Wet prairies are one of Oregon's rarest wetland types. Most occur at lower elevations on bedrock or clay loam soils that have a seasonally perched water table. These sites usually dry out by late spring but depressions may retain water well into the summer. Shallow soils over bedrock, and rock outcrops are included as part of this habitat because they are often intermixed with clay soil sites and the same vegetation may occur on both substrates (e.g., Isoetes nuttallii, Triteleia hyacinthina). There is also some overlap with vernal pool vegetation. Wet prairie in the Willamette and Umpqua valleys are habitat to several rare species of plants. Although best known for tufted hairgrass (Deschampsia caespitosa), wet prairies contain many other species of grasses, sedges and herbs. Before flood control, wet prairies on the Columbia River bottoms were flooded for one or two months every year during the annual "spring freshet" fueled by snowmelt in the Columbia Basin. Most wet prairies have been drained, farmed, grazed, or overrun by exotic species.
Habitat: Flats, irregular surfaces, and depressions constrained by bedrock or hardpan
Water regime: Intermittently to seasonally flooded
Water chemistry: Fresh
Ecoregion*: BM = Blue Mountains, BR = Northern Basin and Range, CB = Columbia Basin, CR = Coast Range, EC = East Cascades, KM = Klamath Mountains, WC = West Cascades, WV = Willamette Valley | ||||
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Scientific & Common Name | Global & State Rank | Ecoregion* | ||
Camassia quamash Lowland Wet Prairie Common camas (Christy 2004: 78; NS) |
G3S3 | KM, WV | ||
Carex aperta Lowland Wet Meadow Columbia sedge (Murray 2000: 14; Christy 2004: 81; NS) |
G1S1 | WC, WV | ||
Carex densa - Deschampsia caespitosa Wet Prairie Dense sedge - tufted hairgrass (Christy 2004: 87, corrected; NVC) |
G2S2 | KM, WV | ||
Carex feta Wet Prairie [Provisional] Green-sheath sedge (Christy 2004: 89) |
G3S2 | WV | ||
Carex pachystachya Wet Prairie [Provisional] Thick-headed sedge (Christy 2004: 97) |
G3S2 | WV | ||
Carex unilateralis - Hordeum brachyantherum Wet Prairie One-sided sedge - meadow barley prairie (NS) |
G2S2 | KM, WV | ||
Deschampsia caespitosa - Artemisia lindleyana Wet Prairie Tufted hairgrass - Columbia River wormwood (Christy 2004: 107; NS) |
G1S1 | WC | ||
Deschampsia caespitosa - Danthonia californica Marsh Tufted Hairgrass - California Oatgrass (Titus 1996-1998: 2; Christy 2004: 108; NS) |
G2S2 | WV, KM | ||
Eleocharis palustris - Carex unilateralis Wet Meadow Creeping spikerush - one-sided sedge (NS) |
G2S2 | WV | ||
Isoetes nuttallii Wet Meadow Nuttall quillwort (Christy 2004: 123; NS) |
G3S3 | WV | ||
Micranthes ferruginea - Camassia quamash Wet Outcrop [Provisional] Rusty saxifrage - Common camas (Glavich 2016: 44) |
G4S3 | CR, WC | ||
Rosa nutkana / Deschampsia caespitosa Wet Shrubland [Provisional] Nootka rose / tufted hairgrass (Pendergrass 1989) |
G2S2 | WV | ||
Rosa nutkana / Oenanthe sarmentosa Shrubland Nootka rose / water parsley shrub swamp (NS) |
G2S2 | WV | ||
Triteleia hyacinthina Wet Outcrop [Provisional] Hyacinth brodiaea (Christy 2004: 148) |
G2S2 | KM, WV |