Erhaltung und Förderung gefährdeter Wasserpflanzen in den Mooren der Drumlinlandschaft Zürcher Oberland (Schweiz)

Abstract

Conservation and promotion of endangered aquatic plants in the mires of the Drumlin Landscape Zurich Oberland (Switzerland) – The macrophytes of small restored peat diggings and fen ditches of a protected mire complex in the eastern Swiss Plateau were surveyed. Altogether 56 hydrophyte and helophyte species were recorded, 28 among them red-listed and Utricularia stygia constituting the most rare one. The present population sizes and distribution patterns are largely the result of habitat management in the course of the last four decades. More than 45 overgrown peat diggings were reopened and maintained by a rotation strategy, locally assisted by bog restoration. At selected stretches of fen ditches the water was retained by controllable weirs in order to prevent desiccation of the drains during warm weather periods with low or no precipitation. Temporally and spatially staggered clearance of overgrown ditches was applied to protect the aquatic organisms. Thus, most of the endangered macrophytes could successfully be conserved and promoted by simple measures of water management.