Thèses : « Determinanti ecologici »

1

Centis, Barbara. « Spatial patterns and ecological determinants of the diatom communities in an alpine flow-regime river (Adige River, North-Eastern Italy). Implications for the ecological status' assessment ». Doctoral thesis, country:IT, 2011. http://hdl.handle.net/10449/22910.

Texte intégral

Résumé :

My PhD work draws from a project called PlanAdige that has been funded by the Basin Authority of River Adige to the Foundation E. Mach of San Michele all’Adige in the early 2007 for a period of three years. The main objective of this project was the study of the watercourse following an integrated approach that would encompass both its physical, chemical and biological features aiming at assessing its ecological status. I believe we are facing a particular moment in Ecological Sciences since we have to deal with “hot topics” such as climate change, water scarcity and resources depletion: meeting today’s environmental challenges requires gaining reliable knowledge about ecosystems in their deeper details (Schmitz, 2007). It is therefore vital to gather all the knowledge and the science that we know in order to cope with these big issues at our best: every little study or survey that has been made can give a contribution to tackle these concerns. For my PhD Internship I have focused my attention on diatoms and rivers, whose links have been widely used to assess watercourses’ general water quality. Diatoms are very important aquatic organisms: some researchers have estimated that there are 10 million diatom species worldwide but only 11.000 have been identified up to date (Poulin & Williams, 1998) and that they account for 25% of the living matter (Werner, 1977). Because of their abundance in marine plankton, especially in nutrient-rich areas of the world’s oceans, diatoms probably account for as much as 20% of global photosynthetic fixation of carbon (ca. 20 Pg carbon fixed per year: Mann, 1999). Diatoms are essential links for energy transfer to upper tropic levels as they are a preferred high quality food source for primary consumers (Brett & Mullen-Navarra, 1997) and are the principal source of biologically induced carbon export from surface to deep waters, therefore playing a central role in nutrient cycling. Some studies have recently showed that it is expected that climate change will affect diatom abundance and community structure (Henson et al., 2010; Widdicombe et al., 2010) as well as increase the density gradient which in turn will suppress the upward flux of nutrients (Behrenfeld et al., 2006). It is expected that warmer climate will preferably favor small-sized diatom cells that show a high surface area to volume ratio (Winder et al., 2009) turning in cell size to be a powerful predictor of optimum dynamic performance (Reynolds et al., 2002). In earlier times, ecological research on rivers focused on the descriptive research of biological communities in small streams (Minshall, 1988; Cummins et al., 1995). Research on large rivers was limited partly by tradition and partly by methodological problems, considering the large geographical scale of these ecosystems. Nowadays, it is clearer that river ecologists are developing a more integrated view of rivers: this reflects the need to increase the knowledge about these systems in all its components. As for diatoms, unfortunately, we yet do not have a full comprehension of the temporal factors shaping the diatom communities of a watercourse (Passy, 2007) also because only few studies have examined both physical and chemical parameters effects on the communities concurrently (Duncan & Blinn, 1989). Little is known about factors driving diatom species diversity and geographic distribution: studies focusing on the mechanisms generating species diversity are needed (Vanormelingen et al., 2008; Larned, 2010) since force fitting has severe consequences both on ecological and management sides (e.g. the Water Framework Directive 2000/60/CE requires ecological lumping of watercourses for ecoregions’ definition). With these premises, the specific objectives of my PhD thesis, are: 1- Assessment of the main biotic and abiotic drivers affecting the composition and temporal dynamics of the diatom communities in the River Adige. In the view that the abiotic environment has probably set the main stage for evolutionary development of specific traits and associated life-history strategies in the ecosystem (Lytle & Poff, 2004) and that these factors drive a large proportion of the subsequent biotic interactions (Biggs et al., 2005), there is a need to clarify the direct measures of these driving forces together with the associated biotic response variables, at different scales. This ambitious objective rises from the scarcity of studies that look at multiple samples per sites over times and which relate results to contemporary management problems (Kelly, 2002). Benthic diatom communities have a spatial and temporal variation:it follows that we cannot conclude much from such studies (Kelly et al., 2009). In addition, most researches up to date have focused only on a limited component of the diatom community (e.g. the epilithon) almost completely neglecting the other ones (epipelon, epiphyton and epipsammon). In addition, only sporadic comparisons were made between benthic and planktonic algae in a same watercourse (Werner & Köhler, 2005). 2- Evaluation of diatom assemblage structures and its drivers at the light of biomonitoring techniques. The need to use diatom indices for water quality is universally claimed: given that diatom communities vary with abiotic and biotic factors, great potentials exist for refining our assessment of biological and pollution condition by accounting for natural variation. These refinements will turn out to be essential for increasing accuracy, precision and fairness of ecological assessments. Much has been said about this topic but there are still some uncertainties to be discussed: there are few studies which have properly addressed the small-scale (e.g. within-riffle scale) community variations in streams (Soininen, 2007) and even fewer that have studied impaired water courses, such as Adige River. 3- Provide a framework of knowledge on diatoms’ autoecology which is the first step to further deal with these organisms. Periphyton communities are solar-powered biogeochemical reactors, biogenic habitats, hydraulic roughness elements, early warning systems of environmental degradation and troves of biodiversity (Larned, 2010) and therefore it is essential to study the rules that govern their components, both individually and among taxa. There is a scarcity of such studies and this turns in consequently hampering of the prediction of changes in resource requirements and endangering of the tout-court application of diatom indices. Little is known about diatom ecology, biology and the factors driving diatom species diversity and geographic distribution (Mann, 1999; Chepurnov et al.,2004): especially in impacted environments and this could lead to ecological biases. For instance, in the case of Adige River which is highly influenced by discharge regimes (Centis et al., 2010), it is essential to know the impact of this variable on diatom communities . It has to be kept in mind that the relationship between diatom species composition and prevailing hydraulic conditions is one of the original research problems in periphyton ecology (Butcher, 1940; Patrick, 1948). 4- These results will be worked out also as contributions to the exploration of diatom index based on phytoplankton that could help figuring the potential of this community in water quality assessment. Even if this topic has been developed for lakes (Thunmark, 1945; Nygaard, 1949; Stockner, 1971; Catalan, 2003) little has been done for rivers, if we exclude the works by Mischke (Mischke, 2007; Mischke & Behrendt, 2006; Mischke & Behrendt, in prep.), and Borics et al. (2007). Overall, the aim of this study is to give a contribution to the evolving legacy of stream ecology: at the past two meetings of the North American Benthological Society (Grand Rapids Michigan, 2009; Santa Fè, New Mexico, 2010) has emerged the need to push towards an holistic perspective that would consider global changes occurring in these riverine ecosystems. A number of conceptual models have been proposed to synthesize empirical information (to cite some: Ward et al., 2002; Benda et al., 2004; Thorp et al., 2006) and they are indeed very valuable in organizing what otherwise might be a collection of seemingly unique case studies. This is especially worthwhile since stream ecology is moving towards the disturbance issue (Stanley et al., 2010) and the multiple stressors perspective (Thorp, pers. comm.).

Styles APA, Harvard, Vancouver, ISO, etc.

2

Keeling, Jonathan Giles Matthew. « Ecological determinants of muntjac deer Muntiacus reevesi behaviour ». Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296650.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

3

Hunter, Chadden Piers. « Ecological determinants of gelada ranging patterns (Theropithecus gelada) ». Thesis, University of Liverpool, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250312.

Texte intégral

Résumé :

The foraging ecology of a band of gelada monkeys (Theropithecus gelada) was studied in the field at Sankaber, Ethiopia, for 14 months. The field site is at high altitude (3300m) and experiences severe variation in climatic and vegetational conditions across distinct wet and dry seasons and between different microhabitats. Gelada live in a complex fission/fusion social system and occupy a unique environmental niche as the world's only graminivorous primate species. Research was directed towards examining the ecological parameters affecting the gelada's group-level behavioural ecology. The nature and distribution of gel ada food resources was found to be a more complex and influential selective force than previously acknowledged. Gelada ranging behaviour varied in relation to spatial and temporal variation in food availability and specific small scale weather patterns, but not in relation to the distribution of sleeping sites, refuges or water sources. Group size and day journey length covaried significantly between seasons and months and the strength of the correlation between the two variables was determined by levels of food availability. The rate at which the main gel ada study band underwent fission or fusion correlated to the degree in which food was patchily distributed but not direct levels of food availability. Distribution of food sources varied significantly between habitats as did levels of visibility. Gelada alarm and flight response rates were found to correlate more strongly to levels of visibility under 10 metres within each habitat than mean levels of visibility per se. Both males and females spent significantly more time feeding, (and feeding on subterranean food items specifically) in the dry season, resulting in a slightly higher mean daily calorific intake than in the wet season. It is suggested that the dry season does not represent a 'nutritional bottleneck' to the gel ada as previously thought, but does constitute a period of increased energy requirements due to seasonal variation in lactation and thermoregulation demands

Styles APA, Harvard, Vancouver, ISO, etc.

4

Pardanani, Neeta N. « Ecological determinants of lyme disease in an endemic community / ». View online ; access limited to URI, 2004. http://wwwlib.umi.com.helin.uri.edu/dissertations/dlnow/3160034.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

5

Mesch, Gustavo Sergio. « The political, ecological and organizational determinants of neighborhood action / ». The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487846354485344.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

6

Menger, Juliana da Silva. « Fatores determinantes da distribuição de aves no interflúvio Purus-Madeira ». Instituto Nacional de Pesquisas da Amazônia, 2011. http://localhost:8080/tede/handle/tede/2010.

Texte intégral

Résumé :

Submitted by Dominick Jesus (dominickdejesus@hotmail.com) on 2016-01-20T18:48:27Z No. of bitstreams: 2 Dissertação_Juliana da Silva Menger.pdf: 1573112 bytes, checksum: 1cbe83caa9b13c0695bfaf7c092161e3 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5)
Made available in DSpace on 2016-01-20T18:48:27Z (GMT). No. of bitstreams: 2 Dissertação_Juliana da Silva Menger.pdf: 1573112 bytes, checksum: 1cbe83caa9b13c0695bfaf7c092161e3 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2011-07-07
Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
Fundação de Amparo à Pesquisa do Estado do Amazonas - FAPEAM
Studies addressing deterministic and stochastic processes that effect changes in species composition among sites (beta diversity) have focused, for the most part, on sessile organisms. These are highly susceptible to random dispersal processes, confirming neutral theory assumptions. At first glance, birds would appear to have high dispersal ability. However, in Amazonian forests most birds are extremely sedentary, with restricted distributions, often limited by large rivers. In this study, we evaluated the environmental effects (palm species composition) relative to geographical distances between sites, as factors related differences in forest bird species composition. We sampled 11 sites in upland forest, separated from one another by 60 km, covering a 670 km extension in the Purus-Madeira interfluve of Western Amazon, Brazil. Similarity in bird assemblage was significantly correlated with palm species composition. Understory and canopy birds assemblages showed similar correlation with palm species composition. When the effect of palm species composition was controlled, distance was not a good indicator of changes in the bird community. Our results suggest that, in this region and at this spatial scale, birds are not limited by geographical distance and can disperse throughout the region studied. Nevertheless, they are not uniformly distributed which can best be explained by environmental variation, represented here by palm species composition. Although our results indicate that geographic distance has no effect on changes in bird composition, we emphasize that studies on a larger spatial scale could help to understand dispersal limitation effects in tropical Amazonian forest bird composition.
Até o presente, estudos abordando fatores determinísticos e estocásticos que afetam mudanças na composição de espécies entre locais enfocaram, em geral, organismos sésseis. Esses organismos são especialmente suscetíveis a processos aleatórios de dispersão, corroborando premissas da teoria neutra. As aves, aparentemente, apresentam boa capacidade de dispersão. No entanto, em florestas amazônicas, muitas espécies de aves são extremamente sedentárias e apresentam distribuição restrita, tipicamente limitada por grandes rios. Neste estudo avaliamos a importância de efeitos ambientais, medidos pela composição de espécies de palmeiras, relativos aos efeitos da distância geográfica, como fatores geradores de diferenças na composição de aves amazônicas. Nós amostramos 11 localidades em uma floresta de terra firme, distantes aproximadamente 60 km entre si, cobrindo uma extensão de 670 km, no interflúvio Purus-Madeira, Amazônia brasileira. A similaridade das assembleias de aves foi significativamente correlacionada com a composição de palmeiras. Aves de sub-bosque e aves de dossel, analisadas separadamente, também apresentaram forte correlação com a composição de palmeiras. Com o efeito ambiental controlado, a distância geográfica não foi um bom indicador de mudanças na avifauna na área de estudo, não explicando a ocorrência de espécies de nenhum dos grupos de aves. Os resultados sugerem que, na escala espacial e na região deste estudo, as aves não são limitadas pela distância geográfica entre as localidades, podendo se dispersar por toda extensão da área estudada. No entanto, a composição de aves muda entre as localidades amostradas e essas mudanças podem ser melhor explicadas pela variação ambiental, representada pela composição de palmeiras. Embora nossos resultados indiquem que a distância geográfica não tenha efeito sobre as mudanças na composição de aves, enfatizamos que estudos em uma escala maior poderão ajudar a entender os efeitos da limitação de dispersão sobre a composição de aves florestais amazônicas.

Styles APA, Harvard, Vancouver, ISO, etc.

7

Erbaugh, J. Mark. « Determinants of agricultural production constraints in Uganda : a socio-ecological approach / ». The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487867541730366.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

8

Maliti, Deodatus Vincent. « Ecological and genetic determinants of malaria vectors feeding and resting behaviours ». Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6933/.

Texte intégral

Résumé :

Ecological and genetic factors play a key role in determining the behaviour of mosquito vectors, which in turn influences malaria transmission and epidemiology. Malaria vector control strategies such as long lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) rely on the timing and location of mosquito vector feeding behaviour, and their choice of resting habitat (inside houses versus outside). In some settings where these control measures have been intensively used, the major malaria vectors have been reported to change their behaviour to bite more often outdoors and/or earlier in the evening before people are protected by LLINs, and to increasingly rest outdoors. Such shifts in vector behaviour may jeopardize the effectiveness of LLIN and IRS strategies. The potential for such changes to undermine malaria control can only be understood by: (1) developing better, standardized sampling tools for the surveillance of mosquito behaviours, and (2) identifying the environmental and genetic factors that contribute to these behavioural changes as is required to predict how quickly they can occur and spread. This study developed and evaluated a range of novel tools to sample host seeking and resting African malaria vectors. These tools were used to characterize a range of epidemiologically relevant malaria vector behaviours within an endemic area of southern Tanzania, and investigate the role of potential ecological and genetic determinants of behavioural variation. Firstly, a novel mosquito electrocuting trap (MET) was developed and evaluated relative to a commercially available insect electrocuting trap (CA-EG) and the gold standard human landing catch (HLC) technique for measuring the abundance and host seeking behaviour of Anopheles gambiae s.l. and An. funestus s.l. A Latin Square experiment was conducted in a rural setting in the Kilombero Valley of Tanzania where the sampling performance of MET was promising, especially in outdoor sampling where it achieved > 58% sampling performance relative to the HLC. In contrast, the CA-EG had poor performance relative to both the MET and HLC and was considered unlikely to be a viable sampling method. This study showed that electrocuting traps can be developed and used as alternative, realistic and exposure-free sampling tools to the HLC technique. Secondly, a series of new lightweight, portable and standardized sampling traps were developed and compared relative to one another to identify which traps are optimal for measuring African malaria vector resting behaviour. Two existing resting traps, the Resting Bucket (RBU) and Resting Box (RBO) were used along with two modified versions of the RBU designed to test the influence of specific design features to mosquito catchability: a modified entry resting bucket (MERBU) and a sticky resting bucket (SRBU). The performance of all traps for sampling indoor and outdoor resting An. gambiae s.l. and An. funestus s.l. were evaluated relative to one another, and the back-pack aspirator method (BPA, indoor collections only). Mosquito vector densities in all resting traps were relatively low (< 3 per night), but were consistently higher in the RBU and RBO. The SRBU had significantly poorer performance outside than inside, which gave rise to highly biased estimates of exophilic behaviour. The MERBU trap performed consistently poorly inside and outdoors. Based on their relative and consistent sampling performance, the RBO and RBU are recommended as the best choice for wider scale surveillance of vector resting behaviour and its response to control measures. Thirdly, a candidate gene approach was used to test if variation in the host seeking behaviour of An. arabiensis is associated with genetic polymorphisms in their circadian rhythm genes. Single nucleotide polymorphisms (SNPs) from 34 loci across 8 circadian genes in An. arabiensis were identified and analyzed for association with the timing (“early=7pm-10pm vs “late” = 4am-7am) and location (indoors vs outdoors) of their host seeking. No associations were found between the host seeking phenotypes and SNP polymorphisms in An. arabiensis. However, a strong genetic population structure was detected within An. arabiensis from the study area, which was correlated with polymorphisms in the Timeless gene (irrespective of the feeding phenotypes or geographical location). The cause of this structuring remains unknown, and further studies to investigate the potential mechanism and epidemiological implications are recommended. Although no association was found in this study, the role of genetics in determining malaria host seeking behaviour cannot be discounted. Other approaches such as transcriptomics and whole genome sequences are recommended in future studies. In combination, results from this study give insights into the optimality of different sampling tools for reliable, ethically conducive monitoring of malaria vector behaviour. Furthermore, they provide baseline assessment of the contribution of some mosquito genetic and environmental factors to mosquito vector behaviour. It is hoped that the most promising sampling tools developed here can be improved and integrated into malaria vector surveillance programmes to obtain reliable information on vector behaviour and how vectors respond to environmental change and wide-scale use of malaria control measures.

Styles APA, Harvard, Vancouver, ISO, etc.

9

Ceschin, Fernanda. « Determinantes da diversidade beta de comunidades aquáticas em planícies de inundação ». reponame:Repositório Institucional da UFPR, 2015. http://hdl.handle.net/1884/38068.

