Floristic gradient of the northeast Paraense secondary forests

this study describes a floristic gradient of secondary forest chronosequence in northeast of pará state - brazil, from 19 sites of different ages, evaluated in different years. we used density data and carried out regression analysis for richness, diversity, density, maximum relative density and equitability in relation to the age. we used the hierarchic grouping method of analysis and the euclidean distance as dissimilarity measure, and applied a principal component analysis (pca) for confirming the groups. after defining the groups, we made an indicating species analysis (indval) on the same matrix used for the grouping analysis. we found a geographic gradient in the chronosequence analyzed and the species tapirira guianensis, vismia guianensis, inga alba, lacistema aggregatum, croton maturensis, abarema jupunba, inga rubiginosa, guateria poepigiana and thyrsodium paraense to be indicators of the northeast para (brazil) secondary forests analyzed in this study.