Structure and floristics of the plant community in Lagoa do São Bento, Maricá, Rio de Janeiro state, Brazil

Abstract

Lagoa do São Bento is a coastal restinga wetland, remnant of a paleolake, located in Maricá, RJ. The study aimed to inventory native aquatic plants, make a floristic comparison with other coastal lagoons and analyze the regeneration of this community after anthropic impacts. In the floristic analysis of aquatic plants, 45 species were listed, 39 of which are Angiosperms and six are Ferns. Aeschynomene paniculata, Hymenachne amplexicaulis, Montrichardia linifera and Torenia thouarsii are new records for the municipality and Tabebuia cassinoides is threatened. Emerging plants (21 spp.) stand out, followed by amphibians (16 spp.), free floating (4 spp.), fixed floating (3 spp.) and tolerant (1 sp.). The comparison showed greater similarity with the Jacarepiá lagoon, in Saquarema, sharing 21 species. The phytosociological inventory listed 87 species, 83 of which were Angiosperms and four Ferns. The species with the highest IVI were: Fuirena umbellata, Pleroma gaudichaudianum, Xyris jupicai, Typha domingensis, Salvinia aff. auriculata, Eleocharis interstincta, Rhynchospora gigantea, Nymphoides humboldtiana, Nymphaea caerulea and Clitoria laurifolia. Shannon, Simpson and equity indexes were 3.83, 0.03 and 0.85, respectively. Native aquatic species represent the majority of the total inventoried (54%), with a considerable supply of exotic and ruderal, whose colonization reflects the anthropic interventions.