Does invasion by an alien plant species affect the soil seed bank

Abstract Questions: How does invasion affect old-field seed bank species richness, composition and density? How consistent are these effects across sites? Does the soil seed bank match vegetation structure in old-fields? Location: Menorca, Balearic Islands, Spain, western Mediterranean basin. Methods: We monitored seed germination in soils from old fields that were both uninvaded and invaded (legacy effect) by the annual geophyte Oxalis pes-caprae. We also added O. pes-caprae bulbs to uninvaded soils to test O. pes-caprae interference with seedling emergence (competitive effect). We compared species composition in the seed bank with that of the vegetation. Results: Species richness in the seed bank and in the vegetation was not significantly different between invaded and uninvaded areas. Uninvaded areas did not have larger seed banks than invaded areas. More seedlings, especially of geophytes, emerged when O. pes-caprae bulbs were added to the soil. Species similarity between invaded and uninvaded areas w...