Ground-dwelling spider families and forest structure variables for monitoring ecologically sustainable logging operations

Summary Approximately 80% of neotropical forests are subject to unsustainable economic practices, such as logging. Spiders are a megadiverse taxonomic group with a particularly great diversity in forest ecosystems and could help indicate the sustainability of logging operations. At six sites at 400–700 m altitude in the piedmont forest of north-western Argentina, spiders collected using pitfall traps and forest structure and spider assemblage structure variables were quantified in order to examine the association between them and to identify indicator spider families. Logging changes forest structure and seems to generate an unsuitable habitat for spiders associated with mature forests. The family taxonomic level is a good surrogate for spider morphospecies. The Mysmenidae, Nemesiidae, Theridiidae, Pholcidae, Hahniidae and Tetragnathidae families were associated with upper canopy cover of 20% or more and with more than two dead fallen trees per 0.1 ha and >15 live trees per 0.1 ha, found in unlogged forests. Bearing in mind that the piedmont forest of north-western Argentina is being logged in the absence of sustainability criteria, we suggest including spiders in monitoring schemes to complement the information obtained from more readily used groups, such as charismatic vertebrates.