Abstract
Spider (Araneae) assemblages were studied over two years by pitfall trapping along an urbanisation gradient of forested habitats (rural forest - suburban forest fragment - urban forest fragment) in a Danish town, using the Globenet protocol. During the two years, we collected 4340 individuals of 90 species, with money spiders (Linyphiidae) and wolf spiders (Lycosidae) being most numerous. One species, Ero aphana, was new to the Danish fauna. In 2004, 45-47 species were captured in the habitats in various stages of urbanisation, while in 2005 (with a smaller collection effort), 28 (urban) - 37 (rural) species were captured. Twenty-five percent of the collected species occurred in all habitats, but about half of them were only collected in one of the urbanisation stages. The number of shared species was the highest between the suburban and urban habitats. The highest similarities between assemblages (characterized by the Renkonen-index) were the within-habitat, between-year comparisons, indicating assemblage stability. Species turnover between years was lowest in the rural forest and highest in the urban forest patch (56.6% vs. 41.5%). Urbanisation did not reduce diversity in terms of species richness but only a minority of the species present in forests was able to remain attached to the reduced-size forest fragments as urbanisation progressed.
Spider (Araneae) assemblages were studied over two years by pitfall trapping along an urbanisation gradient of forested habitats (rural forest - suburban forest fragment - urban forest fragment) in a Danish town, using the Globenet protocol. During the two years, we collected 4340 individuals of 90 species, with money spiders (Linyphiidae) and wolf spiders (Lycosidae) being most numerous. One species, Ero aphana, was new to the Danish fauna. In 2004, 45-47 species were captured in the habitats in various stages of urbanisation, while in 2005 (with a smaller collection effort), 28 (urban) - 37 (rural) species were captured. Twenty-five percent of the collected species occurred in all habitats, but about half of them were only collected in one of the urbanisation stages. The number of shared species was the highest between the suburban and urban habitats. The highest similarities between assemblages (characterized by the Renkonen-index) were the within-habitat, between-year comparisons, indicating assemblage stability. Species turnover between years was lowest in the rural forest and highest in the urban forest patch (56.6% vs. 41.5%). Urbanisation did not reduce diversity in terms of species richness but only a minority of the species present in forests was able to remain attached to the reduced-size forest fragments as urbanisation progressed.
Keywords
Globenet, disturbance, biodiversity, arachnids
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