Long‐term effect of mowing on the restoration of Pannonian sand grassland to replace invasive black locust plantation.

Invasive species are among the main threats to grassland biodiversity, and nature conservation management seeks the best methods to eliminate them and to restore natural habitats. We studied the long‐term effect of mowing on the restoration of Pannonian sand grassland after elimination of invasive black locust (Robinia pseudo‐acacia) plantation in Hungary, Europe. Stands of R. pseudo‐acacia at three sites were felled and stumps herbicide‐treated in the winter of 1994–1995. Mowing with hay removal treatment was applied twice a year in 1995–2001 to assist grassland recovery. A block of 12 adjacent plots of 10 m by 10 m was assigned for the experiment at each site, with six control (unmowed) and six treatment (mowed) plots randomly selected. Vegetation was sampled in June and August yearly in 1995–1999 in all sites, plus in seminatural reference grasslands then re‐sampled six times until 2017 in two sites. Herbicide application with repeated mowing successfully eliminated R. pseudo‐acacia. In the unmowed plots, dense woody cover developed at all sites. Vegetation of mowed plots approached the reference grasslands in sites with better propagule availability of target species according to trajectory analyses. In these sites, higher cover of target species was found in mowed compared to unmowed plots, though still significantly lower than in the reference. Mowed plots were more prone to secondary invasion than the unmowed. The long‐term monitoring revealed that initial mowing assisted the restoration of Pannonian sand grassland, but further management is needed to control secondary invasion and increase target species cover. [ABSTRACT FROM AUTHOR]