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, and more recently 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: these had greater abundance and occupancy than T. angustifolia despite the fact that T. angustifolia produces relatively few hybrid seeds, and therefore highlights the importance of long-distance dispersal for this hybrid range expansion. The distribution of hybrids combined with the paucity of non-F1 hybrids suggests that the western PPR represents a leading edge of the range expansion by invasive T. x glauca. Our results show that T. x 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.