The global issue of biological invasion is one of the main threats to biodiversity. G. paniculata (baby’s breath) is an invasive, herbaceous perennial that forms monotypic stands in the freshwater dune systems of Michigan. Capable of growing a 4-meter long taproot and producing 14,000 seeds annually, it effectively outcompetes native and federally threatened species for limited resources. The goals of this project are to (1) identify the genetic structure of populations and (2) to investigate dispersal patterns in the dunes of Michigan’s lower and upper peninsulas, in order to better understand how this invasion is spreading regionally. In the summers of 2016-2017, leaf tissue samples were collected from 750 individuals from six distinct areas: 1) Arcadia Dunes, 2) Zetterberg Preserve, 3) Sleeping Bear Dunes National Lakeshore, 4) Traverse City, 5) Petoskey State Park, and 6) Grand Marais Bay. The genetic structure and patterns of gene flow were assessed using a combination of G. paniculata - specific nuclear microsatellites and universal chloroplast microsatellite markers. This study is the first to analyze the genetic structure of invasive baby’s breath populations in North America to date.
Results/Conclusions
Our results demonstrated a high degree of genetic structure between populations of G. paniculata in the lower peninsula (FST value = 0.26, p-value < 0.0001). At Zetterberg Preserve, which anecdotally is considered the origin of the infestation in northwest Michigan, individuals demonstrated higher levels of genetic diversity relative to a northern site at Petoskey State Park. Effective number of alleles in the Zetterberg population was higher (NE = 2.97) than that of the Petoskey population (NE = 2.12). In addition, the population at Zetterberg Preserve exhibited a higher observed heterozygosity (HO = 0.649) compared to the Petoskey population (HO= 0.315). Current analyses are continuing to assess how genetic variation changes across this north-south gradient within the lower and upper peninsulas. These population differences could suggest a reduction in genetic diversity as this species spreads north (i.e. through founder effects), or separate colonization events could better describe the genetic variation observed. These results will be used to inform The Nature Conservancy and the National Park Service of G. paniculata populations with a high potential to contribute to further spread and reinvasion of managed areas, likely leading to a more targeted management approach.