Margherita Gioria1, Lenka Moravcová1, Wayne Dawson2, Franz Essl3, Holger Kreft4, Jan Pergl1, Patrick Weigelt3, Marten Winter5, Mark van Kleunen6 and Petr Pyšek1,7
1Institute of Botany, Czech Academy of Sciences, CZ-252 43 Průhonice, Czech Republic
2Department of Biosciences, Durham University, DH1 3LE Durham, United Kingdom
3Division of Conservation Biology, Vegetation and Landscape Ecology, University of Vienna, 1030 Vienna, Austria
4Biodiversity, Macroecology and Biogeography, University of Goettingen, 37077 Goettingen, Germany
5German Centre for Integrative Biodiversity Research, Halle-Jena-Leipzig, 04103 Leipzig, Germany 6Ecology, University of Konstanz, 78457 Konstanz, Germany
7Department of Ecology, Faculty of Science, Charles University in Prague, Viničná 7, CZ-128 44 Praha 2, Czech Republic
Recent evidence indicates that invasive species have a higher probability of forming persistent and denser seed banks compared to their non-invasive but naturalized congeneric species in the native range. This suggests that seed bank persistence is an important determinant of invasive success. Knowledge of the role of the characteristics of seed banks in alien species naturalization is, however, lacking. To address this issue, we tested whether seed bank type (transient vs persistent) and seed bank density (seeds per square meter) play an important role in the naturalization of alien plants at the global scale. To do so, we combined a global seed bank database comprising information on seed bank type and density for over 2000 species from the Global Naturalized Alien Flora database (GloNAF). This included information on naturalization incidence (i.e. whether a species has become naturalized outside its native range) and extent (i.e. number of regions where a species has become naturalized). The combined information on characteristics of the seed bank and naturalization incidence and extent were available for 1917 species in over 11,000 records. Preliminary analyses indicate that the probability of naturalization is higher in species forming persistent seed banks than those only forming transient ones, both in the native and alien ranges. Seed bank density was also positively related with the probability of naturalization but not with naturalization extent, in the native and alien range. These preliminary findings suggest that the capacity to form persistent seed banks is an important predictor of the probability of a species to become naturalized after its introduction in novel ranges, although climatic suitability will affect the number of regions. Knowledge of the characteristics of native seed banks should thus be an important component of risk assessments, although for many species, this information is available from the alien range only, where these species have already become naturalized and invasive.