Sand Dune Ecosystems Research

Great Lakes sand dunes have been key ecological subjects since the late-1890s. Even with 130 years of research, there are still unanswered questions about sand dune ecosystems along the shores of Lakes Michigan and Superior. Jordan Marshall (PFW faculty member) conducts research in Pictured Rocks National Lakeshore and Indiana Dunes National Park focused on plants and insects – pollinators of federally threatened Pitcher’s thistle, plant distribution, and impacts of invasive species.

A 15-year study forthcoming in the Natural Areas Journal (January 2021) by Dr. Marshall investigated plant community changes with the spread of spotted knapweed, an invasive species. Changes include shifts in dominance from normal dune plants to spotted knapweed and the colonization by several native woody species. Trees and shrubs natural colonize the dunes through the process of succession, however, the number of added species suggests accelerated stabilization due to spotted knapweed invasion.

Ongoing research

A jack pine seedling in a stable area of Grand Sable Dunes, Pictured Rocks National Lakeshore.

Mapping and modeling jack pine forest establishment in Pictured Rocks National Lakeshore. Jack pine is a fire adapted species and typically more jack pine seeds germinate after fire. However, fire is not a major disturbance in the sand dunes in Pictured Rocks. Even without fire, jack pine is the typically the first tree species that colonizes as sand dunes age. This project will provide some understanding of the environmental characteristics of the dunes that facilitate jack pine establishment.

Panoramic view of a jack pine forest stand in Grand Sable Dunes, Pictured Rocks National Lakeshore.

Soil crust influences on plant communities in Indiana Dunes National Park. This is a collaboration with Tanya Soule investigating bacterial diversity importance in plant community development. New sand dunes are stressful environments for plants to establish – quickly drying surface, moving sand, nearly zero nutrients. However, soil crusts form as bacteria colonize the sand surface and can provide the initial stages of succession – facilitating plant colonization. This project is investigating the influence of bacterial diversity and community organization on subsequent plant colonization.

Soil crust sample from Indiana Dunes National Park.