abstract: A functioning food web is the basis of a functioning community and ecosystem. Thus, it is important to understand the dynamics that control species behaviors and interactions. Alterations to the fundamental dynamics can prove detrimental to the future success of our environment. Research and analysis focus on the global dynamics involved in intraguild predation (IGP), a three species subsystem involving both competition and predation. A mathematical model is derived using differential equations based on pre-existing models to accurately predict species behavior. Analyses provide sufficient conditions for species persistence and extinction that can be used to explain global dynamics. Dynamics are compared for two separate models, one involving a specialist predator and the second involving a generalist predator, where systems involving a specialist predator are prone to unstable dynamics. Analyses have implications in biological conservation tactics including various methods of prevention and preservation. Simulations are used to compare dynamics between models involving continuous time and those involving discrete time. Furthermore, we derive a semi-discrete model that utilizes both continuous and discrete time series dynamics. Simulations imply that Holling's Type III functional response controls the potential for three species persistence. Complicated dynamics govern the IGP subsystem involving the white-footed mouse, gypsy moth, and oak, and they ultimately cause the synchronized defoliation of forests across the Northeastern United States. Acorn mast seasons occur every 4-5 years, and they occur simultaneously across a vast geographic region due to universal cues. Research confirms that synchronization can be transferred across trophic levels to explain how this IGP system ultimately leads to gypsy moth outbreaks. Geographically referenced data is used to track and slow the spread of gypsy moths further into the United States. Geographic Information Systems (GIS) are used to create visual, readily accessible, displays of trap records, defoliation frequency, and susceptible forest stands. Mathematical models can be used to explain both changes in population densities and geographic movement. Analyses utilizing GIS softwares offer a different, but promising, way of approaching the vast topic of conservation biology. Simulations and maps are produced that can predict the effects of conservation efforts. / Dissertation/Thesis / M.S. Applied Biological Sciences 2012

Submitted by Liliane Ferreira (ljuvencia30@gmail.com) on 2018-04-04T14:02:36Z No. of bitstreams: 2 Tese - Jaques Everton Zanon - 2018.pdf: 3230898 bytes, checksum: 7e20d6f4c53febb70d99701805d33565 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-04-05T12:50:16Z (GMT) No. of bitstreams: 2 Tese - Jaques Everton Zanon - 2018.pdf: 3230898 bytes, checksum: 7e20d6f4c53febb70d99701805d33565 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-04-05T12:50:16Z (GMT). No. of bitstreams: 2 Tese - Jaques Everton Zanon - 2018.pdf: 3230898 bytes, checksum: 7e20d6f4c53febb70d99701805d33565 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Population synchrony occurs when abundance of different local populations increase and decrease simultaneously along time. In terms of other characteristics that can be measured in ecosystems, such as biomass and nutrient contents, intrinsic and extrinsic processes have also been used to explain synchronic variation patterns. Synchrony may clarify whether regional processes are more important than local processes. This study used epiphytic biomass data (chlorophyll-a) from eight locations collected in a floodplain through 11 years. The goal was to estimate epiphytic biomass synchrony. We anticipated that high synchrony levels would be consistent with the strong impact of floods, which affect different floodplain habitats simultaneously. This is equivalent to the Moran effect. In contrast, low synchrony levels would be consistent with the hypothesis that high environmental heterogeneity of floodplains hampers synchrony. Our results indicated low synchrony and its variation was not correlated with geographic or environmental distances and neither with environmental synchrony. Also, regression models demonstrated low predictive power of local environmental variables in predicting biomass variation in the different sites. In addition, we performed a meta-analysis that confirms the generality of our findings. In conclusion, these results challenge the efficiency of epiphytic biomass as an ecological indicator, at least in floodplain system. / Populações locais, mesmo quando distribuídas em amplas extensões espaciais, variam de forma sincrônica, ou seja, suas abundâncias aumentam e diminuem simultaneamente ao longo do tempo. Em termos de outras características que podem ser mensuradas em ecossistemas, tais como, biomassa e teores de nutrientes, os conceitos de coerência temporal, forças intrínsecas e extrínsecas também têm sido utilizadas para explicar padrões sincrônicos de variação. A magnitude do fenômeno de sincronia pode elucidar se o padrão que processos extrínsecos (e.g., efeitos de fontes difusas sobre as concentrações de nutrientes) são mais importantes que processos intrínsecos (efeitos de fontes pontuais). Nesse estudo nós utilizamos dados de biomassa (clorofila a) do perifíton em 8 locais e 37 meses coletados em uma planície de inundação. O objetivo desse estudo foi de avaliar o padrão de sincronia da biomassa perifítica. Primeiro, nós conjecturamos que elevados níveis de sincronia seriam condizentes com o forte impacto das inundações que influenciam simultaneamente diferentes hábitats de uma planície de inundação, analogamente ao efeito de Moran. Por outro lado, baixos níveis de sincronia seriam condizentes com a hipótese de maior importância da heterogeneidade ambiental (ao longo do espaço), uma vez que planícies de inundação são consideradas um mosaico de manchas de habitats. Em suma nós encontramos baixos valores de sincronia. Variações na sincronia não foram correlacionadas com a distâncias geográfica e ambiental tampouco com a sincronia ambiental. Ainda a nossos modelos GLS demonstraram pouco poder preditivo do ambiente local acerca da biomassa. Como conclusão nosso estudo demonstra o baixo poder preditivo da biomassa perifítica acerca de fatores regionais e locais nos ambientes estudados.