Texte intégral

Résumé :

Orientador : Prof. Dr. André Andrian Padial
Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Ecologia e Conservação. Defesa: Curitiba, 20/03/2015
Inclui referências
Área de concentração : Ecologia e Conservação
Resumo: 1. Explicar a variação espacial e temporal da distribuição das comunidades biológicas nos ecossistemas tem sido uma questão central em ecologia. Atualmente esta questão tem sido pensada com enfoque na variação composicional entre unidades amostrais (Diversidade beta - ?). 2. Nesse estudo, a variação da ? temporal das comunidades de peixes sedentários, peixes migradores e macrófitas, foi abordada utilizando a metacomunidade amostrada em um período como unidade amostral. O conjunto de dados utilizado foi obtido de uma série temporal de 13 anos de amostragens na planície de inundação do Alto Rio Paraná, Brasil, de 2000 a 2012. Foram utilizadas como determinantes da ? variáveis representativas dos seguintes processos ecológicos: invasão biológica, variáveis indicadoras do regime hidrológico, produtividade e heterogeneidade ambiental. 3. Os determinantes relevantes para as metacomunidades dependeram da comunidade estudada, sendo os peixes sedentários o grupo mais afetado pelos efeitos homogeneizadores do regime hidrológico. A ? da metacomunidade de peixes sedentários também é significativamente explicada pela riqueza de espécies exóticas, heterogeneidade ambiental e produtividade, indicando alto determinismo ambiental na variação temporal dessa metacomunidade. A variação temporal da metacomunidade de macrófitas foi afetada apenas pelas variáveis de produtividade, porém a metacomunidade de peixes migradores apresentou somente autocorrelação temporal não explicada por nenhum dos determinantes testados. 4. Por fim, a representação do regime hidrológico através de variáveis dummy parece ser a melhor forma de se utilizar informações do regime hidrológico como determinante da ?. Palavras-chave: Homogeneização biótica, regime hidrológico, espécies invasoras, heterogeneidade ambiental, produtividade, autocorrelação.
Abstract: 1. Explaining the temporal and spatial variation of the ecological communities in the ecosystems had been a central issue on Ecology. This issue has been answered focusing on the compositional variation among sampling units (Beta diversity - ?). 2. In this study we explained the sedentary fish, migratory fish and macrophytes communities temporal ?. Data was obtained from a time series of 13 years of sampling in the Upper Paraná River floodplain. The following variables were used as ? determinants: non-native species richness, productivity, environmental heterogeneity, hydrological regime. 3. The relevant determinants for metacommunities differ to each community studied. Sedentary fish were the most affected by the homogenizing determinants of the hydrological regime. Also, the sedentary fish metacommunity can be significantly explained by the non-native species richness, environmental heterogeneity and productivity, indicating high environmental determinism on the temporal variation of this metacommunity. The temporal variation of macrophyte metacommunity was only affected by the productivity variables. On the other hand, the migratory fish metacommunity only presents temporal autocorrelation, which cannot be explained by the tested determinants. 4. Finally, the representation of the hydrological regime through dummy variables seems to be the best way to use information about the hydrological regime as a determinant of ?. Key-words: Biotic homogenization, hydrological regime, exotic species, environmental heterogeneity, productivity, autocorrelation.

Styles APA, Harvard, Vancouver, ISO, etc.

10

PEREIRA, Diego Fernandes Gomes. « Filtros ambientais determinando caracteres funcionais de assembleias de Odonata ». Universidade Federal do Pará, 2017. http://repositorio.ufpa.br/jspui/handle/2011/9402.

Texte intégral

Résumé :

Submitted by Rose Suellen (rosesuellen@ufpa.br) on 2018-01-29T11:42:48Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_FiltrosAmbientaisDeterminando.pdf: 1250268 bytes, checksum: d9cf90fa9852b1ea34a02ce6319ae910 (MD5)
Approved for entry into archive by Rose Suellen (rosesuellen@ufpa.br) on 2018-01-29T11:43:42Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_FiltrosAmbientaisDeterminando.pdf: 1250268 bytes, checksum: d9cf90fa9852b1ea34a02ce6319ae910 (MD5)
Made available in DSpace on 2018-01-29T11:43:42Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_FiltrosAmbientaisDeterminando.pdf: 1250268 bytes, checksum: d9cf90fa9852b1ea34a02ce6319ae910 (MD5) Previous issue date: 2017-03-24
CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
A distribuição de espécies pode ser afetada pela disponibilidade de ambientes que se encaixam dentro do limite de variação do seu nicho e pela interação com outras espécies. Modificações no ambiente, especialmente os de origens antrópicas, são cada vez mais comuns, e a modificação de habitat resultante dessas atividades é considerada uma das principais causas de extinções de espécies. Ecossistemas aquáticos são considerados um dos mais vulneráveis do globo em virtude de sua dependência da paisagem circundante e da rede de drenagem. No entanto, a resposta das espécies a essas alterações não é aleatória, podendo seguir padrões que são dependentes de funcionalidade ou da morfologia especifica de cada táxon. O objetivo deste trabalho foi avaliar se os fatores ambientais funcionam como filtro para o estabelecimento de espécies de Odonata por meio de seus caracteres funcionais e morfológicos, testando as hipóteses de que: a) o ambiente funciona como um filtro sobre as espécies, por meio da facilitação ou impedimento de caracteres e b) que devido aos requerimentos de termorregulação e reprodução, indispensáveis para a colonização e manutenção da população, a largura do tórax e o tipo de oviposição serão as variáveis biológicas mais afetadas. Para isso, amostramos 97 igarapés na Amazônia oriental, distribuídos em um gradiente de condições ambientais que contempla desde áreas totalmente preservadas a muito modificadas pela pecuária e agricultura. Foram utilizados seis caracteres funcionais (comprimento total, comprimento da asa, largura da asa, largura do tórax, comprimento do abdome e categoria de oviposição) e sete variáveis ambientais (índice de integridade ambiental, oxigênio dissolvido, temperatura da água, cobertura de dossel, cobertura de macrófitas, pH e condutividade). Para avaliar se as variáveis ambientais influenciam as assembleias de Odonata, utilizamos uma combinação de análises RLQ e Fourth Corner, na qual avaliamos as relações de sete variáveis. Dentre as variáveis ambientais estudadas, o Índice de Integridade Ambiental apresentou o maior efeito sobre a assembleia de Odonata, tendo relação negativa com a largura da asa, largura do tórax e de oviposição exofítica, e relação positiva com oviposição endofítica. Cobertura de macrófitas foi a segunda variável ambiental mais representativa, apresentando relação negativa com comprimento do abdome e positiva com oviposição exofítica e largura do tórax. Os resultados mostram que ambientes poucos preservados facilitam a ocorrência de organismos com tórax largo e a substituição da categoria de oviposição endofítica pela exofítica. Uma vez que impactos normalmente não modificam a riqueza de libélulas, apenas sua composição, tais resultados indicam que ocorre favorecimento de grupos com estes caracteres, tais como a família Libellulidae, em detrimento de outras famílias e grupos (especialmente de Zygoptera), o que pode resultar em homogeneização da assembleia e perda filogenética e funcional. A preservação de ambientes prístinos é, portanto, indispensável para manter a diversidade de Odonata, sendo a melhor maneira de conservar os muitos grupos ecofisiológicos e comportamentais da ordem. A resposta das assembleias de libélulas, direcionada por caracteres morfológicos e comportamentais, elucida padrões de respostas ecológicas, e a incorporação de hábitos de oviposição em políticas de conservação da ordem se apresenta indispensável para torná-las mais adequadas, pois são críticos para a manutenção de populações e colonização de novos locais.
Species distribution is affected by availability of habitas that fit within the limits of variation of their niche and by interaction with other species. Environmental modifications, especially those of anthropic origin, are increasingly common, and are considered major causes of species extinction during the Anthropocene. Aquatic ecosystems are considered among the most vulnerable on the planet because of its dependence on the surroundings and the drainage system. However, species responses to these changes are not random, and can follow patterns that are caused by the specific functionality or morphology of each taxon. This work’s goal was to evaluate if environmental factors work as ecological filters for the establishment of Odonata species through selection of their functional and morphological characters, testing the hypotheses that a) the environment works as a filter over species, by facilitating or hindering characters and b) that due to their thermoregulatory and reproductive requirements, indispensable for colonization and population maintenance, thorax width and oviposition type will be the most affected biological variables. Considering that, we sampled 97 streams in the oriental side of the Brazilian Amazon Forest, distributed over an environmental gradient which covers areas ranging from untouched primary forest to areas extremely modified by agriculture and livestock. We used six functional traits (total body length, fore wing length, fore wing width, thorax width, abdominal length and oviposition type) and seven environmental variables (habitat integrity index, dissolved oxygen, water temperature, canopy cover, macrophytes cover, pH and condutivity). To evaluate if the environmental variables affected the odonate communities, we used the combination of the RLQ and Fourth Corner analysis, with which we assessed the relation between each of the selected traits with each of the habitat descriptors. Among the studied environmental variables, habitat integrity index presented the largest effect over the community of Odonata, having a negative relation with fore wing width, thorax width and exophytic oviposition, and a positive relation with endophytic oviposition. Macrophytes cover showed a negative relation with abdominal length and a positive relation with thorax width and exophytic oviposition. No other environmental descriptor presented significant relations. The results show that poorly preserved habitats facilitate the occurrence of organisms with larger thorax and the substitution of the endophytic by the exophytic type of oviposition. Since environmental impacts usually do not change Odonata species richness, only community composition, these results point that there is favouritism towards groups of species with those characters, like the Libellulidae family, with detriment to other families or groups (specially of the Zygoptera suborder), what might result in community homogeneity and loss of functional and phylogenetic diversity. Thus, the preservation of primary forest is indispensable for the maintenance of Odonata, being the best way to conserve the different ecophysiological and behavioural groups in the order. The dragonfly communities’ responses, directed by morphological and behavioural traits, enlightens ecological response patterns, and the addition of oviposition categories to conservation policies for the Odonata is critical in making them more effective, as they are absolutely necessary for population stability and colonizing new sites.

Styles APA, Harvard, Vancouver, ISO, etc.

11

Vitória, Rômulo Silveira. « Testando a importância das histórias evolutivas das espécies como um determinante das suas interações em redes ecológicas ». reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/150693.

Texte intégral

Résumé :

Múltiplos fatores determinam as interações entre espécies em redes ecológicas, tais como as barreiras nas suas morfologias, distribuições espaços-temporais, suas abundâncias relativas e histórias evolutivas. Novos métodos estão tornando possível avaliar a importância relativa desses fatores determinantes. Todavia a capacidade de avaliar a importância das histórias evolutivas das espécies é ainda limitada pela escassez de métodos que permitam incluir informações derivadas de filogenias independentes entre os preditores das interações. Esse estudo objetiva superar essa limitação através da inclusão das histórias evolutivas das espécies entre os potenciais determinantes das interações, permitindo a análise comparativa das suas importâncias como estruturadores das redes ecológicas. Usando conceitos dos campos de redes ecológicas e da ecofilogenia foram hipotetizados possíveis cenários filogenéticos preditores das frequências de interações. Para ilustrar o uso desses cenários foi usada a base de dados de uma rede beija-flor-planta da Mata Atlântica do sudeste brasileiro, e foram avaliadas as importâncias relativas das histórias evolutivas das espécies, suas abundâncias e acoplamentos nas suas morfologias e fenologias como determinantes das suas frequências de interações. Os resultados sugerem que as histórias evolutivas de beija-flores e plantas são mais importantes do que as suas abundâncias relativas em estruturar a rede, mas são menos importantes do que barreiras morfológicas e fenológicas. Com o uso de cenários filogenéticos, é oferecida uma extensão de um arcabouço conceitual e metodológico já amplamente utilizado por representar uma forma robusta e flexível de testar a importância de múltiplos fatores e suas combinações como determinantes das interações entre espécies em comunidades.
Multiple factors determine species interactions in ecological networks, such as morphological barriers, spatio-temporal distributions, relative species abundance and their evolutionary history. Novel methods are making it possible to evaluate the relative importance of each of these determinants factors. However, the lack of methods that allow us to incorporate information from independent phylogenies among the predictors of interactions limits our capacity of evaluating the relative importance of evolutionary histories. This work aims to overcome this limitation by including the evolutionary histories of species among the potential determinants of interactions, allowing the comparative analysis of its importance in structuring ecological networks. Different possible phylogenetic scenarios were hypothesized to predict frequencies of species interactions by combining concepts from the fields of ecological networks and ecophylogenetics. The usage of these scenarios is illustrated in a hummingbird-plant interaction network database from the Atlantic Forest in southeastern Brazil, in order to evaluate the relative importance of evolutionary histories of species, species relative abundances, and morphological and phenological barriers as determinants of species interactions frequencies. The results suggests that evolutionary histories of hummingbirds and plants are more important than their relative abundances in structuring their interaction network, but less important than morphological and phenological barriers. Phylogenetic scenarios usage offers an extension to a conceptual and methodological framework widely used by representing a robust and flexible way to evaluate the relative importance of multiple factors and their combinations as determinants of species interactions in communities.

Styles APA, Harvard, Vancouver, ISO, etc.

12

Decker, Gabriela. « Contrastando determinantes ecológicos da riqueza de espécies novas e antigas de mamíferos ». reponame:Repositório Institucional da UFPR, 2015. http://hdl.handle.net/1884/38136.

Texte intégral

Résumé :

Orientadora : Marcio R. Pie
Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Ecologia e Conservação. Defesa: Curitiba, 20/03/2015
Inclui referências
Área de concentração
Resumo: Os gradientes de diversidade de espécies possivelmente estão entre os fenômenos mais comuns e menos conhecidos da ecologia. Os padrões espaciais de diversidade são resultado da interação de processos ecológicos e evolutivos. Em particular, a hipótese de conservação tropical de nicho é uma abordagem que explica com a conservação de nicho pode explicar os gradientes de riqueza de espécies face das mudanças climáticas ao longo do tempo evolutivo. A hipótese é baseada nas premissas de que climas mais quentes foram mais difundidos no passado e de que muitos grupos de espécies se originam em condições tropicais e tiveram dificuldade em entrar em novas condições de clima temperado, devido à conservação de suas características ecológicas. Comumente, esta hipótese é testada por testes que correlacionam características ambientais e filogenéticas, tais como a idade dos clados. Por exemplo, comunidades temperadas e regiões desérticas menos diversas tendem a conter mais espécies de clados derivados, enquanto as áreas tropicais quentes e úmidas suportam espécies de clados mais basais. Isto reflete a incapacidade de muitos clados que inicialmente evoluíram sob condições mais úmidas e quentes, em se adaptar às mudanças climáticas em escalas continentais, tendo assim, sobrevivido em áreas onde a alta precipitação e vegetação abundante persistiram. Neste estudo, nós testamos esses cenários utilizando dados da idade das espécies (inferida pelo respectivo tempo divergência do ancestral comum mais recente) para avaliar as diferenças entre correlatos ecológicos de riqueza de espécies novas e espécies antigas. O estudo incluiu cinco clados de mamíferos terrestres - Marsupiais, Primata, Chiroptera, Artiodactyla, e Carninora. Espécies que divergiram antes ou depois de 10 Mya de seu ancestral comum mais recente foram categorizadas como novas ou antigas, respectivamente. Este idade divide períodos com histórias climáticas notavelmente distintas. Neste estudo, nós verificamos que as diferenças nos correlatos ecológicas das espécies de novas e antigas de mamíferos são altamente dependentes da escala taxonômica, sugerindo que o grau de conservação de nicho é variável entre os clados. Desta forma, as idiossincrasias dos clados são relevantes, ressaltando que é preciso ter precaução em fazer previsões gerais a partir de conclusões alcançadas para grupos mais específicos. O nosso estudo desafia a visão tradicional de que a conservação de nicho é um fator fundamental na estruturação dos padrões de riqueza de espécies. Palavras-chave: riqueza de espécies, correlatos ecológicos, idade das espécies, conservação de nicho.
Abstract: Geographical patterns of diversity and the uneven distribution of species over space are possibly the most ubiquitous and the least understood phenomena in ecology. Recently, the tropical niche conservatism hypothesis has been invoked to explain latitudinal diversity patterns the tropical niche conservatism. This integrative approach outlines how niche conservatism explains contemporary species richness gradients in the face of climate change over evolutionary time. This hypothesis is based on the premises that warmer climates were more widespread in the past, many extant groups originated in tropical conditions and species experienced difficulty to break into new temperate-zone conditions due to conservatism in their ecological requirements. A common test of tropical niche conservatism hypothesis is to examine correlations between environmental and phylogenetic characteristics such as average taxon age. For instance, less diverse temperate communities and desert regions tend to contain more species from derived clades, while warm and wet tropical areas support species from more basal clades, reflecting the inability of many clades that initially evolved under wetter and warmer conditions to adapt to continental-scale climate change, having survived in areas where high precipitation and abundant vegetation persisted. In this study, we tested those scenarios using neontological data to assess differences in ecological predictors of species richness in old versus new species. We include five large terrestrial mammal clades in the analyses - Marsupialia, Primates, Chiroptera, Artiodactyla, and Carnivora - with each species being categorized as either old or new relative to its time for the most recent common ancestor (TMRCA) being above or below 10 Mya, an age that divides periods of markedly different climatic histories. In this study, we found that the differences in ecological correlates of old and new mammal species are highly dependent on the taxonomic scale suggesting that the degree of niche conservatism is variable among distinguished mammal clades. Therefore, idiosyncrasies of clades are important and care must be taken in making more general conclusions from results reached for a specific group. Our study challenges the traditional view that niche conservatism is the main driver underlying the ubiquitous climate-richness pattern. Keywords: species richness, ecological correlates, species ages, niche conservatism.

Styles APA, Harvard, Vancouver, ISO, etc.

13

Aleklett, Kristin Anna Eva. « Examining ecological determinants of community formation and stability in the root microbiota ». Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/56741.

Texte intégral

Résumé :

The root system of a plant is known to host a wide diversity of microbes that can be beneficial or detrimental to the plant. Microbial ecologists have long struggled to understand the factors influencing the composition of these communities. One overlooked aspect of microbial community assembly in root systems is the potential for individual variation among plants, and the potential effect of early colonisation events such as microbial exposure of the seed inside the parent plant and during dispersal. In this dissertation, I relate ecological theory of community assembly to the formation of the root microbiota. I explore the extent of variation between individuals in wild plant populations, and examine the effects of historical contingency in determining bacterial and fungal community assembly and stability in the root microbiota. The main findings in my work showed that: - Wild plants growing in close proximity, sharing environmental conditions will still host distinct bacterial communities in their root systems based on their species identity. We also documented individual variation in root microbiota within all species examined, even the clonal plant species Pilosella aurantiaca. - Bacterial community composition varies significantly across the body of a plant, with different parts of the plant body hosting distinct communities. - Plants are able to form new microbial associations throughout development, but the timing of microbial exposure affects the composition of the microbial community in mature plants. - Microbial community stability fluctuates within weeks during early plant development, with one week-old plants hosting communities most likely to change in composition.
Irving K. Barber School of Arts and Sciences (Okanagan)
Biology, Department of (Okanagan)
Graduate

Styles APA, Harvard, Vancouver, ISO, etc.

14

Cardoso, Danon Clemes. « Determinantes de comunidades de formigas em restinga ». Universidade Federal de Viçosa, 2009. http://locus.ufv.br/handle/123456789/3890.

