Variações florísticas e estruturais em um fragmento de floresta paludosa no Alto Rio Pardo em Santa Rita de Caldas, MG

Abstract

A survey of the tree community of a swamp semidecidual Montana forest, situated in Santa Rita de Caldas, MG at the Upper Rio Pardo river (1156-1203 m of altitude, 22o 05´ 44" S; 46o 21´ 20" W) was accomplished with the purpose of assessing its environment and structural variation. The physiognomic (density, basal area and distribution of size of the trees) and community structure (composition, distribution and diversity of species) were analyzed through 25 plots of 10 X 40 m where tree individuals with diameter at breast height = or > 5 cm were sampled, topographic variables were measured and surface soil samples were collected to obtain their chemical and texture attributes. The survey resulted in 50 botanic families, 78 genera, 110 species and 1982 individuals, as well as three soil classes: Organosoil, Melanic Gleissoil and Haplic Gleissoil, distributed sequentially from the hilltop to the base of the fragment. The tree community presented different structure and floristic composition from other swamp and alluvial forests of Southeast and South of Brazil. The analyses of a canonic correspondence showed a gradient of tree species distribution mainly correlated with variations of quotas and clay contents. Other important variables were unevenness, water table depth and calcium.