I. Habitat Description
The sedge meadows habitat includes lowland areas around lakes, ponds, backwaters, and along seasonally flooded shorelines. Similar to wet meadows, these habitats are close to 100% vegetated with perennial grasses and forbs. The distinction is over 20% of the vegetation consists of sedges (Cyperaceae). Most of the species present are from the genus Carex, true sedges characterized by three-ranked leaves and triangular stems, with grasses and rushes interspersed. Forbs are also present, but may grow poorly under competition with the sedges. Though the peat and muck soils remain saturated most of the year, there is little standing water present (except after flooding or precipitation events). Sedge meadow habitat is rare and limited in occurrence in the Upper Mississippi River system.
II. Sensitivity to Oil Spills
The sedge meadows habitat is highly sensitive to oil spills. This biologically diverse habitat provides a home to many types of plants and animals. Restoration of the plant community may require the purchase of plugs, as many of the area’s plants have low germination rates. Many animal species such as the sandhill crane and common snipe use the sedge meadows for reproduction and feeding purposes. The abundance of small mammals makes these ideal feeding grounds for raptors, mink, and fox. Significant loss of this habitat would greatly affect the populations of these animals and, consequently, the local ecology. Light refined oils with high amounts of water-soluble fractions can cause acute mortality to animals and plants in this habitat. Heavier oils tend to coat vegetation and animals, though the vegetation may survive if oil coats only the stems or if the roots are not affected. Viscous oils will not penetrate into dense vegetation.
III. Sensitivity to Response Methods
The following text describes potential adverse impacts to this habitat resulting from various oil spill response methods and provides recommendations to reduce impact when these methods are implemented. This is not intended to preclude the use of any particular methods, but rather to aid responders in balancing the need to remove oil with the possible adverse effects of removal. More detail about the response methods themselves can be found in the Inland Response Tactics Manual.