Plant species of the Central European flora as aliens in Australia.

The Central European flora is an important source pool of plant species introduced to many regions throughout the world. In this study, we identified a total of 759 plant species of the Central European flora that are currently recognized as alien species in Australia. We explored temporal patterns of introduction of these species to Australia in relation to method of introduction, growth form, naturalization status and taxonomy. Across all species, substantially larger numbers of species were introduced between 1840 and 1880 as well as between 1980 and the present, with a small peak of introductions within the 1930s. These patterns reflect early immigration patterns to Australia, recent improvements in fast and efficient transportation around the globe, and emigration away from difficult conditions brought about by the lead up to the Second World War respectively. We found that the majority of species had deliberate (69%) rather than accidental (31%) introductions and most species have not naturalized (66% casual species, 34% naturalized species). A total of 86 plant families comprising 31 tree species, 91 shrub species, 533 herbaceous species and 61 grass species present in Central Europe have been introduced to Australia. Differential patterns of temporal introduction of species were found as a function of both plant family and growth form and these patterns appear linked to variation in human migration numbers to Australia.