation in transportation costs that drives the spatial pattern of agricultural expansion, but the expected total returns from the venture. I extend the analysis of competing economic uses by comparing spatially explicit estimates of soybean rents to the value of ecosystem services. Although these estimates for these uses are generated from different data sets, models, and estimation techniques, the values are comparable, such that the value of ecosystem services is greater than soybean rents for about 61 percent of the total area. Given this balance, the failure to value ecosystem services reduces total social welfare. Policy instruments that internalize the value of ecosystem services via land conversion taxes, conservation subsidies, or excise taxes can avoid much of this loss. Together, these results suggest that spatially explicit models of economic rents and value of ecosystem services can be used to simulate the location and quantity of land-use change in an economically consistent framework. Such a framework lays the foundation for an enhanced methodology that can evaluate the ability of fiscal policy levers to influence the location of agricultural conversion with the ultimate aim of balancing economic and environmental goals. / 2031-01-02
45

Moléculas, morfologia e geologia: uma abordagem multidisciplinar para entender a história evolutiva de lagartos do gênero Loxopholis (Squamata: Gymnophthalmidae) no norte da América do Sul / Molecules, morphology and geology: a multidisciplinar approach to understand the evolutionary history of Loxopholis (Squamata: Gymnophthalmidae) lizards in the north of South America

Souza, Sergio Marques de 16 January 2017 (has links)
A Amazônia abriga uma grande parcela da biodiversidade mundial, no entanto, existem grandes incertezas sobre os processos de geração e manutenção dessa enorme diversidade, com várias hipóteses propostas até o momento. Diversas características como tamanho pequeno, baixa capacidade de dispersão e fidelidade ao ambiente estritamente florestal fazem de lagartos do gênero Loxopholis (Squamata: Gymnophthalmidae) candidatos ideais para rastrear a história de modificações da paisagem no norte da América do Sul durante o Neogeno. Nesta tese, revisamos a variação morfológica, taxonomia e a distribuição geográfica das espécies do gênero Loxopholis, assim como estimamos as relações filogenéticas e o tempo de divergência entre as espécies com base em sequências de DNA provenientes do genoma mitocondrial e nuclear. Com essa base de dados, construímos um modelo de como ocorreu a história evolutiva de Loxopholis, discutindo os resultados a partir de reconstruções geológicas provenientes da literatura, e fornecendo uma datação independente para eventos geológicos que potencialmente influenciaram a história evolutiva do gênero. Neste estudo, também revelamos que a atual diversidade descrita para Loxopholis está severamente subestimada. Encontramos que a espécie L. osvaldoi representa um complexo de espécies crípticas, contendo de 8 a 14 potenciais espécies novas, com profundas divergências genéticas tanto nos genomas mitocondrial e nuclear, praticamente dobrando a diversidade conhecida no gênero. No entanto, a morfologia em Loxopholis é extremamente conservada, dificultando a diagnose das espécies novas. Finalmente, descrevemos a primeira população bissexual da espécie partenogenética L. percarinatum, discutindo as implicações deste achado para o entendimento relativo a aparição da partenogênese em Loxopholis / The Amazon rainforest houses a significant portion of the world biodiversity, however, there is still a lot of uncertainty about the processes involved in its generation and maintenance, with several hypotheses proposed so far. Loxopholis lizards (Squamata: Gymnophthalmidae) are small-sized; show low vagility, and high fidelity to the humid forest environment, making them ideal to test hypotheses on the history of landscape modifications in Northern South America, during the Neogene. In this thesis, we revise the morphological variation, the taxonomy, and the geographic distribution of Loxopholis species, as well as estimated a phylogenetic hypothesis and divergence times for these species based on sequences from mitochondrial and nuclear DNA. With this dataset, we build a model for the evolutionary history of Loxopholis and compared the results with geologic reconstructions of the Amazon available in the literature, which provided independent time estimates for geological events that potentially affected the evolutionary history of genus. In this study, we also showed that the actual diversity described for Loxopholis was severely underestimated. We found that L. osvaldoi represents a complex of cryptic species with 8-14 potential new species, and strong divergences in both the mitochondrial and the nuclear genomes, virtually doubling the actual diversity in the genus. Finally, we describe the first bisexual population for the parthenogenetic species L. percarinatum, discussing its implications to the origin of parthenogenesis in the genus
46

