The invasiveness of the cattail hybrid Typha x glauca: a study of seedling growth rates

Abstract

Hybridization may play an important role in the formation of invasive species (Ellstrand and Schierenbeck 2000). Throughout North American wetlands the native cattail species Typha latifolia is hybridizing with the introduced species Typha angustifolia. It has been suggested that the hybrid cattail species Typha x glauca is experiencing hybrid vigor and is therefore more invasive than its parent taxa. The objective of this study was to examine whether Typha x glauca is in fact more invasive than its parent taxa by studying the growth patterns of Typha seedlings. The seedlings used in this experiment fit into five different species groups: T. angustifolia, T. latifolia, hybrids produced by pollinating T. angustifolia with T. latifolia, hybrids produced by pollinating T. latifolia with T. angustifolia, and backcrosses produced by pollinating T. x glauca with T. angustifolia. This study consisted of a factorial design experiment that manipulated the environmental conditions of soil moisture and soil nutrients. Data from a previous study examining variation in percent germination between T. latifolia, T. angustifolia and T. x glauca was analyzed. The data from the seedling experiment did not suggest that the F1 T. x glauca seedlings were experiencing hybrid vigor. Instead, the T. x glauca backcross seedlings were the most successful. Further research should be conducted examining the success of advanced hybrids.