O banco de sementes do solo e a regeneração natural em diferentes estádios sucessionais de Floresta Estacional Semidecidual e de pastagem abandonada, Reserva Mata do Paraíso, Viçosa, MG

• Ano de defesa: 2011
• Autor(a) principal: Kunz, Sustanis Horn
• Orientador(a): Martins, Sebastião Venâncio
• Banca de defesa: Neri, Andreza Viana , Ivanauskas, Natália Macedo
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Ciência Florestal
• Departamento: Manejo Florestal; Meio Ambiente e Conservação da Natureza; Silvicultura; Tecnologia e Utilização de
• País: BR
• Palavras-chave em Português: Banco de sementes; Regeneração natural; Sucessão ecológica; Clareiras
• Palavras-chave em Inglês: Seed bank; Natural regeneration; Ecological succession; Clearings
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::CONSERVACAO DA NATUREZA
• Link de acesso: http://locus.ufv.br/handle/123456789/561

Knowing the resilience of fragmented forests and surrounded by pasture areas through the study of soil seed bank and natural regeneration is an important tool to define management actions and ecological restoration, in order to preserve the ecosystem or to accelerate the succession process. One of the most important fragments of Semideciduous seasonal forest in the region of Viçosa, MG is endowed with sites with different successional stadiums and pasture area in regeneration process, but little is known about the floristic relationship of the natural regeneration and of the seed bank among such areas and the answer of these compartments of the ecosystem in the succession process. Thus, this study aimed to evaluate the structure and composition of tree-shrubby species in stratum of natural regeneration of three sites with different reports of disturbance and clearings, besides knowing the composition of the soil seed bank in order to evaluate the resilience of each successional passage and thus better define the actions for forest restoration. For phytosociological structure analysis were allocated 10 plots of 5x10 m in the initial forest (FI), mature forest (FM) and abandoned pasture (PAS), being sampled all individuals in height ≥ 50 cm and diameter at ground height ≤ 5 cm (DAS). In ten clearings present in the site of the mature forest were sampled all individuals with > 1.00 m height and diameter at 1.30 m above the ground (DAP) of less than 5.00 cm. Was performed Detrended Correspondence Analysis (DCA) and analysis of indicator species for the passages of mature forest, initial forest and pasture. The floristic similarity between the clearings, FM and FI was calculated through the Jaccard index. For analysis of the soil seed bank, were collected 30 soil samples in the rainfall and drought season in the passages of FI, FM and PAS, being adopted the method of emergency of plantlets to esteem the abundance and the wealth of herbaceous species, tree shrubby. The structure of the natural regeneration of the initial forest and of the pasture followed the same pattern, with one species showing more than the half of the importance value (VI), mainly due to the high density. In the passage of mature forest and the clearings presents more balanced structure, because was not observed strong dominance by one species, although Coffea arabica L. has been highlighted in VI. The three areas are different in terms of species composition, suggesting that there is not a direction of succession of initial forest sites and of pasture to mature forest. Moreover, the indicative species demonstrate that each passage still maintains characteristics according to the successional stadium that are, being necessary interventions to accelerate the succession process. The analysis of the floristic similarity allowed identifying high floristic heterogeneity between the clearings and the forest passages, suggesting that the natural regeneration community in clearings presents its own regenerating flora. The number of germinated individuals in the seed bank was significantly larger in the initial forest during the rainfall season (15.954 ind.) and in the drought (4.755 ind.), followed by the pasture (rain = 8.941 ind.; drought = 2.367 ind.) and by the mature forest (rain = 2.546 ind.; drought = 932 ind.). Has the wealth presented significant difference just among the passages, being larger in the pasture area (80 species), followed by the initial forest (75) and mature forest (72), not having significant difference between the seasons. Most of the species are herbaceous, corresponding to 49.5% of the total of species and 41.8% of the total number of individuals. The results suggest that the species from the mature forest passage present high potential to be used in restoration programs and indicate high area resilience against any disturbance. In the initial forest, the high abundance of grasses and high density values for Psychotria sessilis Vell. can jeopardize the current state of the area resilience, not being indicated for restoration actions. Otherwise, the passage area, for presenting high density of herbaceous plants, requires monitoring and management actions to accelerate the succession process, once just the bank of seeds will not guarantee the succession and not even the local resilience.