​Usnea arianae was first collected in 1969 in the Algarve (Portugal) on Quercus suber. In Europe, this species was further collected in Brittany (France) in wetlands on Betula pendula, in Atlantic North Western Spain on Acacia dealbata, and most recently in the Dordogne (France), southern Corsica (France), Iberian Peninsula (Caviró 2015) and inland in Switzerland (Clerc & Kissling 2019) within riparian vegetation types.