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

## TL;DR

This study shows that ants modify soil environments in urban areas, affecting the diversity and abundance of soil microarthropods like springtails and mites.

## Contribution

The study reveals species-specific effects of ant activity on detritivorous soil microarthropod communities in urban ecosystems.

## Key findings

- Ant nests significantly alter the abundance and distribution of detritivorous soil microarthropods.
- Predatory soil microarthropods remain largely unaffected by ant activity.
- Soil disturbance by ants acts as an ecological filter shaping microarthropod community composition.

## Abstract

Some animals, like ants, can change their surroundings in ways that affect other species. However, we still do not fully understand how these changes impact soil organisms. In this study, we explored how two common ant species, the black garden ant and the yellow meadow ant, influence the presence and diversity of soil microarthropods (both predators and detritus feeders) in urban soils. We compared soil from ant nests with nearby soil that had no ant activity. Our goal was to see if ant activity changes the number and types of these important soil organisms. The results showed that ant nests do affect both the abundance and the variety of these groups, with different responses depending on the role each group plays in the soil. Some groups remain unchanged, while others decreased in number. These findings show that ants act as ecosystem engineers by shaping who lives in the soil. Understanding these effects is important for protecting belowground biodiversity and can help guide the management of green areas in cities to support healthy and balanced ecosystems.

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.