Range expansion of the invasive hybrid cattail Typha × glauca exceeds that of its maternal plant T. angustifolia in the western Prairie Pothole Region of North America

Abstract

Wetlands around the world face unprecedented threats, including from invasive species. In North America, the invasive cattail hybrid Typha x glauca dominates wetlands around the Laurentian Great Lakes; more recently it was found in high abundance across the central and eastern Prairie Pothole Region, an area that includes one of the world’s largest wetland complexes. Surveys of the Typha hybrid zone have so far been largely conducted in areas where hybrids are well established, and it therefore remains unclear whether the range expansion of this invasive hybrid occurs after the establishment of its maternal species, T. angustifolia. We surveyed 50 wetlands in the western PPR and found that while 75% of plants were native T. latifolia, the second most common group was F₁ hybrids, which had greater abundance and occupancy than T. angustifolia despite the fact that T. angustifolia produces relatively few hybrid seeds; our findings therefore highlight the importance of long-distance dispersal for this hybrid range expansion. The distribution of hybrids combined with the paucity of non-F1 hybrids suggest that the western PPR represents a leading edge of the range expansion by invasive T. × glauca. Our results show that T. × glauca has the capacity for continued range expansion that does not rely on the presence of T. angustifolia, and the impacts of this range expansion should be monitored because of its potential to impede ecosystem services and reduce local biodiversity.