Notes on the woody composition of a vegetation physionomy of the Roraima's savannas, Brazilian Amazonia

Abstract

A floristic inventory of woody species was carried out in one of the vegetation units that compose the savannas landscape of the Roraima State, northernmost of Brazilian Amazonia. This unit is characterized by dense colonization of nests of termites Cornitermes ovatus Emerson. Twenty nine woody species were observed (15 botany families) in three localities used for sampling. The total of species varied from 12 to 20 by locality. The most abundant species were Byrsonima verbascifolia (L.) DC. and Mimosa microcephala Humb. & Bonpl. ex Willd. (dwarf shrubs), Byrsonima cf. intermedia A. Juss. and Randia formosa (Jack.) K. Schum. (shrubby) and, Byrsonima crassifolia (L.) H.B.K. and Curatella americana L. (arboreal). Eight species are common to all localities. Diversity measured by the Index of Shannon (H’) was low for all the areas sampled (<0.90) indicating high specimens concentration in few species. The Index of Sørensen indicated similarities (± 0.60) among studied areas, suggesting a group of landscapes with common plant diversity, representing a same vegetation unit. © 2005, Sociedade Botanica do Brasil. All rights reserved.