O banco de sementes do solo e a restauração ecológica de uma área dominada por Pteridium aquilinum (L.) kuhn no Parque Nacional do Caparaó

• Autor(a) principal: Cunha, Jeane de Fátima
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/596
• topic: Recuperação ecológica; Banco de sementes; Nucleação; Invasão biológica; Unidade de conservação; Ecological recovery; Seed bank; Nucleation; Biological invasion; Conservation unit; CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::MANEJO FLORESTAL

Some forest areas of the National Park of Caparaó (Parque Nacional do Caparaó) are secondary forest formations and they have been changed by fire and deforestation. The disturbances caused in this ecosystem have contributed to the invasion of P. aquilinum (L.) Kuhn (Bracken Fern). P. aquilinum is a very aggressive exotic fern species that prevents the advance of forest regeneration in open areas, such as large glades and abandoned pastures, even when they are inserted in a forest matrix, as in the case of the National Park of Caparaó. In Brazil, there is little research on the knowledge of the regeneration potential of these areas. Thus the current study aimed to know the composition of the species seed bank of an area invaded by P. aquilinum and of a forest in its surroundings and to apply nucleation techniques for the restoration of the area dominated by P. aquilinum. For the study involving the seed bank, 30 soil samples, 30 soil samples in the area dominated by P. aquilinum and 30 samples of fern litter were collected in the forest and taken to the Research Nursery of the Department of Forest Engineering of the Federal University of Viçosa. Samples were kept in the greenhouse and after seedling emergence there was the quantification of arboreous, arbustive, herbaceous, climbing and grass species. Only arbustive, arboreous and herbaceous P. aquilinum species were identified. In the study of nucleation, sixty cores or glades of 2 x 2 m and 10 cores per treatment were assessed. In these open areas, all P. aquilinum cover was removed down to the soil. In the center of each glade, a plot of 1 x 1 m was delimited. The treatments were: T1-liming, T2- seed bank and litter transposition, T3- direct-seeding, T4-liming + seed bank and litter transposition, T5-liming + direct- seeding, T6- Witness. The completely randomized design with 10 replications was adopted. For T2 and T4, 20 samples of 1 x 1 m of the forest surrounding the area of the experiment were collected from the surface layer of the soil (up to 5 cm depth) and from the litter layer. For T3 and T5, seeds of Araucaria angustifolia (Bertol.) were used. In each plot of nucleation, after a year, arbustive-arboreous species were registered, measured in height and diameter at ground level. In both experiments, plants were classified according to succession class and dispersion syndrome. Overall, the most representative forms of life in the seed bank of the three locations were herbaceous and climbing species. With regard to arbustive-arboreous species, it was observed the presence of 1.406 seed banks, 79 in the seed bank of the area dominated by the fern and 34 in the fern litter seed bank, showing statistically significant difference among data. The most prominent environmental group in the three seed banks was the one of the pioneers at both species and individual levels. It was highlighted the zoochory dispersion syndrome in the forest seed bank and, species and individual levels and for the other banks, the anemochory was seen in high numbers. The families of greatest prominence in the forest bank were Salicaceae, Urticaceae, Dennstaedtiaceae and Melastomataceae. In the seed bank of the area dominated by P. aquilinum and in the litter seed bank the family Dennstaedtiaceae predominated and was represented by P. aquilinum. After one year of implementation of the nucleation experiment, 331 individuals belonging to 19 species, 12 genera and 10 plant families were recorded. In nucleation, the ecological group of pioneers and zoochoric dispersion syndrome were predominant. The most prominent families were Solanaceae and Euphorbiaceae. Solanaceae also excelled in a larger number of individuals (56.2%), followed by Fabaceae (10%). The genus Solanum showed greater prominence and abundance. Solanum mauritianum was the most abundant species with 49.5% of individuals and it also stood out due to its higher importance value (45.50%). The results suggest that the area dominated by P. aquilinum affected the resilience of the area, because there was a significant reduction at both individual and arbustive-arboreous species level compared with the forest bank, besides the high density of herbaceous plants and the formation of a dense layer of fern litter. The forest seed bank is also compromised because of the presence of P. aquilinum in it, showing that in face of a disturbance, this species may dominate the area. The adopted nucleation techniques triggered a succession process in the area invaded by P. aquilinum. The treatments with seed bank were the most suitable to facilitate the process of forest regeneration in the area.