Foram analisadas a estrutura e a composição florística de uma formação de restinga arbustiva aberta no Parque Estadual de Itaúnas, ES, e verificada a similaridade entre a flora das formações de restinga arbustiva da Região Sudeste do Brasil. Para o levantamento, foi utilizado o método de intercepto de linha, contemplando indivíduos com altura igual ou superior a 50 cm. Os parâmetros fitossociológicos de frequência e valor de importância (VI) foram calculados. A similaridade da flora das restingas arbustivas da Região Sudeste foi verificada utilizando o índice de Sørensen. Foram encontradas 42 espécies em 28 famílias, sendo Fabaceae e Bromeliaceae as mais ricas (quatro espécies cada). As 10 espécies mais importantes representaram 65,6% do VI total, evidenciando forte estrutura oligárquica, principalmente no estrato herbáceo. Assim, puderam ser apontadas espécies que caracterizam esta formação, a qual é associada com fatores ambientais que condicionam a composição e abundância florística. A análise de similaridade evidenciou que as restingas do sudeste formam dois blocos florísticos distintos, um ao norte (litoral do Espírito Santo) e outro mais ao sul (litoral do Rio de Janeiro). Foram comuns a todas as restingas analisadas Manilkara subsericea,Pilosocereus arrabidae e Byrsonima sericea, podendo ser consideradas de ampla distribuição na costa sudeste.
This study analyzed the structure and floristic composition of an open scrub restinga at Parque Estadual de Itaúnas, Espírito Santo and verified the similarity between floras of the restinga formations in southeastern Brazil. The line intercept method was applied to sample individuals equal or greater than 50 cm tall. The frequency and an importance value were estimated. The similarity of the flora of the restinga formations in southeastern Brazil was performed using the Sørensen index. We surveyed 42 species in 28 families, being Fabaceae and Bromeliaceae the richest families (four species each). The 10 most important species represented 65.6% of the total importance value, showing a strong oligarchic structure, especially in the herbaceous layer. Thus, we identified some species that characterize this formation, which is associated with environmental factors that constrain floristic composition and abundance. The similarity analysis evidenced two distinct floristic blocks of southeastern restingas, one in the north (the coast of Espírito Santo) and another further to the south (coast of Rio de Janeiro). Some species were common to all analyzed resting formations - Manilkara subsericea, Pilosocereus arrabidae and Byrsonima sericea and may be considered of wide distribution on the southeast coast.
The Brazilian shrublands area (restinga) is composed of marine coast vegetation on Quaternary sandy plains, where the species composition can vary depending on the surrounding ecosystems. The aims of this study were to describe the structure and floristic composition of a restinga near the community of Itaúnas, in the northern part of the state of Espírito Santo, to identify any relationships between this restinga and surrounding plant formations, and to determine which are the species that occur preferentially in the coastal forests of Espírito Santo. We sampled woody plants with a diameter at breast height > 2.5 cm, excluding lianas, in 50 plots of 100 m². We selected studies of coastal forests in the states of Espírito Santo and Bahia to prepare a database that would reveal patterns of floristic variation among these areas. We used t wo-way indicator species analysis for the identification of the species that occur preferentially in the coastal forests of Espírito Santo. We identified 114 species belonging to 38 families. Species richness was greatest for Myrtaceae (26 species), followed by Fabaceae (10). The Shannon index for the study area was 3.96. The estimated total density was 3,330 individuals/ha and basal area was 32.02 m²/ha. The highest importance value (IV) was for Protium heptaphyllum (IV, 23.4), indicating that it is characteristic of the Espírito Santo restinga. The results of our floristic analysis indicate that the species composition of the Itaúnas restinga is influenced by the so-called tabuleiro forests (coastal lowland forests on Tertiary deposits), which are most common in northern Espírito Santo. This seems to be the main factor responsible for the gradual reduction in floristic similarity between the restingas in the north of Espírito Santo and those in the south of the state, each constituting a distinct floristic block. In addition, we generated lists of species that occur preferentially in the restinga and tabuleiro forests. Those lists could inform decisions regarding environmental restoration programs.