FLORISTIC-STRUCTURAL VARIATION OF NATURAL REGENERATION ALONG DIFFERENT TOPOGRAPHIC POSITIONS OF AN ECOTONAL FOREST IN SANTA CATARINA, BRAZIL

Studies on the natural regeneration of tree species communities are important for providing information on forest development capacity. This research aimed to evaluate the floristic-structural variations of the tree regenerative component along a topographic gradient in an ecotonal area between a Mixed Ombrophilous Forest and a Deciduous Seasonal Forest of Santa Catarina, Brazil. 30 sampling units of which all regenerating tree species individuals have been identified were allocated in the forest fragment. The sampling units were then distributed along a topographic gradient into lower, intermediate and upper sectors. Abundance, richness, Shannon's diversity index (H') and Pielou's evenness index (J) have been determined for both the whole community as for each sector. The community floristic-structural organization was verified by the means of the nonmetric multidimensional scaling (NMDS), the indicator species analysis and the permutational multivariate analysis of variance (PERMANOVA). Abundance differences among sectors were analyzed through the Kruskal-Wallis test with post hoc multiple nonparametric test while richness differences were verified through rarefaction. Regenerating individuals density in the upper sector [129 (21.300 ind.ha(-1))] was lower than both in the lower [401 (63.800 ind.ha(-1))] and intermediary [241 (36.300 ind. ha(-1))] sectors. There was variation in the floristic-structural composition (p < 0.001) among topographic positions; the lower sector was the most distinct one and showed the highest number of indicator species.