Phytossociology and floristic similarity between plateau and valley `Cerrado` woody vegetation in the Brasília Botanic Gardens, Federal District, Brazil

Abstract

This study aims to check differences in the floristic composition and structure of the woody vegetation of the cerrado (sensu stricto) in two distinct topographic positions, Interfluve (I) and Valley Slope (V) area in the Brasília Botanic Gardens, Federal District, Brazil. In each area ten 20x50m permanent plots were located to survey individuals, basal diameter BD(30cm) > 5cm. UPGMA classification (Sørensen and Morisita similarity indices) was used to assess similarity among plots. Phytosociological analysis indicated the most important species in the interfluve site as: Ouratea hexasperma (A. St.Hil) Baill., Miconia ferruginata DC. and Dalbergia miscolobium Benth., while Eriotheca pubescens (Mart. & Zucc.) Schott & Endl., Ouratea hexasperma (A. St.Hil.) Baill. and Schefflera macrocarpa (Seem) D.C. Frodin were important in the valley slope area. Sørensen and Morisita indices ranged from 0.26 to 0.81 (Sørensen) and from 0.06 to 0.92 respectively. UPGMA classification indicated two main groups in accordance with positions in topography: interfluvic area and valley slope. Topography is highlighted as a strong determinant of the woody species population and community distribution, through its effect in the water table levels, which act in the floristic composition, density (I/V = 1,219/956 ind.ha-1) and basal area (I/V = 8.56/5.64m².ha-1) in the Cerrado (sensu stricto) of Interfluve (I) and Valley Slope (V) in the Brasília Botanic Gardens, Federal District, Brazil.

trees; topography; density; basal area; UPGMA; Brazil