Pistia stratiotes in Slovakia
Pistia stratiotes (Araceae: EPPO A2 List) is a free-floating perennial freshwater macrophyte native to South America. The species is invasive in many regions of the world including Africa, Asia, Central America and the Caribbean, North America, and Oceania. In the EPPO region, the species is established in thermally abnormal waters in Slovenia and Germany and it is invasive in the south of France. Established populations occur in Morocco, Italy and Spain. Recently, P. stratiotes was identified Serbia (RS 2019/127). In South -West Slovakia, occasional records of P. stratiotes have been recorded as early as 2007 (a few individuals found in Podunajská nížina lowland in the Malý Dunaj river) and between 2008-2010 (Čierna voda river). Studies in 2015 and 2018 show that individual plants first appeared in July. Spreading occurred in September and October and although affected by frost, the plants remained at the sites until December. The highest density of plants reached approximately 380 individuals per m2 and an average biomass of 7.3 kg m2. In 2016 and 2017 the species was absent. At present, P. stratiotes can be regarded as transient in Slovakia, but over time, climate change may facilitate spread and establishment.
Ružičková J, Lehotská B, Takáčová A, Semerád M (2019) Morphometry of alien species Pistia stratiotes L. in natural conditions of the Slovak Republic. Biologia 75, 1–10.