Fish assemblage organization in the Amazon River floodplain : species richness, spatial distribution and recruitment processes

Petry, Paulo 25 May 2000 (has links)
The composition and distribution of fish assemblages was examined in a floodplain lake system in the Amazon basin. Quantitative samples were collected during the 1992-1993 flooding season at Marchantaria Island, Solimoes River. A total of 25,819 specimens representing 8 orders, 30 families, 101 genera and 139 species of fish were collected. Analysis of species richness distribution among 7 vegetation strata showed that vegetated sites had higher species richness than unvegetated sites. Stands of Paspalum repens had the most diverse fish fauna. Canonical correspondence analysis (CCA) was used to investigate relationship between fish assemblages and 16 environmental variables. CCA revealed that dissolved oxygen, water transparency, water depth and aquatic vegetation structure were significantly related to fish assemblage organization. The results suggest that physiological adaptations to hypoxia and habitat complexity play a major role in the organization of these assemblages. The morphology, ontogenetic development, shape variability and deposition of otolith microincrements are described for floodplain serrasalmin fishes. Serrasalmin otoliths were similar to other ostariophysan, nevertheless their shape was species-specific. Elliptical Fourier analysis showed that Mylossoma aureum lapilli were highly variable in shape when compared to closely related species. PCA and discriminant function analysis indicated that two distinct forms of lapillus can be recognized for M. aureum, and intra-species variation was higher than inter-species variation. Otolith microincrement analysis was tested for these fishes, and microincrement deposition validation showed that Piaractus brachipomus deposits otolith increments on a daily basis. Patterns of spatial distribution, growth and mortality characteristics of larvae and juvenile were examined for M. aureum inhabiting the Marchantaria Island floodplain. Otolith-derived birth date reconstruction showed that M. aureum spawning season extended from late November to March, and peak larvae recruitment to the island occurred in mid-December. Larvae and juveniles had different spatial distributions in relation to habitat usage. Instantaneous growth coefficients (g) varied from 0.0197(d�����) to 0.265(d�����) among cohorts. Early-season cohorts had wider otolith microincrements and higher instantaneous growth coefficients than late-season cohorts. Mortality estimated by the decline of loge (abundance) regressed on age indicated that cohort-specific instantaneous mortality varied significantly among cohorts, ranging from 0.027(d�����) (2.6%/d) to 0.103(d�����) (9.7%/d). / Graduation date: 2001
47

Using Ungulate Occupancy to Evaluate a Biosphere Reserve Design in Tambopata, Peru

Licona, Miguel M. 2009 August 1900 (has links)
Conservation areas in tropical forests protect the most diverse and threatened ecosystems on the planet. In the Amazon, ungulates are important to forest structure and diversity, but are also food for rural people. I estimated occupancy of white-lipped peccary (Tayassu pecari), collared peccary (T. tajacu), lowland tapir (Tapirus terrestris), and red brocket deer (Mazama americana) in Tambopata, Peru to evaluate how different management designations along with anthropogenic and habitat factors influenced the distribution of these species. I used track surveys (n = 258) and camera surveys (n = 256) to estimate ungulate occupancy and detection at 55 sites in a national reserve, a native community, and adjacent buffer areas from May 2008 to March 2009. The best approximating model for white-lipped peccary, lowland tapir, and red brocket deer included only a variable of travel time from the nearest city (a measure of an area's accessibility). Management designation also had some influence on occupancy. I found significantly higher occupancy for collared peccary and red brocket deer in reserve and buffer areas than in the native community but there was no significant difference in occupancy between the reserve and buffer. These results indicate that passive protection might be an adequate management strategy for inaccessible areas of this region. However, as the Amazon continues to be developed, more active enforcement of park boundaries and regulations should be enacted if wildlife conservation is to be effective.
48

Temporal Variation in Space and Resource Use of Macaws in the Southeastern Peruvian Amazon