Texte intégral

Résumé :

Made available in DSpace on 2015-03-26T13:30:25Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1105450 bytes, checksum: 163c50636e0eaab0ec624fc7342a1a43 (MD5) Previous issue date: 2009-07-23
Fundação de Amparo a Pesquisa do Estado de Minas Gerais
The Brazilian coast presents approximately 9,200 kilometers, which 5.000 km of them are occupied by the Restinga ecosystems. This ecosystem is a set of vegetation formations that develop in sandy plains dating from the Quaternary, within the Atlantic Forest domain. The plant species that occur in Restinga have high plasticity, presenting adaptations for their development under the influence of various biotic and abiotic factors such as drought stress, wind, topography and salinity. These factors influence the occurrence and distribution of plant communities in the Restinga, and similarly, should influence the distribution and diversity of animals. The aim of this dissertation was to test the assumption that the species richness of ants increases with distance from the ocean, as well as the following hypotheses: (1) ant species richness increases with plant species richness, which in turn increases with distance from the sea, (2) ant species richness is proportional to soil cover by plants and litter; (3) ant species richness increases with soil organic matter concentration, (4) ant species richness decreases with soil salinity, and (5) the species richness of ants responds positively to spatial heterogeneity of the environment. Moreover, we tested a second assumption that the distinct Restinga phytophysiognomies have different ant species composition. The ants were sampled in herbaceous and shrubby Restinga of the Morro dos Conventos in Araranguá (SC) using pitfall traps. Sixty-five pitfall traps were placed 10 meters away from each other in transects disposed from the ocean to the continent. At each sampling point, were collected the following explanatory variables: plant species richness, percentage of vegetation cover and litter, concentration of organic matter and salt in soil. In total, we collected 71 species of ants. Our results have confirmed both assumptions. Ant species richness was related to distance from the sea, plant species richness, soil cover by plant and litter. Moreover, we observed that different vegetation types within Restinga have specific communities of ants, where habitats near or with similar environmental conditions had higher similarity among them. These results indicate that the vegetation and environmental factors affected by them are the main factors determining the ant species richness and composition in Restinga.
O litoral brasileiro apresenta aproximadamente 9.200 quilômetros de extensão, das quais 5.000 km são ocupados por ecossistema de Restinga. Este ecossistema é um conjunto de formações vegetacionais que se desenvolvem em dunas e cordões arenosos do período Quaternário dentro do domínio da Floresta Atlântica. As espécies de plantas que ocorrem em Restinga possuem elevada plasticidade, apresentando adaptações para seu desenvolvimento sob influência de vários fatores abióticos como: estresse hídrico, ventos, topografia e salinidade. Tais fatores condicionam a ocorrência e a distribuição das comunidades vegetais em ambientes de Restinga, e similarmente, devem influenciar a distribuição e a diversidade da fauna animal. O presente estudo teve por objetivo testar o pressuposto de que a riqueza de espécies de formigas aumenta com o aumento da distância em que se encontram em relação ao oceano e as seguintes hipóteses explicativas: (1) a riqueza de espécies de formigas aumenta com a riqueza de espécies de plantas, que por sua vez aumenta com a distância do mar; (2) a riqueza de espécies de formigas é diretamente proporcional a cobertura do solo por plantas e serapilheira; (3) a riqueza de espécies de formigas aumenta com a concentração de matéria orgânica no solo; (4) a riqueza de espécies de formigas diminui com o aumento da concentração de sal no solo; e (5) a riqueza de espécies de formigas responde positivamente à heterogeneidade espacial do ambiente. Além disso, nós testamos um segundo pressuposto de que diferentes fitofisionomias de Restinga possuem composição de espécies de formigas específicas. As coletas de formigas foram realizadas na Restinga herbáceo-arbustiva do Morro dos Conventos, em Araranguá (SC) utilizando armadilhas de solo. Foram instaladas 65 armadilhas distantes 10 metros entre si, em dois transectos do oceano para o continente. Em cada ponto amostral, foram coletadas as seguintes variáveis explicativas: riqueza de espécies de plantas, percentagem de cobertura vegetal e de serapilheira, concentração de matéria orgânica e sal no solo. No total, foram coletadas 71 espécies de formigas. Os resultados obtidos permitiram confirmar nossos dois pressupostos. Observamos que a riqueza de espécies de formigas está positivamente relacionada com a distância em que se encontram do mar, com a riqueza de espécies de plantas, cobertura vegetal e cobertura por serapilheira do solo. Além disso, observamos que diferentes fitofisionomias dentro da Restinga apresentam comunidades de formigas específicas, e que em geral, habitats próximos ou com condições ambientais semelhantes apresentaram maior similaridade quanto à composição de espécies. Esses resultados sugerem que a vegetação e os fatores ambientais condicionados por ela, podem ser os principais fatores determinando a riqueza e composição de espécies de formigas em Restinga.

Styles APA, Harvard, Vancouver, ISO, etc.

15

SOUZA, Danielle Gomes de. « Plantas e insetos galhadores : efeitos ascendentes determinando padrões nas assembléias de insetos em diferentes escalas espaciais ». Universidade Federal de Pernambuco, 2013. https://repositorio.ufpe.br/handle/123456789/25025.

Texte intégral

Résumé :

Submitted by Fernanda Rodrigues de Lima (fernanda.rlima@ufpe.br) on 2018-07-05T22:23:44Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE Danielle Gomes de Souza.pdf: 1510462 bytes, checksum: abc18fdd1a46a051fc853117470fb9e6 (MD5)
Made available in DSpace on 2018-07-05T22:23:44Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE Danielle Gomes de Souza.pdf: 1510462 bytes, checksum: abc18fdd1a46a051fc853117470fb9e6 (MD5) Previous issue date: 2013-05-29
FACEPE
As assembléias de insetos herbívoros especializados são componentes fundamentais em florestas tropicais, influenciando diretamente a diversidade de plantas e processos ecossistêmicos. As modificações na paisagem, perda de habitat e os efeitos de borda são considerados primordiais na perda de espécies em níveis global, regional e local. Essa Tese investigou como as modificações antrópicas na paisagem afetaram os padrões das assembléias de plantas jovens, plantas hospedeiras e insetos galhadores em escala local, entre habitats e em uma paisagem hiperfragmentada de floresta Atlântica no Nordeste do Brasil. Detectei que habitats afetados pelos efeitos de borda borda (pequenos fragmentos e bordas florestais) são subgrupos florísticos de interior florestal com notável empobrecimento de plantas hospedeiras que ocasiona em tendência similar para seus insetos galhadores associados. Esses achados reforçam a ideia de que habitats afetados pelas bordas favorecem interações generalista-generalista. Entretanto, nas áreas de floresta madura há maior riqueza de espécies dos grupos bióticos citados anteriormente e por isso sugiro que este habitat é de alta qualidade e fundamental para a manutenção da diversidade deste grupo de herbívoros. Entretanto, a diversidade beta foi maior em pequenos fragmentos devido à susceptibilidade ao hiperdinamismo e eventos estocásticos que direcionam estes fragmentos à distintas trajetórias sucessionais e floras exclusivas. Adicionalmente, examinei os dois principais nichos de regeneração em florestas tropicais: plantas pioneiras e tolerantes a sombra e evidenciei que o principal recurso utilizado pelos insetos foram as plantas tolerantes a sombra. A conectividade estrutural da paisagem influenciou positivamente os grupos bióticos avaliados e finalmente, a análise de ordenação demonstrou composição taxonômica dissimilar entre os habitats avaliados. A tendência emergente do estudo evidencia que os fatores base-topo estruturam as assembléias destes animais e que o desaparecimento das plantas hospedeiras pode conduzir os insetos especializados a co-extinção e perda de história evolutiva.
Specialized herbivores assemblages are essential components in tropical forests, directly influencing plant diversity and ecosystem processes. Landscape modifications, loss of habitat and edge effects are considered primordial factors in species loss at the global, regional and local levels. Here I investigated how anthropogenic shifts in the landscape affected patterns of saplings woody plants, sapling host plants and galling insects on a local scale, and among habitats in a fragmented landscape in Atlantic Forest of Northeastern Brazil. I detected that edge-affected habitats (small fragments and forest edges) are floristic subgroups of interior habitats with distinctive impoverishment of host plants on which causes similar trend to their galling insects associated. These findings reinforce the notion in which edge affected habitats support mainly interactions generalist-generalist. However, in areas of old growth forest there are higher species richness of biotic groups previously mentioned and therefore suggests that core area has high quality and critical to maintaining the diversity of this group of herbivores. Nevertheless, beta diversity was higher in small fragments due to susceptibility to hyperdynamism and stochastic events that drives these fragments to different successional pathways and unique flora. Here was confirmed that the main resource consumed for galling insects was shade tolerant host plants. Landscape complexity positively influenced biotic groups evaluated and finally the ordination analysis showed dissimilar taxonomic composition among habitats assessed. Emerging trend from study shows that bottom up effects shapes assemblages of these animals and the disappearance of host plants may lead insects specialized co-extinction and loss of evolutionary history.

Styles APA, Harvard, Vancouver, ISO, etc.

16

Gonçalves, Teresa Telles. « Determinantes da ocupação de árvores por térmitas (Insecta : Isoptera) ». Universidade Federal de Viçosa, 2005. http://www.locus.ufv.br/handle/123456789/10069.

Texte intégral

Résumé :

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2017-04-17T13:59:43Z No. of bitstreams: 1 texto completo.pdf: 450104 bytes, checksum: acba69a88ae44d30270548fc397045a0 (MD5)
Made available in DSpace on 2017-04-17T13:59:43Z (GMT). No. of bitstreams: 1 texto completo.pdf: 450104 bytes, checksum: acba69a88ae44d30270548fc397045a0 (MD5) Previous issue date: 2005-07-29
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Os cupins, ou térmitas, são organismos muito importantes para a manutenção de um ecossistema, agindo diretamente na decomposição da matéria orgânica e ciclagem de nutrientes. A despeito do considerável número de espécies de cupins que ́ capaz de se estabelecer em árvores, os fatores ecológicos determinando a exploração de árvores por cupins ainda não são bem conhecidos. Este trabalho teve como objetivo principal investigar os determinantes da ocupação de árvores em floresta tropical por térmitas, contribuindo com informações originais sobre cupins e sua relação com as árvores. Os dados foram coletados na área do Parque Estadual do Rio Doce, MG, Brasil e as amostras de cupins e formigas foram identificadas aos níveis de espécies ou e gêneros. Especificamente foram testadas três hipóteses: (i) o aumento do tamanho e da complexidade de forma de crescimento de uma árvore, influenciam positivamente a presença e atividade dos cupins arborícolas; (ii) a presença de formigas afeta negativamente a atividade dos cupins arborícolas, seja por competição ou predação e (iii) cupins arborícolas são positivamente influenciados pelo aumento da quantidade de recursos potenciais existentes no chão, próximos a árvore hospedeira. Os resultados apontam que os três grupos de fatores estudados são importantes determinantes da exploração de árvores por cupins. Os padrões encontrados foram discutidos considerando-se a biologia de cupins, e de formigas quando envolvidas.
Termites are important organisms involved in the maintainence of the ecossystems, acting directly in organic matter decomposition and in the nu- trient cycling. Despite the well known diversity of termites capable of inha- biting arboreal enviroments, the ecological determinants of tree exploitation by termites remain largely unknown. The aim of this work was to investigate the determinants of tree exploitation in tropical forest by termites, contribu- ting with primary information in the relationship between termite and trees. Data was collected in State Park of Rio Doce, MG, Brazil and the samples were indentified to the lowest possible taxonomic level. Specifically we tes- ted three hipotheses: (i) the increment in tree size and growth form have a positive influence on arboreal termite presence and activity; (ii) the pre- sence of ants have a negative effect on the activity of arboreal termites and (iii) arboreal termites are positively influenced by the increment of potencial resources amount in the ground level, below of the host trees. The results point that the three studied groups of factors are important determinants of tree exploitation by termites. The found patterns were discussed considering the biology of termite, and ants when involved.

Styles APA, Harvard, Vancouver, ISO, etc.

17

Oliveira, Daniel de. « Efeitos das vari?veis ambientais locais sobre a abund?ncia, a riqueza e a biomassa da macrofauna de solo em um ecossistema semi?rido no Estado do Rio Grande do Norte, Nordeste do Brasil ». Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/14038.

Texte intégral

Résumé :

Made available in DSpace on 2014-12-17T14:33:08Z (GMT). No. of bitstreams: 1 DanielO_DISSERT.pdf: 1269498 bytes, checksum: 758aaeb33fe30cc21606c68e15b68f35 (MD5) Previous issue date: 2013-08-31
Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
The soil macrofauna is influenced to several biotic and abiotic environmental factors, from changes in the physical environment to a variety of interactions among the species involved, affecting the patterns of biodiversity of soil fauna. The power and specificity of the mechanisms that act on soil organisms vary greatly depending on environmental conditions at different scales of space and time. The Caatinga has great spatial heterogeneity of vegetation, climate and soil, so the soil macrofauna would follow this local spatial variation in the environment? This study aimed to investigate the effects of local environmental variables on biological parameters (taxa richness, total abundance and biomass) of soil macrofauna in a fragment of caatinga in Jo?o C?mara, Rio Grande Norte, Northeast Brazil. The study was conducted in the Caua?u farm, where a grid of 2000m x 500m was drawn, and later, 30 sampling points were randomly selected. The methodology used to collect the macrofauna was the TSBF method. We tested the effects of 10 environmental variables on macrofauna across the plots and across the layers of soil. The hypothesis that macrofauna soil responds to changes in the environment was not supported throughout the plots, but was confirmed to soil layers. The soil macrofauna shows a pattern of concentration in the surface layer and decreases considerably in the deeper layers. This pattern had significant and positive relationship with the aerial plant biomass and fine root stock. The aerial plant biomass releases plant necromass that accumulates in the surface layer, providing an important source of resource and shelter for soil macrofauna, explaining their greater abundance in this layer. The roots are used as a means for the arrival of nutrients to the soil from the primary production, thus a greater amount of root conditions higher food intake for macrofauna, especially the herbivores
A macrofauna de solo est? sujeita a diversos fatores ambientais bi?ticos e abi?ticos, desde varia??es no ambiente f?sico ? variedade de intera??es entre as esp?cies envolvidas, afetando os padr?es de biodiversidade da fauna de solo. A for?a e a especificidade dos mecanismos que atuam sobre os organismos de solo variam bastante de acordo com as condi??es ambientais em diferentes escalas de espa?o e de tempo. A Ccaatinga apresenta grande heterogeneidade espacial da vegeta??o, clima e solo, sendo assim, a macrofauna de solo acompanharia essa varia??o espacial local no ambiente? Este estudo teve como objetivo investigar os efeitos das vari?veis ambientais locais sobre os par?metros biol?gicos (riqueza de t?xons, abund?ncia de indiv?duos e biomassa) da macrofauna de solo em um fragmento de Caatinga no munic?pio de Jo?o C?mara, Rio Grande no Norte, Nordeste do Brasil. O estudo foi conduzido na fazenda Caua?u, onde foi tra?ada uma grade de 2000m x 500m, e posteriormente, foram sorteados 30 pontos de coleta. A metodologia usada para a coleta da macrofauna foi o m?todo TSBF. Foram testados os efeitos de 10 vari?veis ambientais sobre a macrofauna ao longo das parcelas e ao longo das camadas de solo. A hip?tese de que a macrofauna de solo responde as varia??es no ambiente n?o foi corroborada ao longo das parcelas, mas foi confirmada para as camadas de solo. A macrofauna de solo apresenta um padr?o de concentra??o na camada superficial e diminui consideravelmente nas camadas mais profundas. Padr?o esse que teve rela??o significativa e positiva com a biomassa vegetal a?rea e o estoque de ra?zes finas. A biomassa vegetal a?rea libera necromassa vegetal que se acumula na camada de superf?cie, constituindo uma importante fonte de recurso e de abrigo para a macrofauna de solo, explicando sua maior abund?ncia nessa camada. As ra?zes servem como via para a chegada ao solo de nutrientes provenientes da produ??o vegetal, dessa forma, uma maior quantidade de ra?zes condiciona maior entrada de alimento para a macrofauna, principalmente os herb?voros

Styles APA, Harvard, Vancouver, ISO, etc.

18

M'Cormack, Fredanna A. D. « Ecological Determinants of Anemia in Pregnant Women Living in Freetown : Urban Western Area, Sierra Leone ». OpenSIUC, 2008. https://opensiuc.lib.siu.edu/dissertations/262.

Texte intégral

Résumé :

Introduction Anemia prevalence in pregnancy ranges from 51%-60% globally. Genetic disorders, infectious diseases, reproductive factors, nutritional deficiencies, and poverty can affect anemia status. Anemia can negatively impact economic progress, social and intellectual development, and maternal health. Estimates indicate that anemia is the direct cause of 3-7% of maternal deaths and an indirect cause of 20-40% of maternal deaths. Although several initiatives by the international community address the anemia problem, prevalence remains unacceptably high in Sierra Leone at 2,000 per 100,000 live births. This study explored ecological determinants of anemia status of pregnant women living in Freetown, Sierra Leone. Method This was a mixed-method, retrospective, unmatched case-control research study based on the Modified Ecological Model for Health Behavior and Health Promotion. One hundred and seventy one pregnant women, who visited one of five health facilities were interviewed for the study. Anemic participants' (Hgb<11.0g/dL) responses were compared to responses of non-anemic participants and the differences were assessed. Content analysis and descriptive statistics were used to assess qualitative knowledge items, whereas t-tests were conducted to determine if mean knowledge differences existed between those with anemia and those without. Chi-square was used to analyze forced choice attitude items: perceived threat to anemia and perceived benefits of anemia prevention and treatment. Chi-square was also used to analyze selected behaviors and perceived barriers to anemia prevention and treatment. Odds ratio determined the strength of the relationship between the dependent variable (anemia status) and selected exposure variables (modifying factors). Results Seventy-seven percent of participants were anemic (M: Hgb=9.63g/dL). Those with anemia were more likely to first see a health care provider after 12 weeks of pregnancy (p<.05). Participants who earned income in the top two quintiles were less likely to have anemia than those in the lower three quintiles (p=.007). Participants who had anemia were more likely to cite lack of finances as a barrier to seeking prenatal services (p=.007). Although differences existed between participants who had anemia and those who did not have anemia, they were generally not statistically significant for knowledge, behavior or modifying factors. Participants who had pica, however, were more likely to have anemia than those who did not (p=.005). There was misinformation among participants about the use of palm oil, Vimto and "blood tonic" as treatment options. In addition, participants cited family and friends as sources of this same information as well as correct suggestions and information about anemia prevention and treatment. Discussion Health providers need to be clearer about messages that they deliver to service users to reduce misinformation about anemia prevention and treatment. Community awareness about anemia, anemia causes, anemia prevention and anemia treatment needs to be raised. Information, particularly about anemia causes, need to be disseminated and programs to address those causes need to be developed and implemented. Program development and implementation should be a comprehensive effort that includes training traditional birth attendants and lay health workers. Efforts should incorporate health efforts from government agencies, the non-governmental sector, donor groups, and community and civil society groups to deliver culturally and regionally appropriate interventions.

