Data and R scripts for: Quality not quantity: seedlings of the invasive hybrid cattail Typha x glauca outcompete the more abundant seedlings of their maternal parent T. angustifolia x glauca) populations

Hybrid cattails are invasive and expanding their range in North America. Although some of the processes contributing to the spread of hybrid cattails are known, these involve established plants and it is unclear how processes operating during plant mating and seed germination contribute to the hybrid’s success. Specifically, the frequency with which the maternal parent of F1 hybrids (Typha angustifolia) produces hybrid offspring is not known. Also unknown is whether hybrid cattails might outcompete other cattails at during early establishment. We investigated both of these questions by sampling open-pollinated T. angustifolia fruits from 12 sites around Peterborough, ON, Canada; germinating seeds and growing them either with or without seedling competition; and genotyping a sample of those seedlings to examine the frequency with which T. angustifolia produces hybrid offspring and whether this frequency depends on the presence of seedling competition. We found that the minority of seedlings were F1 hybrids, but this depended on whether seedlings were exposed to competition: without competition, 14% of seedlings were hybrids but this number jumped to 29% with competition. Our data indicate that F1 hybrids are formed less frequently than T. angustifolia, but they benefit from competitive interactions with other cattails even at early developmental stages.