Fitocenološki opis rastišč vrste Salvia hispanica (Lamiaceae) na prodiščih v zahodni Sloveniji

In late summer and autumn (late August, beginning of November) of 2018 we observed a mass occurrence (more than 500 specimens) of Salvia hispanica, commonly known as chia, on gravel bars of several rivers in western Slovenia (the Soča and the Sava river basins). It was blooming on many sites in the first half of November, but low daily temperatures in the second half of the month prevented seed development. This Central-American (Mexico, Guatemala) species, which is distributed as a crop also outside its native range, grew mainly in initial plant communities of riverine gravel terraces classified into associations Polygono lapathifoliae-Salicetum eleagni (described as new), Chaerophyllo-Petasitetum officinalisand Bidenti frondosae-Panicetum barbipulvinati nom. prov. The dominating species in these associations are perennials or hemicryptophytes (50%) and annual plants – therophytes (32%). The proportion of alien species (neophytes) is 22% and the proportion of species originating in America is 10%. The warmer climate with less precipitation and less frequent high waters in the last decade, combined with the fact that chia seeds are a commercially available food product or an ingredient in various foods (nutrients), increases the likelihood of successful seed production in chia plants and their distribution in nature. The threat of Salvia hispanicabecoming an invasive species is therefore serious.