Investigations on ecology and distribution of Senecio inaequidens DC. (Asteraceae) in Tuscany (Italy)

We investigated the distribution of the alien species Senecio inaequidens in Tuscany. We verified occurrence and extent of its populations, investigating sites with ecological conditions suitable for it. In particular, we surveyed a large portion of Tuscany’s railways, which proved to be effective dispersion corridors, due to the bio-ecological characteristics of S. inaequidens. Data collected in the field were georeferenced in GIS environment, allowing to produce a map of the current distribution of this species and an estimation of its current population size. The distribution of S. inaequidens in Tuscany can be generally considered to date not alarming, since the plant spreads mainly in secondary anthropogenic environments, particularly along railways and roadsides. However, the current extent of S. inaequidens in Tuscany is considerably larger, compared to past bibliographical reports, and thanks to our survey its status changed from naturalized to invasive. Moreover, four sites are reported as hosting large populations with risk of further spreading, for which monitoring programs are recommended.