Banca de DEFESA: JOSÉ LUIZ ALVES SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : JOSÉ LUIZ ALVES SILVA
DATA : 09/07/2018
HORA: 13:30
LOCAL: Sala de videoconferência POP - Centro de convivência UFRN
TÍTULO:

UNDERSTANDING PLANT FUNCTIONING, COMMUNITY ORGANIZATION, AND EFFECTS OF PLANTS ON THE RESTINGA ECOSYSTEM

PALAVRAS-CHAVES:

Coastal plains, Stressful environments, Seasonally dry forest, Biochemistry, Leaf anatomy, Primary productivity

PÁGINAS: 104
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
RESUMO:

Plant form and function depend on internal stimuli (genetics and phenotypic plasticity) as well as external stimuli (environment) that act in the leaf, stem, and root. Water shortages and poor-nutritional sandy soils in the coastal region are cited as the main external stimuli to plants in the Restinga ecosystem. It has been proposed that coordination among plant organs tends to increase with environmental harshness due to a decrease in the viable niche space and an increase in the costs to adopt ecological strategies out of this viable niche space. The first thesis chapter aimed to test this hypothesis in the Restinga. Pairwise correlations of 21 functional traits of 21 species revealed that the stem had greater internal coordination than the leaf organ. In addition, a multivariate analysis showed high independence between stem and leaves, suggesting that stressful environments do not necessarily have plants with high coordination between organs. These results were published in Ecology and Evolution. Functional coordination is directly linked to the success of plant occurrence and may interfere in the community organization. It is still not clear whether weak neutral effects can influence the distribution of functional traits, even though the community shows random patterns of compositional and phylogenetic structure. We address this question in the second thesis chapter. Functional variation in the community resulted from phenotypic responses of all species and individuals rather than particular sets of species or individuals, indicating environmental responses, but not strong patterns in the spatial distribution of traits. In this regard, we accept that the Restinga in the Northeastern South America is influenced by weak neutral effects. We concluded that occurrence and phylogenetic analyses may be insufficient for a complete understanding of the community and should be complemented with functional analyses. The manuscript was submitted to the Journal of Vegetation Science. A weak environmental response may result from low niche partitioning among species, which has been described as the main mechanism underlying the relationships between biodiversity and ecosystem processes. The third chapter assessed the extent to which biodiversity and the environment influence annual litter production, as well as the combined role of rare to abundant species. A path analysis showed that the canopy cover had the greatest influence on production, followed by species richness. Environmental factors had only indirect effects. In addition, the combined contribution of several rare species was lower than the contribution of a few common species. These results suggest that diversity is important not only in short-term and small-scale experiments in the temperate region but also in the plot-scale of tropical forests, mainly through the role played by common species. As a general conclusion, Restinga ecosystem has patterns that deviate from the ones expected in the literature, which highlights the relevance of its biodiversity

MEMBROS DA BANCA:
Interno - 1714892 - ADRIANO CALIMAN FERREIRA DA SILVA
Presidente - 1837921 - ALEXANDRE FADIGAS DE SOUZA
Externo à Instituição - BERNARDO MONTEIRO FLORES - UNICAMP
Externo ao Programa - 363.178.178-47 - EDSON APARECIDO VIEIRA FILHO - UFRN
Externo à Instituição - MARIANA GOMES BENDER - UFSM