Quantification of biological contamination by exotic tree species in an araucaria forest fragment in Lages, Santa Catarina State/Quantificacao da contaminacao biologica por especies arboreas exoticas em um fragmento de Floresta ombrofila mista em Lages--SC

The present study aimed to evaluate the biological contamination over time in a tree community of Montane Araucaria forest, in advanced successional stage, adjacent to a Pinus taeda L. plantation, in Lages, SC state. For this sake, a total of, 20 x 20m, 25 plots, distributed in five transects with five plots each, were allocated perpendicular to the edge in contact with the pinus plantation. In each plot, all living trees were measured (cbh [greater than or equal to] 5 cm, measured at 1.30 m above soil level), collected and identified. Four years after the first inventory, the same individuals were re-inventoried, the dead individuals and survivor quantified and recruits added. For the two evaluated years, phytosociological descriptors were calculated, indicators of biological invasion quantified for all community as well as for ecological groups and the demographic rates determined. A total of 73 and 74 species were sampled in the first and second years, among of them two exotic species: Pinus taeda and Ligustrum lucidum W.T Aiton. Both species showed low values of the invasion indicators, but with an increment in the participation of Pinus taeda among pioneer species over time. Results of demographic rates suggest that, for different ecological groups, the invasion process is in distinct stages. We conclude that the pioneer species was the most affected component by biological invasion, which reinforces the need for analysis considering the different ecological groups. Keywords: forest fragment; forest dynamics; temporal study. O presente trabalho objetivou avaliar a contaminacao biologica ao longo do tempo em uma comunidade arborea em estagio sucessional avancado/tardio da Floresta Ombrofila Mista Montana, adjacente a um plantio de Pinus taeda L. em Lages--SC. Para isso, foram alocadas 25 parcelas de 20 x 20 m, distribuidas em cinco transecoes de cinco parcelas cada, alocadas perpendiculares a borda de contato com o plantio de pinus. Em cada parcela foram mensurados (DAP [greater than or equal to] 5 cm, medido a 1,30 m do solo), coletados e identificados todos os individuos arboreos vivos. Quatro anos apos o primeiro inventario, os mesmos individuos foram novamente inventariados, quantificando-se os individuos mortos, sobreviventes e adicionando os recrutas. Para os dois periodos foram calculados os descritores fitossociologicos, quantificados os indicadores de invasao para a comunidade como um todo e grupos ecologicos e calculadas as taxas demograficas