Estrutura e classificação sucessional do componente arbóreo de um fragmento de floresta ombrófila densa em Igarassu, Pernambuco

Abstract

The Rain Forest is exposed to the effects of the fragmentation process. This process alterates the climate, physionomical and structural conditions of the comunity, leading many species to extinction, and, as a result, decreasing the biodiversity the Rain Forest has. So, this paper work has as its main objective to analize the vertical and horizontal structure of the arboreal components, in a fragment of a dense ombrophylous forest, located in the city of Igarassu, Pernambuco, verificated floristics and structure diferences on the environments located in fragment besides doing the sucecional classification of the species, identifing the level of occupation of lianas in the area and . The area is composed by 48,84 ha, that can be divided in to two environments. The first, with 21,8 ha, is narrower and more elongated and the second has 27,04 ha with a more round shape, This way, it is expected that environment A susser a greater fragmentation effects.It was placed permanently and systematicly 40 plots of 10,0 X 25,0 m (1 ha). Twenty plots are distributed along the more elongated area (environment A) while the other twenties are distributed in the round area (environment B). There were sampled, in the plots, all the arboreal individuals with CAP (chest high circumference) ≥ 10 cm and estimated their hights with the help of a height pruning scisors with 2 m modules. The research done allowed the identification of 99 species, distributed in to 42 families, among 1793 individuals. The families Myrtaceae e Mimosaceae contributed in a higher score to the species. Although, as an individual, the families bigger in numbers were Lecythidaceae, Anacardiaceae and Araliaceae. As concerning to the importancy value (VI), the species that could be highlighted were Tapirira guianensis, Eschweilera ovata, Schefflera morototoni, Dialium guianense, Byrsonima sericea, Inga thibaudiana, Thyrsodium spruceanum, Cupania racemosa, Bowdichia virgilioides and Miconia prasina. Species as the Tapirira guianensis, Eschweilera ovata ad Schefflera morototoni are shown on other researches done in Pernambuco forests. These species produced a diversity rate Shannon – Wiener (H’) of 3,685 nats/individuals. This diversity rate is inside the patterns found among the studies carried out in Pernambuco. The sucessional classification exposed a higher number of species about to start the sucessesion (pioneers + initial secondary) together with the diametrical distribution showed that configurated a geometric decreasing shape (“J” invertido), with the bigger number of individuals on the three first centres of class, alongside with the vertical structure analysis, which observed the majority of the individuals on the first height classes centres, alllowing the afirmation that the fragment studied represents itself as a secondary forest in a sucession start. The level of infestation of lianas in the area happened to be low (69% did not present any infestation at all), what does not match with the other authors afirmations, insecondary forest formation. Through the analogy performed in the two environment, the flowerly similarity came out more heterogeneous between the two environments, floristic diferences in the two areas. In relation to diversity and structure data between the analyzed enviromrnte, its was not shown any difference in the result, exposing that the shape of each area did not influenced disparities between thamselves.