%0 Journal Article %T Does the Lagoa do Peixe sandbar opening influence the macrophyte richness and composition in Southern Brazil wetlands? %A Ana Silvia Rolon %A Odete Rocha %A Leonardo Maltchik %J Revista de Biolog赤a Tropical %D 2013 %I Universidad de Costa Rica %X The Lagoa do Peixe has its connection with the sea artificially opened every year at the end of winter. However, this management has been carried out without the evaluation of the impact of this opening in the aquatic biodiversity. This information is crucial for the management of the natural resources of the Lagoa do Peixe National Park, the unique Ramsar site in Southern Brazil. The following questions were analyzed: (1) Do richness and composition of aquatic macrophytes from Lagoa do Peixe floodplain varies temporarily according to the sandbar opening and closing? (2) Does the variation pattern of the macrophyte community changed according to the sandbar opening and closing? A set of eight sampling sites of 1ha were selected over the Lagoa do Peixe floodplain: four sites not influenced by the artificial sandbar opening and four sites influenced by this event, being two sites closer to the sandbar opening and the two sites distant to the sandbar opening. The samplings were carried out between November 2007 and October 2009. The results show that although the artificial sandbar breaching does not affect the aquatic macrophyte richness at the floodplain, it affects the dynamics of species composition. The hydrological variation related to this management can be the main factor of the continuous change in the species composition in the floodplain, especially in the Southern portion. In order to avoid impacts in the macrophyte conservation, the artificial sandbar opening should be considered carefully, since the area of study is one of the most important conservation units to wetland systems in Southern Brazil. La Lagoa do Peixe, en el sur de Brasil, tiene conexi車n artificial con el mar, porque cada a o, al final del invierno, se abre un canal con tractor. Sin embargo, esta pr芍ctica se ha levado a cabo sin la evaluaci車n de los efectos de esta apertura en la biodiversidad acu芍tica. Las siguientes preguntas fueron analizadas: (1) Var赤an la riqueza y la composici車n de los macr車fitos acu芍ticos de la llanura de inundaci車n temporal de la Lagoa do Peixe seg迆n la apertura y el cierre del banco arena? (2) Var赤a el patr車n de la comunidad de macr車fitos seg迆n la apertura y el cierre del banco de arena? Los resultados muestran que la eliminaci車n artificial del banco de arena no afecta la riqueza de macr車fitos acu芍ticos en la llanura de inundaci車n, pero s赤 afecta la din芍mica de la composici車n de especies. La variaci車n hidrol車gica relacionada con la apertura puede ser el factor principal del cambio continuo en la composici車n de especies en la llanura de inundaci車n, es %K plantas acu芍ticas %K macr車fitos %K estabilidad de la composici車n %K composici車n de especies %K humedales de llanuras inundables %K eliminaci車n de bancos de arena %K aquatic plants %K floodplain wetlands %K sandbar breaching %K species composition stability %U http://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0034-77442013000100033