Acta
Carpathica
Occidentalis

The first records of invasive Narrow-Leaved Ragwort (Senecio inaequidens) on motorways and expressways in Moravia and Silesia (Czech Republic)

The first records of invasive Senecio inaequidens on motorways and expressways in Moravia and Silesia (Czech Republic) are presented. There were 58 new localities recorded during the 2013-2014 survey. The largest population of about 100 individuals occurs on the motorway D1 between the 171.5 km and 172.0 km (section from Pávov to Brno). Smaller stabilized populations are found on the motorway D2 (section from Brno to the border with Slovakia). Considering the size of these populations, S. inaequidens has occured at these localities for at least several years, successfully breeds and is now in the migration phase of invasion here. At other sites along the motorways D1 and D2, more the less only individual plants were found scattered throughout the network. Similarly, only individual plants of S. inaequidens are already present along the expressways R35, R46 and R52. On the expressway R48, there is one small vital population with some individual plants scattered along the road in both directions. Overall the invasion of S. inaequidens is still in the initial phase on most studied motorways and expressways. Possible self-incompatibility of the individual plant can be a limiting factor of the more rapid invasion as the species spreads by seeds. The total number of localities suggests that intense international and also domestic road transport is undoubtedly an important vector of S. inaequidens spreading. The motorway network is becoming the main gateway of S. inaequidens invasion to the territory of Moravia and Silesia.