Avaliação da diversidade florística e da produção de sementes de espécies florestais nativas na terra indígena Parakanã, Estado do Pará.

Abstract

The need for seeds of forest species with good physiological and genetic quality has increased since the approval of the New Brazilian Forest Code, as it requires the restoration of Legal Reserve Areas (LRA) and Permanent Preservation Areas (PAA), which in the Amazon region represent 80% of the total area of the property. The offering of suitable methodologies for obtaining seeds from native forest species has become a priority, in areas where there is genetic and floristic diversity of species suitable for planting in the region. The present work aimed to evaluate the native forest of the Seed Collection Area (SCA) of the Parakanã Indigenous Land, in Novo Repartimento – PA. Thus, the objective was to assess the floristic diversity, the vertical structure, the patterns of aggregation of the species and the morphometric diversity of Brazilian mahogany (Swietenia macrophylla King.) fruits and seeds, as a model species for the area, which may allow obtaining propagation material for commercialization. Therefore, an alternative to generate income for the ethnic group is promoted, using the forest in a rational and productive way, managing non-timber forest products and keeping the forest standing. The experimental area has 100 hectares inventoried from 25 cm in diameter at breast height (DBH). The floristic composition was evaluated through diversity analysis, accounting for 10,383 individuals, representing 52 botanical families and 528 species. The diversity index (H') found was 4.27, while the evenness (J') was equal to 0.68. Five height classes were identified, and the families Anacardiaceae R.Br., Fabaceae Lindl., Lauraceae Juss., Lecythidaceae A.Rich., Malvaceae Juss. and Moraceae Gaudich. had the highest numbers of individuals composing the upper canopy of the forest, with a height greater than 43 m. Most individuals are in the middle stratum, representing 71.68% of the total. Ten species of silvicultural and ecological importance were selected, representing the different ecological groups, to identify the patterns of aggregation of individuals in the populations. Using Ripley's K function, it was recorded that 40% of the species presented a clustered pattern. Finally, morphometric analyses of the fruits and seeds of Brazilian mahogany were carried out in order to know the diversity in 20 mother trees from the SCA. The results of this study showed high morphometric diversity of fruits and seeds among tree individuals.