Atributos ecológicos que contribuem para invasibilidade da macrófita Hedychium coronarium J. König (Zingiberaceae)

Abstract

Biological invasions are an important cause of biodiversity loss and occur when an exotic species is introduced out of its native range, possibly changing the structure and functioning of invaded communities. The invasion potential of aquatic macrophytes is often greater than showed by terrestrial plants, especially due to their generally high dispersal efficiency. Not coincidentally, aquatic invasive plants have been a major threat to multiple ecosystems worldwide. Hedychium coronarium is a perennial macrophyte native from tropical Asia, where it is common in the understory of moist ecosystems. It has been introduced elsewhere for ornamental uses, where is has showed high invasion potential. In this study we assessed experimentally how the productivity of H. coronarium (aboveground biomass and number of ramets by rhizome; ramet biomass and height) is affected by previous rhizome exposition to contrasting water, temperature and light regimes. We found that increasing flooding was associated to greater ramet and biomass production. In contrast, prolonged rhizome desiccation leaded to high rhizome and ramet mortality. Ramet biomass was slightly lower after rhizome exposition to a 35ºC than to a 25ºC temperature, and productivity was lower under complete darkness than at a 12h daily photoperiod. These findings show that H. coronarium tolerates a broad range of abiotic conditions and may adjust its clonal growth pattern to the local environment. This ability to maintain high invasion potential even under extreme abiotic conditions possibly plays an important role in the dominance of the species in riparian ecosystems and highlights the importance of developing effective management strategies to avoid further spread of the species.