Pristine freshwater fens harbour many species of aquatic macroinvertebrates. Effects of eutrophication and desiccation have strong negative impacts on macroinvertebrate assemblages. To restore degraded fens, the removal of accumulated organic sludge by dredging seems a necessary step. However, degraded fens may harbour relic populations of rare and characteristic species as was found for raised bogs and shallow soft water lakes. This study investigates the effectivity of dredging by comparing dredged and undredged water bodies in two areas (SW & MP). To help interpret the observed differences, a third least impacted area is sampled in addition (WD).

Verberk, W.C.E.P., Kuper ,J.T., Lamers, L.P.M., Christianen, M.J.A., & Esselink, H. (2007). Restoring fen water bodies by removing accumulated organic sludge: what are the effects for aquatic macroinvertebrates? Proceedings of the Netherlands Entomological Society Meeting. Volume 18: pp 115-124.