Banca de DEFESA: BÁRBARA BEZERRA DE CARVALHO MENDES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : BÁRBARA BEZERRA DE CARVALHO MENDES
DATE: 30/06/2023
TIME: 14:00
LOCAL: meet.google.com/qnj-dxjj-fcc
TITLE:

Study of Species Diversity and Persistence Through Two Models Using Computational Simulations

KEY WORDS:

Ecosystem, resources, competition for resources, species diversity, spatial xi heterogeneity, evolutionary theory, trade-off, metapopulation.

PAGES: 76
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUMMARY:

The competition theory states that, in equilibrium, the number of coexisting species competing with each other cannot exceed the number of limiting resources in an ecosystem, known as the Competitive Exclusion Principle. However, there is a biodiversity puzzle for aquatic ecosystems, where it is observed that a limited amount of resources supports the coexistence of a wide variety of phytoplankton species, known as the Plankton Paradox. Experimental results show a unimodal relationship between species diversity and resource quantity/productivity in heterogeneous environments, as well as non-equilibrium dynamics that enable the coexistence of a large number of species competing for limited resources. In the case of competition for interactively essential resources, studies have shown that competition generates fluctuations in species abundance and allows for the coexistence of many species with a lower amount of resources. Different resource limitations favor the dominance of different species, and changes in their quantities can alter species composition. One mechanism that shapes ecological and evolutionary processes observed in nature is dispersal. This concept is part of the life history of many organisms, involving the movement of offspring throughout the life cycle of virtually all plants and animals. Due to its inherent costs, dispersal has trade-offs with many life history traits. In this thesis, our objectives are to study the effects of resource quantity in an ecosystem on diversity by comparing two types of resources (essential and interactively essential) using a spatially structured computational model, and to investigate species persistence through simulations of a metapopulation model where individuals experience trade-offs between survival and dispersal. We investigate how the distribution of resources in the ecosystem, as well as the quantity available for each resource, affect the equilibrium of the ecosystem. We have observed that an increase in spatial heterogeneity leads to an increase in the number of species, reaching a peak at an intermediate level of heterogeneity, and then decreasing for higher levels of heterogeneity. We have also noticed that variations in the type of resource in competition result in variations in diversity peaks and population sizes. Depending on the scenario, specialist or generalist species may dominate. Regarding the studied metapopulation model, we highlight that the costs of dispersal influence the evolutionary outcome, which depends on the shape of the trade-off relationship. In cases of strong trade-offs, increased mortality due to dispersal leads to reduced levels of dispersal, while weak trade-offs result in higher mobility being observed. One of the main findings was the existence of a critical trade-off where the metapopulation is no longer viable, meaning it is destined for extinction.

COMMITTEE MEMBERS:
Externo à Instituição - ALEXANDRE DA SILVA ROSAS - UFPB
Externo ao Programa - 2508764 - PAULO JOSE DUARTE NETO - nullExterno ao Programa - 2324397 - PEDRO HUGO DE FIGUEIREDO - nullExterna ao Programa - 1509422 - TATIJANA STOSIC - nullPresidente - VIVIANE MORAES DE OLIVEIRA