Evaluation of two techniques of leaf-litter translocation on spider (Arachnida: Araneae) and ant assemblies (Hymenoptera: Formicidae)

Abstract

Due to the current rhythm of ecosystem destruction, the development of new techniques aiming at the conservation of forest remnants and their biota is urgent. Our objective was to compare two techniques of leaf-litter translocation (with and without withdrawing the pre-extent litter layer), through observations on spider and ant richness and assemblage composition, in order to define the best way to perform translocation. The study was carried out in two Brazilian Atlantic rain forest remnants (called releaser and receptor fragments) in Salvador, State of Bahia, Brazil. A comparison between the faunas of both fragments was performed before translocation and a significant difference was found both in their richness and composition, which is an essential condition to carry out the experiment. A small scale environmental characterization] was made in order to choose similar units capable of minimizing the stress on leaf-litter organisms living there. Both for spiders and ants, the species richness increased in units that received leaf-litter and it was higherfor spiders in units where the pre-extent litter had not been removed. For the ants, the two forms of translocation seem to be efficient. Nevertheless, taking into account the two groups of organisms, it is suggested that the translocation must be done maintaining the pre-extent leaf-litter. Key words: conservation, litter, fauna manipulation, spiders, ants.