Relationships among site characteristics,taxonomical structure and functional trait distribution of arthropods in forest,urban and agricultural soils of Southern Italy

Urbanization and agriculture cause alterations in soil biodiversity. As arthropods quickly respond to soil changes, they have been recognized as good indicators of soil quality. This study aimed to evaluate if (1) soil physico-chemical properties act as environmental filters of the functional trait distribution of soil arthropod community; (2) the abundance of certain functional traits is linked to different land uses; (3) the taxonomical and functional approaches provide complementary information about the evaluation of biological soil quality. The study was performed at forest, agricultural and urban sites in downtown and surroundings of Naples. The soils were characterized for texture, pH, organic matter content, water content, total Cd, Cr, Cu, Ni, Pb and Zn concentrations. The forest soils showed the highest organic matter and water contents, and the lowest metal concentrations; the agricultural soils showed the lowest organic matter and water contents and high Cd and Cu concentrations, whereas the urban soils showed high Pb and Zn concentrations. The forest soils showed the highest arthropod density, taxa richness and diversity. The distribution of the functional traits in the arthropod communities of the different land uses highlighted similarity only for the preference to occupy soil and for the percentage contribution of detritivores. The abundance of arthropods living above litter and omnivores were positively correlated to Pb and Zn concentrations, whereas predators were positively correlated to Cu concentrations. The findings suggest that the arthropod identification at order level could be enough to detect differences in functional traits among forest, urban, and agricultural soils.