Banca de DEFESA: RAFAELA DE SOUSA GOMES GONÇALVES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : RAFAELA DE SOUSA GOMES GONÇALVES
DATE: 15/12/2021
TIME: 13:00
LOCAL: on-line
TITLE:

Spatial and temporal assessment of the ichthyofauna and their environmental relationships

KEY WORDS:

coastal fish, functional diversity, beta diversity, environmental variables

PAGES: 67
BIG AREA: Ciências Biológicas
AREA: Zoologia
SUBÁREA: Zoologia Aplicada
SUMMARY:

Shallow water estuarine environments have many habitats that favor colonization and
use by different fish species. These coastal ecosystems are undergoing increasingly
impacts resulting from industrial and urban developments in their surroundings,
resulting in a growing loss of biodiversity, which may be accompanied by the losses of
important ecological functions. Investigating the patterns and processes that act on
biodiversity is essential to obtain a more view of the dynamics and roles of communities
in the ecosystems, and for this, short and long-term studies are essential. Studies have
mainly addressed the taxonomic structure, requiring a more integrated approach, aiming
to understand the dynamics and roles of functional groups in space and time. The
present study, divided into two chapters, aims to understand the spatiotemporal
dynamics of the ichthyofauna of shallow areas in a tropical bay in a growing process of
environmental change, exploring taxonomic and functional aspects. In chapter 1, we
seek to describe the relationship between beta diversity and environmental
heterogeneity, in order to test the hypothesis that environmental heterogeneity
influences biodiversity. A weak positive relationship between environmental
heterogeneity and beta diversity was detected, suggesting that more heterogeneous
environments tend to have greater variations in biological composition. In Chapter 2,
we assess temporal changes (1983-1985, 1999-2001, and 2017-2019) in taxonomic and
functional indices. Previous studies have already reported a decline in the fish richness
in the shallow areas of Sepetiba Bay, but the investigation of how the functional groups
have been affected has not yet been investigated. We tested the hypothesis that
functional diversity indices also changed over time, as a result of environmental
changes in the recent decades. We found a substantial decrease in species richness and
abundance in more recent periods compared to 1983-1985. However, the functional
structure remained relatively stable, with the exception of functional richness, which
showed a significant decrease, indicating an impact on the amount of functional space
occupied by the local community, so that some of the resources potentially available to
the community were no longer used. The stability observed in the functional descriptors
can be explained by the fact that estuarine environments tend to have high functional
redundancy due to the restrictions imposed by the marked environmental gradient,
which can result in the convergence of functional traits between species, ensuring that,
despite losses in richness and abundance of species, the main functions can be
maintained. The information obtained in this study confirms that the use of functional
indices is essential to complement taxonomic assessments, giving a detailed view of the
extent of biodiversity loss in impacted environments.

BANKING MEMBERS:
Externo à Instituição - ANDRÉ LUIZ MACHADO PESSANHA - UEPB
Externo à Instituição - FÁBIO LAMEIRO - UFRGS
Externa à Instituição - ELLEN MARTINS CAMARA - UFRRJ
Interno - 387200 - FRANCISCO GERSON ARAUJO
Externa à Instituição - MARCIA CRISTINA COSTA DE AZEVEDO - UFRRJ
Externa à Instituição - TAYNARA PONTES FRANCO - UFRJ