CONICET | Buscador de Institutos y Recursos Humanos

Vegetation associated to the channel of the Paraná river is determined by conditions imposed by flood and drought pulses. The objective of the present work is to characterize vegetation in a representative environment of the lower section of the Paraná river by identifying and describing its plant communities. Multivariate analyses were used to identify and describe eight plant communities: simple forests of marginal levees, mixed forests of internal levees, young forests of marginal levees, ponds rooted communities, oxbows floating communities, community of Panicum prionitis, transitional lowlands and palustrine communities of Polygonum/Paspalum. Among woody communities, young forests of marginal levees present the lowest species richness, while mixed forests of internal levees have the highest richness, with intermediate values found in simple forests of marginal levees. Among herbaceous communities, the palustrine community of Polygonum/Paspalum has the lowest species richness, while the highest species richness is found in the community of Panicum prionitis. Transitional lowlands are not clearly defined phytosociologically, which could be related to their high flood-drought dynamics. Results of the ordination analysis indicate that the axis with highest variability responds to flooding gradient. In general, the successional origin of communities and their distribution along the topographic gradient are determinant factors for their biodiversity.