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Monitoring the specific composition of macrophyte communities in Luis Eduardo Magalhaes reservoir

This study aimed to evaluate the composition and spatial and temporal distribution of a community of macrophytes in response to abiotic factors in Luis Eduardo Magalhães Reservoir, in the Tocantins River. Samplings were collected every two months, from March 2005 to January 2006 in five regions of the reservoir. In each region, 15 collection sites were selected. The abiotic variables measured were the Secchi disk depth, electrical conductivity, air temperature, and rain and water levels. A standardized sampling effort was applied to assess macrophyte species distribution and community composition. In each site, a distance of 100 m from the shore was covered with a boat maintaining low and constant velocity, for approximately 10 minutes. The submerged species were inventoried with a rake attached to a 4m pipe. Incidence data were analyzed using DCA. One-Way ANOVA was applied to evaluate the effects of the periods and regions on the abiotic and biotic variables. The Tukey test a posteriori was applied when significant differences (P<0.05) Checar se seria P maiusculo between the variables were found. A total of 50 species was recorded. The most frequent species were Salvinia auriculata, Oxycaryum cubense and Najas microcarpa (submerged). The highest species richness was observed in the riverine regions of the reservoir (Areias and Tocantins). Our results also showed that the spatial variation in community composition was more accentuated than temporal variation.

beta diversity; temporal distribution; species richnes


Sociedade Brasileira da Ciência das Plantas Daninhas Departamento de Fitotecnia - DFT, Universidade Federal de Viçosa - UFV, 36570-000 - Viçosa-MG - Brasil, Tel./Fax::(+55 31) 3899-2611 - Viçosa - MG - Brazil
E-mail: rpdaninha@gmail.com