Spatial and temporal patterns of land flatworm assemblages in Brazilian Araucaria forests

Araucaria forests are among the most threatened biomes of one of the world’s 25 biodiversity hotspots, the south Brazilian Atlantic Rain Forest. This study was focused on flatworm community structure in three protected areas located on the eastern border of the Araucaria Plateau in south Brazil. We addressed three main questions: (1) How species-rich are Araucaria forests? (2) Are there any differences in the community structure within the three areas? (3) What is the distribution pattern of land flatworms in this type of forest? A total of 51 flatworm species in ten genera and two subfamilies were found. Non-metric multidimensional scaling analysis showed that the assemblage structure differed within the three areas. The abundance and richness varied in time, being affected by an interaction between season and areas. Araucaria forests on the eastern border of the Araucaria Plateau should be considered a hotspot of land planarian diversity, harboring an estimated 64 species. The high combined species richness in the protected areas studied emphasizes the importance of their preservation. Notwithstanding their close proximity, they are not redundant in maintaining regional biodiversity.