Response of drought and fertilization in Erica andevalensis seed banks: significance for conservation management.

The present study attempts to investigate the size, composition and seedling dynamics of the seed bank of a metalliferous and vulnerable species, Erica andevalensis. Samples were taken during spring and autumn from two different sites. We also studied the effects of nutrient solution, irrigation from the river Tinto and irrigation deficit on seeding establishment and survival. Only E. andevalensis and Poaceae species emerged from the seed banks, although the former was dominant (98%). Germination and seedling establishment was totally inhibited by the waters of the river Tinto. Seed density was high in the soils of both seed banks irrigated with water and nutrient solution. We found no seasonal differences in the seed bank and number of germinated seeds and mortality rate and density were similar. From the standpoint of restoration management, the results indicate that the seed bank is a very important factor for successful species establishment.