Ammophila breviligulata: Implications
of using non-local plant sources for native plant restorations in Minnesota
Populations of the same
species diverge genetically due to local adaptation by natural selection and
random genetic drift. The accumulation
of these genetic differences may result in ecotypic variation across the
species range. Depending on the degree
of genetic differentiation among populations, these different ecotypes may no
longer be sexually compatible or may exhibit severe reduction in fitness when
they are hybridized (outbreeding depression).
Growing interest in restoration projects has been accompanied by
mounting concerns over the source and genetic history
of restoration propagules.
Ecological restoration projects often rely upon the introduction of
non-local propagules, such as seed or clonal fragments, to replace or supplement
threatened populations. In Minnesota,
historical dune restoration projects introduced non-local propagules of Ammophila breviligulata from Michigan to
augment the threatened native population. In this case, genetic mixing may threaten the
long-term sustainability of the native population if intraspecific
hybridization between the locally adapted and introduced genotypes occurs and
results in outbreeding depression.
In an effort to assess the potential impact of these
historical plantings of MI genotypes on the remnant native MN population, we conducted the following studies: 1) a molecular
marker study to distinguish native and naturalized nonnative plants in the
field, 2) a common garden and observational study of MN and MI genotypes to
determine if genotypes differ in terms of phenology and morphology, and 3) a
hybridization experiment between MN and MI genotypes to assess the effects of
genetic mixing. Work was performed at
field sites on Minnesota Point in