High genetic diversity promotes a common-garden trial of Quercus robur as a potential seed source

Alien brambles (Rubus, Rosaceae) generate significant ecological and nature conservational threats worldwide, however, the European flora and vegetation is not seriously affected by their impacts.In this study, I report on the distribution and habitats of alien brambles in Hungary, on the basis of comprehensive field studies and complete herbarium revision.The first introduction of a non-native species of bramble (R. phoenicolasius) was reported in 1999 in the country.R. armeniacus was first recognized in 2014 (but it had been present probably decades earlier).It typically occurs in forest-poor landscapes, in regions with larger closed forests it is mainly confined to plantations, but few occurrences in nature-like stand are also found.The occurrences in the forest steppe region indicate its drought tolerance; besides, it is the only bramble species present in the areas of typical forest-steppe climate.The species is obviously advancing (with more than 100 localities altogether) and constitutes an actual threat for the diversity and structure of fringes and wooded grassland mosaics in drier regions.Two new casual aliens, R. laciniatus and R. occidentalis, are reported here for the first time for Hungary.Another two species, R. odoratus and R. xanthocarpus, are known only from cultivation.