Seed longevity and fire: germination responses of an exotic invader herb in NW Patagonia grasslands (Argentine)

FRANZESE JORGELINA1* AND GHERMANDI LUCIANA1

Oporto, Portugal

Congreso; World Conference on Biological Invasions and Ecosystem Functioning (BIOLEF).; 2009

Fire affects grassland composition by selectively influence the recruitment. Some exotic species can increase their abundance as consequence of fire stimulation on seed germination. However, they could respond differently depending on seed age. The aim of this work was to study the effect of fire on germination of seeds (with different storage periods) of Rumex acetosella, an exotic perennial herb that increase its cover after fire. In 2008 we exposed seeds (up to 19 years old) to different “fire treatments”: heat, smoke, charcoal, and ash. Germination depended on seed longevity and fire treatments. Germination increased as younger were the seeds, however, the oldest seeds showed a relatively high germination potential. There was not a defined pattern in germination responses to fire treatments among years, though; we observed a decrease in germination in those seeds exposed to 120 ºC. These results could be useful to determine the invasion potential from the soil seed bank, from which R. acetosella is the third most abundant species.