Florística, fitissociologia e relação solo-vegetação em campo rupestre ferruginoso do Quadrilátero Ferrífero, MG

• Ano de defesa: 2010
• Autor(a) principal: Pereira, Aianã Francisco Santos
• Orientador(a): Schaefer, Carlos Ernesto Gonçalves Reynaud
• Banca de defesa: Santos, Lídia Maria dos , Ferreira Júnior, Walnir Gomes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Botânica
• Departamento: Botânica estrutural; Ecologia e Sistemática
• País: BR
• Palavras-chave em Português: Florística; Campo Rupestre; Ferruginoso
• Palavras-chave em Inglês: Floristic; Campo Rupestre; Ferruginous
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::BOTANICA
• Link de acesso: http://locus.ufv.br/handle/123456789/2540

The Iron Quadrangle is located in a transition area between two major morphoclimatic Brazilian areas confronting in its western border with the Dominion of Cerrado and its eastern border with the mastery of the seas of forested hills. This transition also occurs in relation to Cerrado and Atlantic Forest biomes. The vegetation associated with iron formations, common in the Iron Quadrangle, in Minas Gerais was called Ferruginous Campo rupestre and is associated with outcrops of itabirites or jaspilitos rich in Fe, in different degrees of weathering, the main events in Brazil are in the Serra of Carajás in Para state and in the Iron Quadrangle in Minas Gerais. These are among the ecosystems most threatened and least studied of Minas Gerais. The soil on iron formations are generally shallow, dystrophic, and with high concentration of ferruginous concretions. In the superficial formations of the canga, these factors exert a strong control on the distribution of vegetation cover, submitting the vegetation at strong selection pressure. Within this context, the objective of this study was to characterize the typical soils representative of iron formation on the eastern edge of the Iron Quadrangle in the city of Mariana, Minas Gerais, to study the relationship between the soil attributes and distribution of plant species along of a vegetational gradient and characterize the different phytophysiognomy in the area. To this end, we selected the most conserved fragments belonging to the vegetation types: Herbaceous Ferruginous Campo rupestre, Herbaceos Ferruginous Camo Rupestre Wetland, Shrub Ferruginous Campo Rupestre and Capão Forest. The floristic composition of the area was determined by collecting fertile material at random throughout the area, collections were made at two weekly intervals, in order to cover the dry season and rainy season. The phytosociological composition of herbaceous vegetation was determined through the implementation of plots distributed randomly in the study area. In the area covered by the plots were determined the species composition, the number of individuals, the degree of coverage and abundance of species. The soil characterization of the different phytophysiognomy done by describing a representative soil profile in each phytophysiognomy. The soil classification was performed according to the Brazilian System of Soil Classification. The chemical and physical characterization of soils was carried out through the systematic collection of three single specimens in each portion of the phytosociological survey, the sampling followed the depths of the profile described. To check for differences between the chemical characteristics of soils vegetation types studied, there was an analysis of variance (ANOVA) with Tukey test for significant differences (p <0.05) for that used the program Statistica 6. We calculated the correlation coefficients (Pearson) between soil chemical variables for each study area, being considered significant correlations with p <0.05. The results allowed to stratify the phytophysiognomies present in the area studied, proposing the following phytophysiognomies: (1) Capão semideciduous forests, (2) Shrub Ferruginous Campo Rupestre, (3) Herbaceous Ferruginous Campo Rupestre, (4) Herbaceous Ferruginous Campo Rupestre Wetland. The phytophysiognomies identified were confirmed by the finding of specific patterns of soils and vegetation in each environment. The depth of soil and leaf litter, combined, and the type of weathering of the yoke are determining factors for the distribution of these phytophysiognomies. The environments Herbaceous Field and Field shrub, respectively had shallow soils with A horizon of about 3 cm and total depth of about 15cm, resting on the canga battleship continuous (litoplíntic horizon), both classified as typical Litoplíntic Petric Plinthosol. Among the profiles described, the profile 3, representing the Capão Forest Ranked Latossolic Petric Plinthosol, showed the greatest depth, reaching more than 60 cm. But the rusty soil of Herbaceous Ferruginous Campo Rupestre Wetland was Humic Petric Plinthosol. Soils under phytophysiognomies of Ferruginous Campo Rupestre have always been very poor, acidic and weathered, but are important variables in physical chemical and morphological attributes, which govern or influence the distribution of species and density of the biomass.