Levantamento florístico e estrutura horizontal da Bacia Hidrográfica do Ribeirão da Onça- MG

• Autor(a) principal: Pineli, Adriana Alves Pereira
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UNIFENAS
• Texto Completo: http://tede2.unifenas.br:8080/jspui/handle/jspui/89
• topic: inventário florestal; fitossociologia; remanescentes; forest; inventory; phitosociology; remainders; CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL

The municipal district of Elói Mendes has been suffering important consequences of the deforestation and reduction of forestal cover, mainly at Ribeirão da Onça Hidrographic Basin, which supplies all the urban population. Degradation levels have begun to cause negative significant impacts, compromising the quantity and quality of the water of the streams in the hydrographic basin. Therefore, the aim of this research was to characterize the floristic and horizontal structure and identify the species in the Hidrographic Basin of Ribeirão da Onça , Elói Mendes District, MG. The floristic sample was accomplished in 30 fragments with portions of 5m X 20m, in a sample area of 85,79 ha. The identification of vegetal species was accomplished with DAP (chest-high diameter) ≥ 5 cm. The height of the vegetal species was measured with a graduated PVC tube (5m); above this measure the height was visually estimated. Six hundred and forty-seven vegetal species were studied, distributed in 48 species, 44 genera and 23 families. The families that were more outstanding were Fabaceae, ,Lauraceae, Anacardiaceae, Asteraceae, Boraginaceae, Moraceae and Myrtaceae. The genera that presented the highest number of species were Nectandra, Ocotea, Cordia. The species with more absolute and relative dominance were: Dalbergia miscolobium (m²/ha), Machaerium nictitans (m²/ha,) Luehea candicans (m²/ha).The species with the highest absolute and relative density were: Machaerium nictitans (arv/ha), Casearia sylvestris (arv/ha), Lithraea molleoides (arv/ha). The species with the highest absolute and relative frequence were: Nectandra megapotamica (%), Machaerium nictitans (%),Casearia sylvestris (%). The specieswith the highest index of covering value: Machaerium nictitans, Dalbergia miscolobium, Nectandra megapotamica. The ones with the highest value of importance: Machaerium nictitans, Dalbergia miscolobium, Nectandra megapotamica. The Ribeirão da Onça Hidrographic Basin presents nowadays 6,09% of vegetal cover. Among the species of greater height present in ribeirão da Onça hydrographic Basin, the species Pouteria gardineri, Luehea Candicans, Copaifera langsdorfii, Plathymenia foliosa also presented the most dominance. The height of vegetal species surveyed in Ribeirão da Onça , MG, presents a variation between 4.63m and 19.67 m. In the conditions of this work we can conclude that: the Ribeirão da Onça Hidrographic Basin is mainly characterized by the species: Machaerium nictitans, Casearya sylvestris e Nectranda megapotamica because they have more frequency and density. The Ribeirão da Onça Hidrographic Basin flora presents some species that represent the cerrado such as like Stryphnodendron pulcherrimun, seasonal semideciduous woods, as Cedrella fissilis, ciliary woods, like Cordia ecalyculata and rupestrian field, like the Asteraceae. The presence of the species Ocotea pretiosa in the Ribeirão da Onça , listed as endangered of extinction, shows the importance of those florestal fragments to do the importance of those florestal fragments to the maintenance of floristic wealth.