Arthropod assemblages and functional responses along an urbanization gradient: A trait-based multi-taxa approach

Abstract

Urbanization causes considerable alteration across a wide range of ecosystem functions at regional and global scales. These changes could be key drivers of habitat stability and ecosystem services in urban greenspaces. The aim of this study was to test the influence of urbanization on taxonomic and functional diversities of arthropods of different trophic levels. We collected predator spiders, polyphagous rove beetles, and decomposer woodlice along a rural-suburban-urban gradient by litter sifting. Neither the taxonomic, nor the functional diversity (Rao’s quadratic entropy) using a morphological trait (body size) and ecological traits (habitat affinity, humidity preference, and disturbance sensitivity) of the spiders were significantly different along the urbanization gradient. For rove beetles, taxonomic diversity was significantly higher in rural sites compared to suburban and urban ones, while functional diversity did not differ significantly between sites. Both the taxonomic and the functional diversities of woodlice were significantly higher in the rural sites than in the suburban or urban sites. Detrended canonical correspondence analysis also showed that urbanization did not cause considerably changes in composition of spider assemblages, while rove beetle and woodlouse assemblages showed clear separation between rural and urban sites. This study pointed out that trophic levels may be a crucial driver of the responses to urbanization. Our results suggest that urbanization has a less harmful effect on predator spiders, as they can easily recolonize the managed urban greenspaces. Contrarily, recolonization of arthropods at lower trophic levels (rove beetles and woodlice) into the urban habitats is considerably restricted.