Current situation with invasive Erigeron annuus (l.) Pers. (daisy fleabane) in the Republic of Macedonia

Abstract

Detailed surveys of populations of Erigeron annuus (L.) Pers., an invasive plant species native to Eastern North America, were made in three locations in north-western, northern and eastern parts of the Republic of Macedonia. The population densities were not quantified, but several stands of different sizes were found. A rapid ecological risk assessment, mainly based on knowledge of invasion histories in South-Eastern and Central European countries, showed that this species is a serious threat to Macedonian biodiversity, particularly in the north-western part, where monospecific stands of E. annuus were recorded. Biological invasions of E. annuus affect biodiversity worldwide through its rapid growth and high seed production, phenotypic plasticity in the native range with regard to the availability of soil nutrients and release of compounds to the soil over the period of plant growth. Consequently, invaded ecosystems suffer from significant loss in economic and cultural value.