Banca de QUALIFICAÇÃO: JOYCE ANANDA PAIXÃO DUARTE

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : JOYCE ANANDA PAIXÃO DUARTE
DATA : 24/07/2019
HORA: 08:30
LOCAL: ICA SALA 1
TÍTULO:

ASPECTS OF REPRODUCTIVE ECOLOGY OF Euxylophora paraensis Huber IN A FOREST FRAGMENT IN THE MUNICIPALITY OF PARAGOMINAS-PARÁ.

PALAVRAS-CHAVES:

Pau-amarelo; forest fragmentation; natural regeneration; phenology; Amazônia

PÁGINAS: 50
GRANDE ÁREA: Ciências Agrárias
ÁREA: Recursos Florestais e Engenharia Florestal
RESUMO:

ABSTRACT

In the Brazilian Amazon, forest fragments have increased alarmingly in the region, leading many species to local extinction. Euxylophora paraensis Huber is an endemic species in the north of Brazil that presents a natural occurrence restricted to only the states of Pará and Maranhão. Demographic limitation, intense logging, and increased deforestation in areas of natural occurrence have led to this species entering the endangered species list classified as Critically Endangered. The increasing fragmentation and the threat of extinction of E. paraensis motivated this work whose objective is to understand some aspects of the reproductive biology of the species, such as phenology and natural regeneration in a forest fragment in the municipality of Paragominas - Pará, aiming at their resilience and maintenance of populations in the forest. Vegetative and reproductive phenological observations were made monthly for a period of five years (2013-2017) in 38 individuals: 25 seed bearers in border area, 5 in intermediate area and 7 within the fragment. To characterize the phenodynamics of the E. paraensis population, the activity and intensity indexes of vegetative and reproductive phenophases were calculated monthly. Phenophase synchrony was calculated in the different environments (border, intermediate and interior of the fragment) during the observed period. In order to correlate the abiotic factors (precipitation, mean temperature, hours with sun and radiation) with the phenophases (foliation, floral bud, flower and fruiting) the Spearman correlation was used. To quantify the natural regeneration, ten matrices were selected, five in each environment (edge and interior of the fragment), with regenerating individuals near the matrix tree. The density of individuals at the border and in the interior was compared using a 2x2 factorial design, the factors being the environment (border and interior) and size of individuals (<300cm height and ≥ 300cm height). The annual periodic increment (IPA) of the diameter and height was calculated individually for each plant that remained alive during all measurements. In order to verify the relation of the distribution of the natural regeneration with the distance of the matrix tree and the crown area, the Pearson correlation was calculated followed by Linear Regression Analysis. The spatial distribution pattern of E. paraensis was determined using the Morisita Index (MI) and the level of significance obtained by the Chi-square test. E. paraensis is a perennial species, where leaf fall and budding occur simultaneously and the crown does not completely lose its leaves. Reproductive phenophases are annual. The population presented floral bud, flower and fruit once a year in all observed period. There was high synchrony between the environments (border, intermediate and interior) for all reproductive phenophases, being the most synchronous fruiting in the innermost areas of the fragment. The correlation of reproductive phenomena with climatic variables was highly significant, with rainfall being the only negatively correlated variable, where floral buds, flower opening and fruit presence started with the end of the rainy season. A total of 599 living regenerating individuals were found in the last assessment. The density of regeneration was not significant between the environments, however, there is a tendency for the interior of the fragment to have a greater number of adult individuals and in the border individuals in the earliest stages of life. It was observed a higher diameter increment of the natural regeneration located at the edge of the fragment (ANOVA, p <0.01), regardless of the size of the individual. As for height increment, the environment and the size of the individuals were highly significant (ANOVA, p <0.001). Larger individuals (> 300cm) increase grow faster in height both in the border area and in the interior of the fragment. For the population of E. paraensis, the Morisita index indicated an aggregated spatial distribution pattern (MI = 1.35; χ² = 16.92), probably influenced by the dispersion type of the concentrated seeds close to the mother plant. The results demonstrate that the E. paraensis population has its reproductive ecology influenced by forest fragmentation and the climate of the region. The border area favors the establishment of the natural regeneration. Emission of the buds, flowers and fruits initiates after the end of the rainy season.

MEMBROS DA BANCA:
Presidente - 142.060.489-91 - JOSE NATALINO MACEDO SILVA - Oxford
Externo à Instituição - WILLIAM DE OLIVEIRA SABINO - MPEG
Externo à Instituição - NOEMI VIANNA MARTINS LEÃO - EMBRAPA
Externo à Instituição - EDSON MARCOS LEAL SOARES RAMOS - UFPA