Styles APA, Harvard, Vancouver, ISO, etc.

19

Prudden, H. J. « Determinants of population variability in HIV across West Africa : ecological and mathematical modelling analyses ». Thesis, London School of Hygiene and Tropical Medicine (University of London), 2016. http://researchonline.lshtm.ac.uk/2634790/.

Texte intégral

Résumé :

Introduction: Mathematical models of HIV transmission have played an important role in helping to understand the drivers of the HIV epidemic, and shape the global HIV response. The underlying approaches, assumptions and structures used in HIV modelling have the potential to fundamentally influence the conclusions of any modelling analyses. For this reason, it is important that approaches to modelling HIV transmission in different contexts carefully consider how best to ‘characterise’ a populations distribution of risk and networks of sexual interaction based on data, and the implications of incorporating different levels of epidemiological complexity into their modelling. Across West Africa there are substantial variations in population HIV prevalence - ranging from 0.5-6%. To date, there has been limited exploration of the potential factors influencing this population variation. This PhD aims to inform our understanding of the determinants of population variations in HIV prevalence across West Africa, using a combination of ecological analysis of population data, and both simple and more complex epidemiological modelling. The findings are used both to explore the determinants of HIV transmission across West Africa, and to discuss the implications for future modelling and epidemic appraisal approaches. Methods: A range of modelling and epidemiological analytical approaches were used. Firstly, an existing policy model, The Modes of Transmission (MoT) model, designed to predict patterns of HIV incidence, was revised and re-parameterised using data from Nigeria, to explore the effect on overall conclusions of adding additional heterogeneity into the model, and considering more explicitly how to model HIV risk amongst lower-risk subgroups. Secondly, population data from 13 West African countries were compiled. Linear regression analyses were used to assess potential relationships between HIV prevalence in high-risk groups and population HIV prevalence and the size of high-risk population subgroups and HIV prevalence in the general population. Based on the findings from the MoT and ecological analysis, a dynamic deterministic model was developed to explore the variations in HIV prevalence across West Africa. The population model not only included sex work, client and general population sub-groups, but also included a category of adolescent females (15-24) and a category of males with multiple sexual partners, with a mixing formulation being used to vary the degree the adolescent females form partnerships with clients of female sex workers and the subgroup of males who have multiple partnerships Input parameters were sampled from ranges relevant for West Africa, using Latin Hypercube sampling. The model was fitted to equilibrium prevalence in the general population. Results: A critique and revisions to the MoT, identified high levels of infections in previously unrecognised subgroups. These included 16% of new infections occurring in young females engaging in transactional sex. Findings from the ecological analysis, showed that across West Africa HIV prevalence in FSWs and their clients is not associated with higher HIV prevalence in the general population. Instead, the size of groups of males and females with multiple partners is correlated with higher HIV prevalence levels. The deterministic model generated 11000 fits. Grouping fits, based on epidemic size (with 1% incremental increases from 0-6%), the findings revealed that population sizes of key subgroups is the predominant driver of the epidemic. For epidemics where prevalence is less than 3%, FSW population size is the most important determinant of HIV prevalence. For epidemics above 3%, it is the size of the group of adolescent females with multiple partners and their level of interaction with clients of FSWs that is the most significant variable related to higher HIV prevalence. When the limiting effects on HIV transmission of male circumcision are removed from the model, the findings are less clear, with both sex work and the role of adolescent females with multiple partners being important determinants of the epidemic. Circumcision is however shown to significantly limit the magnitude of an epidemic and epidemic categorisation should account for these variations accordingly. Conclusions: Behavioural heterogeneity has long been recognised as an important component of model development. The results from this thesis show the importance of carefully considering how to compartmentalise population HIV models. Even for simple static models, the inclusion of additional subgroups change model conclusions and suggests different intervention priorities. The use of results and findings from ecological analyses, whilst unable to provide strong evidence of causality, can provide useful insights into the relationship between population level factors or behavioural variables and HIV prevalence in the general population. These findings may then be used to inform model development. Deterministic dynamic modelling used in this thesis demonstrates that the size and sexual networks of vulnerable subgroups in the population may be of key importance in determining levels of HIV epidemics in West Africa. In-particular, adolescent females engaging in noncommercial multiple partnerships, often associated with transactional exchange are an important determinant of the HIV epidemic in West Africa. An improved understanding of this group, their size and motivations for engaging in multiple partnerships, through the use of epidemic mapping techniques and social research, will be important to future HIV intervention activities.

Styles APA, Harvard, Vancouver, ISO, etc.

20

Bradshaw, Elizabeth Louise. « Social and ecological determinants of food availability in the brown hare, Lepus europaeus pallas ». Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386876.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

21

Ossi, Federico. « Ecological determinants of roe deer (Capreolus capreolus) spatial behavior and movement in limiting conditions ». Doctoral thesis, country:FR, 2015. http://hdl.handle.net/10449/26494.

Texte intégral

Résumé :

For the majority of large ungulates living in temperate regions winter is the limiting season, because of the combined effects of lack of resource availability and severity of climatic conditions. Those species that did not develop any particular morphological and physiological adaptation to cope with winter severity may adopt movement and space use tactics instead (like e.g. migration). Specifically, these space use patterns may emerge at different spatiotemporal scales to allow individuals to accede the resources they need and escape unfavourable conditions, thus determining both individual fate and population dynamics. A detailed understanding of the relationship between limiting factors in wintertime, and individual movement response, is remarkable to preserve and manage wildlife successfully, especially in the context of fast-occurring climate change that induces important alterations in landscape and resource distribution (e.g. changes of snow cover patterns). The comparison of movement tactics under different environmental scenarios, e.g. by means of large -scale analysis at the species distribution range, represents a valuable approach to work in that direction and to assess the effects of landscape alteration on individual movement. Roe deer (Capreolus capreolus) is an excellent model species to investigate these issues, because its distribution range covers most of Europe, thanks to its high ecological plasticity. For those populations that live in northern and mountain environments, winter is the limiting season because roe deer lack any morphological and physiological adaptations to cope with winter severity. In spite of the adoption of specific movement tactics such as partial migration from summer to winter ranges, roe deer may still face limiting conditions in some areas of the distribution range exposed to winter severity. Wildlife managers therefore have developed supplemental feeding programs to sustain roe deer (and other ungulate) populations. Regardless of the pervasiveness of this practice and the potential negative ecological consequences (such as for example the enhanced probability of disease transmission), if and how the interplay between distribution of supplemental feeding sites and winter severity may shape roe deer spatial ecology remains mostly unknown. During my PhD, I provided a contribution to investigate in this direction. First, I relied on the data stored and managed in the EURODEER database (www.eurodeer.org) to evaluate across a wide latitudinal and altitudinal gradient how individuals responded to the presence of these patchily distributed resources under different environmental conditions and supplemental feeding management. The comprehensiveness of large scale datasets such as EURODEER is counterbalanced by some limitations in terms of data resolution of some potentially meaningful environmental variables, such as snow cover. To overcome these limitations, I empirically collected accurate data on snow cover and snow sinking-depth to assess the combined effect of snow and of the distribution of feeding stations on winter resource selection in an Alpine population of roe deer. The investigation of the effect of feeding stations on individual space use tactics should go hand in hand with a proper assessment of the inter-individual relationships occurring at feeding stations, which in turn correspond to contacts btween animals. Measurements of contact rates is a relatively new ecological interest, and could be performed either by visual recording of observers, or by means of proximity loggers or, as alternative, using tr acking data that permit to infer spatial relationships from individual trajectories. The latter two approaches are more practical in terms of application, but both need to be carefully calibrated to avoid biased ecological inference derived from the obtained contact measurements. In this context, I performed a detailed analysis and modelling of the factors influencing the connectivity of recently introduced proximity loggers (WSN, Wireless Sensor Network). In parallel, I explored the potential applicability of SECONDO spatiotemporal database for the investigation of spatial relationships among individuals through the more widespread GPS tracking data. The large-scale comparative analyses I conducted along a wide latitudinal and altitudinal gradient showed that the use of feeding sites by roe deer is highly seasonal, and specifically associated to low temperatures and activation of the feeding stations, but not to snow cover. Moreover, I found some indications that winter use of feeding stations was negatively affected by the presence of competitors. Finally, I found a strong signal of the reduction of individual home range size in relation to feeding site use. Local assessment of roe deer winter resource selection partially supported these results: the main drivers of roe deer resource selection included the proximity to feeding stations (although to a lesser extent than expected) and, a more strong inverse relationship with snow sinkng depth. The main driver of roe deer habitat use was presence of forest canopy. The absence of any statistically significant effect of the index used for measuring snow at a large scale (MODIS) supported the importance of local measurements of snow to complement remotely-sensed data. The finding that the use of feeding stations leads individuals to concentrate their movements around these sites supports the hypothesis of high contact rate between individuals at feeding sites. i.e. as they would work as attractive points. The assessment of encounters is preliminary to the evaluation of such hypothesis. I have demonstrated Wireless Sensor Network proximity loggers as tools with high potentiality for assessment of encounters. At the same time, my work has strongly indicated the need to carefully calibrate these tools before applying them for any biological investigation, and provided practical guidelines on how to proceed, including how to model the error probability. Alternatively, I laid the first technical premises to assess encounters from the more widespread GPS tracking data, by means of high-performance queries within an appropriate spatiotemporal database. I conclude that roe deer use feeding stations, but only when winter conditions are particularly harsh (i.e. low temperature, abundant snow cover). In a context of climate change with an alteration of snow pattern distribution due to a general increase of temperatures, it would be essential to understand whether supplemental feeding management will still be a reasonable and effective tool to manage roe deer. More generally, it would be necessary to assess whether roe deer indeed need feeding stations for overwinter survival. This work clearly provides evidence that the distribution of feeding stations modifies roe deer spatial behaviour. A full understanding of the patterns of animal aggregation, derived from the correct measurement of contact rates, is thus fundamental to understand the consequences of supplemental feeding practices on animal welfare, and ecosystem consequences (e.g., disease transmission). Research in these directions would ultimately permit to understand the tradeoff between benefits and costs, both for wildlife, and as a human action, of supplemental feeding practices, thus helping wildlife managers to take the right decisions.

Styles APA, Harvard, Vancouver, ISO, etc.

22

Ossi, Federico. « Ecological determinants of roe deer (Capreolus capreolus) spatial behavior and movement in limiting conditions ». Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10005.

Texte intégral

Résumé :

Pour la grande majorité des grands herbivores vivant en régions tempérées, l'hiver est la saison la plus limitante à cause des effets combinés du manque de ressources et de la sévérité des conditions climatiques. Les espèces qui ne développent pas d'adaptations morphologiques ou physiologiques particulières pour faire face à la sévérité de l'hiver doivent mettre en place des mouvements et des tactiques d'utilisation de l'espace appropriés (comme par exemple les migrations). Plus spécifiquement, ces patrons d'utilisation de l'espace peuvent émerger à différentes échelles spatio-temporelles pour permettre aux individus d'accéder aux ressources dont ils ont besoin et d'échapper aux conditions climatiques défavorables. Ainsi, ces patrons d'utilisation de l'espace déterminent le sort des individus et la dynamique des populations. Une compréhension détaillée de la relation entre les facteurs limitants durant l'hiver et la réponse des animaux en termes de mouvements est prépondérante pour préserver et gérer les populations d'ongulés sauvages avec succès, tout spécialement dans le contexte actuel de changements climatiques rapides qui induisent des modifications importantes dans le paysage et la distribution des ressources (par exemple changement de patrons de couverture neigeuse en hiver). La comparaison de tactiques de mouvements sous différents scénarios de conditions environnementales, par exemple au moyen d'analyses à vaste échelle de l'aire de distribution de l'espèce cible, représente une approche pertinente pour mieux comprendre comment les mouvements des animaux répondent aux changements dans le paysage. Le chevreuil (Capreoluscapreolus) est une espèce modèle particulièrement intéressante pour étudier ces questions parce que la distribution de cette espèce couvre la plupart des pays d'Europe, grâce à sa forte plasticité écologique
For the majority of large ungulates living in temperate regions winter is the limiting season, because of the combined effects of lack of resource availability and severity of climatic conditions. Those species that did not develop any particular morphological and physiological adaptation to cope with winter severity may adopt movement and space use tactics instead (like e.g. migration). Specifically, these space use patterns may emerge at different spatiotemporal scales to allow individuals to accede the resources they need and escape unfavourable conditions, thus determining both individual fate and population dynamics. A detailed understanding of the relationship between limiting factors in wintertime, and individual movement response, is remarkable to preserve and manage wildlife successfully, especially in the context of fast-occurring climate change that induces important alterations in landscape and resource distribution (e.g. changes of snow cover patterns). The comparison of movement tactics under different environmental scenarios, e.g. by means of large –scale analysis at the species distribution range, represents a valuable approach to work in that direction and to assess the effects of landscape alteration on individual movement. Roe deer (Capreolus capreolus) is an excellent model species to investigate these issues, because its distribution range covers most of Europe, thanks to its high ecological plasticity. For those populations that live in northern and mountain environments, winter is the limiting season because roe deer lack any morphological and physiological adaptations to cope with winter severity. In spite of the adoption of specific movement tactics such as partial migration from summer to winter ranges, roe deer may still face limiting conditions in some areas of the distribution range exposed to winter severity

Styles APA, Harvard, Vancouver, ISO, etc.

23

Pitt, Erin L. « The influence of the food environment and socio-ecological determinants on early childhood dietary intake : A mixed methods exploration ». Thesis, Griffith University, 2020. http://hdl.handle.net/10072/393190.

Texte intégral

Résumé :

Introduction: The incidence and prevalence of childhood obesity continues to be a public health concern of global significance with physical inactivity and excess energy intake being key contributors to this problem. Food preferences are vital determinants of food intake in very young children and given that preferences and eating habits are established early in life and are maintained through the adult years, it is critical to establish the foundations of healthy eating as early as possible. Recent decades have seen increasing interest in food environments and health. Indeed, whilst research in this area has been expanding rapidly, it is often difficult to establish consistent relationships regarding the food environment and health outcomes such as obesity. Exploring food environments through mixed methods enquiry and in the Australian context may enhance our current understanding of food environments and diet, particularly food acquisition, provision and consumption decisions and socio-ecological determinants associated with food decisions and practices. Aim and methodology: The overarching purpose of this thesis is to investigate the influence of the food environment and socio-ecological determinants on dietary intake in early childhood and by exploring aspects and determinants of food acquisition, provision and consumption within local food environments. This was achieved by undertaking three separate yet inter-related studies using an explanatory sequential mixed methods research design. The studies within this thesis include 1) a systematic review synthesising qualitative evidence regarding the influence of local food environments on food behaviours; 2) latent variable modelling of cross-sectional and longitudinal cohort data identifying patterns of dietary intake in early childhood and investigating associations with demographic and socio-economic indicators, as well as identifying changes in early childhood dietary patterns over time; and 3) a qualitative interview study exploring how early childhood dietary intake and quality are influenced by caregiver interactions and decisions within local food environments. Results: Regarding food acquisition practices, synthesis of existing qualitative literature identified that availability, accessibility and affordability continue to be key determinants of store choice, often resulting in less healthy food purchasing behaviours. Further to this, availability, quality and characteristics of food stores greatly influence in-store purchases. An array of coping strategies were utilised within different food environments to make optimal purchasing decisions, often within financial constraints. An investigation of food consumption in early childhood identified three patterns of dietary intake at three years of age including 1) Highly Unhealthy, 2) Healthier and 3) Moderately Unhealthy, whilst two patterns were identified at five years of age (Unhealthy and Healthier). Approximately one eighth of children transitioned from the healthier to unhealthy dietary pattern between three and five years. Australian children’s diets continue to fall well short of healthy eating recommendations and diet quality appears to be declining through the childhood years. Unhealthy eating patterns in childhood are associated with factors such as young mothers, working mothers, living in a two-carer household and fathers with a higher Body Mass Index (BMI). The above-mentioned determinants of food access and purchasing behaviours within community and consumer nutrition environments within the systematic review were similarly identified through the qualitative study with caregivers of young children. The latter specifically identified structural and environmental determinants of food environments that influence food behaviours as well as the behaviours and strategies caregivers and children use to acquire, provide and/or consume food within different food environments. Central to this research is that women play a dynamic gatekeeping role regarding food access and provisioning decisions that are made within families. There are also individual agency factors of women/caregivers such as food literacy, use of time and food habits/routines that both influence and contribute to gatekeeper decisions regarding food acquisition and provisioning. However, in making food decisions for the family, women as gatekeepers must also contend with children’s food demands and behaviours as well as father/paternal agency that either supports or hinders women’s ability to uphold their gatekeeper role, within the context of different environments. Implications and conclusions: It is evident that environmental factors continue to be identified as important determinants of food behaviours. Moreover, food environments as well as the provisioning decisions made within these environments are complex, multifaceted and highly contextual. Of particular significance is identifying the dynamic interplay between structural determinants (environments) and human agency in enabling or constraining individuals to enact optimal food provisioning behaviours. This research addresses a significant gap in the literature by exploring the complexities regarding the food environment and dietary intake relationship using mixed methods enquiry and provides a greater understanding regarding the dynamic interplay between food acquisition, provision and consumption and the array of influencing factors both within families and environments. The specific contribution of qualitative data has enabled exploration and expansion of our current understanding of food environments, particularly by adding depth and scope to the existing qualitative literature to guide ongoing theory, interventions and policy development. Given the suboptimal and declining quality of dietary intake in Australian children, it remains imperative to focus health promotion efforts towards the very early years of life in order to reduce disparities and inequalities that contribute to less healthy patterns of eating. It may also be pertinent to explore interactions between individual, environmental and context-specific factors within food environments in order to understand how food environments can support and promote healthy food choices.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Medicine
Griffith Health
Full Text

Styles APA, Harvard, Vancouver, ISO, etc.

24

Moura, Gustavo Correia de. « Fatores determinantes da biomassa, diversidade funcional e ácidos graxos da comunidade zooplanctônica em dois estuários tropicais ». Universidade Estadual da Paraíba, 2015. http://tede.bc.uepb.edu.br/tede/jspui/handle/tede/2255.

