Spatial patterns of microturbellarian assemblages in coastal wetlands from Southern Brazil

BRACCINI JÕAO; BRUSA FRANCISCO; LEAL-ZANCET ANA MARIA

Simposio; X International Symposium on Flatworm Biology; 2012

Wetlands are among the most important ecosystems for conservation in the world, containing a high species diversity compared with other areas, besides showing great economic importance and high levels of different types of impacts. Turbellarians are very abundant in freshwater environments, but they are seldom taken into account in diversity inventories. The diversity of this group in the Neotropical Region is known exclusively from some locations where taxonomical works were done, especially in the Brazilian state of São Paulo. We comparatively analyze the species composition of microturbellarian communities in wetlands of different sizes. We selected nine lagoons of the coastal plain of Rio Grande do Sul classified, according with their sizes, as small (up to 150 square meters), intermediate (from 151 to 1500 square meters) and large (more than 1500 square meters) wetlands. We sampled the wetlands, in three distinct sites, in March 2012. The species were analyzed in vivo by the progressive squash method. A total of 444 specimens, representing 46 species and 20 genera, was sampled, from the following orders: Catenulida, Macrostomida, Lecithoepitheliata and Rhabdocoela. Species richness ranged from 9 to 30 per type of water body. The species composition between the three types of water bodies was distinct with only 6.5% of the recorded species occurring in the three types of wetlands. In the small ecosystems, there was a high abundance of Stenostomum bicaudatum (n=35) and Bothromesostoma evelinae (n=34), with three unknown Stenostomum unique for this type of ecosystem. In the intermediate water bodies, the dominant species were Rhynchoscolex nanus (n=29), Dasyhormus lithophorus (n=28) and Chordarium leucanthum (n=27). These species together with Baicalellia evelinae, Catenula leuca, Suomina turgida, and other unidentified microturbellarian species were unique for this type of wetland. In the large lagoons, the dominant species were Gieysztoria chiqchi (n=41) and Stenostomum grande (n=40). These two species together with Stenostomum amphotum, Stenostomum corderoi, Stenostomum virginianum, and other unidentified species of Catenula, Microstomum, Mesostoma, Strongylostoma and Gieysztoria were unique for this type of water body. Besides a high number of species, the distinct species composition observed in the three types of wetlands indicates the need for conservation of all types of ecosystems.