Florística, fitossociologia e relações solo-vegetação em floresta estacional decidual em Barão de Melgaço, Pantanal de Mato Grosso

• Ano de defesa: 2007
• Autor(a) principal: Duarte, Temilze Gomes
• Orientador(a): Cunha, Cátia Nunes da
• Banca de defesa: Pott, Arnildo , Martins, Sebastião Venâncio , Carmo, Flávia Maria da Silva
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Botânica
• Departamento: Botânica estrutural; Ecologia e Sistemática
• País: BR
• Palavras-chave em Português: Pantanal Mato-grossense; Floresta estacional decidual; Diversidade alfa e beta; Relação solo-vegetação
• Palavras-chave em Inglês: Pantanal Mato-grossense; Seasonal deciduous forest; Alfa and beta diversity; Soil vegetation relations
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::ECOLOGIA::ECOLOGIA DE ECOSSISTEMAS
• Link de acesso: http://locus.ufv.br/handle/123456789/380

Seasonal Deciduous Forests are characterized by well defined climatic seasons, a rainy and a dry one. Their dominant arboreal stratum is predominantly caducifolium during the dry season with over 50% of the trees becoming leafless. They occur in soils relatively fertile with rainfall below 1.600 mm/year and less than 100 mm rainfall during 5-6 months per year, an ecological factor that determines the presence of this type of forests. This study was carried out at the RPPN SESC Pantanal, located in Barão de Melgaço, Mato Grosso, coordinates 16°34 50 S and 56º15 58 W, aiming to: describe and characterize the floristic composition of the arboreal component of Seasonal Deciduous Forests; analyze the geographic distribution of the species; evaluate the alpha and beta diversities; and characterize the structure and chemical and physical attributes of the soil. For the vegetation sampling, four 100 x 100 m plots were established (Areas I, II, III and IV) in 10 x 10 m split plots and all the trees with all CBH = 15.7 cm (circumference and breast height at 1.30 m from the soil) were selected for the study. Analyses of the geographic distribution, leaf seasonality, fruit type, growth habit and succession stage were carried out through bibliographic information. Soil was collected at 0-20 cm depth. A total of 106 species was found, distributed in 88 genera and 40 botanical families (Areas I and II with 63 species each one, Area III, 53 and Area IV, 55). The species were characterized as being of wide neotropical distribution, mostly decidual trees with dry fruits. The family presenting the highest Importance Value (IV %) in the four stands sampled was Arecaceae, influenced by the dominance and density of Scheelea phalerata (VI 96.29%) and basal area overestimated due to the leaf sheaths persistent in the stem. Basal area was 59.81 m² ha-1 (Area I), 44.47 m² ha-1 (Area II), 48.44 m² ha-1 (Area III) and 56.15 m² ha-1 (Area IV); in case the value referring to S. phalerata individuals were to be withdrawn, these values would drop to 25.95 m² ha-1 (Area I), 20.45 m² ha-1 (Area II), 20.38 m² ha-1 (Area III) and 21.43 m² ha-1 (Area IV), compatible with those found in other works on decidual forests. The four areas sampled presented three vertical strata, with most trees being distributed in the intermediary stratum and with the diametric structure presenting the inverted J pattern. Analysis of the diametric structure showed that the individuals are concentrated in the smaller diameter classes thus inferring that the populations sampled are recovering after the removal of impacts that occurred in the area before the establishment of the RPPN, such as selective logging and extensive cattle ranching. Based on the analyses carried out, the stands evaluated are believed to be at the intermediary stage of ecological succession. The Shannon Diversity Indices were 2.78 (Area I), 2.85 (Area II), 2.16 (Area III) and 2.35 (Area IV), values expected for this type of forest formation. Floristic similarity verification between the stands studied through the Sørensen Coefficient reveals a floristic similarity between Areas I and II (0.7) and less similarity between Area III (0.5) and the other areas. The species characterizing these forests are: Scheelea phalerata, Myracrodruon urundeuva, Tabebuia impetiginosa, T. roseoalba, Combretum leprosum, Casearia gossypiosperma, Anadenanthera colubrina var. cebil and Rhamnidium elaeocarpum. The forests studied develop on sandy, euthrophic soils, whose greater fertility is reflected in the structure of the arboreal species. In general, the areas match the typical seasonal forest standard in terms of chemical and physical soil attributes, with high Ca2+, P, Mg and K contents, low levels of Al-3 and high sand contents in the surface layers. These results indicate that the decidual forests studied have their own characteristics and identity, comprising vegetation units with unique floristic and ecological aspects differentiating them from other forest formations.