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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Inventario rapido e identificação de variaveis que limitam a dispersão de exoticos : um estudo sobre peixes no medio Rio Doce (MG, Brasil) / Rapid assessment protocol and determination of restrictive variables to exotic spread: a study on fish in River Doce lakes (MG, Brazil)

Latini, Anderson Oliveira 23 September 2005 (has links)
Orientador: Miguel Petrere Junior / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-08T03:16:38Z (GMT). No. of bitstreams: 1 Latini_AndersonOliveira_D.pdf: 4655776 bytes, checksum: 7c0c9c7fad5c0125a8ac2f9d2fb96371 (MD5) Previous issue date: 2005 / Resumo: As invasões de espécies exóticas são muito comuns hoje em dia e causam problemas sociais, ambientais e econômicos em todo o mundo. Para conhecer estas invasões é importante o estudo de procedimentos rápidos de avaliação da incidência de exóticos e de variáveis que possam limitar a sua dispersão e colonização. Neste trabalho, testei a eficácia de um método de inventário rápido (RAP) para obter a incidência de peixes exóticos em lagos e relacionar a ocorrência destes peixes às variáveis locais e espaciais associadas aos lagos, no trecho médio da bacia do rio Doce, MG. Um conjunto de técnicas passivas e ativas de pescaria consistiu o RAP, que foi usado em 74 lagos e comparado com técnicas de mais de 100 vezes mais esforço amostral. A ocorrência dos peixes exóticos foi relacionada a variáveis locais (área, forma, cobertura de vegetação dos lagos, pH, oxigênio, turbidez e condutividade) e espaciais (tamanho do corredor de dispersão) e associadas com caracteres bionômicos dos peixes (forma de corpo e presença de mecanismos acessórios de respiração) e o interesse dos pescadores locais. O RAP foi efetivo e detectou peixes exóticos mesmo quando estes ocorreram em baixa abundância. Particularmente as informações obtidas de pescadores foram de grande importância para os seus resultados. A probabilidade de ocorrência de tucunarés e apaiaris aumentaram com o incremento da área dos lagos, mas nenhuma outra variável local afetou a ocorrência de peixes exóticos na região. A distância dos lagos aos riachos, considerando a sua cobertura vegetal, é muito importante para explicar a incidência de piranhas e tucunarés nos lagos da região. Estes resultados indicam que o RAP que usei é um método recomendável para avaliar a dispersão de peixes exóticos já que apresenta resultados confiáveis. Além disto, as limitações de ocorrência de peixes exóticos são determinadas basicamente pela distância que os peixes têm de percorrer para se dispersarem. Apesar dos peixes exóticos terem um grande potencial de invasão, a sua dispersão pode ser monitorada pelo inventário rápido sugerido, que é uma ferramenta importante para o estudo do seu impacto e, portanto, importante para direcionar nossas tomadas de decisão a respeito da conservação do ambiente natural / Abstract: Biotic species invasions are very common nowadays and cause severe social, environmental and economic problems around the world. To understand species invasions is important to study rapid assessment protocols of exotic species incidence and the variables that may limit its spread and colonization. Here I tested the efficacy of a rapid assessment protocol (RAP) to analyze exotic fish incidence in lakes and to relate them to local and spatial variables in river Doce lakes. Four different techniques constitute the RAP used in 74 lakes and compared to another protocol with hundred times more sampling effort. The exotic fish incidence was associated to local variables (area and lake form, amount of macrophyte mats, pH, oxygen, turbidity and conductivity) and spatial (waterway length and plant cover) associated to fish attributes (body form and occurrence of additional respiration organ) and fishermen interesting in the fish. The RAP was an effective protocol in exotic fish determination including when these fish occurred with low abundance. Fishermen information was relevant to RAP results. Tucunaré and apaiari probability of occurrence were improved with the lakes area increase but any other local variable affected exotic fish occurrence in lakes. The waterway length considering plant cover is very important to explain piranha and tucunaré incidence. These results indicate that the RAP is a good protocol to evaluate exotic fish spread and that exotics spread is limited by only the waterway length. Despite the large spread and colonization potential of exotics fish of this study, their spread may be monitored by suggested RAP, an important tool to study exotics impact on native environment and to conduct our decisions about environmental conservation / Doutorado / Doutor em Ecologia
2

