05/30/2001 Env Bd Packet - Laserfiche WebLink

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involve or necessitate further investigation of other causes, in addition to tree de- watering impacts, for the changes in hydrology that have occurred. Wetlands Wetlands constitute the second major vegetation type in the southeast quadrant. There are sizeable historic sedge meadow /wet prairie complexes in the large wetland area in the eastern portion of the quadrant. The margins of these wetlands have become invaded in places by recently- developed forest and shrub cover from adjacent forested uplands. Groundwater seeps occurring along upland margins support wetland shrubs, such as red -osier dogwood, Spiraea sp., and various willow species. Gradual invasion into the wetland interior by shrubs has led to de- watering of hydric soils and enhanced conditions for woody growth and upland weedy species. Along the interface with the upland, the wetland edge has become shade suppressed, in places by as much as 20 -50 feet. In other locations, there is an abrupt transition because of the steep slopes adjacent to the wetland margin. With shade - suppression, many of the wetland species have declined, and as in the shade - suppressed savanna, most species requiring high light conditions are suppressed and found with greatly reduced stature. Within the wetland, common plant species include woolgrass (Scirpus cyperinus), tussock sedge (Carex stricta), bluejoint grass (Calamagrostis canadensis), lake sedge (Carex lacustris), Carex rostrata, marsh nettle (Cirsium muticum), marsh dock (Rumex orbiculata), smartweeds (Polygonum spp.), Joe -pye weed (Eupatorium maculatum), boneset (Eupatorium perfoliatum), willow herb (Epilobium coloratum), marsh fern (Thelypteris palustris), sensitive fern (Onoclea sensibilis), and stands of tamarack (Larix laricina). Also commonly found within the wetland and in the wetland margin or ecotone adjacent to upland savanna areas, are cinnamon fern and interrupted fern (Osmunda cinnamomea, O. claytoniana). In locations where upland runoff from developed landscapes has entered the wetland, there are apparent sediment plumes that have been invaded by reed canary grass. Wetland margins closer to human habitation and the highway have developed dense monocultures of this species. This grass invades native vegetation, which subsequently declines due to heavy shade suppression and root competition. Recommendation: With brushing and fire re- introduction, the sedge meadow/wet prairie complex would gradually expand, possibly reaching its original extent, and grading, as it once did, into the open savanna communities that surround it. Reed canary grass will likely require S:98629:040999 9 Lino Lakes Town Center Natural Resource Inventory Report