Marco Antonio Bento

NATURAL REGENERATION OF TREE SPECIES IN A CLOUD FOREST IN SANTA CATARINA, BRAZIL

Os objetivos do presente estudo foram caracterizar a regeneracao natural arborea e relacionar esse estrato com o componente adulto e com variaveis ambientais em um fragmento de floresta nebular em Santa Catarina. Em cada uma das 25 parcelas de 20 × 20 m, onde previamente foi realizado um estudo com caracterizacao do componente adulto e de variaveis ambientais, foram estabelecidas subparcelas, com tamanhos diferenciados de acordo com o tamanho das plantas, para a avaliacao dos regenerantes: Classe 1, plantas com altura de 0,15 cm ate 1 m, avaliadas em 5 m2; Classe 2, plantas com altura entre 1 e 3 m, avaliadas em 10 m2, e; Classe 3, plantas com altura maior que 3 m e DAP menor que 5 cm, avaliadas em 20 m2. Foram determinadas: diversidade (indice de Shannon), equabilidade (Pielou), Indice de Regeneracao Natural (IRN), similaridade com o componente arboreo adulto (Jaccard e Bray-curtis), organizacao floristica-estrutural (escalonamento multidimensional nao-metrico - NMDS) e relacao com as variaveis ambientais. Foram amostrados 518 individuos distribuidos em 28 especies. O valor do indice Shannon (2,51 nat/ind) e da equabilidade de Pielou (0,75) sugerem baixa diversidade e elevada dominância ecologica. A especie de maior IRN foi Symphyopappus itatiayensis (Hieron.) R.M.King & H.Rob (19,36%). As similaridades com os adultos foram de 0,45 (Jaccard) e 0,24 (Bray-Curtis), demonstrando baixa similaridade (<0,50). A compactacao do solo foi a unica variavel que apresentou relacao com a regeneracao, o que pode estar relacionado com a presenca de gado no fragmento.

Avaliação da Restauração Florestal de uma APP Degradada em Santa Catarina

This study evaluated the process of restoration in a degraded Permanent Preservation Area (PPA) in the municipality of Pouso Redondo, Santa Catarina state, six years after the initial plantation of trees and isolation of the area. Tree species were surveyed and increment of richness by natural establishment was quantified. Syndromes of propagule dispersion and regeneration guilds were determined. A total of 918 individuals from 73 species were found; 48 (65.8%) of them were species naturally established in the area. 71.2% of the species were classified as zoochoric (71.2%), and 54.8% as light demanding for climax. After six years, the restoration process was characterized by a trend of richness increment and replacement of initial by late successional species, indicating the relevance of the natural regeneration mechanism.

Heterogeneity of a Tree Species Community in an Alluvial Area of Santa Catarina, Brazil

The aim of the present study was to characterize the floristic-structural heterogeneity of the tree species in an alluvial forest remnant considering three sectors: forest-river edge, forest interior and forest/non-forest matrix edge. Forty-eight plots of 200 m2 were allocated and all tree individuals with a diameter at breast height (dbh) equal to or greater than 5 cm were measured and identified. Data was analyzed by Shannon’s diversity index, Pielou evenness and phytosociological descriptors. Plots were ordered through NMDS. Sixty-six species were sampled and Myrtaceae was found to be the richest family. Diversity and evenness reached 2.96 and 0.71, respectively. Sebastiania commersoniana (Baill.) L.B.Sm. & Downs presented the highest importance value (21.22%). The NMDS showed that tree components are spatially partitioned according to sectors, therefore indicating floristic-structural heterogeneity.

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.