South African Iridaceae with rapid and profuse seedling emergence are more likely to become naturalized in other regions

Abstract

1 Plant invasions constitute a large biological problem and screening protocols are needed to assess the invasive potential of species considered for introduction. However, insufficient information is available on species characteristics associated with successful<br />establishment outside their native range.<br />2 We tested experimentally whether seed and seedling emergence characteristics and<br />early growth of seedlings are associated with naturalization of South African Iridaceae. In a common garden experiment, we compared these characteristics between 30 species that have become naturalized elsewhere and 30 congeneric species that have been introduced elsewhere but have failed to become naturalized. 3 The average seed mass did not differ between naturalized and non-naturalized species<br />but seedlings of naturalized species emerged faster and more profusely than their nonnaturalized congeners. As a consequence of fast seedling emergence, naturalized species reached a larger size early in the season than did non-naturalized species. 4 The results of our study indicate that rapid and profuse seedling emergence play important roles during naturalization, at least for Iridaceae from South Africa.