Banca de DEFESA: AUGUSTO CESAR DA SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : AUGUSTO CESAR DA SILVA
DATE: 16/02/2023
TIME: 14:00
LOCAL: Google Meet - meet.google.com/mdv-mdrx-zne
TITLE:

Biogeographical Patterns and Ecological Strategies in the Caatinga Domain and the Brazilian Dry Diagonal

KEY WORDS:

Bioregionalization; CSR; Drylands; Environmental filters; Human effects; Traits

PAGES: 253
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Despite the growing knowledge about the distribution and functioning of vegetation in seasonally dry environments, its internal structure and the organization of its functional attributes are still poorly understood. The objectives of each chapter of this Thesis were 1) to delineate the compositional sub-regions in the Caatinga domain, considering the species abundances, and evaluating the determinants of their spatial distribution, 2) to identify the functional strategies of the species in the Caatinga within the scope of CSR theory and global functional spectrum, and 3) identify how current or historical environmental and human filters determine the structuring of functional attributes in the Brazilian dry diagonal (Caatinga-Cerrado-Pantanal).For the first chapter, subregions were identified and mapped, partitioning interpolated NMDS ordering axes using the K-means method. We used a selection of GLM models to identify the set of variables that explained bias across subregions. For the second chapter, the classification of ecological strategies using species functional data (leaf area, leaf dry matter content, leaf nitrogen, leaf mass per area, wood density and potential plant height) were used to calculate the CSR and functional space for Caatinga. We used the StratFY matrix and a phylogenetic PCA to generate CSR strategies and functional correlations. For the third chapter, an extended RLQ analysis was used to identify the relationship of attributes and their respective environmental and human filters. . For the first chapter, the K-means analysis identified 10 sub-regions. The combined fractions of aridity, topography and soil, stability of the biome in the Pleistocene and the historical effect of indigenous activities explain most of the variability in the subregions. For the second chapter, the strategies of the species in the caatinga are mostly concentrated in the competitor-stressor space of the CSR triangle. The first two pPCA axes explain 76% of the attribute variation, reflecting in two main functional groups in the Caatinga. For the third chapter, the RLQ indicated the presence of two functional gradients related to categorical attributes of the leaf and fruit filtered by the combination of soil, topography, and current and historical human factors. The spatial structuring patterns of abundance and their functional strategies are an important contribution to understanding the action of environmental filters and functional strategies of species in seasonally dry environments, the results presented here can support important decisions in conservation and management in these environments.

COMMITTEE MEMBERS:
Presidente - 1837921 - ALEXANDRE FADIGAS DE SOUZA
Externa ao Programa - 1813882 - ALICE DE MORAES CALVENTE VERSIEUX - UFRNExterna à Instituição - ANGELA PIERRE VITÓRIA
Interna - 1677189 - GISLENE MARIA DA SILVA GANADE
Externo à Instituição - SERGIO DE FARIA LOPES