Transformando tropeços em passos de dança: o uso de espécies exóticas para estudos biogeográficos / Transforming stumbling blocks into dancing steps: the use of exotic species in biogeographic studies

LIMA JUNIOR, Dilermando Pereira 27 February 2008 (has links)
Made available in DSpace on 2014-07-29T16:21:15Z (GMT). No. of bitstreams: 1 Dissertacao Dilermando P L Jr.pdf: 360879 bytes, checksum: 1c2f22ea2b7828ee7c6779ffd933fed4 (MD5) Previous issue date: 2008-02-27 / The establishment of exotic species is known for the negative impacts it causes. However, it can be used as models to study the ecological and evolutionary causes of biogeography patterns and access whether the niche conservatism is the determinant of the species limits distribution. The main purpose of this study is to evaluate the difference between pools of exotic fish species in biogeographical regions of the world based on the theories of Niche Conservatism and Evolutionary Dynamics of Latitudinal Gradients of Diversity. We found a strong tendency of the niche conservatism with exotic fishes, but no phylogentic structures of the invaders fishes were found. Therefore, predictive models that purpose to evaluate the potential invasion of fishes has to, include extrinsic factors as climatic conditions, propagule pressure, environmental disturbance, human use and intrinsic factors as parental care and body size of the species. / Os estabelecimentos de espécies exóticas são muito conhecidos por seus impactos, contudo podem servir como modelo de estudo das causas ecológicas e evolutivas dos padrões biogeográficos e avaliar se a conservação de nicho é determinante dos limites de distribuições das espécies. Este estudo tem por objetivo avaliar a diferença entre o conjunto de espécies exóticas de peixes nas diferentes regiões biogeográficas do planeta tendo como base as teorias de conservação filogenética e da dinâmica evolutiva de gradientes latitudinais de diversidade. Encontramos uma forte tendência de conservação de nicho, mas nenhum sinal de estruturação filogenética da invasão. Portanto, modelos preditivos que possuem o intuito de avaliar o potencial invasor de peixes têm, necessariamente, têm que incluir fatores extrínsecos às espécies e à condição climática da região nativa, pressão de propágulos, distúrbios no ambiente, uso humano e fatores intrínsecos como cuidado parental e tamanho corporal das espécies.
3

Impact du changement climatique sur la distribution des populations de poissons. Approche par SIG, modèles et scénarios d'évolution du climat / Climate change impacts on fish species distribution. Approach using GIS, models and climate evolution scenario

