Leaf litter Araneofauna in an Atlantic forest remnant in northeast Brazil: Comparative study between two sample methods

Abstract

The spiders are used as indicator species, because they respond well to habitat changes, they are distributed in many micro habitats and form a mega diverse group, with 41.719 species. However, it is still required to assess the effectiveness of sample methods used to study these organisms. Therefore, this study checks if the Winkler extractor and the pitfall trap differ significantly for leaf litter spiders capture in a 72 ha Atlantic Rainforest urban fragment in northeast Brazil. It was collected 399 spiders, distributed in 16 families and 29 species. The Winkler extractor collected 133 individuals, distributed in 12 families and 15 species and the pitfall trap collected 266 individuals, 14 families and 21 species. The pitfall trap captured more species than the Winkler (t = 2.169, p = 0.0455). The family and species composition differed significantly among the two methods: (MRPP: T = -8.6923017, A = 0.17602339; p = 0.000008), (MRPP: T = -3.8960485; A = 0.04390594 p = 0.0007) and (MRPP: T = -8.4598685; A = 0.19235075; p = 0.00001207), respectively. It is suggested that in urban fragments of Atlantic Rainforest, the pitfall trap and the Winkler extractor are complementary methods for leaf litter spider samples, and so, it is recommended the use of both methods. However, assessments of richness can elect the pitfall trap.

Key words: spiders, Winkler extractor, pitfall trap, Joventino Silva Park.