Characterization of diatom communities in restored sewage channels in the Boye catchment, Germany

Restoration programs were initiated in different stream systems within the Boye catchment in the early 1990s to stop and reverse the negative impacts of anthropogenic disturbances. However, our knowledge of the effects of restoration works in this river network, specifically on benthic diatom communities, is still limited. Diatoms were used successfully to assess the impact of restoration works in a range of river networks around the world but received less attention in the Boye catchment. This study aimed to characterize benthic diatom communities in this restored river catchment, using digital microscopy methods. We collected samples in the spring and summer of 2020 at sites restored in different years (1995, 2005, 2010, 2012, and 2013) within the catchment. Our results showed no effect of season, restoration date (year), and location of the site along the streams on the most dominant diatom species. However, some rare taxa indicated significant variations between the seasons. Overall water quality in the streams ranged from moderate to very good, indicating the positive impacts of restoration works conducted in these former sewage channels.