Adamek, Krista Anne 2011 May 1900 (has links)
Space use and resource use of three species of macaws (Ara ararauna, A. chloropterus, and A. macao) were studied for a period of three years in the southeastern Peruvian Amazon. Basic information on wild macaw populations is lacking due to the logistical and behavioral challenges of working with these species in dense rainforest. Population declines world-wide have been attributed significantly to a reduction in food and nesting resources due to habitat loss. This research aims to obtain baseline data on macaws in a region with relatively intact rainforest. Specific objectives were to (1) quantify space use, describe the spatial and temporal variation in movement patterns, explore habitat selection and spatial pattern of resources during the non-breeding season, and (2) identify key nesting and foraging species and determine whether there is seasonal variation in diet, and explore how resources may be related to movements and competition. Individuals from each species were radio-tagged and monitored from 2004 to 2008 by ground, platform, and aerial tracking. Seasonal ranges were estimated using MCP and KDE methods. Diversity and niche measurements and selection were calculated for dietary items, nesting substrate, and habitat. The relationship between palm habitat distribution and A. ararauna movements was explored using landscape analysis techniques. All species had similar home range sizes during the breeding season, ranging from a mean of 1,540 ha to 2,541 ha. Non-breeding ranges were significantly larger for A. ararauna (117,849 ha). Greater than 200 species of plants were consumed, yet seasonal preferences vary. The increase in dietary breadth and decrease in overlap during dry season is unlikely related to food scarcity or competition. Key nesting and dietary species include Mauritia flexuosa, Dipterix micrantha, and Bertholletia excelsa. Palm habitat is a key resource for Ara ararauna and associated with long-distance movements. This research addresses a critical gap in our knowledge regarding macaw movements and resource use in Amazonian rainforest. Despite their mobility, their low fecundity and specialized nesting requirements can impact reproductive success and population growth if habitat loss continues on its current trajectory.
49

What are the mechanisms responsible for the wet season onset over tropical South America

Li, Wenhong, January 2003 (has links) (PDF)
Thesis (Ph. D.)--School of Earth and Atmospheric Sciences, Georgia Institute of Technology, 2004. Directed by Rong Fu. / Includes bibliographical references (leaves 119-131).
50

Forest diversity and conservation in the western Amazon based on tree inventory and remote sensing data

Wang, Yung-ho Ophelia 01 February 2012 (has links)
This dissertation contributes to debates in conservation biogeography by examining the spatial heterogeneity of local and regional tree diversity feature using ground and remotely sensed data, and by taking approaches to design a spatially explicit landscape zonation map for future conservation planning in western Amazon, one of the most biodiverse regions on Earth. Fine scale tree diversity and conservation-related studies took place in tropical rainforests in southeastern Ecuador, whereas coarse scale tree diversity research was conducted using data from eastern Ecuador and northern Peru. The lack of species assemblages within three 1-ha tree inventory plots in southeastern Ecuador and the weak correlations with biophysical environment implied that neutral processes may contribute to species diversity. In contrast, differences in species assemblages between plots corresponded to relative geographic locations of the plots, indicating that geographic distance or dispersal limitation may play an important role influencing diversity patterns at a regional scale. Species of high local abundance was found in 1-ha tree inventory plots in western Amazon. Changes in density of locally abundant species between western and eastern plots indicated that some species may have limited distributions. Shifts in species dominance and the significant relationship between floristic variation and geographic distances between plots implied dispersal limitation. Variation in rainfall showed significant relationship with species composition. Therefore, dispersal limitation and precipitation seasonality are potentially the most significant factors that contribute to spatial differences in tree diversity in western Amazon. Characteristics of canopy shadows and palm stem density based on fine-resolution aerial photographs were characterized as exploratory analyses to extract alpha and beta diversity features using remotely sensed data. A zonation map design using multispectral habitat classification and other remote sensing data performed well in its spatial arrangement when potential indigenous land use was integrated. Based on the results of analyses for conservation biogeography, this dissertation concludes that local and regional tree diversity may be influenced by dispersal limitation and seasonality, and that the application of remote sensing for biodiversity conservation is feasible in very species-rich forests. / text

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