Old Meets New: Combining Herbarium Databases with Genetic Methods to Evaluate the Invasion Status of Baby’s Breath (Gypsophila paniculata) in North America

Aim This paper aims to inform our knowledge of common baby’s breath’s ( Gypsophila paniculata ) current population structure and invasion status using a combination of contemporary genetic methods and historical herbarium data. Taxon Gypsophila paniculata (Angiosperms: Eudicot, Caryophyllaceae) Location Samples were collected from seven locations spanning a portion of the plant’s North American range: Washington, North Dakota, Minnesota, and Michigan, United States. Methods To analyze contemporary population structure, individuals of G. paniculata from 7 distinct sampling locations were collected and genotyped at 14 microsatellite loci. Population structure was inferred using both Bayesian and multivariate methods. To investigate G. paniculata’ s invasion status, public herbarium databases were searched for mention of the species. Records were combined, resulting in a database of 307 herbarium collections dating from the late 1800’s to current day. Using this database, invasion curves were created at different geospatial scales. Results Results of genetic analyses suggest the presence of at least two genetic clusters spanning our seven sampling locations. Sampling locations in Washington, North Dakota, Minnesota, and northwestern Michigan form one genetic cluster, distinct from our two more southern sampling locations in Michigan, which form a second cluster with increased relative genetic diversity. Invasion curves created for these two clusters show different time periods of invasion. An invasion curve created for North America suggests G. paniculata’ s range may still be expanding. Main conclusions Gypsophila paniculata has likely undergone at least two distinct invasions in North America, and its range may still be expanding. Restricted genetic diversity seen across a wide geographic area could be a signature of limited seed distributors present during the early period of this garden ornamental’s invasion.