Loss of biodiversity and species richness is occurring worldwide. Wetlands and fens are important to many red listed species, which are in decline. Through analysing data collected yearly, in a 15-year long study at a calcareous fen on Öland (Sweden), with experimental plots subjected to different treatments (no disturbance, grazing, and cutting with grazing). The results indicated patterns in 1) species richness 2) the occupancy of sensitive species and 3) vegetation height at the sites, between different plant communities.

The disturbance regimes showed variation in the effects on species richness, depending on the communities. Communities consisting of Cladium mariscus indicated a positive effect from both types of disturbances (grazing, cutting with grazing). Molinia caerulea communities did not have an apparent difference in response between the treatments. Communities consisting of Schoenus ferrugineus had a higher species richness in the grazing disturbance compared to a disturbance consisting of cutting with grazing. The occupancy of sensitive species was reviewed and analysed, with grazing being a significant treatment (compared to the control plots). Additionally the vegetational height was a result of the different treatments and the effect varied between the communities, with C. mariscus showing a decrease in height with a more extensive disturbances.

This study raises the importance of disturbance regimes in fens and wetlands, the relevance of long term studies, and the effect of disturbance regimes in different communities when restoring and maintaining wetlands.