Aim: This study reports an investigation of limnological characteristics
and aquatic macrophyte occurrence in a neotropical reservoir in order to assess the
spatio-temporal variation of water and sediment variables and their influence on plant
distribution. Methods: Macrophytes, water and sediment samples were collected from
a Brazilian reservoir in different seasons from four main arms of the reservoir. In total
sixteen water-sediment variables were analyzed including N:P ratio and Trophic State
Index. The plants were collected using a quadrat sampling procedure and the dry weight
per sample was measured. MANOVA was performed to evaluate spatial and temporal
variation of environmental variables as well as seasonal biomass differences. To assess
the relationship among environmental variables and macrophytes an ordination analysis
(using Canonical Correspondence Analysis: CCA) was carried out. Results: The spatial
and temporal variation of limnological variables generated a heterogeneous system which
supports the presence of different species of macrophyte. pH, dissolved oxygen and
sediment composition were important predictors of Polygonum lapathifolium occurrence
while nutrients were associated with Eichhornia crassipes and Pistia stratiotes. Inorganic
substances were related to biomass variation of Eichhornia azurea and Myriophyllum
aquaticum. Conclusions: The spatial variation of the environmental variables has caused
heterogeneity in the reservoir and it may support the occurrence of different species of
macrophyte. Limnological variables highlighted in CCA are important to predict the
species occurrence and their control in the study area
