The Apostle Islands National Lakeshore supports several types of coastal and interior wetlands including lagoons, bogs, freshwater estuaries, marshes and peatlands that provide many important ecological functions.
We investigated wetland hydrology, geomorphology, vegetation, macro-invertebrates, and fish to identify communities or wetland types that are most at risk of climate-related impacts.
The interaction between Lake Superior water levels and hydrologic connectivity between the wetlands and the lake influence how these wetlands will respond to changing conditions.
For example, the hydrology of wetlands located behind semipermanent sand barriers responds quickly to intense rain events whereas wetlands with open connections to Lake Superior are influenced more by storm and seiche-driven fluctuations than heavy precipitation events.
Floral and faunal communities inhabiting the park’s coastal wetlands must be adapted to these different water level patterns. Because various climate related drivers (e.g., storm and seiche intensity vs. intense precipitation events) are at play, the park’s wetlands will likely respond in differing ways. For example, as lake levels shifted from a 15-year below-average period (1998-2013) to above-average depths in 2014, the plant community response was more dynamic among coastal wetland types lacking a sphagnum peat mat.
The Lakeshore’s peatlands have so far exhibited resilience to changes in hydrology, but sustained monitoring may capture a time lag in peatland response. The relatively remote location of Apostle Island wetlands makes them important reference systems, though climaterelated factors are likely to alter these systems in unique ways.
Dr. Matt Cooper and Dr. Sarah Johnson
Mary Griggs Burke Center for Freshwater
Innovation, Northland College
Matt Cooper is a Research Assistant Professor at Central Michigan University and teaching faculty at Muskegon Community College.
Matt received his BS and MS from Grand Valley State University and PhD from the University of Notre Dame.
He has worked in Great Lakes coastal wetlands for many years and is one of the project managers for the Great Lakes Coastal Wetland Monitoring Program, a long-term program funded by the US EPA that is tracking the condition of over 1,000 wetlands across the Great Lakes.
Sarah Johnson is an Associate Professor of Natural Resources, the Sigurd Olson Professor of Natural Sciences, and faculty affiliate with the Mary Griggs Burke Center for Freshwater Innovation at Northland College.
Sarah received a PhD in Botany from UW-Madison and has worked in the Great Lakes region or in coastal systems for 20 years, starting with an internship with the Apostle Islands National Lakeshore.
She is a plant ecologist who researches vegetation change and teaches field botany, wetlands, and other natural history courses.