PROTECTING WISCONSIN'S BIODIVERSITY

Wet prairies are characterized by their grass and sedge dominance on moist mineral soils. They often occur as a fringe along the upland edge of sedge meadows or emergent marshes or on the lower edge of wet-mesic prairies. They can be distinguished from wet-mesic prairies by their higher water table (usually within 12" of the surface during a normal year), taller (usually 3' or more), more rank vegetation, and higher prevalence of grasses and forbs associated with wetter habitats such as bluejoint grass, prairie cord grass, Joe-Pye-weed, boneset (Eupatorium perfoliatum), common water hemlock (Cicuta maculata), swamp milkweed (Asclepias incarnata), and water smartweed (Persicaria amphibia). In addition, wet prairies lack grasses found in drier habitats such as Indian grass, little bluestem, and prairie dropseed.

Wet prairies also share similarities with southern sedge meadows, though sedge meadows tend to occur on organic soils (rarely mineral soils) while wet prairies almost always occur on mineral soils. Wet prairies also have a higher prevalence of grasses such as prairie cordgrass, bluejoint grass, and occasionally big bluestem, while southern sedge meadows have a higher prevalence of sedges. Similarly, calcareous fens (sometimes called prairie fens due to their prairie flora) are also usually located on organic soils (peat and/or marl) rather than mineral soils. While fens impacted by past land use such as plowing or hydrologic alteration can have vegetation very similar to a wet prairie (including prairie cord grass and tall sunflower), examination of the soil with a soil probe (at least 36-40" deep) will almost always reveal peat (sometimes oxidizing to mucky mineral) and marl rather than a shallow clay layer that typifies wet prairies.

Wet prairies have some forbs in common with emergent marshes but lack the dominance of cattails and bulrushes that typify marshes, although aggressive non-native cattails (e.g.,Typha angustifolia, T. glauca) may invade and take over wet prairies, blurring this distinction.

Wet prairies also sometimes occur in wetland complexes with shrub-carr, and can become invaded by shrubs if the hydrology and fire regime is disrupted. The dividing line between shrub-carr and prairie is generally the degree of shrub cover, with shrub-carr having greater than 50% cover but the length of time shrubs have been dominant and the presence of prairie indicators can help distinguish a shrub-invaded but restorable wet prairie from a shrub-carr with a long presence on the landscape.