Banca de QUALIFICAÇÃO: FABIANE BARRETO SOUZA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : FABIANE BARRETO SOUZA
DATE: 22/11/2022
TIME: 10:00
LOCAL: Salvador, BA
TITLE:

Influence of environmental variables on the structure of streams fish assemblages from Chapada Diamantina, Brazil

KEY WORDS:

Functional ecology, environmental variables, Community ecology

PAGES: 20
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUBÁREA: Ecologia de Ecossistemas
SUMMARY:

The main goal of this work is measuring the relative importance of environmental variables at local and catchment scales on functional structure of stream fish assemblages. To do so, we use the Hierarchical Modelling of Species Communities framework, a JSDMs model that quantify community level responses to the environment. With this analysis, we intend to answer the following questions (a) Are local variables more important than catchment factors on structuring the assemblage compositions of streams? (b) The ecomorphological traits influence the response of the species to the environmental variables? (c) The biotic interactions influence species occurrences?  We fitted models with two alternative response data: community matrix (site x species) with Presence/Absence data (PA), and Abundance data (ABU). In addition, given that species response may vary according to scale, we tested models considering the environmental variable to each scale separately (Local and Catchment) and with all variables together. Species traits (20 ecomorphological morphological traits) were also included in the model. The variables at local scale together explained a total of 72.9 % of the variance in the PA model and 73% for the ABU model. The traits explain only 33.93% of the variation in species abundances and 30.51% in species occurrence. For the PA model no significative relations between the species were found. For the ABU model were found a positive correlation between Copionodon pecten and Hypostomus sp., Copionondon pecten and Pamphorichthys hollandi, and between Hypostomus sp and Pamphorichthys hollandi. Our results highlight that the structure of fish assemblage on streams need to be assessed under different environmental scales, but the use of quantitative local-scale metrics is best predictor for headwater stream from caatinga, specially from the Chapada Diamantina region.

COMMITTEE MEMBERS:
Interno - ***.495.557-** - ALEXANDRE CLISTENES DE ALCANTARA SANTOS - UNIRIO
Externo à Instituição - ADRE TEIXEIRA DA SILVA - UEFS
Externo à Instituição - NUNO ALBERTO MARINHEIRO CAIOLA