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

Abstract

Coastal sand dunes are dynamic ecosystems with elevated levels of disturbance and are highly susceptible to plant invasions. One invasive plant that is of concern to the Great Lakes system is Gypsophila paniculata L. (perennial baby’s breath). The presence of G. paniculata negatively impacts native species and has the potential to alter ecosystem dynamics. Our research goals were to (1) estimate the genetic structure of invasive G. paniculata along the Michigan dune system and (2) identify landscape features that influence gene flow in this area. We analyzed 12 populations at 14 nuclear and two chloroplast microsatellite loci. We found strong genetic structure among populations (global FST = 0.228), and pairwise comparisons among all populations yielded significant FST values. Results from clustering analysis via STRUCTURE and discriminant analysis of principal components (DAPC) suggest two main genetic clusters that are separated by the Leelanau Peninsula, and this is supported by the distribution of chloroplast haplotypes. Land cover and topography better explained pairwise genetic distances than geographic distance alone, suggesting that these factors influence the genetic distribution of populations within the dunes system. Together, these data aid in our understanding of how invasive populations move through the dune landscape, providing valuable information for managing the spread of this species.

Repeat photography of Lake Michigan coastal dunes: Expansion of vegetation since 1900 and possible drivers

“…By their nature, dunes are disturbed landscapes and, as such, can be susceptible to invasive species colonization. G. paniculata, with its deep taproot and large seed disbursement, has successfully directly competed for limited resources from more sensitive native species such as Pitcher's thistle (Cirsium pitcher) (Leimbach-Maus et al, 2020;Yang et al, 2019). Grass planting programs, such as those around Ottawa Beach in the 1980s, have accomplished much the same effect, as one of our repeat photo pairs from that area demonstrates.…”

“…Dunes to the south (Leimbach-Maus et al, 2020). By their nature, dunes are disturbed landscapes and, as such, can be susceptible to invasive species colonization.…”

Effective dispersal patterns in prairie plant species across human‐modified landscapes

“…Interpretation of effective dispersal requires consideration of spatial and temporal scales affecting populations (Robledo‐Arnuncio et al., 2014; Twyford et al., 2020); for most plants, individual genetic relationships within fine scales (e.g., scale of less than 1 km radius) will be dominated by annual dispersal events (Grasty et al., 2020), while population structure at large scales (e.g., scale of 100 km radius) will be formed by cumulative multi‐generational gene flow (Elleouet & Aitken, 2019). Depending on the dispersal ecology of a species, studies conducted at the mesoscale (e.g., scale of 10 km radius) may capture the interface between drivers of dispersal, such as dispersal vector behaviour or landscape features, and evolutionary consequences, such as prolonged gene flow, drift and colonization dynamics (Arredondo et al., 2018; Leimbach‐Maus et al., 2018; Schweiger et al., 2004). Mesoscale studies are of particular interest as they coincide with typical management‐level scales (Browne & Karubian, 2018; Myers et al., 2004; Williams, 2017), and only a few studies have considered plant landscape genetics at a scale where genetic differentiation is primarily due to contemporary dispersal events (Emel et al., 2021; Rivkin & Johnson, 2022).…”

“…Isolation by distance models are most reliable in fine‐scale homogeneous landscapes that experience consistent conditions for dispersal or large scales at which coalescence relationships dominate genetic structure estimates. At the mesoscale, evolutionary relationships are often faint, and IBD models do not capture spatial variation in landscape features, habitat quality and fragmentation, or dispersal vector behaviour (Arredondo et al., 2018; Leimbach‐Maus et al., 2018; Mateo‐Sánchez et al., 2015). In this context, dispersal may be influenced by topographical or land use features, such as land elevation, tree canopy coverage, rivers or streams, urbanization, agricultural conversion and meteorological events (Cruzan & Hendrickson, 2020; Sork & Waits, 2010).…”

“…Isolation by resistance is based on circuit theory and postulates some landscape features are more favourable to dispersal, while other landscape features constrain dispersal (termed ‘conduits’ and ‘resistors’, respectively) (McRae et al., 2008). By comparing landscape features to population genetic differentiation, we can infer how the rate of gene flow fluctuates across heterogeneous landscapes (Chiappero et al., 2023; Leimbach‐Maus et al., 2018; Segelbacher et al., 2010; Sork & Waits, 2010).…”