Ground-dwelling Spider Communities Respond to Changes in Riparian Vegetation Widths
Mateus Marques Pires
Programa de Pós-graduação em Biologia, Universidade do Vale do Rio dos Sinos – UNISINOS, Campus São Leopoldo, Av. Unisinos, 950, Bairro Cristo Rei, CEP 93.022-750, São Leopoldo (RS), Brazil
Programa de Pós-graduação em Biologia de Ambientes Aquáticos Continentais, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande – FURG, Av. Itália, Km 8 - Campus Carreiros, CEP 96203-900, Rio Grande (RS), Brazil.
Everton Nei Lopes Rodrigues
Programa de Pós-graduação em Biologia, Universidade do Vale do Rio dos Sinos – UNISINOS, Campus São Leopoldo, Av. Unisinos, 950, Bairro Cristo Rei, CEP 93.022-750, São Leopoldo (RS), Brazil.
Matheus dos Santos Rocha
Programa de Pós-graduação em Biologia, Universidade do Vale do Rio dos Sinos – UNISINOS, Campus São Leopoldo, Av. Unisinos, 950, Bairro Cristo Rei, CEP 93.022-750, São Leopoldo (RS), Brazil.
José Alessandro Radici Costi
Programa de Pós-graduação em Biologia, Universidade do Vale do Rio dos Sinos – UNISINOS, Campus São Leopoldo, Av. Unisinos, 950, Bairro Cristo Rei, CEP 93.022-750, São Leopoldo (RS), Brazil.
Gustavo Viega
Programa de Pós-graduação em Ecologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul – UFRGS, Av. Bento Gonçalves 9500, Bairro Agronomia, CEP 90650-001, Porto Alegre (RS), Brazil.
Cristina Stenert
Programa de Pós-graduação em Biologia de Ambientes Aquáticos Continentais, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande – FURG, Av. Itália, Km 8 - Campus Carreiros, CEP 96203-900, Rio Grande (RS), Brazil.
Leonardo Maltchik
Programa de Pós-graduação em Biologia de Ambientes Aquáticos Continentais, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande – FURG, Av. Itália, Km 8 - Campus Carreiros, CEP 96203-900, Rio Grande (RS), Brazil.
Communicated by I-Min Tso
Spiders play a key role in the ecological dynamics in riparian habitats. However, most studies on the effects of changes in riparian habitats on spider communities have focused on the conversion of riparian forest to other than uses rather than on a gradient of forest widths. We assessed the community structure of ground-dwelling spiders in riparian vegetation fragments with varying widths in Southern Brazil. We selected four fragments with different riparian vegetation widths (> 40 m; < 30 m; < 15 m; < 5 m). In each fragment, spiders were seasonally collected using pitfall traps. We tested the effects of riparian vegetation widths and environmental variables (litter height, litter cover and canopy openness) on the taxonomic and guild composition of spider communities. The taxonomic and guild composition of ground-dwelling spiders varied among the widest (> 40 and < 30 m) and narrower riparian widths (< 15 m and < 5 m). While hunting spiders were associated with the narrower widths, web-building spiders were associated with the wider widths. Spider composition was influenced by the leaf litter height in the widest widths (> 40 and < 30 m) and by canopy openness in the narrowest width (< 15 m). Reductions in riparian vegetation were associated with significant changes in the community structure of ground-dwelling spiders, likely through top-down mechanisms associated with the higher litter input in wider fragments. In summary, the fragmentation of the riparian forests of Sothern Brazil are negatively associated with web-building spiders.
