Fitossociologia e florística do componente arbóreo em toposseqüência na reserva biológica de Saltinho, Pernambuco.

Abstract

The forests have these characteristics phytosociological and floristic alter due to the complexity of factors that environment, therefore, study of species-related relief and soils it is necessary for a greater understanding of these relationships. The present work aimed to analyze the structure phytosociological and floristic in the toposequence on a patch of dense rain forest. The study was developed in the Biological Reserve of Saltinho,Pernambuco. The survey floristic and phytosociological was conducted in 42 plots (10 x 25 meters), considering the alive trees with circunference at breast height (cbh) ≥ 15 cm. The parcels were distributed in the toposequence (lowland, slope and top). The vegetation was analyzed by the density, frequency, dominance parameters and importance value. The floristic diversity for the Shannon-Wiener (H’) index, the floristic similarity for the euclidian distance. In the soil was analysed physical-chemicals variables. The correlation between vegetation and soil was analysed by canonical correspondence. In the toposequence occured 1484 individuals, 38 families, 74 genera and 111 species. The lowland position was represented by 492 individuals, distributed in 23 families, 32 genera and 41 species; the slope with 470 individuals, in 50 families, 34 genera and 69 species and top with 522 individuals, 32 families, 51 genera and 68 species. Among the species with the greatest importance value (IV) in the toposequence were: Bowdichia virgilioides, Brosimum rubescens, Cupania sp., Eschweilera ovata, Genipa americana, Helicostylis tomentosa, Henriettea succosa, Lacistema pubescens, Miconia minutiflora, M. prasina, Pachira aquatica, Pogonophora schomburgkiana, Protium giganteum, P. heptaphyllum, Schefflera morototoni, Simarouba amara, Sloanea sp., Syzygium jambolanum, Tapirira guianensis, Thyrsodium spruceanum, Virola gardneri and Xylopia frutescens. The highest concentration of individuals occurred in the classes of smaller diameters. The smaller diameter was 4.77 cm and 120.95 cm the higher. The Shannon-Wiener diversity index (H') was 2.64 nats/ind. in the lowland, 3.68 and 3.21 nats/ind. in the slope and top, respectively. The major floristic similarity was between the slope and top. The most humidity grades were in the top and lowland. The grades of P, Ca, Mg, K, H + Al and total organic carbon were higher in the layer 0 - 10 cm. The pH grade was higher in the layer 10 - 30 cm. In lowland Tapirira guianensis, Miconia minutiflora, Xylopia frutescens, Pachira aquatica and Syzygium jambolanum were correlated with the higher grades of pH, Ca, Mg, bases sum and bases of saturation. In the slope Lacistema pubescens, Bowdichia virgilioides, Cupania sp. and Casearia javitensis, were not correlated with any chemistry variable. At the top Pogonophora schomburgkiana, Helicostylis tomentosa, Paypayrola blanchetiana, Brosimum guianense, Sorocea hilarii, Cupania racemosa and Siparuna guianensis were correlated with the higher grades of H + Al, total organic carbon and cation exchange capacity. Concluding that did exist habitats preferences for species, that floristic diversity combined with the register of values for Pernambuco, but the absolute density of species correlated with the soil chemical variables was not sufficient to explain the species distribution in the topossequence.