Successful transfer of species-rich grassland by means of green hay or threshing material: Does the method matter in the long term?

Questions We investigated the transfer of seeds from species-rich grassland using green hay and seed material from on-site threshing to answer the following questions: do these two methods differ in terms of restoration success; and how do the two methods behave in their long-term effect concerning species composition and species presence? Location Styria, Austria. Methods We harvested seed material of a species-rich Arrhenatherion meadow by green hay and on-site threshing and transferred it to a receptor site. Transferable species were identified by vegetation survey and seed sample analyses. We analysed transfer rates and vegetation cover for the donor site species pool and Arrhenatherion target species, covering a 10-year observation period. Species composition and presence were derived from plant surveys. Results The restoration success of both methods was similar within the observation period. Although donor site species declined, the establishment of target species was satisfactory and species-rich grassland was successfully established, despite different site conditions between donor and receptor sites and strong dynamics in species composition over time. Conclusions Both harvesting methods are well suited for restoring species-rich grassland, and the actual choice ultimately depends on the costs and the given circumstances. Even if donor and receptor site differ in their site conditions, species-rich grassland can be established successfully. The prerequisite for this is that: (a) a high proportion of transferred species is able to establish; and (b) specific restoration goals do not exclude vegetation development according to specific receptor site conditions.