Banca de QUALIFICAÇÃO: ANDRÉ YURI SANTOS PORTIOLE BELO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : ANDRÉ YURI SANTOS PORTIOLE BELO
DATA : 31/10/2018
HORA: 14:30
LOCAL: Sala de Reuniões - DECOL
TÍTULO:

THE IMPORTANCE OF SOLAR EXHIBITION AS THE MECHANISM MEDIATOR OF THE EFFECTS OF THE DIVERSITY OF LITTER ON THE DECOMPOSITION PROCESS.

PALAVRAS-CHAVES:

Decomposition, litter functional diversity, environmental context, photodegradation.

 

PÁGINAS: 61
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
RESUMO:

Organic matter decomposition is an important mechanism for nutrient cycling and carbon balance in ecosystems. Studies over the last two decades have pointed to an important role of the litter diversity, especially the functional one, as a determining factor of the decomposition rates. Evidence also points to the importance of the environmental context as a mediating factor of such diversity effects. All known mechanisms by which the diversity of litter affects decomposition results from biotic interactions of the decomposing fauna with each other and with the litter, suggesting that the importance of the diversity of litter in environmental contexts that favors the decomposition through direct action of abiotic mechanisms should be weak or nonexistent. The objective of this work was to verify experimentally how the effects of the litter diversity in the decomposition vary between two environmental contexts, one where the abiotic decomposition through photodegradation is relevant and another where the fauna performance assumes greater importance. Litterbags containing 3 g of foliar debris from 4 species handled in monoculture and combined in all possible bi-cultures were placed to decompose for 6 months in a condition under vegetation (favoring biotic decomposition) and exposed to the sun (favoring abiotic decomposition). In general, the decomposition was around 30% higher in the exposed condition than under the vegetation, indicating the importance of the photodegradation process in the decomposition. No significant effects of the mixture of litter on the decomposition of the mixture as a whole and its isolated components were observed. There was also no interaction of diversity with the environmental context for any situation. However, some non-additive antagonistic effects occurred tenuously in function of functional diversity, but most of these presented more consistent with an idiosyncratic pattern among the mixtures, tending the mixture of debris to decelerate the decomposition in some treatments. The higher variability (standard deviation) in the decomposition rates of the detritus exposed to the direct effect of photodegradation suggests that the positioning (i.e. percentage of overlap) of litter on litterbag can be an important factor in determining non-additive effects in situations where photodegradation is important. This effect combined with a probable negative selection effect, that is, species with a greater specific leaf area would be more likely to decompose rapidly in monocultures than mixtures, should be the ones responsible for the results. These results are the first to present possible mechanism of how the diversity of debris can affect the decomposition through the direct action of abiotic factors on the decomposition.

MEMBROS DA BANCA:
Presidente - 1714892 - ADRIANO CALIMAN FERREIRA DA SILVA
Interno - 1837921 - ALEXANDRE FADIGAS DE SOUZA
Externo à Instituição - JOSÉ LUIZ ALVES SILVA