In this paper were investigated the ants' communities that inhabit the Atlantic Rainforest fragments surrounded by an urban ecosystem well developed. The richness, the species frequency of occurrence, as well the similarity between the three areas of the city of São Paulo were investigated: Parque da Previdência (PP), Reserva Florestal "Armando Salles de Oliveira" (CUASO) and Horto Oswaldo Cruz (HOC). Pit-fall tramps were put in places where the public visitation is not allowed, during a whole week in the months of March, June, September and December of 2001. Considering the three fragments were collected 79 ant species belonging to nine subfamilies and 32 genera. The biggest species richness was presented by the Subfamily Myrmicinae and the genera Pheidole and Hypoponera. In PP were registered 62 species, in CUASO 46 and in HOC 43. The biggest similarity was found between PP and CUASO and possibly this similarity may be due to the size of both areas and to a similarity between the sites of nesting and feeding. In general, the ants' fauna is generalist, with the presence of some specialists genera as Discothyrea, Acanthognathus, Gnamptogenys, Oxyepoecus and Pyramica or genera that have feeding habits still unknown (Heteroponera and Myrmelachista). The presence of Pheidole megacephala Fabricius, 1793, Linepithema humile Mayr, 1868, Wasmannia auropunctata Roger, 1863, Paratrechina fulva Mayr, 1862, P. longicornis Latreille, 1802 and Tapinoma melanocephalum Fabricius, 1793, species characteristic of household areas, was also observed.
Atlantic Rainforest; urban ecosystem; Formicidae; richness
