The research was designed to assess benefits of passive restoration, consisting of blocking from drainage ditches and in effect raise the groundwater level, its influence on properties of soil, water, species of plants and mesofauna in the fen Caltho-Alnetum community. The research was carried out in Outer Flysh Carpathians, the area of the Babiogórski National Park (Poland) in 2011–2014. It was established that the degraded communities showed positive reaction to an attempt to restore the original groundwater level. The increase in the groundwater level changed chemical properties of soil and water of the community such as: pH, sorption properties and the ionic composition of groundwater. Changes in habitat conditions resulted in different species composition of soil mesofauna and plants growing in the restorative community.