16 



NORTH AMERICAN FAUNA 73 



Northern Sedge Meadow 



This community occurs throughout the Valley and makes up a large pro- 

 portion of the aquatic habitats. These wetlands occur primarily north of the 

 Tension Zone. Northern Sedge Meadow usually forms on the bed of an 

 ancient lake or along and adjacent to larger streams and rivers. Soils asso- 

 ciated with this community consist primarily of decaying vegetation and 

 have a low mineral content. Groundwater is usually at or near the surface, 

 providing a spongy texture to the soil surface. Probably the largest and best 

 developed examples of Northern Sedge Meadow are associated with the bed 

 of Glacial Lake Grantsburg in Burnett and Pine counties. 



Principal vegetation of this community includes foxtail sedge, crested 

 sedge, inland sedge, slender sedge, tussock sedge, fox sedge, cattail, blue- 

 joint grass, manna grass, and dark-green bulrush. Important forbs include 

 marsh cinquefoil, marsh milkweed, purple-stem aster, marsh bellflower, 

 spotted joe-pye weed, meadow sweet, and small bedstraw. 



Northern Sedge Meadows do not support the diversity and abundance of 

 breeding birds usually associated with other wetland types. However, sev- 

 eral species breed in this community almost exclusively. Principal breeding 

 species include American bittern, mallard, marsh hawk*, ring-necked 

 pheasant, sandhill crane*, sora, common snipe*, short-billed marsh wren*, 

 yellow warbler, common yellowthroat*, red- winged blackbird, brown-headed 

 cowbird, LeConte's sparrow* (local), swamp sparrow, and song sparrow. 



Alder Thicket and Shrub Carr 



Both Alder Thicket and Shrub Carr communities are similar in geologic 

 origin and flora. One major difference between these habitats is that alder is 

 replaced by willow, particularly silver willow, in Shrub Carrs. Both habitat 

 types are usually associated with ancient lake beds or the floodplains of 

 streams and rivers. In many instances, these habitats develop from the inva- 

 sion of woody shrubs in a Northern Sedge Meadow. Alder Thicket and Shrub 

 Carr communities occur regularly throughout the Valley. However, there 

 appears to be a predominance of Alder Thickets north of the Tension Zone, 

 and Shrub Carrs occur most frequently within and south of the Tension 

 Zone. 



Principal vegetation associated with the Shrub Carr community includes 

 silver willow and red-osier dogwood in the shrub layer. Common grasses and 

 forbs include marsh shield fern, yellowish sedge, bluejoint grass, reed canary 

 grass, manna grass, marsh milkweed, jewelweed, spotted joe-pye weed, 

 water horehound, and meadowsweet. Characteristic breeding birds of Shrub 

 Carr include mallard, blue-winged teal, marsh hawk, ring-necked pheasant*, 

 common snipe, willow flycatcher*, short-billed marsh wren, veery, yellow 

 warbler*, common yellowthroat, red-winged blackbird, brown-headed cow- 

 bird, swamp sparrow, and song sparrow. 



Vegetation associated with Alder Thicket habitat includes speckled alder 

 and red-osier dogwood in the shrub layer. Characteristic grasses and forbs 

 include dark-green bulrush, tall manna grass, bluejoint grass, marsh milk- 

 weed, marsh bellflower, turtlehead, spotted joe-pye weed, jewelweed, field 

 mint, and great water dock. Characteristic breeding birds of Alder Thicket 

 include alder flycatcher*, tree swallow, gray catbird, veery*, golden-winged 



