Banca de DEFESA: Leonardo Beserra da Silva

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : Leonardo Beserra da Silva
DATE: 29/08/2024
TIME: 09:00
LOCAL: Videoconferencia
TITLE:

Diversity and spatial dynamics of the phytoplankton community in lakes on the floodplain of the Middle Araguaia River

KEY WORDS:

Metacommunities, beta diversity, land use and occupation, dispersal.

PAGES: 59
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

The spatial patterns dynamics of biological community structure can be better understood through the metacommunity theory. This approach evaluates the effects of local processes and regional processes. In addition, beta diversity can be used in a complementary way to understand how these different processes cause changes in biological communities. Floodplains are dynamic environments controlled mainly by the flood pulse, which promotes the homogenization of the physical and chemical characteristics of water bodies, including biological communities. Among these communities, phytoplankton differ in that they are a polyphyletic group whose main characteristic is the ability to carry out photosynthesis and live in the water column. This group can be influenced by environmental factors and the dispersal capacity of its individuals. Dispersal occurs passively, with organisms being carried mainly by water flow, wind or trapped by animals. For these dispersal events to be successful, connectivity between habitat patches is essential. In view of the above, the aim of this thesis is to evaluate the predictors of phytoplankton community and beta diversity in lakes on the Araguaia River floodplain and finally to evaluate the action of backwaters in the main channel of the Araguaia River as stepping stones for phytoplankton dispersal. To evaluate the influence of environmental and spatial predictors on the phytoplankton community, we used the Metacommunity Theory with the variance partitioning approach. To analyze beta diversity, which was considered as the total variation of the community and divided into two compartments (turnover and nestedness), we carried out redundancy analyses based on a distance matrix to investigate the action of the predictors in each of the compartments. Finally, to detect the action of backwaters as stepping stones, the densities of each environmental factor (backwater, river channel and opposite bank) were compared, and the richness was compared in the same way. For these tests, we used Analysis of Variance for repeated samples (ANOVA) and the Friedman test for non-parametric data. The spatial predictor was the main predictor of the phytoplankton community, and we found a beta diversity value of 0.34 and 0.22 for the taxonomic data and functional groups, respectively. Finally, the backwaters did not differ in density or richness from the other types of environments evaluated. Our results highlight the importance of having an integrated analysis of different predictors and theories for a better understanding of phytoplankton dynamics.

COMMITTEE MEMBERS:
Externo à Instituição - Hasley Rodrigo Pereira - SEDUC
Externo à Instituição - Hugo de Oliveira Barbosa - CNPq
Interna - 3049879 - ERINA VITORIO RODRIGUES
Presidente - 1524495 - LUDGERO CARDOSO GALLI VIEIRA
Interno - 2275533 - LUIZ FELIPPE SALEMI