Urban and agricultural impacts in the structure and diversity of tree vegetation in riparian forest

Abstract

The study was conducted on the Água Turva Stream bank, in the Hydrographic Microbasin of the Jirau Alto River, in Dois Vizinhos county, Paraná state, aiming to evaluate the environmental impacts of the urban occupations and agricultural activities on the floristic composition and the phytosociological structure of the arboreal stratum of the riparian forest, to obtain information on species diversity and biological invasion, which will enable the establishment of future forest restoration programs. The data collect was realized in ten sample points demarcated along the stream, where 20 sample plots of 10.0 x 10.0 m (100.0 m2) were demarcated, 10 in each stream margin. The species were identified and evaluated regarding the following variables: the CAP (Circumference at Breast Height) and total height of all the trees with CAP ? 15.0 cm (DBH ? 4.8 cm). The vegetation structure was analyzed based on the phytosociological estimators and the indexes of diversity, equability and environmental impact index of exotic species. It was concluded that the riparian forest of the Água Turva creek is quite impacted, both in the rural and urban areas, with invasion of exotic species, mainly Hovenia dulcis (japanese grape) and Musa sp. (banana tree).