Texte intégral

Résumé :

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-02-29T12:41:37Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) PDF - Gustavo Correia de Moura.pdf: 4048269 bytes, checksum: 93440f590dbf6da5c94a68be759a0082 (MD5)
Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-03-10T15:14:56Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) PDF - Gustavo Correia de Moura.pdf: 4048269 bytes, checksum: 93440f590dbf6da5c94a68be759a0082 (MD5)
Made available in DSpace on 2016-03-10T15:14:56Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) PDF - Gustavo Correia de Moura.pdf: 4048269 bytes, checksum: 93440f590dbf6da5c94a68be759a0082 (MD5) Previous issue date: 2015-08-31
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
This study aimed to analyze the drivers factors of biomass, functional diversity and fatty acids of the zooplankton community in two tropical estuaries with different trophic states (Mamanguape and Paraíba do Norte), located in Northeastern Brazil. The study was divided into two manuscripts which were sampled in dry and rainy season, as follows: Nov/2013 to Jul/2014, for the first manuscript and Dec/2014 and Jul/2014 to the second manuscript, respectively. Four sample zones were selected along each estuary and in each one were selected three sites where at each site three biotic samples (zooplankton community) and abiotic (environmental variables) were sampled. The fatty acid profiles were obtained from gas chromatography techniques from selected copepod species. In the first study, we tested whether the estuarine connectivity, the phylogenetic relationships and the local environmental conditions are the main drivers of the pattern of distribution of biomass and functional diversity of the zooplankton community. It was observed that these three components are sufficient to explain the variation in Mamanguape estuary that is located in a conservation area, and different than is commonly expected, the connectivity can provide greater explicability for the community distribution, when compared to the environmental conditions. However, the three components used were not sufficient to explain the variation in Paraíba do Norte estuary which is influenced by anthropogenic impacts. The study shows the importance of spatial variable to assess the drivers factors of biomass and functional diversity of the zooplankton community, as this part of the analysis the effects of dispersal ability of species and the physical forces acting on the system. Moreover, a thorough investigation is needed to clarify the factors that determine and shape the zooplankton communities in high impacted tropical systems. In the second study, we tested whether the profiles of fatty acids can reveal spatial and temporal changes in diet of copepods, and therefore can be used as indicators of the trophic status of estuaries. It was observed that the fatty acid composition of zooplanktonic organisms revealed seasonal and temporal variations in trophic ecology of copepods in both tropical estuaries. In addition, the profiles of fatty acids were able to reveal differences in the quality of potential food sources in the two estuaries with different levels of anthropogenic impact, with a lower quality of food sources in the most impacted system (Paraíba do Norte estuary). In this study the profiles of fatty acids were sensitive to natural and anthropogenic stresses, being a fast tool to assess the trophic status of tropical estuaries.
O presente estudo teve por objetivo analisar os fatores direcionadores da biomassa, diversidade funcional e ácidos graxos da comunidade zooplanctônica em dois estuários tropicais com diferentes estados tróficos (Mamanguape e Paraíba do Norte), localizados no Nordeste do Brasil. O estudo foi dividido em dois manuscritos os quais tiveram amostragens realizadas no período de seca e cheia, sendo: nov/2013 e jul/2014, para o primeiro manuscrito e dez/2014 e jul/2014 para o segundo manuscrito, respectivamente. Foram selecionados quatro zonas amostrais ao longo de cada estuário e em cada uma foram selecionados três pontos onde em cada ponto três amostras bióticas (comunidade zooplanctônica) e abióticas (variáveis ambientais) foram coletadas. Os perfis de ácidos graxos foram obtidos à partir de técnicas de cromatografia gasosa das espécies de copépodes selecionados. No primeiro estudo, foi testado se a conectividade estuarina, as relações filogenéticas e as condições ambientais locais são os principais direcionadores do padrão de distribuição da biomassa e diversidade funcional da comunidade zooplanctônica. Observou-se que esses três componentes são suficientes para explicar a variação no estuário Mamanguape que se localiza em uma área de conservação, e que diferente do que é comumente esperado, a conectividade pode apresentar uma explicabilidade maior na distribuição da comunidade, quando comparada às condições ambientais. No entanto, os três componentes utilizados não foram suficientes para explicar a variação no estuário Paraíba do Norte o qual sofre a influência de impactos antrópicos. O estudo mostra a importância da variável espacial para avaliar os fatores direcionadores da biomassa e diversidade funcional da comunidade zooplanctônica, visto que esta integra à análise os efeitos da capacidade de dispersão das espécies e das forças físicas que atuam no sistema. Além disso, uma investigação aprofundada é necessária para esclarecer os fatores que determinam e moldam as comunidades zooplanctônicas em sistemas tropicais muito impactados. No segundo estudo, foi testado se os perfis de ácidos graxos podem revelar mudanças espaciais e temporais na dieta de copépodos, e por conseguinte, possam ser usados como indicadores do estado trófico dos sistemas estuarinos. Foi possível observar que a composição de ácidos gráxos dos organismo zooplanctônicos revelaram variações sazonais e temporal na ecologia trófica dos copépodos nos dois estuários tropicais. Além disso, os perfis de ácidos gráxos foram capazes de revelar diferenças na qualidade das potenciais fontes de alimento nos dois estuários com diferentes níveis de impacto antrópico, com uma menor qualidade de fontes alimentares presente no sistema mais impactado (estuário do Paraíba do Norte). Nesse estudo os perfis de ácidos gráxos foram sensíveis à estresses naturais e antrópicos, mostrando ser uma ferramenta rápida para avaliar o estado trófico de estuários tropicais.

Styles APA, Harvard, Vancouver, ISO, etc.

25

Ribeiro, Vanessa Soares. « Determinantes das comunidades de formigas em ambientes costeiros ». Universidade Federal de Viçosa, 2016. http://www.locus.ufv.br/handle/123456789/11827.

Texte intégral

Résumé :

Submitted by Nathália Faria da Silva (nathaliafsilva.ufv@gmail.com) on 2017-10-02T15:04:21Z No. of bitstreams: 1 texto completo.pdf: 659383 bytes, checksum: 512c1537761340d55806223d2ee344c2 (MD5)
Made available in DSpace on 2017-10-02T15:04:21Z (GMT). No. of bitstreams: 1 texto completo.pdf: 659383 bytes, checksum: 512c1537761340d55806223d2ee344c2 (MD5) Previous issue date: 2016-02-26
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Fatores abióticos podem limitar a composição e riqueza de espécies. Em Restingas tais fatores possuem peculiaridades que influenciam diretamente a ocorrência e distribuição das espécies de plantas. Essa influência é responsável pela formação das zonas de vegetação denominadas fitofisionomias. Cada fitofisionomia possui peculiaridades capazes de determinar a riqueza e composição de espécies da fauna. A diferença que existente entre as fitofisionomias em Restinga tem sido relatada por diversos autores. Entretanto, poucos estudos tratam como os fatores abióticos e a flora pode interferir na fauna, sendo que destes todos tratam apenas de uma avaliação em escala local. Assim, o presente estudo teve como objetivo mostrar que tais diferenças são capazes de promover diferença na riqueza e composição da fauna de Restinga. Para isso foram analisadas o efeito das condições ambientais impostas pelas fitofisionomias em espécies de formigas em um escala regional. Os resultados mostram que as diferenças nas condições das fitofisionomias possuem efeito direto na comunidade de formigas de Restinga. A composição de especies de formigas foi diferente quando considerado as fitofisionomias de duna frontal e depressão pós-duna. A riqueza de espécies de formigas também foi maior em depressão pós-duna do que em duna frontal. Tais resultados mostram que os padrões de riqueza e composição de espécies de formigas são afetados de forma direta pelas condições do ambientais condicionados pelas diferentes fitofisionomias.
Abiotic factors may limit the composition and species richness. In Restingas such factors have peculiarities that directly influence the vegetation. This influence is responsible for the formation of vegetation zones called physiognomies. Each physiognomies has peculiarities able to determine the richness and composition of fauna species. The difference existing between physiognomies in Restinga has been reported by several authors. However, few studies address how the abiotic factors and flora can interfere in the fauna, and all of these studies deal only with an evaluation at the local scale. Thus, this study aimed to show that such differences are able to promote difference in the richness and composition of the Restinga fauna. For that analyzed the effect of environmental conditions imposed by two phytophysiognomies form ants species on a regional scale. The results show that differences in conditions of phytophysiognomies have a direct effect on the community of Restinga ants. The composition of ant species was different when considering the phytophysiognomy of frontal dune and post-dune depression. The species richness of ants was also higher in post-dune depression than in frontal dune. These results show that patterns of ant species richness and composition are directly affected by environmental conditions of phytophysiognomies.

Styles APA, Harvard, Vancouver, ISO, etc.

26

Lyimo, Issa. « Ecological and evolutionary determinants of anopheline host species choice and its implications for malaria transmission ». Thesis, University of Glasgow, 2010. http://theses.gla.ac.uk/2585/.

Texte intégral

Résumé :

Despite the importance of host species choice of mosquito vectors to the epidemiology and control of malaria, our understanding of the ecological and evolutionary factors that drive the host species preference in these vectors is very limited. My PhD thesis aimed to experimentally investigate the potential ecological and evolutionary determinants of the host species choice of the African malaria vectors Anopheles arabiensis and An. gambiae s.s, which are amongst the most highly specialized and efficient malaria vectors in the world, and identify a control strategy that reduces their anthrophily. I used a unique semi-field system where these vectors were able to interact naturally with hosts of different species to establish whether their fitness depends on type of host species, they encounter and feed upon. My initial prediction was that highly host-specific feeding behaviour of these vectors is a product of natural selection whereby mosquito fitness is highest on their naturally preferred host types. This prediction was met in An. arabiensis, whose feeding success and lifetime egg production was predicted to be higher on their naturally preferred bovid hosts. However, I did not detect any association between the preference of An. gambiae s.s for humans and their lifetime reproductive success, although they obtain larger blood meals and survived longer on these naturally preferred human hosts. These findings suggest the role of host species on mosquito fitness varies between vector species. I then evaluated whether the host species-specific fitness of malaria vectors may be attributed to intrinsic defensive behaviours and haematological properties that make some host species being more beneficial than others. My initial prediction was that mosquito feeding success and fitness would be the highest in the absence of host defensive behaviours and, more specifically, that the least defensive host species would be the most highly preferred in nature. I have found that the feeding success (probability of obtaining a blood meal) of An. arabiensis is greater on host species with least effective defenses (e.g. bovids). However, this association was not apparent for anthrophilic An. gambiae s.s. Surprisingly, I found that the subsequent fitness (blood meal size and survival) of both vector species was generally greater on hosts who were free to exhibit defensive behaviours than those whose behaviours were restricted. These findings suggest that natural physical defensive behaviours made by hosts including humans may not impose strong fitness costs to malaria vectors. Therefore, I conclude that if natural host defensive behaviours shape the host species preference of malaria vectors they do so by influencing the probability of acquiring a blood meal but not the value of the blood meal if obtained. I also assessed whether the nutritive value of host blood, as determined by haematological properties of packed cell volume (PCV) and haemoglobin concentration (Hb), could explain variation in fitness of malaria vectors on different host species. I found that the PCV and Hb of host species that are commonly encountered by malaria vectors in their natural environments vary significantly. I further found that the variation in these haematological properties influence the feeding success (e.g. blood intake rate) of the anthrophilic An. gambiae s.s but not the An. arabiensis. Anopheles gambiae s.s obtain full blood meal faster on hosts with low and medium levels of PCV. Surprisingly, these haematological traits were predicted to have opposite effects on the survival of both vector species. The survival of An. gambiae s.s was positively correlated with host PCV, but negatively correlated with their Hb. In contrast, the survival of An. arabiensis was predicted to be positively correlated with host Hb, but negatively related with PCV. Overall, there was no clear evidence that haematological properties of the host species preferred by these mosquito vectors are optimal for their fitness. I then extended my investigations to a laboratory investigation to measure the impact of host species diversity on the fitness of An. gambiae s.s throughout their life. Under these conditions, I found that An. gambiae s.s had similar fitness after either feeding on a uniform (human-only) or mixed host species. These findings indicate that the blood composition of different species may be unlikely to reduce the fitness of An. gambiae s.s My PhD thesis also experimentally measured the impact of using simple intervention (e.g. an untreated bed net) on reducing the fitness of malaria vectors that acquire from human hosts. I found that the lifetime reproductive output of An. arabiensis on protected human was significantly lower than on bovid hosts. In contrast, the use of untreated nets by humans reduced survival of anthrophilic An. gambiae s.s, but the reduction was not predicted to be sufficient to significantly reduce the total lifetime reproductive output of these mosquitoes on human hosts than on animal alternatives. These findings suggest that the widespread use of simple untreated net may generate selection pressures for An. arabiensis to maintain their feeding on bovid hosts and to a lesser extent for An. gambiae s.s to reduce their anthrophily. The findings of my PhD research have implications for the epidemiology and control of malaria. I found that host species and their intrinsic properties may influence aspects of the feeding success, blood meal size and survival of malaria vectors which are the key determinants of malaria transmission intensity. I further demonstrate that selectively protecting humans with untreated nets may generate selection pressures for malaria vectors to reduce their anthrophily and consequently the transmission intensity of malaria. These findings suggest integrating existing interventions (e.g., use of untreated and insecticide treated bed nets) with environmental management that increases availability of an alternate host species (e.g. zooprophylaxis) may generate selection pressures for An. gambiae s.s to reduce their anthrophily, and An. arabiensis to maintain their feeding on alternative animal hosts (zoophily). Overall, I discuss the impacts of host species choice and intrinsic host factors on the fitness of African malaria vectors, the impacts of intervention on their fitness and their potential to select for a host shift, and the implications to epidemiology and control of malaria. I finally highlight gaps in the knowledge of the evolution of host species choice in malaria vectors where more research is required.

Styles APA, Harvard, Vancouver, ISO, etc.

27

M'Cormack, Fredanna Antoinette Durosimi. « Ecological determinants of anemia in pregnant women living in Freetown : urban western area, Sierra Leone / ». Available to subscribers only, 2009. http://proquest.umi.com/pqdweb?did=1791777711&sid=5&Fmt=2&clientId=1509&RQT=309&VName=PQD.

Texte intégral

Résumé :

Thesis (Ph. D.)--Southern Illinois University Carbondale, 2009.
"Department of Health Education." Keywords: Anemia in pregnancy, Ecological determinants, Freetown, Health education, Maternal health, Sierra Leone, Anemia, Women, Pregnancy. Includes bibliographical references (p. 202-212). Also available online.

Styles APA, Harvard, Vancouver, ISO, etc.

28

Gardezi, Tariq. « Spatial scale and the ecological determinants of the distribution and diversity of fishes in Ontario lakes ». Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115911.

Texte intégral

Résumé :

Data on the occurrence of freshwater fishes in Ontario lakes were used to evaluate the scale of the processes that are primarily responsible for shaping their distributions and patterns of diversity. In Chapter 2 it is shown that, regardless of the scale of analysis, the most important factors structuring their distributions are climatic measures of energy, suggesting that species tend to be able to survive heterogeneous conditions falling within large areas encompassing their climatic affinities. In Chapter 3 it is shown that the relationship between species richness and energy (annual potential evapotranspiration) changes according to the scale on which it is measured. The species-energy relationship is weak at the local scale and stronger and steeper at increasing regional scales. This scale dependence is due to the ability of high energy regions to accommodate relatively large numbers of rare or infrequent species, and reflects the regional scale at which species respond to environmental gradients, particularly those related to energy. In Chapter 4 the relationship between local and regional species richness is examined. It is found that mean richness of lakes is linearly related to the species richness of the watersheds in which they reside. Together, the results point to the importance of processes that are regional in scale for shaping species' distributions and patterns of diversity.

Styles APA, Harvard, Vancouver, ISO, etc.

29

Scarborough, Peter D. « Environmental and behavioural determinants of geographic variation in coronary heart disease in England : an ecological study ». Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:271ef376-be81-440a-985b-811fa14434f0.

Texte intégral

Résumé :

Coronary heart disease rates show substantial geographic variation in England, which could be due to environmental variables (e.g. climate, air quality) or behavioural risk factors for coronary heart disease within populations. Previous work investigating this geographic variation has either used ecological analysis (i.e. areas as units of observation) or individual-level analysis. Ecological studies have been unable to account adequately for differences in behavioural risk factors within populations; individual-level studies have been under-powered at the area-level to include all potentially explanatory environmental variables. This thesis reports on ecological multi-level and spatial error regression analyses of coronary heart disease mortality and hospitalisation rates for all wards in England using environmental variables and synthetic estimates of the prevalence of behavioural risk factors as explanatory variables. Existing sets of synthetic estimates were subjected to studies of their validity. Validated synthetic estimates of the prevalence of smoking, low fruit and vegetable consumption, raised blood pressure, obesity and raised cholesterol were combined into a single index of unhealthy lifestyle to take account of collinearity between them. Final models successfully explained around 80% of large scale geographic variation (i.e. variation between wards in different areas of the country) in mortality rates for coronary heart disease and 60% in hospitalisation rates, and around 20% of the small scale geographic variation (i.e. variation between wards in close proximity) in mortality rates, and 30% in hospitalisation rates. The climate explained around 15% of large scale geographic variation in coronary heart disease rates after adjustment for the index of unhealthy lifestyle and socioeconomic deprivation. Urbanicity and air pollution explained a small amount of small scale geographic variation in coronary heart disease rates. The majority of explained geographic variation was due to the index of unhealthy lifestyle and deprivation. The results of this thesis confirm and extend findings from the British Regional Heart Study, report on the validity of synthetic estimates currently used to guide healthcare resource allocation, and introduce an index of unhealthy lifestyle that could be used in future ecological studies of chronic disease.

Styles APA, Harvard, Vancouver, ISO, etc.

30

Landry, Shawn. « Connecting Pixels to People : Management Agents and Social-ecological Determinants of Changes to Street Tree Distributions ». Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4715.

