Influence of Different Land-Use Types on Soil Arthropod Communities in an Urban Area: A Case Study from Rome (Italy)

Soil represents a fundamental yet delicate ecosystem susceptible to threats and alterations that can significantly impact its biota, especially in urban areas. Soil microarthropods may serve as bioindicators of soil quality. The aim of this study was to provide a comprehensive investigation of the response of soil microarthropod communities to anthropogenic pressures and to assess the biological quality of the soil in urban Rome (Italy). Microarthropods were extracted from soil samples collected at 16 sites, representing four distinct land-use types (disturbed unmanaged green spaces, disturbed managed green spaces, urban forests, and natural forests as reference) along a disturbance gradient. The basic soil properties and landscape characteristics were measured at each sampling site. Values of community diversity (calculated as Hill’s numbers based on biological forms reflecting specialization to the edaphic life), total microarthropod density, and soil biological quality indices based on microarthropod biological forms (QBS-ar and its variation QBS-ab, which also considers group abundances), were calculated for each sampling site and compared among land-use types. Land-use types varied in soil chemo-physical characteristics, with soils of managed and unmanaged green spaces being more alkaline, sodic, and compacted, and with lower organic matter, carbon, and nitrogen levels compared to urban and natural forests. Microarthropod diversity decreased from semi-natural or natural forests to highly disturbed urban sites. QBS-ar and QBS-ab values significantly differed among almost all land-use types, with managed urban green spaces exhibiting lower values than the unmanaged ones. No significant differences were observed between urban and natural forests. Soil pH, soil compaction, cation exchange capacity, C/N ratio, and vegetation cover appeared to be the most significant factors influencing the diversity and composition of microarthropod biological forms, as well as the QBS-ar and QBS-ab indices. Although with the limit of using biological forms instead of species, our investigation reaffirmed the valuable role of large, forested patches within cities for soil conservation and the preservation of their microarthropod communities. The potential of green spaces as suitable habitats for soil microarthropods should be carefully considered in urban management plans.