ABSTRACT
This study aimed to evaluate the structure of the tree community of a submontane atlantic rain forest at the Imbaú region, Silva Jardim, RJ. We tested the hypothesis that forest fragmentation causes a reduction in species richness and diversity in these fragments. Four replicate plots of 100 × 5 m were systematically located in each of the five forest fragments. All trees with DBH ≥ 5 cm were measured (DBH and height) and identified. The most important families were Meliaceae, Sapindaceae, and Fabaceae. Amongst species, Guarea guidonia and Cupania oblongifolia occurred with high values of importance. These species had not been reported as important species in other fragments already analyzed for the same region. The fragments showed a predominance of early secondary species, as a consequence of forest fragmentation process, and indicating a secondary succession stage. The Shannon diversity index (H') varied from 2.82 to 3.62 nats.ind-1 between fragments, and can be considered within the range found for other secondary Atlantic forests. However, when considered all fragments together, the diversity index was close to values found for mature forests (4.0 nats.ind-1), supporting the initial hypothesis. These results suggest that the Imbaú region still has an expressive species richness and diversity, indicating its importance for conservation of the local woody flora.
Key words:
forest structure; forest fragmentation; phytosociology; species richness; species diversity; conservation