Texte intégral

Résumé :

Street trees are an important component of the urban forest that can provide direct and indirect benefits to social and ecological sustainability in cities. Temporal and spatial interactions between human and non-human management agents determine the distribution and health of street tree populations in urban areas. This dissertation seeks to enhance our understanding of the spatial patterns and processes affecting street trees by investigating the agents and social-ecological determinants of changes to street tree distributions in urban residential neighborhoods. The research was guided by three primary questions: (1) Are recent changes to the spatial distribution of street trees influenced by socio-demographic household and neighborhood characteristics? (2) Which management agents are the strongest predictors of recent changes to street tree distributions and does the contribution of these agents vary in relationship to social-ecological patterns within a city? (3) To what extent are household street tree management decisions related to the built and bioecological material characteristics of the public right-of-way? These questions were investigated in a case study that examined street tree management and public right-of-way (PROW) canopy change associated with single-family residential areas in and near the City of Tampa, Florida. The methodological approach employed a multi-method design using a conceptual framework developed to capture the complexity of management within human ecosystems. Urban remote sensing and spatial analytical techniques were used to examine the geographic association between patterns of street tree change and socio-demographic characteristics. Household survey techniques were utilized to examine the determinants of street tree management; specifically planting, removal, and trimming. Interviews with key informants familiar with urban forest management provided additional insights to complement the location specific knowledge of household survey respondents. Street tree change was examined for the period of 2003 to 2006, and information about household management actions also included recent years (i.e., 2009-2011). A citywide pattern of street tree increases was disproportionately distributed with respect to socioeconomic status; with greater increases in affluent neighborhoods. Patterns of change within local portions of the study area revealed significant and spatially variable relationships with socioeconomic status, as well as race/ethnicity variables and indicators of lifestyle differences. The findings suggest that the citywide pattern of change associated with socioeconomic status may perpetuate an inequitable outcome in the distribution of street trees at the expense of less affluent neighborhoods. The local patterns of change indicate that the processes driving street tree distributions may also reflect differences in attitudes toward trees. The case study did not find sufficient evidence to link the actions of individual agents with street tree change. Street tree increases were more likely in areas where tree trimming had been reported and where property market values were greater, but less likely in PROW segments with overhead power lines. Households, public agencies and builders, but not neighborhoods, were the primary human street tree management agents. Past and ongoing land development and redevelopment decisions, including the configuration of PROW infrastructures, may be one of the most important factors affecting patterns of street tree change. Landscape decisions and practices influenced by household and neighborhood group dynamics also appear to be important factors affecting street tree change. Damages caused by storm event and differences in tree species lifecycle characteristics represent important non-human agents of street tree change. The findings indicated that public agencies are not the only managers of street trees and household tree management does not stop at the boundary of private property. There was no evidence of a relationship between household management actions and the material conditions of the PROW. However, there was a relationship between the presence of either power lines or sidewalks and household survey responses about who should bear responsibility for street tree management and the liability. Household respondents expressed an increased sense of personal responsibility for street tree management when a sidewalk was in front of their home. This dissertation addressed an important gap in understanding about the factors driving street tree change. Planting, removal, and trimming of street trees in Tampa is a shared responsibility with complex spatial patterns and multi-scalar drivers. An important conclusion is that the sustainability of street tree populations within the urban forest will require urban planners and managers to better understand how these management agents cooperate if they are to promote healthy, safe and beneficial street tree populations as a part of the urban forest.

Styles APA, Harvard, Vancouver, ISO, etc.

31

Huicho, Luis, Carlos A. Huayanay-Espinoza, Eder Herrera-Perez, Eddy R. Segura, de Guzman Jessica Niño, María Rivera-Ch et Aluisio J. D. Barros. « Factors behind the success story of under-five stunting in Peru : a district ecological multilevel analysis ». BioMed Central Ltd, 2017. http://hdl.handle.net/10757/622308.

Texte intégral

Résumé :

Background: Stunting prevalence in children less than 5 years has remained stagnated in Peru from 1992 to 2007, with a rapid reduction thereafter. We aimed to assess the role of different predictors on stunting reduction over time and across departments, from 2000 to 2012. Methods: We used various secondary data sources to describe time trends of stunting and of possible predictors that included distal to proximal determinants. We determined a ranking of departments by annual change of stunting and of different predictors. To account for variation over time and across departments, we used an ecological hierarchical approach based on a multilevel mixed-effects regression model, considering stunting as the outcome. Our unit of analysis was one department-year. Results: Stunting followed a decreasing trend in all departments, with differing slopes. The reduction pace was higher from 2007–2008 onwards. The departments with the highest annual stunting reduction were Cusco (−2.31%), Amazonas (−1.57%), Puno (−1.54%), Huanuco (−1.52%), and Ancash (−1.44). Those with the lowest reduction were Ica (−0.67%), Ucayali (−0.64%), Tumbes (−0.45%), Lima (−0.37%), and Tacna (−0.31%). Amazon and Andean departments, with the highest baseline poverty rates and concentrating the highest rural populations, showed the highest stunting reduction. In the multilevel analysis, when accounting for confounding, social determinants seemed to be the most important factors influencing annual stunting reduction, with significant variation between departments. Conclusions: Stunting reduction may be explained by the adoption of anti-poverty policies and sustained implementation of equitable crosscutting interventions, with focus on poorest areas. Inclusion of quality indicators for reproductive, maternal, neonatal and child health interventions may enable further analyses to show the influence of these factors. After a long stagnation period, Peru reduced dramatically its national and departmental stunting prevalence, thanks to a combination of social determinants and crosscutting factors. This experience offers useful lessons to other countries trying to improve their children’s nutrition.
Revisión por pares

Styles APA, Harvard, Vancouver, ISO, etc.

32

Weege, Stephanie. « Determinantes da estrutura ecológica e evolutiva das comunidades florestais no sul do Brasil ». reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/142812.

Texte intégral

Résumé :

Existem muitas teorias a respeito dos processos pelos quais comunidades se organizam. Uma das questões mais importantes diz respeito às diferenças dos padrões de distribuição das espécies em relação a escalas de observação, visando entender a estrutura das comunidades. Neste contexto, aspectos evolutivos e históricos têm sido empregados e vêm se mostrando eficientes. O sul do Brasil possui um mosaico de vegetações florestais, assim como clima e relevo heterogêneos, levando-nos a questionar se a estrutura da vegetação é devida a filtros ambientais ou a restrições determinadas pelo conjunto regional de espécies. Utilizamos tipo de vegetação, dados climáticos, edáficos e das variações de altitude, para modelar a riqueza e composição de espécies e linhagens e o agrupamento filogenético, para 324 localidades, assim como, a frequência de mudanças de nicho entre tipos de vegetação. Testamos também o padrão de sobreposição de nichos entre espécies, em função das suas distâncias filogenéticas, para diferentes escalas geográficas e taxonômicas. Nossos resultados indicam que restrições causadas pelos conjuntos regionais de espécies e linhagens podem ser responsáveis pela maior parte das variações na estrutura das comunidades em escala local, enquanto que a colonização das diferentes formações depende da tolerância das linhagens às condições ambientais. Porém, processos de diferenciação e retenção de nichos ocorrem simultaneamente e variam de acordo com a escala de observação, a diversidade, a escala taxonômica e as variáveis utilizadas, corroborando com a constatação de que a complexidade dificulta a compreensão dos mecanismos pelos quais as comunidades se organizam e explica a divergência nos resultados presentes na bibliografia.
There are many theories about how communities are organized. One of the most important questions is related to how differences in species distribution patterns are generated and how they vary across different scales of observation, which answers would foster the understanding of community assembly. In this context, evolutionary and historical interpretation of patterns has been effective. Southern Brazil has a heterogeneous distribution of forest types, climate and terrain aspects. This led us to question whether the vegetation is assembled due either to environmental filters or restrictions determined by the regional species. We used climatic and soil data, type of vegetation and altitude to model richness, composition of species and lineages and phylogenetic clustering obtained from 324 plots. In addition we estimated the frequency of niche shifts among vegetation types. We also tested the amounts of niche overlap among species for both different geographic and taxonomic scales, correlating pairwise niche overlap estimates with species phylogenetic distances. Our results indicate that restrictions caused by regional species pools and lineage distribution may be responsible for most of the variations in community structure at local scale, while the colonization of the different formations depends on the tolerance of the lineages to environmental conditions. However, processes of niche conservatism and differentiation occur simultaneously and change accordingly to the observational scale, plot diversity, taxonomic scale and the choice of variables describing niches, therefore indicating that the complexity of these issues makes it difficult to understand the mechanisms by which communities are assembled and helps to explain divergence in results present in literature elsewhere.

Styles APA, Harvard, Vancouver, ISO, etc.

33

Nesara, Paul. « Determinants of Low Birth Weight in a Population-Based Sample of Zimbabwe ». ScholarWorks, 2018. https://scholarworks.waldenu.edu/dissertations/5577.

Texte intégral

Résumé :

Low birth weight (LBW) is a major public health concern globally. Despite its negative social and economic impact on the family and community at large, it has remained relatively unexplored at population level in Zimbabwe. The purpose of the study was to establish determinants of LBW using data from the 2015 Zimbabwe Demographic and Health Survey. The socioecological model was the conceptual framework for the study. A secondary analysis was conducted on 4,227 mother-infant dyads. Independent variables were duration of pregnancy, number of births within the past 5-year period, exposure to mass media, type of fuel used for cooking in the household, and intimate partner violence. Covariates were maternal age at delivery, place of residence, anemia, marital status, education, wealth index, ever terminated pregnancy, infant sex, and alcohol consumption. For parsimony, statistical significance was set at p < 0.05 at the 95% confidence interval (CI). Multivariable logistic regression analysis showed that mild maternal anemia (adjusted odds ratio [aOR] 1.83 CI 1.17-2.87 p = 0.01), moderate to severe anemia (aOR 1.80 CI 1.01-3.19 p = 0.05), and being a female neonate (aOR 1.48 CI 1.17-2.87 p = 0.008) had higher odds for LBW. Pregnancy duration of 8 months (aOR 0.01 CI 0.003-0.039 p < 0.001) and of 9 months (aOR 0.12 CI 0.04-0.33 p = 0.001) had lower odds for LBW. Birth of 2 infants within a 5-year period (aOR 2.40 CI 1.24-4.66 p = 0.01) was associated with LBW. Implications for positive social change include coming up with a health policy on the management of anemia during pregnancy and health promotion messages to promote optimal birth spacing, including strategies that reduce chances for preterm deliveries.

Styles APA, Harvard, Vancouver, ISO, etc.

34

Martins, Fernanda Alves. « Determinantes da diversidade de odonata no Brasil : uma abordagem em diferentes escalas espaciais ». Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/5933.

Texte intégral

Résumé :

Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2016-08-10T17:58:39Z No. of bitstreams: 1 Tese - Fernanda Alves Martins - 2016.pdf: 7514352 bytes, checksum: 26ab210eab88a067ec233c173df6ef87 (MD5)
Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-08-15T13:35:27Z (GMT) No. of bitstreams: 1 Tese - Fernanda Alves Martins - 2016.pdf: 7514352 bytes, checksum: 26ab210eab88a067ec233c173df6ef87 (MD5)
Made available in DSpace on 2016-08-15T13:35:27Z (GMT). No. of bitstreams: 1 Tese - Fernanda Alves Martins - 2016.pdf: 7514352 bytes, checksum: 26ab210eab88a067ec233c173df6ef87 (MD5) Previous issue date: 2016-05-24
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The interactions between the organisms and their physical environment and among the organisms themselves occur at definite spatial scales, and give rise to spatial patterns that may be assessed to a better understanding of these relationships. Thus, in order to understand the variation in species diversity, it is necessary to link the scale in which the variation is measured to the scale in which the processes operate. The main objective of this work is thus to identify the factors that best explain the diversity of dragonflies’ tropical assemblages and determine how they interact across scales. The work is based on the Community Assembly conceptual framework that relies on the idea that community assembly is affected by spatial processes hierarchically arranged. Dragonflies are good models because they comprise two distinct groups of species regarding to body size, thermoregulatory responses and dispersal ability. Due to their ecological differences, they may respond differently to local as well as to regional environmental conditions. Despite of their ecological differences, our results suggest that richness patterns for both groups are affected by the same factors, i.e., they respond in a similar fashion to the analysed factors. In regional scales, environmental filters, such as temperature seasonality, affect species richness. The abundance is the main predictor of local species richness. Nevertheless, the assemblages’ compositional patterns are different. Comparatively, Zygoptera (low-dispersal group) assemblages are more affected by local scale processes than Anisoptera. Our results suggest a better integration of metacommunity theory (focused on the role of dispersal shaping different spatial dynamics in the assemblages) and community assembly theory. The fact that the dispersal processes is more important at smaller scales indicate the potential importance of occupancy dynamics at this scale, calling for explicitly incorporating dispersal, affecting the spatial dynamics at different spatial scales. Furthermore, our results suggest that rather than being mutually exclusive, neutral and deterministic processes acts jointly on community assembly.
As interações ecológicas entre os organismos e seus ambientes ocorrem em diferentes escalas espaciais, dando origem a padrões espaciais de composição e riqueza das espécies. O objetivo principal desta tese é investigar fatores que operam em diferentes escalas na estruturação das comunidades de libélulas tropicais. O estudo se apoia no marco conceitual de Community Assembly, que se baseia na ideia de que a organização das comunidades ecológicas é afetada por processos hierárquicos espacialmente organizados. Libélulas são bons modelos de estudo porque compreendem dois grupos de espécies que diferem em características ecofisiológica tais como tamanho corporal afetando as relações com seus ambientes locais e regionais, influenciando os padrões de diversidade resultantes. A subordem Zygoptera compreende organismos com menor tamanho corporal e possuem menor habilidade de dispersão enquanto que Anisoptera é composta por espécies com maior tamanho corporal e maior habilidade de dispersão. Apesar das diferenças ecofisiológicas, nossos resultados indicam que a riqueza de espécies nos dois grupos de libélulas responde de maneira similar aos fatores analisados. Em escalas regionais, a riqueza de espécies de ambos os grupos é influenciada de maneira consistente por filtros ambientais, tais como as variações sazonais da temperatura ambiente. Em escalas locais, a riqueza dos dois grupos é determinada primariamente pela abundância total. No entanto, os padrões de composição das comunidades são diferentes para Zygoptera e Anisoptera. As comunidades de Zygoptera são mais afetadas por fatores que ocorrem em escala local do que Anisoptera. Nossos resultados sugerem que a dispersão desempenha um importante papel em escalas espaciais reduzidas, indicando a importância que as dinâmicas de ocupação podem ter na formação das comunidades ecológicas. Nesse sentido, sugerimos uma maior integração da teoria de metacomunidades (que enfatiza a importância do processo de dispersão na formação das dinâmicas espaciais nas comunidades) e com a teoria de Community Asssembly, com a incorporação explícita do processo de dispersão, afetando as dinâmicas espaciais nas diferentes escalas. Além disso, nossos resultados sugerem que processos neutros e processos determinados pelo nicho não são mutuamente exclusivos, mas atuam conjuntamente na formação das comunidades ecológicas.

Styles APA, Harvard, Vancouver, ISO, etc.

35

Hill, Russell Anthony. « Ecological and demographic determinants of time budgets in baboons : implications for cross-populational models of baboon socioecology ». Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366387.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

36

Haney, Karen Sue. « Determinants of the distribution of hazardous waste facilities in Ohio 1970-1990 : environmental racism or ecological functionalism / ». Connect to resource, 1994. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=osu1244063473.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

37

Tirone, Inês Worm. « Why buy green housecleaning products ? » Master's thesis, Instituto Superior de Economia e Gestão, 2018. http://hdl.handle.net/10400.5/16562.

Texte intégral

Résumé :

Mestrado em Marketing
Na sociedade atual a compra de produtos de limpeza ecológicos surge como uma alternativa sustentável aos produtos convencionais que são constituídos por químicos agressivos que afetam a saúde individual e o ambiente. Este estudo apresenta como principal objetivo a análise detalhada dos determinantes que compõem o processo de decisão de compra de produtos de limpeza de casa ecológicos. Com esta finalidade, foi desenvolvido um estudo em profundidade a compradores de produtos de limpeza de casa ecológicos, recorrendo a entrevistas semiestruturadas e a biografias de consumo. Todos os fatores determinantes em análise apresentam um impacto diferente no processo de decisão de compra, variando de comprador para comprador.
Nowadays, buyers are looking for ecological housecleaning products as an alternative to conventional options made of harsh chemicals that harm their personal health and the environment. This study aims to analyse in detail the individual relevance of different determinants that influence the purchase of ecological housecleaning products. For this purpose and to gain the adequate knowledge, a qualitative study was made to ecological housecleaning product buyers, using semi-structured in-depth interviews and consumption biographies. The results suggest that the ecological housecleaning product purchase is based on determinants that are evaluated differently by each individual buyer forming a complex decision process.
info:eu-repo/semantics/publishedVersion

Styles APA, Harvard, Vancouver, ISO, etc.

38

Thorne, Cecilia. « New interpretations of developmental psycbology regarding the determinants of conduct ». Pontificia Universidad Católica del Perú, 2013. http://repositorio.pucp.edu.pe/index/handle/123456789/101471.

Texte intégral

Résumé :

Two current positions in the field of human development are presented. On the one hand, Scarr' s theory abour the effects of genotype on environment is discussed. On the other hand, the ecological theory of Bronfenbrenner, which describes human developmenr as an interaction between the developing person and his/her environment. The author discusses some aspects of both positions that need furrher study in order ro prevent negarive effects and have a better understanding of child development, in third world countries.
El artículo presenta dos posiciones actuales que buscan explicar el desarrollo humano desde perspectivas diferentes. Por un lado, se presenta la posición de Scarr acerca de los efectos de los genotipos sobre el ambiente, donde el peso de la interpretación está dado en los aspectos hereditarios. Por otro lado, la teoría ecológica sustentada por Bronfenbrenner que define al desarrollo humano como una interacción entre la persona en desarrollo y su medio ambiente. La aurora discute algunos aspectos de ambas posiciones en los que sería importante profundizar para prevenir negativos y tener una mejor comprensión del desarrollo del niño, en países en vías de desarrollo.

Styles APA, Harvard, Vancouver, ISO, etc.

39

Pretorius, Michelle. « Mesocarnivores in Protected Areas : ecological and anthropogenic determinants of habitat use in northern Kwa-Zulu Natal, South Africa ». Master's thesis, Faculty of Science, 2019. https://hdl.handle.net/11427/31789.

Texte intégral

Résumé :

Protected areas (PAs) form the cornerstone for most carnivore conservation strategies. However, climate change, increased isolation and human pressure along PA boundaries are together reducing the effectiveness of PAs to conserve carnivores. Mesocarnivores, in particular, frequently move beyond the boundaries of PAs where they threaten human livelihoods, and as a result, are often subject to chronic persecution. In South Africa, we know little about the conservation status of mesocarnivores both within and outside of PAs, as most research focuses on large, charismatic apex predators. The goal of my study was to leverage data collected from large carnivore studies to understand variation in mesocarnivore species richness within PAs. Camera trap surveys were conducted as part of Panthera’s 2015 national leopard monitoring programme in seven PAs across northern KwaZulu-Natal (KZN), South Africa. Using a multi-species extension of the Royle-Nichols occupancy model, my study explored environmental, interspecific and anthropogenic drivers of mesocarnivore habitat use and species richness. I found a surprisingly low number of detections (N = 356) for all five mesocarnivore species and considerable variation across PAs. Small PAs with a recent history of human disturbance supported more mesocarnivore species and at higher relative abundance. Mesocarnivore species richness was found to decline with increased vegetation and leopard abundance but increased towards the edge of PAs. Variation in species richness estimates decreased significantly with vegetation productivity and domestic dog abundance. Together these results suggest that (1) the edges may provide a refuge for mesocarnivores from more dominant species, (2) mesocarnivores exhibited resilience/adaptability to human disturbance, and (3) primary productivity and domestic dog abundance could mediate mesocarnivore distributions within PAs. My study showed that camera trap data derived from a single-species survey can be used to make inferences about non-target species to great success. Current PAs in KZN may not adequately conserve mesocarnivores, and as a result, emphasis should be placed on coexistence with mesocarnivores in marginal habitat outside of PAs.

