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

Abstract

28Aim: This paper aims to inform our knowledge of common baby's breath's (Gypsophila 29 paniculata) current population structure and invasion status using a combination of 30 contemporary genetic methods and historical herbarium data. 31 Taxon: Gypsophila paniculata (Angiosperms: Eudicot, Caryophyllaceae) 32 Location: Samples were collected from seven locations spanning a portion of the plant's North 33 American range: Washington, North Dakota, Minnesota, and Michigan, United States. 34 Methods: To analyze contemporary population structure, individuals of G. paniculata from 7 35 distinct sampling locations were collected and genotyped at 14 microsatellite loci. Population 36 structure was inferred using both Bayesian and multivariate methods. To investigate G. 37 paniculata's invasion status, public herbarium databases were searched for mention of the 38 species. Records were combined, resulting in a database of 307 herbarium collections dating 39 from the late 1800's to current day. Using this database, invasion curves were created at different 40 geospatial scales. 41 Results: Results of genetic analyses suggest the presence of at least two genetic clusters 42 spanning our seven sampling locations. Sampling locations in Washington, North Dakota, 43 Minnesota, and northwestern Michigan form one genetic cluster, distinct from our two more 44 southern sampling locations in Michigan, which form a second cluster with increased relative 45 genetic diversity. Invasion curves created for these two clusters show different time periods of 46 invasion. An invasion curve created for North America suggests G. paniculata's range may still 47 be expanding. 48 Main conclusions: Gypsophila paniculata has likely undergone at least two distinct invasions in 49 North America, and its range may still be expanding. Restricted genetic diversity seen across a 50 wide geographic area could be a signature of limited seed distributors present during the early 51 period of this garden ornamental's invasion.52

Examining the molecular mechanisms contributing to the success of an invasive species across different ecosystems

“…To better understand these mechanisms, we investigated two populations of G. paniculata growing at opposite ends of the species’ introduced range in the United States. Based on herbarium records, G. paniculata populations have been established in the sand dunes of Petoskey, MI, since the early 1910s and in the sagebrush steppes of Washington since the 1930s (Lamar & Partridge, 2019). This has likely provided sufficient time for these populations to begin adapting to these divergent ecosystems.…”

“…We predict that the populations will differ in gene expression patterns and that those differences will be reflective of the environment in which they inhabit. Given that baby's breath established in these environments approximately 100 years ago (Lamar & Partridge, 2019), we also predict that this should be enough time to see divergence in allele frequencies for genes that are important to these distinct habitats. This will allow us to identify potential targets of local adaptive evolution for future testing.…”

“…Originally introduced into North America in the late 1800s for use in the floral industry (Darwent, 1975; Darwent & Coupland, 1966), G. paniculata quickly spread and can now be found growing in diverse ecosystems across North America, often outcompeting and crowding out the native species (Baskett, Emery, & Rudgers, 2011). While relatively little is known about the history of invasive baby's breath populations in the United States, a recent population genetic analysis using 14 microsatellite markers identified at least two distinct population clusters, with one of these clusters including populations that span from the upper portion of Michigan's lower peninsula to the eastern side of the Cascade Mountains (Lamar & Partridge, 2019). The environments that these populations occur in range from quartz‐sand dunes in Michigan to disturbed roadsides in Minnesota, prairies in North Dakota, and sagebrush steppes in eastern Washington.…”

Genetic Structure of Invasive Baby’s Breath (Gypsophila paniculata L.) Populations in a Michigan Dune System

“…A perennial iteroparous forb, G. paniculata is native to the Eurasian steppe region and was introduced to North American in the late 1880s [ 25 , 26 ]. Since its introduction, it has spread throughout the western United States and Canada and has established across a diverse array of habitats, including sand dunes, prairies, disturbed roadsides, and sage brush steppes [ 26 , 27 , 28 ]. In Michigan, G. paniculata negatively impacts the coastal dune community by crowding out sensitive species such as Pitcher’s thistle ( Cirsium pitcher ) through direct competition for limited resources, forming monotypic stands in the open dune habitat, preventing the reestablishment of native species, and limiting pollinator visits to native species [ 29 , 30 , 31 ].…”

“…Similar work assessing the population structure of invasive G. paniculata populations within the mid-western and western United States have found that these invasive populations are distributed among at least two distinct genetic clusters, both of which are present in the Michigan sand dunes [ 28 ]. Our goal for this study was to more extensively sample populations throughout Michigan to gain a better understanding of how these populations are distributed and how they disperse throughout the dune landscape.…”