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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

Modelo metapopulacional de múltiplas espécies em ambiente heterogêneo

Silva, Otonio Dutra da January 2018 (has links)
Os modelos metapopulacionais são uma ferramenta muito importante nos estudos de habitats fragmentados. Sendo a natureza bastante diversificada, a análise de ambientes heterogêneos e primordial para a construção de uma dinâmica mais próxima da realidade. Com isso, buscou-se construir um modelo metapopulacional heterogêneo de múltiplas espécies, cujo objetivo e encontrar um critério de estabilidade assintótica de orbitas de sincronização parcial. Para tanto e descrito um ambiente com n patches ou sítios conectados por movimentos de migração divididos em conjuntos, que apresentam diferentes características de sobrevivência e reprodução de cada espécie. Obteve-se uma representação para matriz Jacobiana do sistema, al em de um critério para o cálculo do expoente de Lyapunov. Sendo possível, então, uma generalização para um modelo metapopulacional heterogêneo de múltiplas espécies. / The metapopulational models are an important appliance in the fragmented habitats studies."The nature is very diversi ed, so the heterogeneous environments analysis is primordial for close construction of dynamics realities. Therefore, this research aimed to construct a metapopulational heterogeneous model of multiple species in order to nd an asymptotic stability standard of partial synchronization of orbits. Hence an environment with n patches or connected sites by migration movements were described, whose were divided into groups with di erent survival and reproduction characteristics of each species. A Jacobian matrix of system representation was obtained, as well as a Lyapunov exponent calculation criteria. Thus, a generalization for a heterogeneous metapopulational model of multiple species was possible.
2

Modelo metapopulacional de múltiplas espécies em ambiente heterogêneo

Silva, Otonio Dutra da January 2018 (has links)
Os modelos metapopulacionais são uma ferramenta muito importante nos estudos de habitats fragmentados. Sendo a natureza bastante diversificada, a análise de ambientes heterogêneos e primordial para a construção de uma dinâmica mais próxima da realidade. Com isso, buscou-se construir um modelo metapopulacional heterogêneo de múltiplas espécies, cujo objetivo e encontrar um critério de estabilidade assintótica de orbitas de sincronização parcial. Para tanto e descrito um ambiente com n patches ou sítios conectados por movimentos de migração divididos em conjuntos, que apresentam diferentes características de sobrevivência e reprodução de cada espécie. Obteve-se uma representação para matriz Jacobiana do sistema, al em de um critério para o cálculo do expoente de Lyapunov. Sendo possível, então, uma generalização para um modelo metapopulacional heterogêneo de múltiplas espécies. / The metapopulational models are an important appliance in the fragmented habitats studies."The nature is very diversi ed, so the heterogeneous environments analysis is primordial for close construction of dynamics realities. Therefore, this research aimed to construct a metapopulational heterogeneous model of multiple species in order to nd an asymptotic stability standard of partial synchronization of orbits. Hence an environment with n patches or connected sites by migration movements were described, whose were divided into groups with di erent survival and reproduction characteristics of each species. A Jacobian matrix of system representation was obtained, as well as a Lyapunov exponent calculation criteria. Thus, a generalization for a heterogeneous metapopulational model of multiple species was possible.
3

Population genetic patterns in continuous environments in relation to conservation management

Wennerström, Lovisa January 2016 (has links)
Genetic variation is a prerequisite for the viability and evolution of species. Information on population genetic patterns on spatial and temporal scales is therefore important for effective management and for protection of biodiversity. However, incorporation of genetics into management has been difficult, even though the need has been stressed for decades. In this thesis population genetic patterns in continuous environments are described, compared among species, and related to conservation management. The model systems are moose (Alces alces) in Sweden and multiple species in the Baltic Sea, with particular focus on the Northern pike (Esox lucius). The spatial scope of the studies is large, and much focus is dedicated towards comprehensive sampling over large geographic areas. The moose population in Sweden is shown to be divided into two major subpopulations, a northern and a southern one. Both subpopulations show genetic signals of major population bottlenecks, which coincide with known population reductions due to high hunting pressure (Paper I). The Northern pike in the Baltic Sea shows relatively weak, but temporally stable population genetic structure. An isolation by distance pattern suggests that gene flow primarily takes place among neighboring populations, either over shortest waterway distance or along the mainland coast, with island populations acting as stepping stones (Paper III). In a comparative study of seven Baltic Sea species no shared genetic patterns were found, either in terms of genetic divergence among or genetic diversity within geographic regions. These results complicate the incorporation of genetic data into management, because it suggests that no generalization can be made among species in the Baltic Sea, but that species-specific management is needed (Paper II). Over the last 50 years, 61 species in the Baltic Sea have been studied with respect to spatial genetic patterns. For over 20 of these species information of direct relevance for management is available. Relevant information is synthesized into management recommendations (Paper IV). This thesis provides vital information on spatial and temporal genetic structure for a number of ecologically and socio-economically important species. It shows that such information is important to consider species by species and that both local and metapopulation approaches are needed to effectively manage genetic diversity in e.g. moose and pike. Further, it identifies for which organisms in the Baltic Sea genetic information exists, how it can be used, and where important information is lacking. In order to successfully make use of genetic data in management, effective communication channels between academia and policy-makers are needed. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.</p>
4

Spatio-Temporal Analysis of Foraging Behaviors of Anelosimus studiosus Utilizing Mathematical Modeling of Multiple Spider Interaction on a Cooperative Web

Quijano, Alex John, Joyner, Michele L., Ross, Chelsea, Watts, J. Colton, Seier, Edith, Jones, Thomas C. 07 November 2016 (has links)
In this paper, we develop a model for predation movements of a subsocial spider species, Anelosimus studiosus. We expand on a previous model to include multiple spider interaction on the web as well as a latency period during predation. We then use the model to test different spatial configurations to determine the optimal spacing of spiders within a colony for successful capture during predation. The model simulations indicate that spiders uniformly spacing out along the edge of the web results in the most successful predation strategy. This is similar to the behavior observed by Ross (2013) in which it was determined to be statistically significant that during certain times of the day, spiders were positioned along the edge more than expected under complete spatial randomness.

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