Impact of Biogenic Structures of the Soil-Nesting Ants Lasius niger and Lasius flavus on the Soil Microarthropod Community in Urban Green Spaces

Organisms that physically modify their environment, known as ecosystem engineers, can influence resource availability, species interactions and the structure of soil communities. However, the specific effect of ecosystem engineers like ants on the abundance and diversity of non-engineering soil organisms remains understudied. To address this knowledge gap, we conducted a survey of a multi-taxon belowground community of soil microarthropods—Collembola, Mesostigmata, Oribatida and Actinedida—in urban areas, comparing nest mounds of the ant species Lasius niger and Lasius flavus with areas without ant-nesting activity (control). We hypothesised differences in abundance and distribution patterns of different soil microarthropod taxa between ant mounds and the control soil. We also hypothesised that ant-induced soil disturbance is species-specific, and may result in different patterns of diversity and composition of soil microarthropod assemblages within trophic levels, such as among detritivores (e.g., Collembola) and predators (e.g., Mesostigmata). Our results reveal how ecological filters shape different soil microarthropod groups’ responses to ant-driven changes in their environment. As we expected, soil disturbance caused by ant nest-building activity significantly influenced the abundance, distribution patterns and diversity of soil microarthropods, especially in the assembly of detritivorous—but not predatory—guilds of soil microarthropods.