Styles APA, Harvard, Vancouver, ISO, etc.

40

Oliveira, Ayra Souza Faria de. « Uso da zona ripária como fator determinante da estrutura de uma assembleia de lagartos em área de terra-firme na Amazônia Central ». Instituto Nacional de Pesquisas da Amazônia, 2017. http://bdtd.inpa.gov.br/handle/tede/2536.

Texte intégral

Résumé :

Submitted by Inácio de Oliveira Lima Neto (inacio.neto@inpa.gov.br) on 2018-06-08T18:45:22Z No. of bitstreams: 1 Ayra Souza Faria de Oliveira.pdf: 1179597 bytes, checksum: a79bbcfc609ca1d9b3be78f23d3249a8 (MD5)
Made available in DSpace on 2018-06-08T18:45:22Z (GMT). No. of bitstreams: 1 Ayra Souza Faria de Oliveira.pdf: 1179597 bytes, checksum: a79bbcfc609ca1d9b3be78f23d3249a8 (MD5) Previous issue date: 2017-07-21
Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
Fundação de Amparo à Pesquisa do Estado do Amazonas - FAPEAM
The factors determining assemblage structure act at different scales, with heterogeneity dominant at the local scale. In Amazonia, such heterogeneity is represented by the different forest types of the region, which provide a great diversity of shelter and food for animal species. Recent changes in Brazilian environmental legislation have put at risk the maintenance of habitat heterogeneity by favoring the suppression of several types of vegetation, notably those in riparian zones. Several Amazonian animal groups have close ecological ties to the presence of water bodies and the environmental gradients provided by them. To understand ecological relationships between species and their environment, model organisms such as lizards are widely used because they are sensitive to environmental changes and because of their success in occupying different habitat types. In this study, an assemblage of lizard species was characterized in terms of distribution and association using biological variables relevant to the group. Twenty species distributed in 10 families were studied. At the scale used in this study, multiple regression models did not indicate a significant effect of environmental variables. However, the riparian zone exerted a strong influence on the species composition and piecewise regression estimated its use to be some 211 m. Several species occurred only in the riparian zone. Our results demonstrate that the current environmental legislation in the country is not adequate to cover the observed variation in habitat use by Amazonian lizards.
Os fatores determinantes na estruturação de uma assembleia atuam em diferentes escalas, sendo a heterogeneidade predominante em escala local. Na região Amazônica, essa heterogeneidade pode ser representada pelos diferentes tipos florestais existentes, que proporcionam maior diversidade de abrigo e alimento para as espécies. Mudanças recentes na legislação ambiental brasileira puseram em risco a manutenção da heterogeneidade dos habitats por favorecer a supressão vegetal de diversas áreas, como as zonas ripárias. Diversos grupos animais estão estreitamente relacionados à presença de corpos d’água e aos gradientes ambientais proporcionados por eles. Para compreender a relação ecológica das espécies com o meio, organismos modelo como os lagartos são amplamente utilizados por serem sensíveis às alterações ambientais e em função do sucesso em ocupar diversos tipos de habitat. Neste estudo, uma assembleia de lagartos foi caracterizada quanto à distribuição e associação com variáveis ambientais biologicamente relevantes para o grupo. Foram registradas 20 espécies distribuídas em 10 famílias. Na escala adotada, os modelos de regressão múltipla não indicaram efeito significativo das variáveis ambientais. No entanto, a zona ripária exerceu forte influência sobre a composição de espécies e seu uso foi estimado em cerca de 211 m por meio de regressão segmentada. Diversas espécies tiveram sua ocorrência limitada à zona ripária. Nossos resultados demonstram que a legislação ambiental vigente no país não é suficiente para abranger avariação observada entre os lagartos amazônicos.

Styles APA, Harvard, Vancouver, ISO, etc.

41

BATISTA, Gilberto Nicacio. « Determinantes da estrutura de comunidades de insetos aquáticos em riachos na Amazônia : o papel do habitat e da escala especial ». Universidade Federal do Pará, 2017. http://repositorio.ufpa.br/jspui/handle/2011/9394.

Texte intégral

Résumé :

Submitted by Rose Suellen (rosesuellen@ufpa.br) on 2018-01-26T12:59:40Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_DeterminantesEstruturaComunidades.pdf: 4661730 bytes, checksum: a898759eb5ba6076e760cf3c89b0f1b6 (MD5)
Approved for entry into archive by Rose Suellen (rosesuellen@ufpa.br) on 2018-01-26T13:00:17Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_DeterminantesEstruturaComunidades.pdf: 4661730 bytes, checksum: a898759eb5ba6076e760cf3c89b0f1b6 (MD5)
Made available in DSpace on 2018-01-26T13:00:17Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_DeterminantesEstruturaComunidades.pdf: 4661730 bytes, checksum: a898759eb5ba6076e760cf3c89b0f1b6 (MD5) Previous issue date: 2017-01-30
CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
Os ecossistemas aquáticos são ambientes altamente complexos, pois os seus componentes bióticos e abióticos são dependentes da variação na estrutura física e das características limnológicas, que em geral, são fatores que atuam de forma específica em diferentes escalas espaciais e temporais. Assim, considerando essa complexidade dos habitats encontrados em ecossistemas lóticos amazônicos esta tese tem como objetivo geral avaliar quais são os fatores determinantes dos padrões de distribuição das comunidades de insetos aquáticos em riachos e suas relações com a variação ambiental desses ecossistemas e os efeitos da escala geográfica (variação espacial). Para responder a este objetivo a tese foi dividida em quatro capítulos. No primeiro através de uma análise cienciométrica foi realizada uma avaliação em escala mundial do uso de insetos da família Chironomidae (Diptera) em ecossistemas aquáticos e suas respostas como bioindicadores nesses ambientes. Encontramos que as principais questões apresentadas nos estudos foram relacionadas aos impactos antrópicos causados pelas atividades humanas sobre os ecossistemas aquáticos e as dificuldades taxonômicas sobre a utilização das espécies em biomonitoramentos. No segundo foram analisados os padrões de distribuição e diversidade de comunidades de Chironomidae, sob as predições da Teoria de Metacomunidades, para avaliar as relações das assembleias com a variação da escala espacial e do ambiente. Como principais resultados, encontramos que as assembleias são afetadas principalmente por componentes da estrutura física do habitat e parcialmente limitadas pela dispersão entre os riachos quando consideradas em larga escala na região hidrográfica. No terceiro capítulo, foi avaliada a composição de traços morfológicos e funcionais das comunidades de insetos aquáticos (Coleoptera, Diptera, Ephemeroptera, Hemiptera, Lepidoptera, Megaloptera, Odonata, Plecoptera, Trichoptera) e as suas respostas à variação na estrutura do habitat consideradas sob as premissas da Teoria de Habitat Templet. Assim, encontramos como resultados deste capítulo, relações entre a distribuição dos traços morfológicos e funcionais com as variáveis da estrutura do habitat e a características limnológicas dos riachos. No quarto capítulo foram avaliados os efeitos da variação espacial e ambiental sobre a similaridade de composição das comunidades de insetos das ordens Ephemeroptera, Plecoptera e Trichoptera em riachos de duas regiões hidrográficas distintas. Neste último capítulo, encontramos diferenças na composição das comunidades como resultado da distância geográfica e das características ambientais locais de cada região. Demonstramos como a estrutura do habitat dos riachos pode afetar as comunidades de insetos aquáticos em diferentes contextos de escala geográfica. Também, as características dos hábitats foram importantes para a seleção de atributos ecológicos e funcionais das comunidades de insetos aquáticos. Com isso, a partir dos resultados encontrados, concluímos que as variáveis que compõem a estrutura física dos riachos são fatores determinantes na estruturação das comunidades de insetos aquáticos em escalas geográficas em contextos regionais e locais específicos. Além disso, foi destacada a importância dos fatores locais (proporção da vegetação ripária/composição dos substratos/características limnológicas) em relação a composição de características morfológicas e funcionais das assembleias, enquanto que os fatores regionais (distância geográfica/limitação de dispersão) foram os componentes determinantes da similaridade da estrutura das comunidades.
Aquatic ecosystems are highly complex environments, mainly due to interactions between their abiotic and biotic components; they are dependent on variation in physical structure and limnological characteristics, which in general, are factors that specifically act on different spatial and temporal scales. Therefore, considering this complexity in structuring stream habitats, particularly in Amazonian lotic ecosystems, this doctoral thesis aims to evaluate which are the determining factors to structure aquatic insect communities and their distribution according to environmental variation and geographical distances. To meet this goal the thesis is divided into four chapters. In the first, a systematic revision was carried out with a global assessment about the use of insects (Chironomidae: Diptera) in monitoring aquatic ecosystems and their responses as bioindicators. We found that the main issues presented in the studies were related to anthropogenic impacts on aquatic ecosystems and the taxonomic difficulties on the use of species identification to biomonitoring. The second shows analysis of distribution patterns and diversity of Chironomidae communities, under predictions of Metacommunity models, to evaluate the relations of the assemblages with the spatial scale and the environment. The main results showed that the assemblages were mainly affected by components of the physical habitat structure and partly the communities were limited by dispersal among the streams when considered at large scale in the region studied. The third showed analysis of functional composition on the communities of aquatic insects (Coleoptera, Diptera, Ephemeroptera, Hemiptera, Lepidoptera, Megaloptera, Odonata, Plecoptera, Trichoptera) and their responses to variation in habitat structure considered under the assumptions of the Habitat Templet. Overall, we found relationships between the distribution of morphological and functional traits with the physical habitat variables. The fourth chapter evaluates the effect of spatial distance on the community similarity of Ephemeroptera, Trichoptera, Plecoptera communities in two regions of Eastern Amazon. In this final chapter, we find differences in the composition of communities expressed as species replacement because of the geographical distance and local environmental characteristics of each region. Finally, the studies developed in this thesis summarized how the structure of the habitat of streams can affect the aquatic insect communities and variation in the riparian structure and physical habitat, can cause variation in taxonomical composition and functional attributes. In summary, from these findings, we conclude that the physical habitat variables are determining factors in structuring aquatic insect communities. In addition, it is highlighted the importance of local factors (riparian vegetation structure/composition of substrates/limnological characteristics) as explanatory variables for taxonomical and functional composition. In addition, the regional factors (geographical distance / dispersal limitation) are essential components to affect similarity and structure of the communities.

Styles APA, Harvard, Vancouver, ISO, etc.

42

Galbiati, Carla. « Determinantes da riqueza de espécies de cupins (Insecta : Isoptera) ». Universidade Federal de Viçosa, 2004. http://www.locus.ufv.br/handle/123456789/9954.

Texte intégral

Résumé :

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2017-03-30T17:07:12Z No. of bitstreams: 1 texto completo.pdf: 314085 bytes, checksum: c12d44f8f7ad869b5e68333465074099 (MD5)
Made available in DSpace on 2017-03-30T17:07:12Z (GMT). No. of bitstreams: 1 texto completo.pdf: 314085 bytes, checksum: c12d44f8f7ad869b5e68333465074099 (MD5) Previous issue date: 2004-07-23
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O aumento da riqueza de espécies pode ser determinado por processos relacio- nados ao aumento da área, como o tamanho das populações e da disponibilidade de recurso. Para a comunidade de térmitas foram observadas dois padrões dife- rentes entre espécie e área, positivo e ausente, e poucos trabalhos testaram as causas desses padrões. O objetivo desta tese foi determinar quais as relações entre a riqueza de espécies e i) a área do fragmento florestal e ii) os processos locais, testando as causas dessas relações para comunidade de térmitas. No primeiro capítulo foi testado a relação entre a riqueza de espécie, a abundância e a composição de espécies com a área do fragmento florestal. Os térmitas foram coletados em 12 remanescentes florestais, com área variando de 3,21 a 60,63 hectares em Viçosa, Minas Gerais. A riqueza de espécies e o tamanho das po- pulações das espécies não responderam à área do remanescente. A maioria das espécies foi mais freqüente em altas abundâncias. Apenas uma espécie foi mais freqüente em remanescentes com áreas menores, indicando que a substituição por espécies invasoras não foi determinado pela fragmentação e não resultou em mudança na composição de espécies. As espécies de térmitas são resistentes à fragmentação e isso pode ser devido a escala espacial da fragmentação ser maior que a área de vida dos térmitas, ou porque esses insetos não controlam a taxa de regeneração do recurso alimentar. No segundo capítulo foi testada como a relação entre a diversidade alfa e beta variou com a área do remanescente e os processos envolvidos nessas relações. A coleta dos térmitas foi feita nos mes- mos remanescentes do primeiro capítulo. A relação espécie-área positiva não foi confirmada para térmitas nesses remanescentes, e a diversidade alfa e beta não aumentou com a área. Uma relação significativa entre a riqueza local e regional não foi observada, indicando uma comunidade saturada. Espécies especialistas parecem ser a explicação para a ausência da relação entre alfa e beta e a área do remanescente. No terceiro capítulo foi verificado se a riqueza de térmitas au- mentou com a heterogeneidade e se a riqueza de espécies foi maior em níveis intermediários de produtividade. Os cupins foram coletados em nove transectos no Parque Estadual de Ibitipoca, em Ibitipoca, Minas Gerais. O número de es- pécies de térmitas não mostrou relação com a heterogeneidade. A riqueza de térmitas diminuiu com o aumento da quantidade de serapilheira (produtividade). Esses resultados sugerem que térmitas podem não ser limitados pela heteroge- neidade ambiental e que existe uma curva quadrática com pico de riqueza de térmitas em níveis intermediários de produtividade. A predação e a limitação de recursos essenciais podem ser possíveis explicações para a riqueza local de térmitas.
The increase in species richness can be determinat by processes relative to the increase of area, as populations size and resource abundance. In termite communities two different patterns were observed, a positive relationship of spe- cies with area and an absence relationship, and few papers tested the causes of this relationship. The aim of this thesis was to determine the relationship between species richness and: i) remnant area, ii) local processes; testing the cause of these relationships in termite communities. In the first chapter of this thesis we tested relationship between: species richness, species abundance and species composition with remnant area. Termites were collected in 12 forest remnants with areas ranging from 3.21 to 60.63 hectares in Viçosa, Minas Gerais, Brazil. Species richness and abundance did not respond to remnant area. Most species should a higher of frequency in remnants where their abundance was high. Only one specie was more frequent in smaller remnants, but the compensation by ma- trix species not significant changes in SAR. Termite species are resistant to forest habitat fragmentation which maY be due to the spatial scale in which fragmenta- tion occurs is larger than the home range of termites, or because this is a donnor- control community. In the second chapter the response of termite species richness to remnant area was tested, testing how alpha and beta diversity vary with rem- nant area, and which processes may be involved in such relationships. Termite sampling was in the same remnants of the first chapter. The positive species-area relationship was not confirmed in these remnants, and alpha and beta diversities did not increase with remnant area. Local-regional relationship was not obser- ved suggesting a saturated community. Specialists seem to be the explanation to absence of these relationships. In the third chapter was tested whether termite species richness increases with heterogeneity and if species richness is highest at intermediate levels of productivity. Termite communities were collected in nine transects in the State Park of Ibitipoca, Minas Gerais, Brazil. Species richness did not respond to heterogeneity, and species richness responded negatively to the amount of litter (surrogate of productivity). This results suggest that termite can’t be limited by environmental heterogeneity and that a hump-shaped curve repre- sents the relationship between species richness and productivity. Predation and restriction of essential resources can be a possible explanation to local termite species richness.

Styles APA, Harvard, Vancouver, ISO, etc.

43

Edmond, Yanique Marie. « Ecological determinants of parenting practices among Latin American and Caribbean mothers of adolescents findings from the new immigrant survey / ». College Park, Md. : University of Maryland, 2007. http://hdl.handle.net/1903/7306.

Texte intégral

Résumé :

Thesis (Ph. D.) -- University of Maryland, College Park, 2007.
Thesis research directed by: Family Studies. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

Styles APA, Harvard, Vancouver, ISO, etc.

44

Luu, Shyuemeng. « The Determinants of Post-discharge Healthcare Utilization and Outcomes for Veterans with Posttraumatic Stress Disorder : A Social Ecological Perspective ». VCU Scholars Compass, 2000. https://scholarscompass.vcu.edu/etd/5231.

Texte intégral

Résumé :

Posttraumatic stress disorder (PTSD) has a persistent nature: PTSD troubles patients even decades after the occurrence of traumatic events. The “health behavioral model” is adopted to examine the effects of external environmental, predisposing, enabling, and need for care factors on the use of VA post-discharge ambulatory care and readmissions. Data were obtained from the Patient Treatment File (PTF) and the Outpatient Care File (OPT), the Area Resource File (ARF), American Hospital Association data sets (AHA), and the Uniform Crime Report (UCR). The use of VA post-discharge ambulatory care is analyzed by using structural equation modeling (SEM). The readmission to VAMCs is evaluated by Cox regression with forward selection. A cross-sectional study is performed on 1,420 PTSD veterans admitted to Veterans Affairs Medical Centers (VAMCs) in 1994 and 1,517 veterans in 1998 in the Veterans Integrated Services Networks 6 (VISN 6). In both years, the most important determinants of the use of VA post-discharge ambulatory care is “prior use of outpatient care services.” For the 1994 sample, prior use of inpatient services impeded the utilization of post-discharge ambulatory care. For the 1998 sample, barriers to access to care and the length of stay for other mental health encounters in the last year reduced the utilization of post-discharge ambulatory care. For readmission in both years, higher numbers of medical or mental VA post-discharge visits reduce the likelihood of readmission to VAMCs. The service lines program was found to increase the use of VA post-discharge ambulatory care and decrease readmission rates for PTSD veterans. The application of the “health behavioral model” can be extended to outcome research to investigate the contributing factors. A risk adjustment system can also be developed based upon the findings. Communities, VAMCs, and PTSD patients and their families should work to raise awareness of the factors that contributing to both use of care and outcomes, and should form a comprehensive network to improve the wellbeing of PTSD veterans.

Styles APA, Harvard, Vancouver, ISO, etc.

45

Silva, Luciana Zago da. « Fatores determinantes no uso do espaço por Callithrix Penicillata (E. Geoffroy, 1812) introduzidos em fragmento urbano ». reponame:Repositório Institucional da UFPR, 2012. http://hdl.handle.net/1884/27296.