Kaimuddin, Awaluddin Halirin 28 June 2016 (has links)
La compréhension des interactions liant la répartition des espèces, la biodiversité, les habitats marins et le changement climatique est nécessaire voire fondamentale pour la mise en oeuvre d’une gestion efficace de la conservation, par exemple la mise en place d’aires marines protégées. Dans cette étude, nous avons travaillé sur l’évolution de richesse de 89 espèces de poissons notées «rares» ou «exotiques» (observées en dehors de leur aire de répartition connue) lié au changement climatique. Nous avons modélisé et prédit leur distribution saisonnière par le modèle SIG en fonction de leurs niches écologiques (déterminée dans cette étude). En superposant tous les modèles en fonction du temps, cette approche permet d’identifier des zones d’occupation préférentielle de forte biodiversité (hotspots). La méthode offre une alternative pour mesurer la richesse d’espèces de façon saisonnière dans des zones peu connues, et de suivre leur mouvement au cours de temps, puis avoir information de base sur l’efficacité de positionnement des aires marines protégés liées à ces zones hotspots. La zone d’étude s’est située dans trois grands écosystèmes marins : le courant des Canaries, le plateau sud de l’Atlantique Européen et les mers celtiques. La région centrale est une zone de transition (entre les eaux tropicales et tempérés) connue pour sa sensibilité aux effets du changement climatique. De 1982 à 2012, la SST augmente constamment au fil du temps, avec des tendances et des magnitudes qui varient selon l’écosystème. Une augmentation du nombre d'espèces dans un écosystème dans une période a été généralement suivie par une tendance à la baisse ou à la hausse dans des écosystèmes adjacents. Les niches écologiques des espèces étudiées ont été estimées par l’extraction des valeurs environnementales à l’échelle mondiale au point d'occurrence au moment de l'observation. Les résultats de niches sont cohérents avec ceux obtenus à partir d’études observationnelles ou expérimentales. La flexibilité du modèle SIG nous a permis de suivre l'évolution saisonnière de distribution des espèces au fil du temps. En général, les espèces montrent une tendance à élargir leur distribution vers le nord, montrant l'effet du réchauffement de l'océan sur la distribution des poissons marins. L’approche de modèle peut être utilisée pour modéliser la distribution des espèces moins connues, ou dans des zones où les données d’occurrences sont peu nombreuses, ainsi que pour prédire le modèle de distribution future. L'analyse spatiale de la superficie des AMPs (Aires Marines Protégées) par pays appartenant à la zone d'étude, montre que le Royaume-Uni puis la France possèdent le plus grand nombre d'AMP ainsi que les superficies totales protégées les plus importantes. La fréquence à laquelle les AMPs (Aires Marines Protégées) sont touchées par les zones de hotspots est fortement influencée par les variations de l’environnement, les zones favorables évoluant alors au fil des saisons. Ainsi, il est important de prendre en compte les variations saisonnières pour la création des AMPs afin de préserver les capacités adaptative des espèces soumises au changement global. / Understanding connectivities among species distributions, biodiversity, marine habitats and climate change is necessary for the design of an effective conservation management, such as in the implementation of marine protected area (MPA). In this study, we observed the richness of 89 "rare" or "exotic" fish species (observed outside their known distribution range) related to climate change. We modeled and predicted their seasonal distributions according to the species ecological niches (determined in this study) using the GIS model. Superposing the models of all species using GIS, we determined the preferential zones or zones of high biodiversity (hotspots) over time. The GIS approach offers an alternative to measure seasonal species richness in poor-data areas. This approach allowed also species track movement over time. This information could be then used to measure the effectiveness of MPA positioning related to the hotspot areas. Our study area covers a wide latitudinal range of the Eastern Atlantic waters, from the warm tropical/subtropical waters to the temperate waters. This area is located in three large marine ecosystems: the Canary current, the South European Atlantic Shelf and the Celtic Seas. The transitional zone in the central region has well known for its sensitivity to the detection of climate change. From 1982 to 2012, the SST in all of studied ecosystems has increased consistently over time, with magnitude and trend varied among ecosystems. The change of number of species in each decadal period differed among ecosystems. Increasing number of species in an ecosystem was generally followed by decreasing trend in adjacent ecosystems. Species ecological niches were obtained by extracting the environmental values in the location of species occurrence at the time of observation. The environmental data and the occurrence records used were at global scale, and the methods yields coherent results with the results obtained from observational studies. The flexibility of GIS Model used in this study allowed us to follow the evolution of species seasonal distribution over time. Generally, most of the studied species showed a northbound trend in their distribution. These northbound tendencies were more evident in the middle region, confirming the effect of global warming in shifting marine species distribution. This approach provides an alternative of measuring seasonal richness of poor-known species and/or modeling in poor-data areas. The results present a complete picture of predictive number of species in an area over time. MPAs superficial analysis by country (countries lying in the study area) showed that UK has the highest number of MPA and the largest protected areas, following by France and Mauritania. Frequencies of the MPAs touched by the hotspot were strongly influenced by seasonal variations. Thus, considering seasonal variations in a conservation effort could preserve species adaptive variation under environmental changes. Overall, our works provide several alternative methods for species distribution studies and for studies poor-known species in data-poor area. The results provide evidences of ocean warming effect in shifting marine fish distribution.

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