Ground-dwelling spiders (Arachnida, Araneae) in different vegetational formations in a Neotropical floodplain

Spiders are generalist predators distributed in a wide variety of species found in tropical ecosystems, including wetlands such as the Brazilian Pantanal. We evaluated the composition, abundance and richness of ground-dwelling spider assemblage along a vegetation mosaic in the Brazilian Pantanal. For the evaluation, 30 transects were spaced 1 km apart in a 5 x 5 km2 area according to RAPELD methodology. Each sample point was characterized by a transect with five pitfall traps, which remained installed for eight days. A total of 724 spiders, distributed in 28 families and 50 species were collected. Lycosidae, Gnaphosidae and Salticidae showed the highest abundance, and Salticidae, Linyphiidae and Lycosidae had the highest richness. No differences were observed in the composition, abundance and richness of ground-dwelling spiders between the sampled vegetation units, however, the dominance of Lycosidae and Gnaphosidae highlighted a close association with vegetation formations composed of grasses, murundu fields and pasture. Hunting spiders were more prevalent than weavers in all vegetation types. Results demonstrate that the different vegetation types found within the Pantanal are similarly favorable environments to maintain the species richness of spiders in this important Brazilian wetland. Keywords: behavioral guilds, biodiversity, edaphic fauna, wetlands.