Spread of Sporobolus neglectus and S. vaginiflorus (Poaceae) in Slovenia and neighbouring countries

Abstract

Systematic field sampling revealed that within 50 years since the first records in Slovenia, Sporobolus neglectus and S. vaginiflorus became widespread. They are two superficially similar N American annual grass species with cleistogamous spikelets and similar ecology that are confined to dry ruderal places in their European secondary range, especially along roads. The oldest records of naturalised populations of both species in Europe date back to the 1950s, when both were found for the first time in the Vipava valley (SW Slovenia). They spread slowly in the next decades to NE Italy, N Croatia, and S Austria until recently, when an explosive expansion has been observed along almost all the main roads in lowland and montane Slovenia. In addition to that, one or both of them have recently been recorded scattered in SE Europe (Hungary, Serbia, B&H, Montenegro) and W Europe (France, Switzerland). Sporobolus vaginiflorus is herein reported for the first time for Serbia, Herzegovina (in B&H), and Slavonia (in Croatia).

Keywords

• invasive species
• neophytes
• Sporobolus neglectus
• Sporobolus vaginiflorus
• road banks
• Slovenia
• Europe