Is <i>Poa annua</i> a skin‐changer? Annual–perennial life history shift enables the species to conquer Antarctica

An extended lifespan of Poa annua may be of adaptive value during the invasion of harsh environments. Our aim was to investigate whether this trait is population-specific or general for the species. Individuals representing eight populations were cultivated under experimental conditions for two Antarctic growing seasons separated by polar winter conditions. Our experiment indicated that the species is capable of extending its life history toward perenniality regardless of population origin. Adventitious roots at the lower nodes were observed in overwintering plants from all the studied populations. We observed a similar response regardless of the source population. Plants exposed to stress from both climatic and edaphic conditions did not survive the simulated Antarctic winter. Plants grown in optimal gardening soil expressed a life history with vegetative growth during the first vegetation season and flowered and produced seeds only during their second growing season. P. annua may exhibit at least a two-year life cycle under harsh Antarctic conditions. This trait is general for the species and determines high survival potential, which may initiate an invasion breakout under climate change. Shifts in species life history traits should be considered in the management of alien species invasions occurring under harsh environments.