Establishment Limitations of Sensitive Target Species <scp> <i>Potentilla alba</i> </scp> L. in Grasslands Restored on Arable Land

ABSTRACT Species in grasslands restored from former arable land have multiple obstacles when establishing. Understanding whether these limitations stem from soil chemical or microbial differences could help to create suitable environments for specific target and other species with similar requirements. Our study aimed to identify the key factors limiting the establishment of Potentilla alba . This species is common in ancient dry grasslands but has surprisingly poor performance in formerly tilled soils. We investigated the mycorrhizal status of P. alba , how ancient and restored grassland soils differ, whether ancient soil enhances germination and mycorrhizal colonization, and if sward gaps and soil inoculation influence seedling establishment. We established a pot experiment testing the P. alba germination in ancient and restored grassland soils. We also conducted a field experiment in a restored grassland using seeds and plant transplants of P. alba that were pre‐grown in pots with restored and ancient grassland soil. We measured soil chemical, physical, and microbial parameters, explored the mycorrhizal status, and colonization rate of the species. We found that P. alba forms arbuscular mycorrhiza but establishes worse, and has a lower colonization rate of arbuscular mycorrhizal fungi in previously tilled, P‐rich restored soils. Seedling establishment was increased by disturbance of the sward but not by inoculation by microbially more rich ancient grassland soil. Disruption of soil microbial legacies caused by tillage is likely responsible for poor establishment of P. alba on grasslands restored on former arable land.