Banca de QUALIFICAÇÃO: RÓGER WILIAN MARINHO CAVALCANTE

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : RÓGER WILIAN MARINHO CAVALCANTE
DATE: 27/05/2026
TIME: 14:00
LOCAL: Licbio
TITLE:

The influence of fire seasonality on the composition and structure of sub-shrub communities in the savannas of the Campos Amazonicos National Park

KEY WORDS:

Fire; seasonality; Amazonian savannas; diversity; subshrub layer.

PAGES: 51
BIG AREA: Ciências Biológicas
AREA: Botânica
SUMMARY:

Fire is one of the main ecological agents responsible for structuring savanna ecosystems, directly influencing the composition, diversity, and functioning of plant communities. In Amazonian savannas, however, the effects of fire seasonality remain poorly understood, especially regarding the subshrub layer, a sensitive and functionally relevant component in the dynamics of these systems. In this context, the present study aimed to evaluate how different periods of fire occurrence—early and mid dry season—influence the composition and structure of subshrub communities in the Campos Amazônicos National Park. The study was conducted in two experimental zones (A and B) with distinct physiognomic characteristics, where plots were established under three treatments: burning in the early dry season, burning in the mid dry season, and unburned control areas. Sampling was carried out before the fire events (2019) and two years after (2021), considering variables such as species richness, abundance, Shannon diversity (H’), and Pielou’s evenness (J’). Analyses were performed in the R environment using the vegan package. A total of 60 morphotypes distributed across 26 families were recorded, with Melastomataceae, Malpighiaceae, and Fabaceae being the most representative. Zone B showed higher richness (49 species), but lower diversity (H’ = 2.33) and evenness (J’ = 0.60), indicating greater species dominance, whereas Zone A presented lower richness (45 species), but higher diversity (H’ = 2.66) and evenness (J’ = 0.70). Floristic similarity between areas was high (Jaccard index = 0.78), with shared dominant species. The results indicate that community structure is strongly shaped by dominance patterns and that differences in fire seasonality tend to influence the distribution of abundances and the structural organization of communities. Overall, the data suggest that burns occurring at different times of the year modulate disturbance intensity and act as environmental filters, favoring species with greater fire tolerance and influencing patterns of diversity and evenness. These findings contribute to a better understanding of fire dynamics in Amazonian savannas and provide support for adaptive fire management strategies in protected areas.

COMMITTEE MEMBERS:
Interna - 1387002 - OSVANDA SILVA DE MOURA
Interna - ***.324.392-** - MARCELA ALVARES OLIVEIRA - UNIR