Landscape mosaic of Araucaria forest and forest monocultures influencing understorey spider assemblages in southern Brazil

Abstract

This study investigates how abundance, diversity and composition of understorey spiders were influenced by four different forest habitats in a southern Brazilian Araucaria forest. The study area encompasses a landscape mosaic comprised of Araucaria forest, Araucaria plantation, Pinus plantation, and Eucalyptus plantation. Understorey spiders were collected by beating the vegetation inside three patches of each forest habitat. To assess possible predictors of spider assemblage structure, several patch features were analysed: potential prey abundances, estimation of vegetation cover, diversity index of vegetation types, patch ages, patch areas, and geographical distance between patches.To assess the influence of high-level taxa approaches on spider assemblage patterns, analyses were carried out individually for family, genera and species levels. Additionally, Mantel tests were carried out in underlying similarity matrices between each taxon. Significant differences in spider abundances among forest habitats were found. Pinus plantations showed the highest abundance of spiders and Eucalyptus plantations showed the lowest abundance. Spider abundance was significantly influenced by patch ages, geographical distance and vegetation cover. Expected numbers of families, genera and species did not vary among forest habitats. Spider composition of two Eucalyptus patches differed from the other forest patches, probably due to their low vegetation cover and isolation. Genera composition was the best correlate of species composition, showing that a higher-level surrogate can be an alternative to the species approach.The understorey spider diversity in this managed area could be maintained when suitable habitat structures are provided, thus ensuring the connectivity between different habitat types. Further studies should focus on individual species responses to the conversion of native forest to monocultures.

Diversity, composition and phenology of araneid orb-weavers (Araneae, Araneidae) associated with riparian forests in southern Brazil

“…The same is valid for BaldisseRa et al (2008) considering mixed broad-leaved/Araucaria forests and Pinus plantations, sampling manually from the tree-shrub layer, attaining 37% similarity only with our data.…”

“…Spiders in this family are generally among the most abundant and speciose of those sampled from the treeshrub plant strata in faunal inventories in southern Brazil, even from distinct ecosystems (indRusiak & kotzian, 1998;BaldisseRa et al, 2004;RodRigues, 2005;silva & aRaujo, 2005;Bonaldo et al, 2007;podgaiski et al, 2007;BaldisseRa et al, 2008;RodRigues et al, 2014). A species list was presented by indRusiak & Buss (2003) for the central region of Rio Grande do Sul State, and in the list of spiders species of Rio Grande do Sul State (Buckup et al, 2010) cite Araneidae as the family with the highest number of species to the State (210 species).…”

Carabid beetle assemblages in three environments in the Araucaria humid forest of southern Brazil

“…Environmental structure can define resource availability for predatory arthropods. Baldissera et al (2008) compared spider diversity in the shrub layer of exotic silviculture of Pinus ellioti and Eucalyptus sp. and natural forests of Araucaria angustifolia, indicating the influence habitat structure can have on predators since a higher diversity was found for Eucalyptus sp.…”

“…Some implications of the presence of silviculture environments on the beetle fauna in southern Brazil are discussed in Ganho & Marinoni (2006) (for other predatory invertebrate group (arachnids) see Baldissera et al 2008).…”

Spider community responds to litter complexity: insights from a small-scale experiment in an exotic pine stand

“…Schmidt et al, 2005;Corcuera et al, 2015;Marín et al, 2016), to our knowledge there are no published studies addressing such topic in Brazil, particularly regarding to pine plantations. Specifically in South Brazil, some attempts were done in order to compare spider diversity patterns between agroecosystems and adjacent native ecosystems, such as the studies of Baldissera et al (2008) in tree plantations, including pine, and native Araucaria forest, Rodrigues et al (2009) in rice field, grassland and native forest, and Rodrigues et al (2010) in Eucalyptus plantations and natural grasslands. Other studies in agroecosystems in South Brazil describe spider assemblages, for example, in olive groves (Ricalde et al, 2016), corn plantations (Da Silva et al, 2014), citrus groves (Ott et al, 2007) and irrigated rice (Rodrigues et al, 2008).…”