Estudo populacional e do potencial invasor da espécie exótica Leucaena leucocephala (Lam.) de Wit em floresta estacional semidecidual

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

28/06/2010

RESUMO

Leucaena leucocephala (Lam.) de Wit is one of the more than 100 species of exotic invasive vascular flora currently registered in Brazil. Planted as hedge at the edge of the semideciduous forest remnant in the IbiporA Forest Park about 25 year ago, it occupieds part of the edge of the remnant, raising the hypothesis that it might invade areas of native forest in the interior. With the objective of analyzing aspects of the biology of the species and testing the invasion hypothesis, alometric studies were carried out of the size structure, spatial structure and demography at one yearly interval. Five transects were traced (10 x 200 m) subdivided into 20 plots (10 x 10 m) covering a sample area of one hectare. All the individuals present in the transects with height equal or greater than 20 cm and diameter at soil height equal or greater than 0.1 cm were marked and mapped and the height and diameter at the base were recorded, in the sample period from November to Febrauary 2007/8 and 2008/9 (referred to as 2007 and 2008). The sampled population consisted of 1974 individuals and 2986 individuals, respectively, with a specific density of 0.658 individuals x m-2 in 2007 and 0.995 individuals x m-2 in 2008, within the 60 m band from the external limit of the remnant. The individuals invested resources firstly for growth in diameter, though the individuals of the I and II immature classes presented lengthening characterizing a species that requires light to reach the canopy and presented an increasing risk of breakage until they reached the adult phase. The height and diameter structure was in the shape of an inverted J indicating condition to remain in the IbiporA Forst. The dispersion occurred in bands and the spatial structure presented a cluster pattern on the external limit of the remnant. The population had a growth rate of the 1.5% to year and duplication time of the 1,4 year and there were high rates of seedling recruitment but low recruitment in the II juvenile and I immature size classes. The results obtained to evidenced that Leucaena leucocephala is not stable in the IbiporA Forest Park and can amplify the area occupied in the forest remnant, but finds unfavorable conditions to reach the adult phase. Possible disturbances from prolonged drought periods that can cause opening of the native vegetation canopy may increase the chances of invasion.

ASSUNTO(S)

leucena leguminosas plantas - alometria plantas - população florestas - plantas invasoras parque florestal de ibiporã (pr) leucaena leguminosae plant allometry

ACESSO AO ARTIGO

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