Dinâmica temporal do estrato herbáceo-arbustivo de uma área de campo limpo úmido em Alto Paraíso de Goiás, Brasil Temporal dynamics of the shrub and herbaceous layer of an area of moist grassland in Alto Paraíso de Goiás, Brazil

Abstract

Este trabalho avaliou a dinâmica estrutural e florística de uma comunidade de espécies herbáceo-arbustivas de uma área de campo limpo úmido em Alto Paraíso de Goiás, o primeiro inventário realizado em 2000 (T0) e o segundo em 2007 (T1). A diversidade de Shannon entre os períodos foi comparada pelo teste-t de Hutcheson e a similaridade florística, pelo índice de similaridade de Chao-Sørensen. As relações florísticas e a cobertura, entre os períodos e as linhas, foram avaliadas por meio de análises de correspondência retificada (DCA). Foram amostradas 98 espécies, 88 no T0 e 67 no T1, sendo 31 exclusivas do T0 e 10 do T1. A diversidade florística na comunidade foi elevada nos dois períodos, porém diferente entre esses (t = 7,12; p This study evaluated the floristic and structural dynamics of a community of herbaceous-shrub species in an area of moist grassland in Alto Paraíso de Goiás. Th e fi rst inventory was undertaken in 2000 (T0) and the second in 2007 (T1). Shannon's diversity between the periods was compared by Hutchesons´s t-test, and the floristic similarity by the Chao-Sørensen similarity index. Floristic composition and cover, between periods and lines, were evaluated by detrended correspondence analysis (DCA). We sampled 98 species, 88 at T0 and 67 at T1; 31 were unique to T0 and 10 to T1. Floristic diversity in the community was high in both periods, but diff erent between them (t = 7.12, p <0.001), due to variation in species number and coverage. Similarity between the two surveys was high (Chao-Sørensen CI = ± 0.841 ± 0.074). The DCA ordination indicated relationships between the floristic composition and cover with a gradient of moisture and organic matter in the soil identified in T0. Th ere were changes in the lines in the seasonal zones, which became more similar in those constantly saturated with water. During an interval of seven years the moist grassland showed changes in floristic composition and mainly in structure due to increased cover of the clumped tussock perennial species, which were favored by higher soil moisture due to high rainfall in the region.

Keywords

• Avaliação temporal
• Chapada dos Veadeiros
• diversidade
• interseção na linha
• Paspalum lineare
• Chapada dos Veadeiros
• diversity
• line intercept
• Paspalum lineare
• temporal evaluation