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When entomophilous plants are introduced to a new region, they may leave behind their usual pollinators. In particular, plant species with specialized pollination may then be less likely to establish and spread (i.e. become invasive). Moreover, other reproductive characteristics such as self-compatibility and flowering duration may also affect invasion success., Here, we specifically asked whether plant species' specialization towards pollinator species and families, respectively, as measured in the native range, self-compatibility, flowering duration and their interactions are related to the degree of invasion (i.e. a measure of regional abundance) in non-native regions., We used plant-pollinator interaction data from 119 German grassland sites to calculate unbiased indices of plant specialization towards pollinator species and families for 118 European plant species. We related these specialization indices, flowering duration, self-compatibility and their interactions to the degree of invasion of each species in seven large countries on four non- Eurasian continents., In all models, plant species with long flowering durations had the highest degree of invasion. The best model included the specialization index based on pollinator species instead of the one based on pollinator families. Specialization towards pollinator species had a marginally significant positive effect on the degree of invasion in non-native regions for self-compatible, but not for self-incompatible species., Synthesis. We showed that long flowering duration is related to the degree of invasion in other parts of the world, and a trend that pollinator generalization in the native range may interact with self-compatibility in determining the degree of invasion. Therefore, we conclude that such reproductive characteristics should be considered in risk assessment and management of introduced plant species. [ABSTRACT FROM AUTHOR]

Abstract: Traits that differ between invasive alien and native plant species are frequently interpreted as traits conferring invasiveness. However, such differences could reflect an introduction bias of alien species, particularly cultivated ones, or human-mediated selection of cultivars of these species with certain traits. We tested whether this is the case for germination characteristics that are frequently reported to be associated with invasiveness. In a glasshouse experiment, we compared germination characteristics of 42 plant species native to Switzerland and 47 cultivated alien species including 26 cultivars. To test whether differences in germination between these groups of species depend on an important environmental factor, we used two light levels. Cultivated alien plant species germinated earlier and more successfully than related native plant species under both light conditions. Similarly, among cultivated alien species, cultivars germinated earlier and with higher proportions than non-cultivars. Our results indicate that previously reported differences in germination characteristics between invasive alien and native species might reflect introduction bias and human-mediated selection for these characteristics. Nevertheless, because fast and abundant germination is also frequently associated with naturalization and invasiveness among alien introduced species, our results suggest that biased introduction and human-mediated selection of ornamental plants with these characteristics might increase the risk that these species ultimately become invasive. Therefore, it is important that studies testing for determinants of invasiveness include non-invasive alien species in addition to invasive alien species. Zusammenfassung Merkmalsunterschiede zwischen invasiven gebietsfremden und heimischen Pflanzenarten werden oft dahingehend interpretiert, dass sie Invasionen ermöglichen. Allerdings könnten diese Unterschiede auch auf selektiver Einführung und Selektion von gebietsfremden Arten, insbesondere Zierpflanzenarten oder Kulturvarietäten mit diesen Eigenschaften beruhen. Wir untersuchten, ob dies für Keimungseigenschaften, die oft mit Invasivität verbunden werden, der Fall ist. In einem Gewächshaus- experiment verglichen wir die Keimungseigenschaften von 42 in der Schweiz heimischen Arten und 47 gebietsfremden Zierpflanzenarten, darunter 26 Kulturvarietäten. Um zu testen, ob Keimungsunterschiede zwischen Zierpflanzenarten und heimischen Arten von einem wichtigen Umweltfaktor abhängig sind, nutzten wir zwei unterschiedliche Lichtintensitäten. Gebietsfremde Zierpflanzenarten keimten im Vergleich zu heimischen Arten früher und mit höheren Keimungsraten unter beiden Lichtintensitäten. Von den Zierpflanzenarten keimten die Kulturvarietäten früher und mit höheren Keimungsraten. Unsere Resultate weisen darauf hin, dass die bisher gefundenen Keimungsmerkmalunterschiede zwischen invasiven gebietsfremden und heimischen Arten selektive Einführung und Selektion widerspiegeln. Da schnelle und reichliche Keimung oft mit Naturalisierung und Invasivität verbunden ist, suggerieren unsere Resultate dass selektive Einführung und Selektion von Kulturpflanzenarten mit diesen Eigenschaften das Invasionsrisiko dieser Arten erhöhen. Aus diesem Grund ist es wichtig, dass Studien, die nach diesen Merkmalen suchen, sowohl invasive als auch nicht-invasive gebietsfremde Arten berücksichtigen. [Copyright &y& Elsevier]