Rebecca Anderson

Ammophila breviligulata: Implications of using non-local plant sources for native plant restorations in Minnesota

Ecological restoration projects often rely upon the introduction of nonlocal propagules, such as seed or clonal fragments, to replace or supplement threatened populations. In Minnesota, historical dune restoration projects introduced nonlocal propagules of Ammophila breviligulata from Michigan to augment the threatened native population. Despite the good intentions of such efforts, there is mounting concern over the source and genetic history of the propagules used in these restoration projects. If the MN and MI populations are substantially genetically diverged, genetic mixing between the two populations could lead to outbreeding depression; characterized by high mortality, slower growth, and reduced seed production. the negative effects of inbreeding depression, commonly referred to as hybrid vigor. Additionally, introduced genotypes of beachgrass from MI could compete with threatened native genotypes and become dominant if they possess a fitness advantage or numerical advantage; occurring through either vegetative spread via rhizomes or through the recruitment of seedlings.

In an effort to assess the potential impact of these historical plantings of MI commercial genotypes on the threatened native MN population, I conducted the following studies: 1) an ISSR molecular marker study to distinguish native and naturalized nonlocal plants and to assess genetic composition and diversity within and among populations, 2) field-based observational and common garden studies of MN and MI genotypes to determine if genotypes differ in terms of phenology and morphology , 3) a proximity study to assess spatial constraints that may restrict gene flow, 4) a manipulated within- vs. between-population crossing experiment between MN and MI genotypes to assess the effects of genetic mixing relative to parental fitness and 5) a pollination experiment to assess natural rates of inbreeding and the extent of inbreeding depression in both MN and MI populations growing in Minnesota.