Plant communities of two peat-shrub species – Spiraea salicifolia and Potentilla fruticosa were studied in the Rhodope Mts., with emphasis on their use as a resource for the mammals associated with them. These shrubs are boreal relicts among the dominant coniferous forests. The field surveys were conducted in the spring-autumn period of 2021–2022. In both study areas, the species composition of the mammals was studied by camera traps for medium and large mammals, and by Sherman live traps for small mammals. The species registered were roe deer (Capreolus capreolus), red fox (Vulpes vulpes), wild boar (Sus scrofa), pine marten (Martes martes), European hare (Lepus europaeus), red squirrel (Sciurus vulgaris), bank vole (Myodes glareolus) and yellow-necked mouse (Apodemus flavicollis). Having in mind that small mammals are vital prey base for avian and mammalian predators, it is not surprising that M. glareolus and A. flavicollis individuals were captured in the habitats that they probably use as shelters. The pine marten inhabits the forests by which the community of P. fruticosa is surrounded, but probably feeds on the rodents in the shrub. In this way, it probably provides it with an alternative to the forest food base and hunting ground. From the presented results, it seems that the L. europaeus uses P. fruticosa shrubs as food. Therefore, the plant communities of the two relict peat-shrub species studied probably provide shelter and food for the mammals. Their importance is established for at least one species of mammal with conservation significance at national and European level – M. martes. Therefore, it is necessary to continue and expand the future monitoring on mammal diversity of these relict communities.