Sandy Wet Prairies

Description

The Sandy Wet Prairies ecological site reference is a wet to wet-mesic prairie that includes a diversity of wet-tolerant grasses and forbs. Variation in water table allows both wetland and non-wetland species to thrive on this site. Grass species include prairie cordgrass, big bluestem, and Indiangrass. Sedges are an important component, especially in wetter areas. Several dozen species are possible. The most noteworthy species are Bicknell’s sedge (Carex bicknellii Britton), woolly sedge (Carex pellita Muhl ex. Willd.), and Buxbaum’s sedge (Carex buxbaumii Wahlen B.). Tussock-forming species like Hayden’s sedge (Carex haydenii Dewey) and upright sedge (Carex stricta Lam.) may also be important in wet conditions. Common forbs include classic tallgrass prairie species like prairie blazing star (Liatris pycnostachya Michx.) and compassplant (Silphium laciniatum L.), as well as species typical of wetland conditions like four flower yellow loosestrife (Lysimachia quadriflora Sims) and swamp milkweed (Asclepias incarnata L.). Shrub cover was typically low and likely included leadplant (Amorpha canescens Pursh), willows (Salix L.) and dogwoods
(Cornus L.), which quickly spread in the absence of frequent fire.

Community phases within the reference state are generally dependent upon the impacts of fire or grazing. Fire is a trigger that occurs during dry periods and promotes continued herbaceous vegetation dominance and removes dense thatch. This promotes seedling regeneration. Fire removes plant litter, helps cycle nutrients, and allows light to reach the seedbed. Frequent fire maintains the community in a grassland state by keeping fire-sensitive woody species from gaining dominance. A secondary trigger for maintenance or conversion of this ecological site is grazing. Intensive grazing can reduce the extent of highly palatable species thereby allowing the growth of less desirable plants to increase.

Submodel

Description

Soil tillage and hydrological modification (ditching, tiling) are the primary mechanisms transitioning this site to a Tillage State. Tillage alters dynamic soil properties such as bulk density, structure, organic carbon content, and saturated hydraulic conductivity. Most areas in this state will remain in use for crop production in the foreseeable future – primarily in an intensive corn and soybean rotation. Certain practices can mitigate the soil health impacts of traditional agricultural practices. Conservation tillage minimizes soil disturbance and can improve soil structure and overall soil health. Corn or soybean plantings and a cover crop rotation can build soil structure, improve infiltration rates, reduce runoff and erosion, and protect water quality.

A few areas within the Sandy Wet Prairies ecological site have been seeded back to grasses. Under conservation programs. Native grasses and forbs benefit wildlife and pollinators; however, these sites generally lack the diversity of a reference state condition. Cool-season grasses are also feasible. Species selection will depend on the landowner's objectives and site specifics.

Submodel

Description

The absence of a natural disturbances, such as fire, can revert areas to the Wooded State. These sites often have other disturbances such as unmanaged grazing, altered hydrology, and invasive species. Community composition and characteristics will vary depending on seed sources and the type, severity, and length of disturbances. Tree species often include eastern cottonwood, black willow, green ash, and boxelder. Shrubs include dogwood and willow.

State 3 may be a conservation easement. Areas not in a conservation program are assumed to be jurisdictional wetlands, making it unlikely they will be transitioned to State 2 due to various wetland programs and laws, including the Swampbuster provision of the Food Security Act of 1985 (P.L. 99-198, as amended by P.L. 115-25) and the Minnesota Wetland Conservation Act (WCA) of 1991 (M.R. 8420.0100, as amended in 2009).

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