Summary of the experiences of Hungarian botanical gardens with terrestrial plant species included in the European Union’s list of invasive alien species

Abstract

Besides the anthropogenic fragmentation, alteration and destruction of habitats, the spread of invasive alien species and their habitat transformation significantly contribute to the decline of biodiversity worldwide. The defense against invasive organisms can be effective only if the countries of a larger region act on together. Therefore, the European Union set up a common regulation in 2014. Within this framework, a list of species was published, against which common measures are necessary and possible. As the first step of defense, it is worth collecting the experience gathered formally in a country about the species on the list. Botanical gardens have a long tradition in collecting horticultural and ecological knowledge on non-native plant species. For this reason, by using a questionnaire survey, we assessed the experiences of Hungarian botanical gardens on terrestrial plant species listed in the 2017/1263 executive regulation (list of invasive species dangerous for the whole EU) which are not yet widespread in Hungary. From the studied nine terrestrial species, which are on the list of European Invasive Species, but absent or not widespread in Hungary, six are cultivated in the 13 respondent botanical gardens in Hungary. The saltbush (Baccharis halimifolia) is the most frequent appearing in seven gardens, while the Brazilian and Chilean giant rhubarb (Gunnera manicata and G. tinctoria, the two species treated as one taxon) and the large-leaved lupin (Lupinus polyphyllus) can be found in six gardens. According to our survey, it cannot be excluded for two species (saltbush and large-leaved lupin) that they can be able to spread spontaneously and can become invasive at least in some regions of Hungary. Botanical gardens provide an excellent opportunity for long-term observations on the biology and ecology of plant species which are rare or hardly feasible for ecological research. Thus, botanical gardens can play important role in the assessment of the invasive potential of alien plant species.