Estrutura e diversidade florística das diferentes fisionomias de Cerrado e suas correlações com o solo na Estação Ecológica de Jataí, Luiz Antônio, SP.
Toppa, Rogério Hartung
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Jataí Ecologycal Station, located at Luiz Antonio city, has a great habitat diversity spread from strict aquatic environments, like rivers, creeks and lakes, to wetlands and flood plains, till vegetation kinds free from flooding. The following steps were adopted to this work: 1) mapping and characterizing different phytophysiognomies found at Jataí Ecologycal Station, and determining each physiognomy area; 2) carrying out a floristic survey; 3) carrying out the phytossociological survey of Cerrado existing physiognomies at the area; 4) characterizing granullometrically and chemically the soil under each plot; 5) comprehending existing correlations among Cerrado soil and phytophisiognomies recorded. The following working hypothesis were tested: 1) There are different phytophysiognomical kinds of vegetations at Jataí Ecologycal Station, occupying distinct areas. Null hypothesis Jataí Ecologycal Station is physiognomically homogeneous. 2) Floristic composition and structure of different physiognomies at Jataí Ecologycal Station are correlated with granullometrical and chemical features of the soil. Null hypothesis There is no correlation between soil characteristics and phytophysiognomies. To evaluate these hypothesis, phytophysiognomies mapping, vegetation analysis, soil analysis and soil versus vegetation correlation analysis were carried out. Based on photointerpretatives analysis and on field survey, eight phytophysiognomies classes were determined ( cerradão , regenerating cerrado, semi-deciduous forest, flood plain vegetation, campo sujo , cerrado stricto sensu , Pinus and Eucalyptus reflorestation). Most of the Jataí Ecologycal Station (60,72% or 5471,8 ha) has cerradão as principal vegetation. To the phytosociologycal survey, 2631 individuals were sampled at cerradão , being 1229 in the lower layer (0,25ha; 4.916 ind./ha) and 1412 in the upper layer (1ha). A total of 118 species were identified in the cerradão two layers. In the cerrado stricto sensu , 642 individuals were recorded, being 190 in the lower layer (0,25ha; 760 ind./ha) and 452 in the upper layer (1ha). A number of 50 species were identified in the two cerrado stricto sensu phytofisiognomies layers. The diversity index (H ), considering the two studied vegetation types, was 3,44 (70,45% equitability). Indexes were 3,20 in the cerradão (67,08% equitability) and 2,99 in the cerrado stricto sensu (76,43% equitability). In the upper layer of the cerradão , the basal area was 18,37m2/ha, and cerrado stricto sensu was 4,20m2/ha. Statistical analysis showed that cerradão and stricto sensu cerrado phytophysiognomies are distinct according to chemical and granulometrical soil properties. Granulometrical features seemed to be important environmental variables to distinguish the two studied phytophysiognomies. Based on the obtained results, it is believed that soil has an indirect correlation on species density and on vegetal physiognomies occurency at studied area.