Floristic and phytogeographical relationships of the tree component in forest remnants from the vicinities of Lake Taruma, Viamão municipality, Rio Grande do Sul state, Brazil.
This paper describes a tree component survey of forest remnants in the vicinities of Lake Tarumã and also shows the results of a phytogeographical analysis on the origin of the species surveyed at Viamão municipality, in the Brazilian state of Rio Grande do Sul. The studied region is situated near the urban center of the municipality and has small forest remnants. The survey was conducted by the "walking" method, with monthly collections being performed from 2008 to 2010. We identified 112 species from 40 families, of which 16 species are exotic and two are included in the red list of threatened plant species from Rio Grande do Sul. Most species are widely distributed in the state; followed by the ones that occur in the surroundings of the meridional plateau, being originated either in seasonal or Atlantic forest regions; which in turn are followed by species of exclusively Atlantic origin. Our results corroborate those of other studies in the state and emphasize the importance of the Atlantic corridor to the local floristic composition. The study area also shows high species richness, which thus highlights the extreme importance of preserving this site.