The vascular flora and vegetation of Queimada Grande Island, São Paulo State, southeastern Brazil

Flora vascular e vegetação da Ilha Queimada Grande, São Paulo, sudeste do Brasil

Abstract

Studies of the vegetation on islands off the coast of southeastern Brazil are still very scarce, despite their importance for assessing, managing, and conserving insular biodiversity. We present here a list of the vascular flora of Queimada Grande Island (QGI; 24°29′10″ S, 46°40′30″ W, 57 ha, 33.2 km from the coast) in southeastern Brazil and describe its phytophysiognomies. The island is covered mainly by Atlantic Forest (Dense Ombrophilous Forest), as well as with rock outcrop and anthropogenic vegetation with herbaceous-shrub phytophysiognomies. QGI showed relatively low species richness (S = 125) when compared to other Brazilian coastal islands. Herbaceous (52) and climbing species (31) predominated on QGI. The richest families were Fabaceae (11 species), Poaceae (9), and Apocynaceae, Asteraceae and Orchidaceae (8 species each). Most species (S = 112) are autochthonous from different phytophysiognomies of the southeastern Brazilian Atlantic Forest complex. Many species associated with anthropically disturbed areas (S = 26) can be found on QGI, including the invasive grass Melinis minutiflora. There was a slight predominance of zoochory (S = 50). We did not identify any species endemic to QGI. One of its species (Cattleya intermedia, Orchidaceae) is vulnerable at both national and regional levels, and another (Barrosoa apiculata, Asteraceae) is presumably extinct on the mainland in São Paulo State. The vascular flora of QGI originated from the mainland Atlantic Forest complex, following the pattern of other coastal islands in southeastern Brazil. The flora and vegetation of QGI reflect the combination of insular conditions, the small size of the island, habitat restriction, steep topography, incipient soils, and the past use of the area with the introduction of several foreign species. We recommend permanent monitoring of the vegetation cover of QGI and its management, in order to ensure the conservation of the local native biota.

Keywords:
Atlantic Forest; biodiversity conservation; coastal islands; dispersal syndromes; invasive species; protected areas