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Dynamics of structured populations

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Renato Mendes Coutinho
Total Authors: 1
Document type: Doctoral Thesis
Press: São Paulo. 2016-08-26.
Institution: Universidade Estadual Paulista (Unesp). Instituto de Física Teórica (IFT). São Paulo
Defense date:
Advisor: Roberto André Kraenkel

This thesis broaches the dynamics of structured biological populations. These structures consist of anything that distinguishes individuals of the same population: sex, age, stage, size, spatial location, individual characteristics, etc. We explored a wide range of ecological systems and modeling approaches, working closely with biologists and ecologists in problems arising in specific contexts. We studied some spatially explicit models for dispersal in connection with stage structure. Those include an integrodifference model for a blowfly invasion in Brazil during the 1970s, parametrized with laboratory and reanalyzed field data to predict a posteriori the invasion speed, obtaining a reasonable agreement. We also study the phenomenon known as habitat split, where immature individuals of species with complex life history, such as amphibians dependent on water streams to reproduce, are physically separated from their adult habitat, what can increase their mortality dramatically and lead to sharp extinction thresholds. We also investigate a model for population migration from a patch in a scenario of strong seasonality, where dispersal is possible only during part of the year, leading to distinct scenarios depending on that duration relative to the characteristic time for diffusion into the matrix. Then we look at problems involving coexisting species in communities, beginning with the dynamics and coexistence of two species engaging in intraguild mutualism, in which they are both specialist predators on a common, shared resource, but benefit from each other’s presence because of increased predation efficiency, leading to stable coexistence. We also develop an eco-epidemiological model for malaria transmission in the Atlantic Forest that incorporates feedbacks from ecological factors into biting rate and mosquito population size. Parametrized with data, it explains the absence of malaria transmission in the area, in contrast to the Ross-MacDonald model. We introduce a novel framework to predict the population dynamics of cold-blooded animals taking into account temperature variation and stage structure. We use individual life-history traits (birth, death and development rates) and their response to temperature to parametrize the population dynamics model, applying it to two sets of questions: population viability and (temperature-dependant) intra-specific competition. Finally, we explore the dynamics of predator-prey communities in which each population is composed by many species, characterized by their traits. Prey can invest more in defense against predators, at the cost of slower growth, while predators can be more or less selective on which prey it feeds on, but selective predators are more efficient. These traits can vary along a range of values, each species corresponding to a trait value. While traditional theory simplifies the description of the system by modeling only the aggregate measures of the distribution of traits in the population, we follow the dynamics of the whole system in order to learn how trait distributions with large variance, especially bimodal ones, change the outcomes of the community dynamics. We observe a range of behaviors, and characterize under which circumstances we expect to see drastic deviations from the usual aggregate models. (AU)

FAPESP's process: 10/09464-1 - Structured populations dynamics
Grantee:Renato Mendes Coutinho
Support Opportunities: Scholarships in Brazil - Doctorate