Desert ant mound size reshapes soil microarthropod alpha but not beta diversity distribution

Mound size, engineered by desert ants, critically reshapes soil microarthropod diversity distribution in desert ecosystems by modifying key microhabitat conditions. This study investigated the effects of different-sized mounds on the diversity of soil microarthropods in revegetated plantations of the Tengger Desert. Within revegetated plantations, we measured ant mound size and then collected soil microarthropods from both mounds and open spaces for the calculation of alpha and beta diversity. We found that ant mound significantly increased the abundance and alpha diversity (taxonomic richness, Shannon index, and Simpson index) of soil microarthropods, but significantly reduced their beta diversity. Furthermore, small mounds had a stronger influence on the alpha diversity of soil microarthropods compared to large ant mounds, while both large and small mound showed similar negative effects on the beta diversity. pSEM showed that ant activity directly reduced soil microarthropod alpha diversity, but indirectly increased it via mound size-mediated soil potassium enrichment. For beta diversity, mound expansion from ant activity decreased diversity, while mound size itself increased diversity through reduced spatial heterogeneity of soil total phosphorus. Our research reveals the changes in soil microarthropod diversity following ant mound size, advancing our understanding of the ecological functions of ants during the restoration of revegetated plantations.