Floristics and phytosociology of a swamp forest in Brotas, state of Sao Paulo, Brazil

Results of a floristic and phytossociological survey of the tree-shrub component on the swamp forest along the Onca stream, Municipality of Brotas, SP (22 degrees 10' and 22 degrees 15' South, 47 degrees 55' and 48 degrees 00' West) are here presented. Data was collected by means of a phytossociological survey, using twenty 10 x 10m quadrats in which all individuals with PBH (perimeter at breast height) greater than or equal to 15cm were recorded. There were sampled 536 individuals, belonging to 22 families, 25 genera and 33 species. The richest families were Myrtaceae (6 sp) and Meliaceae (4 sp). Calophyllum brasiliense Camb., Protium almecega March., Cedrella odorata L., Styrax pohlii A. DC., Talauma ovata a St. Hil., Dendropanax cuneatum (DC) Done et Planch. and Tapirira guianensis Aubl. were the most important species. The vertical structure was caracterized by two strata, and the emergents. The Shannon diversity index (H') was 2,52. There was a low floristic but a high structural similarity between this area and others compared, leading to the conclusion that swamp forests share, as common features, a low diversity and a high dominance at species level, and a characteristic flora distinct of that found on the riparian forests.