Variaciones en la composición florística de tipos de bosque asociados con Pachira quinata (Jacq.) W.S. Alverson en el Bosque Universitario “El Caimital”, Barinas, Venezuela

The biological diversity is a very important topic within the discussions on sustainability, and today is one of the major challenges for the management and conservation of forests. The objective of this work was to determine whether the forest communities associated with the presence of the tree species Pachira quinata differentiated according to geomorphologic position show differences in their floristic composition when as measured by several quantitative diversity indexes. Six one ha plots (two for each forest type) selected according to a restricted random design were established. In each plot, all individuals of tree species with dbh = 10 cm were measured, and individuals with dbh between 2.5 and 10 cm were counted in a subsample. Several diversity indexes were used to estimate the alpha and beta diversities, as well as the Index of Importance Value (IVI). A cluster analysis was carried out to find out if there were floristic similitudes among the forest types. It was found that for individuals with dbh = 10 cm both, the Analysis of Diversity Indexes (Jaccard and Sorensen) and cluster analysis allowed for the identification of two groups according to their floristic similitude. One group included the forest types located in geomorphologic positions identified as “banco” and “subbanco”, the second group included the forest type located in “bajio” characterized by drainage limitations that can be tolerated only by some species; therefore, differing in floristic composition and having lower diversity than the other types of forest.