Does the Lagoa do Peixe sandbar opening influence the macrophyte richness and composition in Southern Brazil wetlands?

Abstract

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.

Effects of an artificial and annual opening of a natural sandbar on the fish community in a coastal lagoon system: a case study in Lagoa do Peixe floodplains, southern Brazil

“…The ichthyofauna along the saline gradient of the Lagoa do Peixe is represented by limnetic, marine and estuarinerelated species (Loebmann and Vieira, 2005); however, the richness, composition and temporal dynamics of the ichthyofauna in the floodplain ponds are unknown. Recent studies show that the artificial sandbar opening of Lagoa do Peixe influences plant, invertebrate and tadpole communities in the floodplain ponds (Crippa et al, 2013;Rolon et al, 2013;Moreira et al, 2014), knowledge of which is crucial for the management of natural resources in the Lagoa do Peixe National Park, a unique Ramsar wetlands site of international importance in southern Brazil.…”