Floristic surveys of Restinga Forests in southern Bahia, Brazil, reveal the effects of geography on community composition

Abstract

The Restinga forests of southern Bahia state, Brazil, grow on sandy coastal Quaternary sediments. As their floras are relatively poorly known, the present study assessed their floristic compositions. We surveyed four sites at Maraú and Itacaré and identified 302 angiosperm species belonging to 184 genera of 75 families. The most species rich families were: Fabaceae (35 species), Myrtaceae (25), Rubiaceae (21), Sapotaceae (13), Bromeliaceae (12), Annonaceae (11), Erythroxylaceae (10), Melastomataceae (9), and Apocynaceae (8). Local floras include elements with distributions restricted to the Atlantic Forest domain, those disjunct between the Amazon and Atlantic Forest domains, and those also occurring in moist forests and dry vegetation of central Brazil. The hypothesis that the floristic compositions of restinga forests are influenced by neighboring wet forests was tested using cluster and principal component analyses of eleven restinga forests and nine Atlantic wet forest sites. The results supported five main groups, with most of them including both restinga forests and their adjacent wet forest sites, thus corroborating the hypothesis that wet forests in geographical proximity greatly influence the floristic compositions of restinga forests.