Texte intégral

Résumé :

Resumo: o movimento dos organismos é uma característica fundamental da vida dirigida por processos que agem por escalas espaciais e temporais. A fragmentação de habitats e a introdução de espécies exóticas vêm destacando cada vez mais a relação entre alterações ambientais e o movimento dos organismos. A compreensão de causas, padrões, mecanismos e conseqüências dos movimentos dos organismos são, portanto, fundamentais para o controle de espécies invasoras. Espécies do gênero Callithrix vêm sendo indevidamente introduzidas em diversas regiões. O objetivo deste trabalho foi determinar e relacionar com fatores ambientais, demográficos e comportamentais o uso do espaço de três grupos de Callithrix penicillata introduzidos, como uma forma de subsidiar futuros planos de manejo. O trabalho foi realizado no Parque Ecológico do Córrego Grande, um fragmento urbano de 21,5 ha de Floresta Ombrófila Densa em estágios iniciais e médios de regeneração, localizado na Ilha de Santa Catarina. Foram realizadas por 12 meses amostragens mensais de 2 dias por grupo em que foram registradas suas composições etárias e, pelo método de varredura instantânea, os comportamentos realizados, itens alimentares consumidos e localização por pontos de GPS (Sistema de Posicionamento Global). Com esses pontos foram calculados os percursos diários, as áreas de vida por esquadrinhamento (ESQ) e mínimo polígono convexo (MPC) e os índices de linearidade, de intensidade do uso do habitat e de diversidade do uso do espaço. A média dos percursos diários do grupo GN foi de 1158m + 415m; a de GG, 1164m + 261m; e a de GP, 1181m + 286m. A área de vida anual por ESQ de GN foi de 8,88ha, enquanto a de GG foi de 5,57ha e a de GP, 5,38ha. Houve uma sobreposição nas áreas entre GN e GG de 1,18ha, entre GG e GP, de 0,56ha e entre GN, GG e GP, de 0,06ha. Por MPC, a área de vida anual de GN foi 9,82ha, enquanto a de GG foi 5,15ha e a de GP, 5,69ha, havendo sobreposições entre as áreas de GN e GG de 1,08ha; entre GG e GP, de 0,54ha; e entre GN e GP, de 0,02ha. Foram detectadas diferenças significativas no uso do espaço entre os grupos estudados e as variáveis demográficas estiveram correlacionadas a tais diferenças. As diferenças sazonais também foram significativas, entretanto, não estiveram correlacionadas com variáveis ambientais. Variáveis comportamentais, alimentares e sociais correlacionaram-se significativamente com as variáveis espaciais. A demografia, a sazonalidade, os padrões de atividades, os hábitos alimentares e os comportamentos sociais foram, portanto, fatores determinantes no uso do espaço por C. penicillata no presente estudo. E o número de indivíduos por classe etária, os comportamentos alimentares, a disponibilidade e distribuição dos recursos alimentares e os hábitos territoriais são variáveis que afetam as decisões destes animais em como utilizar o tempo e o espaço no habitat em que foram introduzidos.

Styles APA, Harvard, Vancouver, ISO, etc.

46

Gomes, Lucas Gontijo. « Determinantes de riqueza e padrões de uso de plantas hospedeiras por moscas-das-frutas (diptera:tephritidae) ». Universidade Federal de Goiás, 2013. http://repositorio.bc.ufg.br/tede/handle/tede/3297.

Texte intégral

Résumé :

Submitted by Jaqueline Silva (jtas29@gmail.com) on 2014-10-06T17:46:50Z No. of bitstreams: 2 Dissertação - Lucas Gontijo Gomes - 2013.pdf: 491866 bytes, checksum: e2e59f1185f536c08f62a07a0db31bf8 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5)
Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-10-06T19:17:43Z (GMT) No. of bitstreams: 2 Dissertação - Lucas Gontijo Gomes - 2013.pdf: 491866 bytes, checksum: e2e59f1185f536c08f62a07a0db31bf8 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5)
Made available in DSpace on 2014-10-06T19:17:43Z (GMT). No. of bitstreams: 2 Dissertação - Lucas Gontijo Gomes - 2013.pdf: 491866 bytes, checksum: e2e59f1185f536c08f62a07a0db31bf8 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-07-19
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
(Sem resumo em inglês)
Maioria dos insetos herbívoros se alimenta de um subconjunto de plantas proximamente relacionadas. Como consequência, locais com maior diversidade filogenética de plantas devem ter maior riqueza de herbívoros. Entretanto o mesmo parece não ser verdade quando o incremento na riqueza local de plantas é devido ao elevado número de espécies de plantas exóticas. Sendo assim, eu perguntei se a riqueza local de herbívoros é predita pela riqueza de plantas nativas, pela riqueza de plantas exóticas e pela diversidade filogenética das plantas hospedeiras. Adicionalmente perguntamos se a diversidade filogenética de plantas de um local tende a aumentar com o aumento do número de plantas exóticas. Para responder essas perguntas eu usei dados secundários de interações entre moscas-das-frutas e plantas frutíferas. Eu encontrei que a riqueza de plantas nativas explica a riqueza local de herbívoros melhor até do que o número total de plantas hospedeiras. Encontramos que a diversidade filogenética das plantas também explica a riqueza de herbívoros, embora fracamente. Plantas exóticas não aumentam desproporcionalmente a diversidade filogenética de plantas de um local. Os resultados indicam que o compartilhamento de história evolutiva entre plantas e herbívoros e restrições filogenéticas no consumo da hospedeira são importantes na determinação de interação entre herbívoros e plantas. Eles sugerem também que usar o número de espécies de plantas nativas e exóticas (sem distinção entre elas) para explicar a riqueza de herbívoros em um local pode não ser a melhor opção.

Styles APA, Harvard, Vancouver, ISO, etc.

47

Sitzia, Tommaso. « The role of hedgerows as corridors for plant species : determinants analysis and efficiency evaluation ». Doctoral thesis, Università degli studi di Padova, 2004. http://hdl.handle.net/11577/3425958.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

48

Andreote, Fernando Dini. « Fatores determinantes na composição da comunidade bacteriana associada às plantas ». Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/11/11137/tde-28112007-101523/.

Texte intégral

Résumé :

A interação entre bactérias e plantas resulta na ocorrência de vários processos biológicos no ambiente e pode ser regulada por diferentes fatores. Considerando que um recíproco reconhecimento ocorre entre as espécies de bactérias e plantas, alterações nos fatores bióticos e abióticos interferem diretamente nesta interação levando a modificações na composição das comunidades bacterianas associadas às plantas. No presente trabalho foram avaliados diferentes fatores que estão diretamente relacionados a este assunto. Atualmente, a aplicação de técnicas de microbiologia molecular permite acessar alterações causadas nestas comunidades de maneira independente do cultivo bacteriano. Desta maneira, foi demonstrado que na rizosfera de plantas de tabaco, os diferentes estágios de desenvolvimento são os principais determinantes da composição da comunidade bacteriana em detrimento do genótipo das plantas, sejam estas transgênicas ou convencionais. Utilizando plantas transgênicas e convencionais de eucalipto de diferentes genótipos, foi verificado que diferentes plantas não transgênicas podem apresentar comunidades bacterianas mais distintas do que quando os clones não transgênicos são comparados com os transgênicos. No entanto, efeitos específicos podem ocorrer na interação bactéria-planta, como o observado pela inibição da população de Methylobacterium spp. em plantas transgênicas de eucalipto TR-15. Avaliando o efeito da inoculação de bactérias endofíticas na composição de comunidades bacterianas associadas à plantas de batata de diferentes cultivares, os resultados mostram que a inoculação de Pseudomonas putida altera a comunidade bacteriana de maneira similar a alteração da variedade da planta. Os demais isolados avaliados, classificados como Paenibacillus sp. e M. mesophilicum, causam menores alterações na composição das comunidades bacterianas. Adicionalmente foi demonstrado que a colonização das plantas de batata pelo endófito P. putida resulta em pequena alteração no perfil metabólico da planta hospedeira. Por fim, buscando melhores métodos de isolamento da comunidade bacteriana da rizosfera de batata, os resultados mostraram que a mimetização do ambiente pode resultar em melhor acesso da diversidade bacteriana por meio de isolamento e cultivo das espécies componentes desta comunidade.
The plant-bacteria interactions result in the occurrence of biological process in the environment and might be regulated by different factors. Considering that a reciprocal recognition occur amongst bacteria and plants species, shifts in biotic and abiotic factors interfere directly on these interactions, leading to modifications in the composition of bacterial communities to plants associated. In the present work different factors related to this subject were evaluated. Nowadays, the applications of techniques of molecular microbiology allow assessing the shifts caused on these communities by a culture independent approach. On this way, it was demonstrated that in rhizosphere of tobacco plants, different stages of plants development are main determinants of bacterial community composition rather than the plants genotypes, transgenic or not. Using plants transgenic or not, carrying different genotypes, it was verified that different non-transgenic plants could harbor bacterial communities more distinct than those observed in association with transgenic plants. However, specific effects could be observed like the inhibition of Methylobacterium spp. population in eucalyptus transgenic plants TR-15. Considering the effect of endophytic bacteria inoculation in the composition of bacterial communities associated to different cultivars of potato plants, the results show that inoculation of Pseudomonas putida causes similar shifts in the bacterial community similarly to those observed when different cultivars are considered. Other evaluated strains, classified as Paenibacillus sp. and M. mesophilicum, caused minor alterations in the composition of bacterial communities. In addition, it was demonstrated that plant colonization by endophytic P. putida results in small effects on the metabolic profile of host plant. At least, aiming better methodologies for bacteria isolation from potato rhizosphere, the results show that mimicking the natural environment could result in a better assessment of bacterial diversity by isolation of species present in this community.

Styles APA, Harvard, Vancouver, ISO, etc.

49

Halpenny, Carli. « Interrelationships among gastrointestinal infections, stunting and their socio-ecological determinants in impoverished Panamanian preschool children : a spatio-temporal ecohealth approach ». Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=114379.

Texte intégral

Résumé :

Background: Although growth stunting, height for age Z score (HAZ) <-2SD, results from sustained poor diet and frequent infection both of which are influenced by social and biophysical factors, few studies have used a transdisciplinary ecohealth framework for a comprehensive analysis of this relationship. Objective: To examine the interrelationships between preschool child stunting and gastrointestinal infections within the biophysical, social and spatial context of extreme poverty among the Ngäbe in Western Panama where conditional food voucher (FV) and cash transfer (CT) programs occurred. Methods: A 16-mo longitudinal study of 356 preschool children involved two reinfection cycles following albendazole treatment. Data collection included repeated fecal samples, household socio-behavioural questionnaires, multiple dietary records and anthropometric measures, water samples, GPS and participatory workshops. An asset-based household wealth index (HW), an index of household dispersion (HD), index of chronicity of diarrhea (CDI) and protozoan infection (CPI), and dietary pattern scores were generated and incorporated into spatial cluster analysis and multiple regression models of anthropometric and infection outcomes. Influence diagrams created during small group workshops identified participant perceptions of health. Results: Households with higher HWI had a latrine, aqueduct access, cell phone, and/or stove and HD ranged from 5–113 households/km2. High prevalence clusters of hookworm and Trichuris (but not Ascaris) occurred in regions with lowest HWI and HD. Ascaris and hookworm reinfection was driven by individual susceptibility traits (stunting) whereas Trichuris reinfection was dependent on household (maternal education) and regional (high prevalence cluster) characteristics. The high frequency of diarrhea was consistent with community perceptions of health priorities and of the link between diarrhea and poor water quality. Both E. coli counts and CDI were higher in households without aqueduct access. Sixty percent of children were stunted and 22% were underweight. The detrimental effect of CPI on HAZ was driven by household density but moderated by household wealth. Diet also influenced growth. The basic diet (rice, beans, coffee, sugar) was supplemented with fruits and vegetables (FV region) or market snacks (CT region). A "Market" diet pattern was concentrated in the CT region close to the road. Meat was beneficial for linear growth but only in the FV region whereas carbohydrates (sweets in FV region and root vegetables in CT region) were detrimental, even after controlling for infection and socio-economic status. With regard to weight gain, fish and eggs were beneficial in the FV region whereas, in the CT region, milk products were beneficial, but chips and sweets were detrimental. Implications: This transdisciplinary research highlighted key public health messages necessary to improve growth and reduce infection in this vulnerable population.
Contexte: Le retard de croissance, correspondant à une valeur centrée réduite (z-score) de la taille par rapport à l'âge (ZTA) inférieur à deux écarts type, découle d'une diète pauvre et d'infections fréquentes qui sont influencées par des facteurs sociaux et biophysiques. Seulement peu d'études ont utilisé une approche multidisciplinaire santé-écologie pour analyser la relation entre ces facteurs et la fréquence des arrêt de croissance. Objectif: Examiner les relations entre le retard de croissance chez les enfants en âge préscolaire et les infections gastro-intestinales avec le contexte social, biophysique et spatial dans des conditions de pauvreté extrêmes chez les peoples Ngabe de l'ouest du Panamá, où prennent place des programmes d'aide alimentaire (AA) et de transfert monétaire (TM). Méthodes: Dans le carde d'une étude de 16 mois, nous avons suivi 356 enfants d'âge préscolaire impliqués dans deux cycles de réinfections à la suite d'un traitement à l'albendazole. Les données recueillies inclues des échantillons répétés de matière fécale, questionnaires sur les comportements sociaux des ménages, journaux alimentaires et mesures anthropométriques, échantillons d'eau, données de système de localisation GPS et ateliers participatifs. Des indices de richesse des ménages (IRM) basé sur le patrimoine, de dispersion des ménages (IDM), de chronicité des la diarrhée (ICD) et de l'infection aux protozoaires (CIP), et une note sur les habitude alimentaires ont été calculés. Ces indices ont été inclus dans une analyse spatiale de regroupement et des analyses de régression linéaire multiple pour prédire les mesures anthropométriques et le résultat des infections. Les diagrammes d'influence créés durant les ateliers ont permis d'évaluer les perceptions des participants par rapport à la santé. Résultats Les ménages avec les IRM élevés avaient une toilette, l'accès à l'aqueduc, un téléphone cellulaire et/ou un poêle. Leur IDM variait de 5-113 ménages/km2. Des regroupements de prévalence d'ankylostome et de Trichuris (mais pas d'Ascaris) étaient présents dans les régions avec les IRM et les IDM les plus faibles. Les réinfections par Ascaris et par des ankylostomes étaient influencées par des traits de sensibilité personnelle (retard de croissance): la réinfection par Trichuris dépendait des caractéristiques du ménage (éducation maternelle) et de la région (regroupement de prévalence élevée). La fréquence élevé de diarrhée correspondait avec la perception de la communauté sur les priorité en matière de santé et avec la mauvaise qualité des eaux. Les dénombrements d'E. coli et le ICD étaient plus élevés dans les ménages qui n'avaient pas accès à l'aqueduc. Soixante-six pour cent des enfants étaient atteints d'arrêt de croissance et 22% souffraient d'insuffisance pondérale. L'effet nuisible de la CIP sur la ZTA était principalement influencé par la densité de ménage mais aussi par le patrimoine du ménage. Le régime alimentaire avait aussi un effet sur la croissance. Le régime de base (riz, haricots, café, sucre) était complété avec des fruits et des légumes (région AA) ou des friandises du marché (région TM). Un régime « du marché » était concentré dans la région TM proche de la route. La présence de viande avait un effet bénéfique sur la croissance linéaire seulement dans la région AA alors que les glucides (sucreries dans la région AA et légumes racines dans le région TM) avait un effet néfaste, même en tenant compte des infections et du statut socio-économique. Le poisson et les œufs avaient un effet bénéfique sur le gain de masse corporelle dans la région AA. Dans la région TM, les produits laitiers avait un effet bénéfique sur la prise de masse alors que les croustilles et les sucreries avaient un effet néfaste. Implications: Cette étude multidisciplinaire souligne des messages important en santé publique pour améliorer la croissance et diminuer les infections dans cette population vulnérable.

Styles APA, Harvard, Vancouver, ISO, etc.

50

Norris, Darren. « Vivendo em uma paisagem defaunada : fatores determinantes nas relações espaciais de grandes mamíferos / ». Rio Claro : [s.n.], 2012. http://hdl.handle.net/11449/106533.

Texte intégral

Résumé :

Orientador: Mauro Galetti
Coorientador: Silvio Frosini de Barros Ferraz
Banca: Marco Aurelio Pizo Ferreira
Banca: Maria Luisa da Silva Pinto Jorge
Banca: Adriano Garcia Chiarello
Banca: Rafael Dias Loyola
Somente a introdução está em português
Resumo: Existe uma necessidade urgente de se desenvolver conhecimento ecológico de apoio à conservação e gestão da rede protegida da Mata Atlântica dentro da região biogeográfica Serra do Mar. Resultados de pesquisas anteriores mostraram variações elevadas nas abundâncias dos grandes mamíferos dentro destas grandes áreas protegidas, que são comparáveis, se não maiores, do que as encontradas nos ecossistemas fragmentados da Mata Atlântica. Neste trabalho demonstrou-se como variáveis ambientais e antrópicas influenciam grandes mamíferos em remanescentes contínuos da Mata Atlântica Brasileira na região biogeográfica da Serra do Mar. Remanescentes contínuos da Mata Atlântica apresentam um ambiente altamente heterogêneo, resultado de fatores ambientais e impactos antrópicos. Os resultados apresentados nos 4 capítulos dessa tese destacam que, embora a Mata Atlântica seja o bioma mais intensamente estudado para mamíferos no Brasil, ainda não se atingiu o conhecimento necessário para a conservação e gestão eficaz desta classe na Mata Atlântica. Estudos adicionais são necessários para permitir a definição de zonas dentro das áreas protegidas, como definido pela legislação brasileira (Lei: 9.985/2000 (SNUC)). Este zoneamento é necessário para a realização dos objetivos múltiplos das áreas protegidas (incluindo a manutenção da biodiversidade e o fornecimento dos serviços dos ecossistemas) dentro do contexto sócio-econômico em um escala regional e nacional
Abstract: There is an urgent need to develop ecological knowledge to support conservation and management of the protected area network within the Serra do Mar biogeographical region. Results of previous research showed a high variation in the abundance of large mammals within large protected areas of Atlantic Forest within this region that is comparable if not greater than that found in fragmented Atlantic Forest ecosystems. This thesis shows how environmental variables and anthropogenic impacts influence large mammals within the remaining continuous Atlantic Forest remnants of the Serra do Mar. Continuous Atlantic Forest remnants are highly heterogeneous and this heterogeneity results from environmental factors and human impacts. The results presented in the four chapters of this thesis highlight that, although the Atlantic Forest is the most intensely studied biome for mammals in Brazil, the knowledge necessary for the conservation and effective management of this class in the Atlantic Forest is still lacking. Additional studies are needed to allow the establishment of zones within protected areas as defined by Brazilian legislation (Law: 9.985/2000 (SNUC)). This zoning is necessary to achieve the multiple objectives of protected areas (including the maintenance of biodiversity and the provision of ecosystem services) within the socioeconomic development in a regional and national scale
Doutor

Styles APA, Harvard, Vancouver, ISO, etc.

Thèses sur le sujet « Determinanti ecologici »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres