Bruna Salami

INVASÃO POR ESPÉCIES ARBÓREAS EXÓTICAS EM REMANESCENTES FLORESTAIS NO PLANALTO SUL CATARINENSE

This study evaluated the invasion by exotic tree species in two Mixed Ombrophilous Forest (FOM) fragments (F1 and F2) in Lages, SC. A total of 25 plots were allocated in each fragment, distributed in five transects, 20x100 m, perpendicular to the edges and, at least, 100 m apart from each other, where the adult (dbh - diameter at breast height > 5 cm) and the regenerative (dbh 10 cm) component individuals were evaluated. These were identified and measured (circumference and height). For each component and fragment, the biological invasion index (BII) was determined. The relation between BII and the distance from the edge was evaluated by simple linear regressions. The grouping among exotic and native species was analyzed through Spearman correlation and clusters. A total of 3,701 individuals distributed in 105 species were sampled, being five invasive species. In F1 a relative low value of BII (0.05 and 0.54) occurred, with Pinus taeda L. as the most expressive species in the invasion, and it was grouped with native pioneers species. The BIIs in F2 were elevated (0.61 and 1.96), mainly due to the expressive participation of Ligustrum lucidum W.T. Aiton., grouped with typical species of FOM. No relation between the distance from the edges and the intensity of the invasion were observed. The results demonstrated that the fragments showed different biological invasion patterns that were determined by the nature of surrounding matrix and the ecological characteristics of the invasive species.

COMPOSIÇÃO FLORÍSTICO-ESTRUTURAL AO LONGO DE UM GRADIENTE DE BORDA EM FRAGMENTO DE FLORESTA OMBRÓFILA MISTA ALTO-MONTANA EM SANTA CATARINA

The objectives of this study were to characterize the floristic and structure of the tree component in Upper Montane Araucaria Forest fragment and to evaluate the influence of the edge effects on tree species organization, structure, richness and diversity. For this, a total of 50, 10 x 20 m, permanent plots divided in five transects spaced, at least, 100 m from each other, were established in the a forest fragment, located in the municipality of Bom Jardim da Serra, SC. The trees with circumference at breast height (CBH) ≥ 15,7 cm were measured (CBH and total height), identified and classified according to the regeneration guilds. The data were analyzed through the index of importance values (IVI), a NMDS analysis (Nonmetric Multidimensional Scaling), a generalized additive model and simple linear regressions. A total of 1,457 individuals, distributed in 29 families, 43 genera and 55 species were surveyed. The most relative important species was Dicksonia sellowiana Hook. There was no influence of edge effect on tree community organization, structure (average diameter, average height and density) and guilds participation. However, values of diversity, richness and evenness were higher at edge areas. We conclude that part of the variation in values related to tree species diversity in the Upper Montane Araucaria Forest was determined by edge distance.

EFEITO DE BORDA COMO FONTE DA HETEROGENEIDADE DO COMPONENTE ARBÓREO EM UMA FLORESTA COM ARAUCÁRIA NO SUL DO BRASIL

This study aimed to evaluate changes in the organization of tree species communities due to edge effects in a forest remnant in southern Brazil. Five transects were installed in the study area, perpendicular to the forest edge, with the dimensions of 100x20 m, subdivided into ten plots. The edge sector was defined for the distance of 0-50 m and the interior for the distance of 50-100 m. All trees with circumference at breast height ≥ 15.7 were measured, identified and classified into regeneration guilds. The sectors were compared using the t test for normally distributed variables, Mann-Whitney test for non-normal distributions, rarefaction, for richness, and Chi-square test applied to a contingency table, to check the distribution of individuals of different regeneration guilds. The sectorization as a function of edge and interior represented an important source of forest heterogeneity, once the most marginal part of the fragment was characterized by a tree component of higher density, smaller average height and prevalence of individuals of light demanding species. In the context of biodiversity conservation of the Araucaria Forest, this study suggests the need for conservation of forest fragments which size and spatial configuration allow the existence of interior area, in order to contemplate the protection of non-tolerant species of edge conditions.

DISTRIBUIÇÃO E RIQUEZA DE ESPÉCIES ARBÓREAS RARAS EM FRAGMENTOS DE FLORESTA OMBRÓFILA MISTA AO LONGO DE UM GRADIENTE ALTITUDINAL, EM SANTA CATARINA

The present study aimed to analyze how the distribution and the richness of rare tree species occur along an altitudinal gradient, in Araucaria Forests fragments. For this purpose, tree species (diameter at breast height > 5 cm) were sampled in 10 forest fragments located on different altitudinal floors in “Planalto Sul-Catarinense” region, totaling 10 ha of sampling area. The species with only one or two individuals in at least one fragment were classified as rare. The species distribution was verified by a dendrogram constructed through the Jaccard floristic distance index and the UPGMA clustering algorithm. The total species richness per fragment and the number of rare species were compared among montane and upper-montane sub-formation by the Mann-Whitney (U) test. The relationship between altitude and values of total richness and number of rare species in each fragment were determined by simple linear regressions. The results indicated the formation of two groups of rare species, in function of the altitude floor. Despite the fact that total richness of communities decreased with increasing altitude, the number of rare tree species did not significantly change. We conclude that in the “Planalto Sul-Catarinense” region, the fragments of Araucaria Forest have different set of rare tree species according to altitude and that the reduction of the richness of communities with increasing altitudinal floor is not accompanied by a reduction in the number of rare species.

Similaridade florística das florestas superomontanas no domínio Atlântico, Brasil

This study investigated the floristic similarity of the tree component of 39 upper montane forest fragments in Atlantic domain, Brazil, and the influence of geographic and climatic variables on the patterns observed. It was created a binary matrix of presence and absence of the tree species compiled from the 39 floristic and phytosociological survey. For the relationship of the floristic composition of the areas with the environmental and spatial variables, the geographic coordinates and climate data of each area were extracted. The floristic similarity of the fragments was measured using a dendrogram and for determination of environmental and spatial variables influence on floristic patterns, a nonmetric multidimensional scaling analysis (NMDS) was used. The dendrogram analysis and the NMDS showed the formation of clusters, predominantly among fragments located in the same phytogeographic unit. The existence of an environmental gradient based on the climatic conditions was observed. In areas with higher thermal seasonality, annual temperature range, precipitation, latitude and longitude, upper montane forests with rain forest matrix occurred, and in areas with higher average temperature, daily temperature range, isothermality, seasonality of precipitation and minimum temperature in the coldest month, upper montane forests with seasonal matrix occurred.