The Eastern North American Temperate Freshwater Marsh, Wet Meadow and Shrubland is a hydrologically dynamic ecosystem highly sensitive to shifts in water availability. Across the Midwest, climate change is expected to intensify two primary stressors, flooding and drought, resulting in increased hydrologic variability that may threaten the persistence of these wetlands. Increased spring precipitation and more frequent extreme rainfall events are projected to cause deeper, longer-lasting inundation, while rising temperatures, reduced snowpack, and heightened evaporative demand are likely to increase the frequency and severity of droughts.

Changes in hydrology may significantly alter both habitat structure and community composition. Physical disturbance from scouring and erosion may intensify, while nutrient and sediment loading from surrounding land uses may lead to eutrophication and terrestrialization. Vegetation zonation is likely to become destabilized under more extreme hydrological conditions, with flood-tolerant or droughtadapted species replacing those with narrower hydrologic tolerances.

The two habitat groups within this broader ecosystem show differing vulnerabilities. The Eastern North American Freshwater Marsh, including both Great Lakes coastal and inland systems, is considered among the most hydrologically dynamic and disturbance-prone wetland types. Vegetation in these marshes is typically stratified along water depth gradients, forming distinct zones that depend on variable hydrology to persist, but deep or prolonged inundation can disrupt this zonation and reduce plant diversity. In contrast, the Midwest Wet Prairie, Wet Meadow and Shrub Swamp, generally lacks persistent surface water and relies on precipitation and snowmelt to maintain seasonal saturation. As a result, this habitat group is especially prone to drying and potentially susceptible to woody encroachment and shifts toward drier-adapted plant communities.

Across both habitat groups, invasive species are expected to gain a competitive edge under future climate conditions. Invasive wetland plants often exhibit high plasticity and can tolerate a wide range of disturbances and hydrologic conditions, allowing them to expand rapidly during both flood and drought periods. Interacting pressures underscore the growing vulnerability of the Eastern North American Temperate Freshwater Marsh, Wet Meadow and Shrubland under future climate scenarios.