Great Lakes sand dunes and beaches represent the most extensive freshwater dunes in the world.  Because this habitat is a fragile system which is highly susceptible to human and natural disturbances and invasion by exotic species, restoration efforts involving planting of American beachgrass (Ammophila breviligulata) have become common.  Recently, ecologists have become aware that two commonly ignored factors: soil biota and plant genotype, may be important factors to consider in implementing successful restorations.  Soil microbes, such as arbuscular mycorrhizal fungi (AMF), form symbioses with plants that can help infected plants in stressful environments by increasing drought tolerance and nutrient uptake, and so may help facilitate dune restorations.  A number of genotypes of Ammophila are sold commercially in the Great Lakes region, though little is known about these varieties, or their relative performance along the Great Lakes.  Here we report on results from two controlled restoration experiments along Lake Michigan near Chicago.  We compared survival and performance of two widely planted Ammophila varieties: ‘Cape’ which was developed from East Coast Atlantic dunes populations, and ‘Vans’ which was originally isolated from Michigan Great Lakes dunes.  We also evaluated potential benefits of adding soil amendments to these restorations.

Results/Conclusions After the first year, we found that ‘Cape’ plants had two to three times higher survival in the restorations than the ‘Vans’ plants.  Soil amendments increased the survival of ‘Vans’ plants, but had no effect on survival of ‘Cape’ plants.  Interestingly, ‘Cape’ plants were also 100% infected with a systemic endophytic fungus, while ‘Vans’ plants were not infected.  These preliminary results indicate potential interactions between endophyte infection and AMF colonization in plants. The findings from this study will help to inform future restoration efforts, especially where restoration activities can unintentionally alter microbial biota through introduction of nursery soil or new plant varieties, potentially affecting long-term dynamics of vegetation on the dunes.